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Botany  for  high  schools 
and  colleges 

Charles  Edwin  Bessey^^  ,,,; 


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THE 


[CAN  Science  Series 

FOR  SCHOOLS  AND  COLLEGES. 


bjects  of  the  series  are  to  supply  the  lack— in  some  subjects 
thoritative  books  whose  principles  are,  so  far  as  practicable, 
tiliar  American  facts,  and  also  to  supply  the  other  lack  that 
ience  perennially  creates,  of  text-books  which  at  least  do  nok 
>st  funeral isations.  The  books  of  this  series  systematically 
t  Science,  as  the  term  is  usually  employed  with  reference  to 
.  The  scheme  includes  an  Advanced  Course,  a  Briefer  Course, 
■y  Course. 

ft0  be  careful  to  state  which  course  i§  desired^Advanoed, 
mtary, 

Zodogy. 

Barker,  Professor         By   A.   S.   Packard,   Profeasor 
r  of  Pennsylvania.       ^f  Zoology  and  Geology  In  Brown 
University. 


;n,  Professor  In  the 
University. 
•«r,  850  pp. 
387  pp. 
urse^  272  pp. 

vcoMB,  Professor  in 
ins  University,  and 
DEN,  Director  of  the 

y. 

•«c,  612  pp. 
352  pp. 

T.  Sedgwick,  Pro- 
[assachusetts  Insti- 
oj?y,  and  Edmund 
essor  in  Bryn  Mawr 

ditctoi'y,  193  pp. 

ET,  Professor  in  the 
Nebraska;  formerly 
icultoral  College. 
w,  611  pp. 
202  pp. 


Advanced  CkMirse,  722  pp. 
Britfer  Course^  338  pp. 
Elementary  Cimrse^  200  pp. 

The  Human  Body. 

By  H.  Newell  Martin,  Profes- 
sor v  in  the  Johns  Hopkins  Univer> 

slty. 

Advanced  Chwrmy  (XSl  +  84  JEfX* 
Copies  without  the  Appendix  on 
Reproduction  win  be  sent  when 
specially  ordered. 

Briber  Cottne,  877  pp. 

Elementary  Cowrm,  261  pp. 

I^olitical  Economy, 

By  Francis  A.  Walker,  Presi- 
dent Massachusetts  Institute  o< 
Technology. 

Advanced  CounSf  490  pp. 

Britfer  Course^  415  pp. 


HOLT  &  CO.,  Publishers.  NEW  YORK 


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AMERICAN  SCIENCE  SERIES 


BOTANY 


FOB 


HIGH  SCHOOLS  AND    COLLEGES 


BT 

CHARLES  E.  BESSEY,  Ph.D., 

PROFESSOR  OF  BOTANY  IN  THB  UNIYBRSITT  OF  NEBRASKA;  FORMERLY  PROFESSOR  OF 

BOTANY   IN  THB  IOWA  AGRICULTURAL  COLLEGE;    ASSOCIATE  EDITOR  OF 

THB  '*  AMERICAN  NATURALIST'*   (DEPARTMENT  OF  BOTANY) 


SIXTH    EDITION,    REVISED 


NEW  YORK 

HENRY  HOLT  AND  COMPANY 

1889 


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Oopyright,  1880, 

by 

Hknrt  Holt  &  Co. 


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PREFACE. 


This  book  is  designed  to  serve  as  an  Introduction 
to  the  Study  of  Plants.  It  does  not  profess  to  give  a 
complete  account  of  the  Vegetable  Kingdom,  but 
only  such  an  outline  as  will  best  subserve  the  pur- 
poses of  the  work. 

In  its  preparation  there  have  been  kept  in  view 
the  wants  of  the  large  number,  in  the  schools  and 
out,  who  wish  to  obtain,  as  a  branch  of  a  liberal  cul- 
ture, a  general  knowledge  of  the  structure  of  plants, 
with  some  idea  as  to  their  classification  into  the 
larger  divisions  and  subdivisions  of  the  Vegetable 
Kingdom.  For  this  class  of  students  and  general 
readers,  what  is  here  given  will  in  most  cases  be 
amply  sufficient  to  enable  any  one  to  understand  the 
greater  part  of  the  current  biological  literature,  in  so 
far  as  it  relates  to  vegetable  organisms.  For  the 
student  who  desires  to  pursue  the  subject  further, 
or  who  intends  to  make  botany  a  special  study,  this 
book  aims  to  lead  him  to  become  himself  an  observer 
and  investigator,  and  thus  to  obtain  at  first  hand  his 
knowledge  of  the  anatomy  and  physiology  of  plants : 
accordingly  the  presentation  of  the  matter  has  been 
made  such  as  to  fit  the  book  for  constant  use  in  the 
Laboratory,  the  text  supplying  the  outline  sketch, 
which  may  be  filled  up  by  each  student,  with  the  aid 
of  the  scalpel  and  compound  microscope. 

This  book  is  an  expansion  and  considerable  modi- 
fication of  the  material  of  several  courses  of  lectures 


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iv  PREFACE, 

annually  delivered  to  college  students.  In  general 
plan,  Part  I.  follows  pretty  nearly  that  of  Sachs'  ad- 
mirable *'Lehrbuch,"  and  in  many  instances  it  has 
seemed  to  me  that  I  could  not  do  better  than  to 
adopt  the  particular  treatment  which  a  subject  has 
received  at  the  hands  of  the  distinguished  German 
botanist.  This  has  been  rendered  possible  through 
the  liberality  of  my  publishers,  and  the  courtesy  of 
Engelmann  of  Leipzig,  the  publisher  of  many  of 
Sachs'  works,  by  which  many  of  the  cuts  of  the 
"Lehrbuch"  are  here  reproduced.  This  book  will 
thus,  to  a  considerable  extent,  serve  as  an  introduc- 
tion to  that  work.  Free  use  has  also  been  made  of 
the  recent  works  of  De  Bary,  Hofmeister,  Strasbur- 
ger,  Nageli,  Schwendener,  and  othei*s,  to  whose  writ- 
ings numerous  references  are  made. 

In  Part  II.  the  general  disposition  of  the  lower 
plants  is  a  considerable  modification  of  that  proposed 
by  Sachs ;  that  of  the  higher  plants  is  made  to  con- 
form to  the  system  of  classification  in  vogue  in  this 
country  and  in  England,  as  outlined  in  Dr.  J.  D. 
Hooker's  "Synopsis  of  the  Classes,  Sub-classes,  Co- 
horts and  Orders,"  in  the  English  edition  of 
Le  Maout  and  Decaisne's  "Traits  Gen^rale  de  Botan- 
ique,"  and  as  given  much  more  fully  in  Bentham  and 
Hooker's  still  unfinished  ''Genera  Plantarum."  The 
notes  upon  the  economic  values  of  the  more  impor- 
tant plants  of  each  order  are  based  upon  my  own  lec- 
tures upon  Economic  Botany.  1  have  also  freely 
used  the  similar  notes  in  Le  Maout  and  Decaisne's 
work,  cited  above ;  Balfour's  "  Class-Book  of  Bot- 
any," Archer's  "Economic  Botany,"  Smith's  "Do- 
mestic Botany,"  Laslett's  "Timber  and  Timber 
Trees,"  etc.,  etc. 

Necessarily,  there  is  but  little  that  is  really  new  in  a 
treatise  like  this.  Aside  from  a  more  or  less  important 
and  original  arrangement  of  the  matter,  so  as  to 


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PREVAVB,  ? 

secure  a  more  logical  presentation  of  tlie  subject, 
there  are  but  two  considerable  innovations,  consist- 
ing (I.)  in  the  recognition  (in  Chapter  VI.)  of  seven 
quite  well  marked  kinds  of  tissue.  In  this,  however, 
while  not  adopting  De  Bary's  classification,  1  have 
followed  his  method  of  treating  the  subject,  as  given 
in  his  recent  work  on  the  comparative  anatomy  of 
plants  ("  Vergleichende  Anatomie  der  Vegetations- 
organe  der  Phanerogamen  und  Fame.")  (II.)  The 
second  considerable  innovation  occurs  in  Part  II. ;  it 
consists  in  raising  the  Protophyta,  Zygosporeae,  Oos- 
poreae  and  Carpospore«e  to  the  dignity  of  Primary 
Divisions  of  the  vegetable  kingdom,  co-ordinate  with 
the  Bryopliyta,  Pteridophyta  and  Phanerogamia. 
The  usefulness  of  both  of  these  departures  from  the 
common  practice  has  been  subjected  to  the  test  of 
the  laboratory,  and  the  lecture  and  class-room,  with 
the  most  satisfactory  results ;  and  I  am  led  to  hope 
that  in  the  hands  of  others  they  may  also  serve  to 
give  a  clearer  and  more  accurate  notion  of  the  struc- 
ture of  plants.  Should  they  do  this  they  will  need  no 
further  apology  or  defense. 

Of  the  illustrations,  many  are  entirely  new  ;  many 
others  have  been  re-drawn,  from  various  sources, 
with  slight  modifications,  expressly  for  this  work, 
and  all  from  other  sources  are  specially  acknowl- 
edged in  their  places. 

I  desire  here  to  acknowledge  my  indebtedness  to 
Dr.  Asa  Gray,  whom  it  is  an  honor  to  own  as  my 
sometime  teacher,  for  kindly  aid  and  counsel  in  the 
preparation  of  the  lectures  upon  which  this  work  is 
based ;  and  in  the  same  way  I  am  indebted  to  Dr. 
Qt.  L.  Goodale,  Dr.  W.  G.  Farlow  and  Professor  A. 
N.  Prentiss.  For  aid  in  the  immediate  preparation 
of  the  material  for  the  press,  acknowledgment  is  due 
many  of  my  personal  friends :  Mr.  J.  C.  Arthur  fur- 
nished the  original  drawings  of  the  water-pores  ol 


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V'l  PREFACE. 

Fuchsia^  and  of  various  tissues  of  Ecliiiiocystis ; 
Professor  H.  L.  Smith,  of  Hobart  College,  New- 
York,  contributed  the  sketch  of  the  classitication  of 
the  Diatomaceie  ;  Dr.  T.  F.  Allen  furnished  a  synop- 
sis of  the  classitication  of  the  Characeae  ;  Dr.  B.  D. 
Halsted  also  furnished  material  and  notes  upon  our 
native  species  of  Characese  ;  my  colleague,  Professor 
VV.  H.  Wynn,  kindly  determined  some  of  the  more 
difficult  etymologies;  to  my  wife  I  am  deeply  in- 
debted for  efficient  aid  in  the  laborious  tasks  of 
proof-reading  and  indexing. 

Should  this  book  serve  to  interest  the  student  in 
the  study  of  plants  as  living  things,  should  it  succeed 
in  directing  him  rather  to  the  plants  themselves  than 
to  the  books  which  have  been  written  about  them, 
should  it  contribute  somewhat  to  the  general  read- 
er's knowledge  of  the  structure  and  relationship  of 
the  plants  around  him,  the  objects  kept  in  view  in  its 
preparation  will  have  been  attained. 

C.  E.  B. 

Ajml  12,  1880. 


PREFACE  TO  THE  SIXTH  EDITION. 

The  second,  third,  and  fourth  editions,  appearing  respec- 
tively in  1881, 1883,  and  1885,  contained  a  considerable  num- 
ber of  corrections  and  additions.     In  the  fifth  edition  (1888) 
that  modification  of  the  secoud,  third,  and  fourth  branches 
of  the  Vegettible  Kingdom  (Zygophyta,  Oophyta,  and  Carpo- 
phyta)  previously  used  in  the  *' Essentials  of  Botany,*' was 
iiid  a  number  of  important  paragraphs  were  added 
tes.     The  changes  in  the  present  edition,  a  dozen 
umber,  include  some  additions  and  a  number  of 

C.  E.  B. 

[TY  OF  Nebraska, 
s'COLN,  AprU  18,  1889. 


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CONTENTS. 


PAKT  L  GENERAL  ANATOMY  AND  PHYSIOLOGY. 


CHAPTER    1. 
Protoplasm. 

PAGB 

General  Cliaractera — Chemical  Composition — Consistence — Power 
of  Imbibing  Water — Vacuoles  —  Pliysical  Activity — Naked 
Protoplasm — Protoplasm  Enclosed  in  Cell  Walls 1 

CHAPTER  II. 

The  Plant-Cell. 

General  Statement — Ectoplasm  and  Endoplasm — Bands  and  Strings 
of  Protoplasm — Nucleus — Size  of  Cells — Forms  of  Cells — The 
Cell  the  Unit  in  Plants 15 

CHAPTER   III. 

The  Cell-Walu 

Composition — Growth  in  Surface^Growth  in  Thickness — The 
Markings  on  Cell  Walla — Theories  as  to  the  Mode  of  Thick- 
ening— -Stratification  of  the  Cell  Wall — Formation  of  Chem- 
ically Different  Layers — The  Formation  of  Mucilage — Incom- 
bustible Substances  in  the  Wall. .    21 

CHAPTER   IV. 
The  Formation  op  New  Cells. 

Cell-Formation  by  Division  :  (a)  Fission;  (6)  Internal  Cell -Forma- 
tion— Cell -Format  ion  by  Union — Examples 36 


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viii  CONTENTS. 

CHAPTER    V. 
The  Products  op  the  Celu 

FA6I 

§  1.  Chlorophyll — §  3.  8urch,  CoinpoeitioD,  Form,  Molecular 
Stracture — Granuloee  aad  Siarch-Celluloee — Formatioa  of 
Starch  Granules  in  the  Chlorophyll-Bodies-:— Formation  of 
Ordinary  Starch  Granules — §  3.  Aleurone  and  Crystalloids — 
§  4.  Crystals  in  Cells— §  6.  The  Cell  Sap— §  6.  Oils,  Resins. 
Gums,  Acids  and  Alkaloids 50 

CHAPTER   VI. 

Tissues. 

§  1.  The  Various  Agtrregations  of  Cells :  (a)  Single  Cells  ;  (6)  Fam- 
ilies ;  (c)  Fusions ;  {d)  Tissues  ;  The  Cell. Wall  in  Tissues— 
§  2.  The  Principal  Tissues — Parenchyma — Collenchyma — 
Sclerenchyma — Fibrous  Tissue — liSticiferous  Tissue  —  Sieve 
Tissue— Tracheary  Tissue— §  3.  The  Primary  Meristem...    ..     65 

CHAPTER  VII. 

The  Tissue  Systems. 

§  1.  The  Differentiation  of  Tissues  into  Systems— §  2.  The  Epi- 
dermal System  of  Tissues — Epidermis — Trichomes — Stomata 
—  §  3.  The  Fibro- Vascular  System  of  Tissues  —  General 
Structure — The  Fibro- Vascular  Bundlesof  Pteris.Polypodium, 
Adiantum,  £k|uiaetum,  Selaginella,  Lyoopodium,  Zea,  Acorus, 
Ricinus  and  Ranunculus — Of  Xylem  and  Phloem — Collateral, 
Concentric,  and  Radial  Bundles  —  Development  of  Flbro- 
Vascular  Bundles— §  4.  The  Fundamental  System— The  Tis- 
sues it  Contains — Cork — Lenticels 89 

CHAPTER  VIIL 
Intercellular  Spaces,  and  Secretion  Reservoirs 128 

CHAPTER  IX 

The  Plant-Body. 

§  1.  Generalized  Forms— Thallome — Caulome— Trichome— Roc^^ 
Particular  Relations  of  Phyllome  to  Caulome — General  Modes 
of  Branching  of  Members— §  2.  Stems— The  Puncium  Vegeta- 
tionis— Buds— Adventitious  Stems— §  3.  Of  Leaves  in  General 
— §  4.  The  Arrangement  of  Leaves— §  5.  The  Internal  Struc- 
ture of  Leaves— §  6.  The  Roots  of  Plants,  Structure,  Root-Cap, 
Growth— Formation  of  New  RooU— Arrangement  of  Roots. . .  133 


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CONTENTS,  IX 

CHAPTER    X. 
The  Chemical  Constituents  of  Plants. 

rAOB 

§  1.  The  Water  in  the  Plant—Amount  of  Water  in  Plants— Water 
in  the  Protoplasm — Water  in  the  Cell  Walls — Water  in  the 
Intercellular  Spaces — Equilibrium  of  the  Water  in  the  Plant — 
Disturbance  of  Equilibrium — Evaporation  of  Water — Amount 
of  Evaporation — The  Movement  of  the  Water  in  the  Plant 
— §  2.  As  to  Solutions— §  3.  Plant  Food— The  Most  Important 
Elements — The  Compounds  Used — How  the  Food  is  Obtained 
—How  Transported  in  the  Plant 1G6 

CHAPTER  XI. 
The  Chemical  Processes  in  the  Plant. 

§  1.  Assimilation — ^  2.  Metastasis — Its  General  Nature — ^Trans- 
formation of  Starch — Nutrition  of  Protoplasm — The  Storing  of 
Reserve  Material — The  Use  of  Reserve  Material — The  Nutri- 
tion of  Parasites  and  Saprophytes — The  Formation  of  Alkaloids 
— ^Results  of  Metastasis 178 

CHAPTER  XII. 
The  Relations  op  Plants  to  External  Agents. 

§  1.  Temperature — General  Relations — Absorption  of  Water  as  Af- 
fected by  Temperature— Evaporation— Assimilation— Metasta- 
sis— Death  from  too  Hijjfh  a  Temperature— Death  from  too 
Low  a  Temperature — g  2.  Light:  General  Relations  of  Light 
to  Assimilation,  Light,  and  Metastasis — §  3.  Heliotropism — 
§  4  Geotropism — §  5.  Certain  Movements  of  Plants  :  General 
Statement,  Spontaneous  Movements,  Movements  Dependent 
upon  External  Stimuli,  Movements  of  Nutation.  Movements 
ofTorsion , 184 


PART  II.    SPECIAL  ANATOMY  AND  PHYSIOLOGY. 


CHAPTER  XIII. 
Classification. 

Principles  of  a  Natural  Gassification— Critical — A  Comparison  of 
several  Systems oo<j 


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X  CONTENTS. 

CHAPTER  XIV. 
The  Protophyta. 

PAOB 

%  1.  Myxomyoetes — g  2.  Schizomycetes— §  3.  Cyanopbyce© 206 

CHAPTER  XV. 

The  Zygophtta. 

gl.  ZouBpore»--§  2.  ConjugataB 220 

CHAPTER    XVI. 

The  Oophyta. 

g  1.  Volvos  and  itB  Allies— §  2.  (£dogoDieflB--§  3.  Coeloblastese— 
§4.  Fucaceae 248 

CHAPTER   XVII. 

The  Carpophyta. 

§  1.  Coleocliapte— §  2.  Floridese— §  8.  Ascomycetes— g  4.  Baaidio- 
mycetee — g  5.  CharacesB— §  6.  The  Classification  of  Thallo- 
pliytes '. 270 

CHAPTER    XVIII. 

The  Bryophyta. 
gl.  Hepaticafr— g  2.  Musci 841 

CHAPTER  XIX. 

The  Pteridophyta. 

gl.  Equisetin®— g  2.  FilicinaB— §  3.  Lycopodin® 861 

CHAPTER  XX. 

The   Phanbrooamia. 

g  1.  General  Cliaracters — g  2.  Gymnospermfe— g  3.  An^ospemue 
— Glossology  of  Anffiosperms — The  Tissues  of  Angiospenns — 
Classification  and  Economic  Botany  of  Monocotyledons — Class- 
'"  "*  n  and  Economic  Botany  of  Dicotyledons 889 

CHAPTER  XXI. 

Concluding  Observations. 

er  of  Species  of  Plants— The  AflBnities  of  the  Groups  of 
—The  Distribution  of  Plants  in  Time 566 


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BOTANY. 


PART  I. 
GENERAL  MATOMY  AND  PHYSIOLOGY. 


CHAPTER    I. 

PROTOPLASM. 

1. — K  we  examine  a  thin  slice  of  any  growing  part  of  a 
plant  (Fig.  1)  under  a  microscope  of  a  moderately  high 
power  (400  to  500  diameters),  there  may  be  seen  large  num- 
bers of  cavities  which  are  more  or  less  filled  with  an  almost 
transparent  semi-fluid  substance.  In  very  young  parts,  as 
in  buds  and  the  tips  of  roots,  this  substance  entirely  fills  the 
cavities,  and  makes  up  almost  the  whole  mass,  while  in  older 
parts  it  occurs  in  less  quantity,  and  usually  disappears  in 
quite  old  tissues.  This  substance  is  the  living  portion  of 
the  plant,  the  active,  vital  thing  which  gives  to  it  its  sensi- 
bility to  heat,  cold,  and  other  agents,  and  the  power  of  mov- 
ing, of  appropriating  food,  and  of  increasing  its  size ;  it  is,  in 
fact;  that  which  is  sensitive^  which  moves,  appropriates  food, 
and  increases  in  size.  This  sensitive,  moving,  assimilating, 
and  growing  substance  is  named  Protoplasm.* 

It  is  a  fact  of  ^reat  bioloj^ical  interest  that  in  animals  the  essential 
oonatitaent  of  all  living  parts  is  a  substance  similar  to  the  protoplasm 
of  plants.  We  cannot  distinguish  the  two  by  any  chemical  or  physical 
tests,  and  can  only  say  that,  taken  as  a  whole,  the  protoplasm  of  plants 

♦  So  named  by  its  discoverer,  Dr.  Hugo  Von  Mohl,  in  1846.  It  is  the 
Bioplasm  of  Dr.  Lionel  Beale  and  his  followers. 


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'Z  BOTANY. 

diflfbrs  from  that  of  animals  in  its  secretions.  And  jet  these  secre 
tions  are  not  strictly  confined  to  plants  ;  cellulose,  starch,  chlorophyll, 
and  other  products  of  vegetable  protoplasm  formerly  regarded  as  pe- 
culiar to  plants  are  now  known  to  occur  in  undoubted  animals.  Botanists 
and  zoologists  have  labored  long  in  vain  to  discover  absolute  differences 
between  the  animal  and  the  vegetable  kingdoms,  between  the  higher 
plants  and  the  higher  animals  tliere  are  ^reat  and  constant  differences/ 

in  none  uf  the  higher  animals,  for  ex- 
ample, is  chlorophyll  produced;  but 
in  the  lower  orders  of  both  kingdoms 
not  one  of  the  differences  observed  to 
hold  between  the  higher  plants  and 
animals  exists. 

2. — The  exact  chemical  oompo- 
sition  of  protoplasm  has  not  hith- 
erto been  made  out,  but  it  is 
known  to  be  an  albuminous, 
watery  substance,  combined  with 
a  small  quantity  of  ash.  It  is 
probably  a  complex  mixture  of 
chemical  compounds,  and  not  a 
single  compound.  It  contains  at 
some  time  or  another  all  the  chem- 
ical constituents  of  plants.  Oil, 
granules  of  stirch,  and  other  or- 
ganic substances  are  frequently 
present  in  it,  but  they  are  to  be  re- 
garded as  products  rather  than 
proper  constituents  of  protoplasm. 


Fig.  1.— A  little  more  than  half  of 
a  longitudinal  section  of  the  apex  of 
a  yoang  root  of  the  Indian  com. 
The  part  above  s  is  the  body  of  the 


root,  that  below  ft  is  the  root-cap  ; 
t>,  thick  outer  whI]  of  the  epidermic; 
m  Tonng  pith-ceUB ;  /,  young  wood- 
cells  ;  g,  a  young  vessel ;  «,  T,  inner 
yonneer  part  of  root-cap ;  a,  o,  out- 
er older  part  of  root-cap.— After 
Bachs. 


(a)  Water  makes  up  a  considerahle 
part  of  the  bulk  of  ordinary  protoplasm, 
and  is  much  more  ahundant  in  its 
active  than  in  its  dormant  conditions. 
In  the  protoplasm  of  Puligo  variana 
(one  of  the  Slime  Mouldp)  just  before 
the  formation  of  its  spores  there  is  70 
per  cent  of  water ;  in  dry  seeds,  on  the  other  hand,  the  amount  is  not 
more  than  about  8  to  10  per  cent. 

(6)  As  to  its  molecular  constitution,  Strasburger  holds*  that  proto- 
plasm is  composed  of  minute  solid  particles  (not,  however,  of  a  crystal- 
line form),  separated  from  each  other  by  layers  of  water  (see  Cell-wall. 

♦  •*  Studien  Uber  Protoplasma,"  1876. 


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PROTOPLASM.  3 

paragraph  37,  and  Starch,  paragraph  69).  The  thicker  the  layers  of 
water  are,  the  more  watery  is  the  protoplasm,  and  vice  verm, 

(e)  Tests.  1.  If  a  protoplasmic  mass  is  moistened  with  a  solation  of 
iodine,  it  at  once  assames  a  deep  yellow  or  brown  color. 

2.  If  treated  with  a  solution  of  copper  sulphate  and  afterwards  with 
potash,  it  assames  a  dark  violet  color. 


A 


Fig.  d.— Parenchyma  cells  from  the  central  cortical  layer  of  the  root  of  Fritillaria 
immialia,  longitudinal  i^ections.  A,  yery  young  cells  lying  clopt?  above  the  apex  of 
the  root.  etiU  without  cell  sap  or  vacuoles.  B,  cells  of  the  same  description  about 
two  millimetres  above  the  apex  of  the  root ;  by  the  entrance  of  cell  sap  the  vacuoles 
0.  », »  have  been  formed.  (7,  cells  of  the  same  description  about  seven  to  eight  mil- 
limetres above  The  apex  of  the  root.  In  all  the  figures,  hy  cell-wall ;  p,  protoplasm  ; 
k,  nucleus  ;  kk,  nucleoli ;  «,  vacuoles  ;  xy,  swelling  of  the  nucleus  nnder  the  lnfla« 
ence  of  the  water  in  preparing  the  specimen,     x  500.— After  Sachs. 

8.  Treated  with  a  solution  of  sugar,  and  afterwards  with  sulphuric 
acid,  it  becomes  rose-red. 

4.  The  presence  of  protoplasm  may  be  demonstrated  in  a  tissue  by 
the  application  of  various  staiuing  fluids,  as  magenta,  carmine,  etc. 


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4  BOTANY. 

5.  In  a  dilute  solution  of  potasli  protoplasm  is  dissolved  ;  if,  bow 
ever,  the  solution  is  concentrated,  the  form  of  the  protoplasm  remains 
unaltered  for  weeks,  but  upon  the  addition  of  water  it  at  once  dissolves. 

6.  Protoplasm  coagulates  upon  the  application  of  beat  (50  degrees 
Centigrade),  or  when  immersed  in  alooliol  or  dilute  mineral  acids. 

8. — In  consistence  protoplasm  is  a  soft-solid  substance, 
varying  from  an  almost  perfect  fluidity  on  the  one  hand  to 
a  considerable  degree  of  hardness  and  even  brittleness  on 

the  other.  This  difference  in  con- 
sistence is  mainly  due  to  the  vary- 
ing amounts  of  water  imbibed  by 
it,  hence  the  same  mass  may  at 
different  times  vary  greatly  in  this 
regard.  Generally  there  may  be 
seen  in  protoplasm  a  large  number 
of  minute  granules  enclosed  in  a 
transparent  medium  (Fig.  2,  A)  ; 
in  some  instances,  however,  the 
granules  are  entirely  wanting,  or 
nearly  so.  By  the  withdrawal  of 
these  granules  for  a  little  distance 
from  the  surface  toward  the  cen- 
tre, a  mass  of  granular  protoplasm 
^   „    ^  ^  ,      ,.       ,         (the  endoplasm)  may  appear  to  be 

Fig.  8— optical  section  of  a  r**-   ^  ,    ,  ,  i       i •  i 

fractine  branch  of  a  iargepia»»mo-  surrouudcd  by  a  iiyaline  envelope, 

dium  of  I'uligo  variaru  (j&haliurn    , ,  i       i  •  i  • 

Mptieum  of  aaihore) :  the  narrow   the     protoplasmiC     skm,    Or     CCtO- 

iii wen to"bi«jSoSnded^by^a^^  plasm  (the  HantscliicM  of  Prings- 
Itffint'S^JSSeisJ^iSj^ste:  heim,  and  Hauptplamna  of  Stras- 
Xt  ^Xlt\T;x^rlX^f^l  burger)  (Fig.  3).     It  is  almost  al- 

li?o°"lSJ?iSd^Xraiin?^^  ^*y«  ^^™®^  ^^^^  protoplasm  is 
veiope.   X  aoo.-After  Hofmeieter.  exposed  in  watcr  or  air  ;  but  it,  or 

something  very  much  like  it,  appears  to  be  generally 
present,  even  in  closed  cells. 

(a)  The  fine  ^'mnules  are  probably  not  proper  constituents  of  proto- 
plasm, but  finely  divided  assimilated  food-materials  immersed  in  the 
proper  protoplasm,  which  is  its^^lf  colorless  and  transparent.  Proto- 
plasm destitute  of  granules  may  be  found  in  the  cotyledons  of  the 
bean  {Phaseotus),  In  other  cases,  e.g.,  in  the  zygospores  of  Spirogyra, 
the  granular  and  coloring  matters  are  so  abundant  that  the  hyaline 
basis  can  no  longer  be  distinguished. 


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PROTOPLASM.  6 

if)  Strasburger*  maintainB  that  the  hyaline  envelope  is  not  aimply  a 
portion  of  tlie  basis  or  {ground  substance  of  tbe  protoplasm  deprived 
of  its  granules,  but  that  it  is  a  definite  modification  of  it,  and  endowed 
with  various  properties  quite  distinct  from  tbose  of  tbe  ground  sul>- 
Btance. 

4. — ^Active  protoplasm  possesses  the  power  of  imbibing 
water  into  its  substance,  and  as  a  consequence,  of  increasing 
its  mass.  This  power  varies  with  the  changes  in  external, 
and  also  in  internal  conditions  ;  many  seeds,  for  .example, 
which  do  not  swell  up  (through  absorbing  water)  in  cold 
water,  will  do  so  when  placed  in  that  of  a  higher  tempera- 
ture ;  but  in  some  seeds  it  appears  that  imbibition  of  water 
will  not  take  place  until  after  a  period  of  rest. 

6. — When  the  amount  of  water  imbibed  is  so  great  that 
the  protoplasm  may  be  said  to  be  more  than  saturated  with 
it,  the  excess  is  separated  within  the  protoplasmic  mass  in 
the  form  of  rounded  drops,  termed  Vaouoles  ( Vacuoli),  In 
closed  cells  these  may  become  so  largo  and  abundant  as  to 
be  separated  only  by  thin  plates  of  the  protoplasm  (Fig.  2, 
B).  As  such  vacuoles  become  still  larger,  the  plates  are 
broken  through,  and  eventually  wo  may  have  but  one  large 
vacuole  surrounded  by  a  thin  layer  of  protoplasm,  which 
lines  the  interior  of  the  cell  wall  (Fig  2,  C).  In  this  way 
some  masses  of  protoplasm  assume  a  bladder-like  or  vesicular 
form,  so  unlike  their  original  form  that  until  very  recently 
their  real  nature  has  not  been  understood.!  Frequently 
when  the  plates  which  separate  vacuoles  break  down,  instead 
of  breaking  entirely  away  they  become  pierced  with  several 
large  openings,  leaving  strings  or  bands  of  protoplasm  which 
extend  across  the  cavity. 

Occasionally,  wlien  vacuoles  unite,  small  masses  of  the  protoplasm 
which  previously  separated  them  become  detached  as  free  rounded 

♦  •*  Studien  aber  Proioplasma,"  1870.  See  also  Qr.  Jour.  Mic.  Science, 
1877,  p.  124  et  seq. 

t  Von  Mohl  gave  to  this  layer  the  name  Primordial  Utricle,  and  it  is 
still  frequently  used,  but  the  term  is  obj»*ctionable,  and  Sachs'  name  of 
Protoplasmic  Sac  is  to  be  preferred.  Treatment  with  glycerine,  strong 
alcohol,  or  any  otlier  substance  which  removes  the  water,  will  cause 
the  protoplasmic  sac  to  contract  and  become  visible. 


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6 


BOTANY. 


masses  in  the  large  vacuole  ;  these  again  may  prodace  vacuoles  within 
themselves,  and  thus  give  rise  to  a  peculiar  and  at  first  sight  perplex- 
ing structure  (Fig.  4). 

6.— The  most  remarkable  peculiarity  of  living  protoplasm  is 
its  physical  activity.  When  the  proper  conditions  are  pres- 
ent, a  living  mass  of  protoplasm  is  apparently  never  at  rest, 

but,  on  the  contrary, 
continually  altering  its 
shape  and  changing  the 
position  of  its  constit- 
uent parts.  The  move- 
ments are  all  of  the 
same  general  nature ; 
each  one  may  be  regard- 
ed as  the  aggregate  re- 
sult of  the  chemical  and 
physical  changes  taking 
place  in  the  substance 
of  the  protoplasm. 

We  may  study  the  ac- 
tivity of  protoplasm 
under  two  conditions, 
which  will  give  us  the 
two  cases.  (1.)  The 
Activity  of  Naked  Pro- 

Pig.  4.— FoiTOR  of  the  protoplasm  contained  In  toplasm,   and    (2. )   The 
cells.    A  and  ^.  of  Indian  Corn  (Zea  t¥iaU)\  A^    l    ,>    >.        m  t%   \      ^ 

cells  from  the  first  leaf-shear'.i  of  a  germinating  Activity  01   irrotoplasm 

plant,  showing  the  frothy  condition  of  the  proto-  ^„^i^„^j  ;„  «  n^ll  «,«n 

plasni.  the  many  vacnolea  separated  by  thin  CnclOSCd  m  a  Cell-Wall. 
plates.  ^,  cells  from  the  flr(«t  intemode  of  the  n  m-u^  A/>Hirii~«r  nt 
germinating  pl.nt;  the  protoplasm  is  broken  up         /.—  J. no  .a.0UYll^  oi 

Into  many  rounded  masfes,  in  each  of  which  there  If  ak  6  d     ProtOplasm. 

is  a  vacuole,  b  :  these  are  the  so-called  "  sap-vesi-  rni  i  • 

cles/'    C,  a  cell  from  the  tuber  of  the  Jerusalem  The       lOW       Organisms 

Artichoke  {HeUanthM  tuberotnta)  after  the  action  of  •,  . ,       ,? 

iodine  and  dilute  sulphuric  acid ;  A.  cell-wall ;  *.  kUOWn  aS  the  Myxomy- 

nucleus;  p.  coutracto5  protoplasm-After  Sachs.  ^^^^^^  ^^  Slime  Moulds, 

present  the  best  examples  of  the  activity  of  naked  vegetable 
protoplasm.  In  their  plasmodia  (as  the  masses  of  naked  proto- 
plasm are  called),  many  kinds  of  movements  may  be  observed, 
the  commonest  of  which  is  streaming.  In  plasmodia  com- 
posed of  thin  {i.e.,  watery)  protoplasm,  streams  or  currents 
of  the  latter  may  be  seen  running  in  various  directions 


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PROTOPLASM  MOVEMENTS,  7 

(Fig.  5).  The  streams  are  made  clearly  visible  by  the  motion 
of  the  granules  which  are  carried  along  by  the  moving  hya- 
line portion  of    the    protoplasm.     After  running  in  one 


J^^'  ^VT"^  '™*^*  ma*8  of  the  naked  protoplasm  (plamiodium)  of  DidvnUum  ur 
pula  ;  the  arrows  ahow  the  direction  or  the  currenti.    x  80.-After  HotaSuST 

direction  for  some  minutes  (about  five)  the  current  stops, 
*nd  then  it  usually  sets  in  an  exactly  opposite  direction  for 
about  the  same  length  of  time,  and  carries  back  the  previ- 
ously moved  protoplasm. 


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BOTANY, 


f  .^Tif 


The  formation  of  tbe  new  current  may  be  explained  as  follows : 

Let  A B  be  a  stream  in  which  the  movemeut  is  from  A 

to  B ;  clearly  there  will  be  an  aggregation  of  protoplasm  about  B. 
When  tbe  current  in  the  direction  A  B  stops,  the  new  one,  in  the 
reverse  direction,  B  A,  begins  at  A,  by  the  movement  toward  it  of  the 
particles  nearest  to  it ;  next  the  partich^s  further  ofif  move  toward  A  ; 
after  this,  those  still  further  off,  and  so  on.  The  current  txt^md%  hack^ 
ward.  So,  too,  when  a  stream  begins  de  noWt  it  is  propagated  back* 
ward  from  the  point  of  beginning. 

8.— Mass-Movement  (Amcdba-Movement).   In  the  flowing 

back  and  forth  in  the 
streams  the  movement 
may  be  greater  in  one 
direction  than  in  the 
other;  this  causes  a 
slow  motion  of  the 
whole  Plasmodium  in 
the  direction  of 
the  greatest  movement. 
When  this  takes  place 
in  the  case  of  streams 
which  begin  in  the  mar- 
gin of  the  Plasmodium, 
protuberances  of  vari- 
ous shapes  arise ;  these 
may  be  extended  into 
branches  {pseudopo- 
dia)y  which  may  again 
be  branched  one  or 
times.      By  the 


Pig.  6.— Ontline  of  a  plw»modinm  of  Didymium  ^^1*® 

mrpula  forming  peeudopodia.  The  heavy  black  anastomosinff  of  thcSC 
line  indicates  the  ontline  at  the  beeinning  of  the  o 

observation  ;  the  pacudopodium  a-b  formed  in  8  branches  a  COmpleX 
Beconds.  c-d  In  80,  and  <?-«  In  55  seconds,    x  10.  j       v  • 

-After  Hoftneisten  movmg  and    changmg 

network  is  formed.  (See  Fig.  140,  page  208)  There  is  pos- 
sibly to  be  separated  from  the  above-described  mass-move- 
ment that  more  or  less  rapid  change  of  external  contour 
which  has,  from  its  resemblance  to  the  motions  of  the 
Amoeba,  been  denominated  the  Amoeba-movement  (Fig.  6). 
It  is  best  observed  in  the  so-called  "Amoeba-form  "  stage  of 
the  swarm-spores  of  the  Mvxomycetes. 


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PROTOPLASM  MOVEMENTS.  9 

While  in  thinner  protoplasm  the  streaming  and  mass- 
movements  are  always  horizontal,  or,  at  least,  parallel  with 
the  surface  upon  which  the  plasmodium  rests,  in  the  case  of 
tougher  protoplasm  they  may  give  rise  to  branches  which 
have  an  upward  direction,  as  in  the  formation  of  sporangia. 

9.— Efibot  of  External  Influenoes.  The  movements  of 
the  protopksm  of  the  Myxomycetes,  and  probably  to  a 
greater  or  less  extent  of  all  plants,  are  suspended  by  certain 
external  influences.  Violent  jarring,  pressure,  a  thrust  as 
with  the  point  of  a  pin  or  pencil,  electrical  discharges, 
sudden  changes  of  the  temperature,  and  sudden  changes  in 
the  concentration  of  the  surrounding  fluid,  stop  the  move- 
ments, and  cause  the  plasmodium  to  contract  into  one  or 
more  spheroidal  masses.  When  these  influences  cease,  if 
they  have  not  been  so  violent  as  to  destroy  the  organization 
of  the  protoplasm,  it  returns  after  a  greater  or  less  length 
of  time  to  its  original  form,  and  the  movements  are  resumed. 

(a)  The  effect  of  mecbanicsil  disturbances  (jarring,  pressure,  and 
thrust)  may  be  best  studied  in  tbe  tougher  or  least  fluid  plasniodia 
(e.g,^  of  Stemonitis  fusea). 

(b)  The  effect  of  electri<al  discbarges  may  be  studied  by  placing  a 
small  Plasmodium  {e.g.,  Didymium Merptda)  upon  a  glass  plaie  provided 
with  platinum  points  which  are  iu  connection  with  tlie  poles  of  an 
induction  apparatus.  When  a  discbarge  takes  place  through  a  narrow 
branch  (pseudopodium)  it  contracts  so  violently  as  to  be  broken  up  into 
a  row  of  little  spheres ;  if  it  takes  place  through  the  mass  of  the  plas- 
modium it  becomes  more  or  less  spherical  by  its  contraction.  In  any 
case,  if  the  sliock  has  not  been  too  severe,  the  protoplasm  after  a  while 
returns  to  its  normal  shape  again.* 

(c)  The  Plasmodium  of  Didgmium  serpiUa,  when  removed  from  a  tem- 

*  Euhne  performed  the  foUowing  curious  experiment.  Taking  a 
portion  of  the  plasmodium  of  Didymium  serpula,  in  its  resting  state, 
he  mixed  it  with  water  so  as  to  make  a  pulpy  or  pasty  mass.  With 
this  he  filled  a  piece  of  the  intestine  of  a  water-beetle,  and  tying  the 
ends,  laid  it  across  the  electrodes  of  an  induction  apparatus.  The  pre- 
paration  was  kept  in  a  film  of  water  in  a  damp  chamber  for  twenty-four 
hoars,  at  the  end  of  which  time  it  was  considt^rably  distended.  He  now 
allowed  the  electrical  current  to  pass  through  it,  when  it  contracted 
itself  "  like  a  colossal  muscle-fibre."  Upon  extending  it  by  pulling  at 
the  ends,  and  then  sending  through  it  a  stronger  electrical  current,  it 
contracted  itself  one  third  of  iU  length. 


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10  BOTANY. 

peiature  of  20**  C.  to  one  of  80**  C.  (68**  to  86**  FftUr.\  withdraws  its  pseod- 
opodia  and  ct^sea  its  activity  in  the  space  of  five  minutes.  In  an  hour 
after  the  restoration  of  the  normal  temperature  (20°  C.)  the  movements 
begin  again.  If  the  temperature  is  raised  to  85"  C.  (Od"*  Fahr.)  the 
organization  of  the  Plasmodium  is  destroyed. 

The  Plasmodium  of  Fuligo  variant,  Sommf.  {.^EthaUum  aeptteum, 
Fr.),  wlien  placed  in  a  chamber -surrounded  by  ice,  contracts  into  a 
rounded  form  and  ceases  ali  motion ;  upon  gradually  raising  the  tem- 
perature again  the  normal  state  is  resumed. 

(d)  In  glycerine,  a  concentrated  solution  of  sugar,  a  five  per  cent  solu- 
tion of  potassium  nitrate,  or  a  five  per  cent  solution  of  sodium  chloride,  a 
Plasmodium  contracts,  and  becomes  rounded  and  moticinless.  A  sudden 
decrease  in  the  concentration  of  the  solution  by  which  a  plasmodium 
is  surrounded  also  results  in  a  stoppage  uf  its  movements.  A  Plasmo- 
dium of  Didymium  serpiUa,  when  plact^  in  a  one  per  cent  solution 
of  potassium  nitrate,  and  allowed  time  to  regain  its  activity,  suddenly 
rounds  itself  up  and  stops  its  movements  when  the  preparation  is 
washed  out  with  distilled  water ;  after  the  lapse  of  a  few  minutes  (ten 
to  twelve)  the  activity  begins  to  show  itself  again,  and  in  half  an  hour 
the  normal  state  is  restored. 

10.— Ciliary  Movement.  The  swimm  ing  of  swarm -spores, 
spermatozoids,  and  many  other  naked  protoplasmic  bodies,  is 
due  to  the  rapid  vibratory  motion  of  extremely  small  whip- 
like extensions  of  the  hyaline  portion  of  the  protoplasm. 

Examples  of  ciliary  movement  are  very  common.  In  some  swarm- 
spores,  as  in  those  of  Vaucheria,  the  whole  surface  is  covered  with  short 
cilia  ;  in  others,  as  in  (Edogonium.  the  cilia  form  a  crown  aliout  the  hya- 
line anterior  extremity  ;  those  of  Pandorina  and  Cladophora,  and  the 
spermatozoids  of  Bryophytes  and  Pteridophytes,  have  two  or  more  cUia ; 
while  the  swarm -spores  of  Myxnmycetes  have  but  one. 

The  rapidity  of  tlie  swimming  motion  produced  by  cilia  is  consider- 
able, as  shown  by  measurements  made  by  Hofmeister*  in  the  case  of 
swarm-spores,  viz.  : 

Fuligo  mrians  (JSthalium  septicum), ..        .7  to  .9  mm.  per  second. 

Lyeogola  epidendrum .83  mm. 

(Edogonium  f>esicatum 15  to  .20  mm.  **        " 

Vaucheria  sp lOto.Umm.  " 

1 1  .—The  Activity  of  Protoplasm  Enclosed  in  a  Cell-wall. 
The  movements  of  protoplasm  in  closed  cells  differ  but 
littlB  from  those  in  naked  ones  ;  the  differences  are  such  as 
are  due  to  the  fact  that  in  the  latter  case  the  protoplasm  is 

♦  "  Lehre  von  der  Pflanzenzelle,"  p.  80. 


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PROTOPLASM  MOVEMENTS.  H 

free  to  move  in  any  direction,  while  in  the  former  its  move- 
ments are  greatly  restricted  by  the  surrounding  walls.  In 
closed  cells  there  are  two  general  kinds  of  movements — one 
a  streaming,  the  other  a  mass  movemen<>— comparable  to  the 
streaming  and  Amoeba  movements  of  the  naked  cells  or  pro- 
toplasmic masses.  No  movement  takes  place,  however  (at  any 
rate  to  no  great  extent),  until  the  vacuoles  are  quite  large. 

12. — The  streaming  movements  occur  in  the  protoplasmic 
strings,  bands,  and  plates  which  cross  or  separate  the  vacu- 
oles, and  in  the  lining  layer  of  protoplasm  which  invests  the 
inner  surface  of  the  cell-wall.  The  motion,  in  many  cases, 
shows  the  same  alternation  as  in  the  Myxomycetes,  the  direc- 
tion of  the  streaming  usually  being  reversed  after  the  lapse 
of  a  few  minutes. 

The  mass-movement  in  closed  cells  is  not  as  clearly  sepa- 
rated from  the  streaming  as  in  naked  cells.  It  usually  con- 
sists in  a  sliding  or  gliding  of  the  protoplasm  upon  the  inner 
surface  of  the  cell-wall,  in  much  the  same  way  as  the  naked 
Plasmodium  of  one  of  the  Myxomycetes  moves  upon  the  sur- 
face of  its  support.  The  limited  space  in  which  its  move- 
ment must  take  place  in  closed  cells,  and  its  disposition  over 
the  whole  inner  surface  of  the  wall,  compel  the  protoplasm 
to  move  in  opposite  directions  upon  opposite  sides  of  the 
celL  There  is  thus  a  kind  of  rotation  of  the  protoplasm 
when  the  movement  of  all  its  parts  is  uniform. 

(a)  The  streamiDg  movements  roaj  be  stadled  in  the  Btamen-haini  of 
TradescanUa  Virginica,  the  stinging  hairs  of  the  nettle  (Urtica),  the 
ludrs  of  Cucurbita,  Edndium,  and  Solanum  tttberomm,  the  styles  of 
Zea  mais,  the  easily  separated  cells  of  the  ripe  frait  of  Symphoncar- 
pus  raeenuwuB,  the  joung  pollen  grains  of  (Enothera,  and  the  paren- 
chyma of  succulent  monocotyledons — e.g.,  in  the  flower  peduncles  and 
the  filaments  of  Tradeseantia,  The  parenchyma  cells  of  the  leaves  of 
many  trees  and  of  the  prothallia  of  ferns  and  Equisetums  show  a  net- 
work of  hyaline  strings  in  which  a  streaming  may  with  difficulty  be  seen. 

Among  the  lower  plants  good  examples  may  be  found  iu  the  hyphso 
of  some  SaprolegniflB,  and  in  the  cells  of  Spirogyra^  Clasterium,  Dentin 
edia,  and  Coseinodiseus. 

(b)  In  many  cases  {e^g.,  in  the  unfertilized  embryo- sac  of  Ynany 
Phanerogams,  in  the  young  endosperm  cells,  and  in  the  spore-mother- 
oells  of  Anthaeeros  kevis) — where  the  strings  and  bands  resemble  those 
in  the  cases  cited  above — no  movement  of  the  protoplasm  is  visible. 


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12  BOTANY. 

doubtlefMi  because  of  the  mechauical  injury  of  the  cells  in  making  the 
preparation,  and  the  disturbing  iniiuence  of  the  water  in  which  it  is 
mounted, 
^c)  In  the  stamen-hairs  of  Tradescantia   Virginiea  the  protoplasm 


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Dradeteantia 
»mic  sac  has 
water  by  the 
e  strings  and 
Lhe  arrows.— 


1-wall,  and 
he  nucleus 
>as8  to  the 
gs,  alwaj^B, 


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PROTOPLASM  MOVEMENTS,  13 

however,  more  or  less  parallel  witli  tlie  longer  axis  of  tlie  cell  (Fig.  7). 
In  a  string  tliere  may  be  one,  two,  or  three  currents ;  when  there  are 
two  they  are  in  opposite  directions ;  when  there  are  three  the  central 
one  takes  one  direction  and  the  two  outer  ones  the  other. 

The  strings  are  not  stationary  iu  the  cell,  but,  on  the  contrary,  they 
change  their  position  with  a  considerable  rapidity,  and  in  a  prepara- 
tion soon  pass  out  of  the  focus  of  the  microscope.*  By  this  change  of 
place  two  strings  may  come  together  and  fuse  into  one,  or  a  string  may 
pass  to  the  side  of  the  cell  and  become  obliterated  by  fusing  with  the 
protoplasmic  sac.  New  strings  may  be  formed  by  a  process  exactly 
opposite  to  the  one  just  described.  A  stream  in  the  substance  of  the 
lining  protoplasm  forms  a  ridge  projecting  into  the  vacuole  ;  this  rid^e 
gradually  becomes  higher,  and  finally  breaks  away  from  the  protoplas- 
mic sac,  retaining  its  connection  only  at  the  ends.  After  a  stream  Las 
heen  running  in  a  certain  direction  for  from  ten  to  fifteen  minutes,  the 
motion  suddenly  becomes  slower  and  soon  stops  entirely  for  from  a  few 
seconds  to  several  minutes,  and  then  begins  to  move  in  the  opposite 
direction.  The  new  movement  begins  and  spreads  as  in  the  Mvxomy- 
cetes  (see  paragraph  7). 

(d)  In  the  hairs  of  CueurhUa  Pepo  the  arrangement  of  the  protoplasm 
is  much  as  in  Trade*cantia,  The  strings  and  bands  are,  however, 
broader,  and  frequently  contain  several  currents,  and  the  nucleus, 
instead  of  being  imbedded  in  the  lining  layer  of  protoplasm,  is  in 
a  centrally  placed  mass.  There  is  a  more  rapid  change  in  the  form 
and  position  of  the  bands  and  strings  than  in  Tradescantia,  but  the 
streaming  motion  is,  on  the  contrary,  considerably  slower.  The  reversal 
of  the  streaming  currents  takes  place  iu  from  seven  to  twenty  minutes. 

(«)  In  most  cases  tlie  streams  lie  in  the  lining  protoplasmic  layer  of 
the  cell,  or  form  low  ridges  upon  its  inner  surface.  This  is  the  case 
in  the  hairs  of  the  style  of  Campanula^  in  hyphae  (of  fungi),  and  in  the 
suspensor  and  young  embryo  of  Funkia  cciruUa,  In  long  cells,  the 
movement  being  parallel  with  the  longer  axis,  there  may  be,  as  in  the 
pollen  tube  of  ZciUra  marina,  currents  passing  up  one  side  and  down 
the  other.} 

*  This  fact  must  be  borne  in  mind  in  studying  the  movements  of  pro- 
toplasm in  these  cells,  otherwise  grave  mistakes  may  be  made.  One 
string  may  move  out  of  focus,  and  another,  with  a  contrary  current, 
may  move  into  it,  and  thus  a  reversal  of  the  current  in  the  first  string 
may  erroneously  be  supposed  to  have  taken  place. 

t  To  study  the  movements  of  protoplasm  in  pollen  tubes  it  is  usuaLy 
necessary  only  to  make  a  thin  longitudinal  slice  of  the  stigma,  and  to 
mount  and  cover  it  in  the  usual  way,  using  no  water,  however.  After 
placing  it  under  the  microscope  the  preparation  should  be  carefully 
crushed,  when  some  of  the  pollen  tubes  may  be  distinctly  seen.  Their 
movements  frequently  continue  for  some  hours  in  such  preparations- 


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14  BOTANT. 

(/)  The  paaeage  from  the  condition  in  the  last  examples  (the  bo- 
called  eireulation  of  protoplasm)  is  an  easy  one  to  the  cases  where  the 
whole  mass  of  protoplasm  moves  along  the  cell- wall  as  a  bruad  stream, 
passing  up  one  side  and  down  the  other  (the  so-called  rotation  of  pro- 
toplasm). Common  and  well-known  examples  of  this  kind  of  mass-move- 
ment  occur  in  Chara,Naia»,  and  VaUUneria.  It  may  also  (on  the 
authority  of  Meyen)  be  studied  in  the  root-hairs  of  many  land  plant*— 
tf^.,  of  Impatiens  Balsamina,  Vicia  faha^  IpomcMk  purpurea,  Cueumii, 
OueurbUa,  Eanunculua  sceUratua,  and  MarcharUia  polymarpha. 

Note. — ^In  the  study  of  the  structures  treated  of  in  Chapters  I  to  Y 
inclusive,  the  student  will  do  well  to  consult  a  recent  laboratory  man- 
ual—"  Botanical  Micro-Chemistry,"  by  V.  A.  Poulsen  (William  Tre- 
lease,  1884). 


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CHAPTER   II. 

THE    PLANT-CELL. 

18. — In  some  cases  plant  protoplasm  has  no  definite  or 
constant  form.  This  is  its  permanent  condition  in  some  of 
the  lowest  plants — e,g,,  the  Myxomycetes.  In  most  other 
lower  plants,  and  in  all  the  higher  ones,  it  has  this  condition 
only  temporarily,  if  at  all.  In  the  great  majority  of  cases, 
however,  the  protoplasm  of  which  a  plant  is  composed  has  a 
definite,  and,  within  certain  limits,  a  constant  form.  It  usu- 
ally appears  in  more  or  less  rounded  or  cubical  masses  of 
minute  size,  and  which  may  or  may  not  be  surrounded  by  a 
cell-wall.     In  this  condition  it  constitutes  the  Plant-Cell. 

The  undifferentiated  protoplasm  of  tbe  Myxomycetes  reminds  us  of 
the  lower  Monera  among  animals.  In  Bathybius  and  Protamoeba  the 
naked  protoplasm  of  which  they  are  composed  has  no  constant  form. 
In  Protomyxa  we  have  a  few  simple  transformations  which  are  in  every 
respect  comparable  to  those  of  the  Myxomycetes.*  In  higher  animals 
the  protoplasm  exists  in  minute  and  definitely  marked  masses,  termed 
cells,  or  corpuscles,  and  these  have  been  shown  to  be  the  exact  homo- 
iogues  of  the  cells  of  plants. 

14. — While  in  young  cells  provided  with  a  wall  the  pro- 
toplasm fills  the  whole  ciavity,  as  in  ^,  Fig.  2  (p.  3),  in 
older  ones  it  never  does  so,  and  generally  these  contain  only 
a  very  small  portion  of  it,  as  a  thin  layer  covering  the  inner 
surface  of  the  cell-wall  {B  and  C,  Fig.  2).  Close  examina- 
tion shows  that  this  protoplasmic  sac  consists  of  (1)  a  firmer 
hyaline  layer,  the  ectoplasm,  which  is  in  contact  with  the 

*  See  further  on  this  subject  in  paragraph  222,  Chapter  XI.  For  a 
short  account  of  these  intereistinjr  animal  forms  mentioned  above,  the 
student  is  referred  to  Dr.  Packard's  '  *  Zoology  for  Students  and  Gen* 
eral  Readers/'  (p.  18  et  ivc.)  in  the  series  of  which  the  present  work 
forms  a  part,  and  his  "  Life-Histories  of  Animals,"  where  are  also  given 
numerous  references  to  fuller  accounts. 


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16  BOTANY, 

cell-wall ;  and  (2)  within  this  a  less  dense  granular  one,  the 
endoplasm  ;  the  two  layers  are,  however,  not  separated  from 
each  other  by  any  sharp  line  of  demarkation.* 

When  tlie  endoplasm  attains  a  considerable  thickness  it  becomes  dif- 
ferentiated into  an  external  denser  layer  and  an  internal  less  dense 
one.  Often  one  of  these  layers  may  be  foond  to  be  in  motion  while  the 
other  is  at  rest.f 

15. — There  may  almost  always  be  seen  in  plant-cells  bands 
or  strings  of  protoplasm  which  lie  in  or  between  the  vacu- 
oles (Fig.  2,  B),  They  are  at  first  thickish  plates  which 
separate  vacuoles,  but  afterward  they  become  narrower  as 
the  vacuoles  enlarge,  and  at  last  they  disappear  entirely.  In 
these  bands  and  strings,  as  previously  stated  (paragraph  12), 
streaming  movements  are  frequently  to  be  seen. 

16. — Each  of  the  protoplasm  masses  constituting  the  cells 
of  most  plants  usually  has  a  portion  of  its  interior  substance 
differentiated  into  a  firmer  rounded  body,  the  nucleus  Its 
normal  position  is  in  the  centre  of  the  cell ;  but  it  may  be 
displaced  and  pushed  aside  by  the  vacuoles,  so  that  in  an 
optical  section  of  the  cell  it  may  often  appear  to  be  in  the 
margin.  The  nucleus  is  to  be  regai'ded  simply  as  a  modified 
part  of  the  protoplasm  of  the  cell,  and  not  as  something  dis- 
tinct from  it.  It  may  dissolve,  and  its  substance  pass  into 
that  of  the  remainder  of  the  cell ;  afterward  a  nucleus  may 
form  again  ;  and  this  may  occur  a  number  of  times.  Com- 
monly in  each  nucleus  one  or  more  small  rounded  granules 
may  be  seen ;  these  are  called  the  nucleoli.  The  nucleus 
may  form  a  skin  {hautschicht)  about  itself,  and  vacuoli  may 
be  present  in  its  interior. 

17. — Cells  are  of  very  varying  sizes.  They  differ  in  dif- 
ferent plants,  and  also  in  the  different  parts  of  the  same 
plant.  In  but  few  cases,  however,  are  they  of  great  size,  by 
far  the  larger  number  being  microscopic.    The  most  striking 

*  These  two  layers  were  first  described  by  Prlngsheim  in  his  "  Theorie 
der  Pflanzenzelle/'  1854. 

t  Cf.  Strasburger,  "  Studien  ttber  Protoplasma,"  1876  ;  and  Qr,  Jr. 
Mic.  Science,  1877,  pp.  124-132. 


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THE  PLANT-CELL. 


17 


examples  of  large  cells  are  found  in  the  Thallophytes ;  Nitella, 
for  example,  has  cells  50  mm.  (2  inches)  long,  and  1  mm. 
(.04  inch)  thick.  According  to  Von  Mohl,  the  bast-cells 
of  a  species  of  palm  (Astrocaryum)  are  from  3.6  to  5.6  mm. 
(.13  to  .21  inch)  in  length.  For  ordinary  plants  the  average 
size  of  the  cells  may  be  given  as  from  .1  to  .02  mm.  (.004  to 
.0008  inch).  From  this  average  size  the  dimensions  of  cells 
decrease  to  exceedingly  small  magnitudes.  In  the  Yeast 
Plant  {Saccharomyces  cerevism)  the  cells  are  about  .008  mm. 
(.0003  inch)  in  diameter.  The  cells  of  Bacterium  termo  are 
from  .0021  to  .0028  mm.  long  and  from  .0028  to  .0005  mm. 
broad  (.0001-.00008  by  .00008-.00002  inch). 

The  following  table,  taken  from  Hofmeister's  **  Lelire  von  der  Pflan- 
zenzeUe/'  is  useful  aa  showing  bow  tlie  dimensions  of  similar  cells 
vary  in  dififerent  plants  : 

Table  op  Dimensions  op  Various  Kinds  op  Cells  op  Woody 

Plants. 

(In  decimals  of  a  millimetre.) 


3l 

it 

^  9    • 

3^ 

ii 

111 

<«f 

«? 

Ss'O 

8^ 

|il 

3| 

If  I 

lu^ 

^ 

> 

.301 

.413 

.6i8 

.889 

.808 

1.179 

.801 

.M.3 

.718 

.a)5 

.404 

.... 

.616 

.218 

.630 

.... 

.798 

.... 

1.898 

.406 

.821 

.487 

.178 

.888 

.041 

.076 

.011 

.017 

.876 

.619 

.885 

.667 

.048 

.077 

.019 

.087 

.842 

.912 

.468 

.504 

.057 

.066 

081 

.076 

s  ? 


xacE 


C&mbiam-celle,  average  length 

VeMel-lIke  wood-celle,  averaze  length.. 

Bast-like  wood-cells,  average  length 

Tesfel-cells  of  the  wood,  average  length 

Latticed  cells  of  yoang  secondary  bark,  aver- 
age length 

Bast-cells  of  yoang  secondary  bark,  average 
length  

Cells  of  mednUarv  ray  in  the  cambinm  ring, 
ma»1mam  length  in  tangential  section 

I>o.,do.,mazimam  width  in  tangential  sec- 
tion   

Ceils  of  mednllary  ray  in  the  young  wood, 
average  length  in  tangential  section 

Do.,  do.,  average  width  in  tangential  section. 

Cells  of  mednllary  ray  in  the  young  secon- 
dary baric,  average  length  in  tangential 
section 

Do.,  do.,  average  width  in  tangential  sec- 
tion  


.786 

\\'m 

1.168 

.466 

.066 

.680 
.075 

.744 
.076 


1.611 
8.020 


8.188 

.049 

.014 

.096 
.019 

.172 
.086 


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18  BOTANY. 

18. — ^Every  free  mass  of  protoplasm  tends  to  assume  a 
spherical  form.  The  free  cells  of  the  unicellular  water  plants 
are  generally  more  or  less  rounded,  as  are  cilso  the  floating 
spores  of  most  aquatic  Thallophytes.  In  plants  composed  of 
masses  of  cells  their  mutual  pressure  gives  them  an  angular 
outline.  Where  the  pressure  is  slight  the  cells  depart  but 
jittle  from  the  spherical  shape,  but  as  it  becomes  greater 
they  assume  more  and  more  the  form  of  bodies  bounded  by 
planes.  If  the  diameters  of  the  individual  cells  are  equal 
and  the  development  of  the  mass  of  cells  has  been  uniform* 
in  every  direction,  we  may  have  regular  cubes,  or  twelve-sided 
bodies,  i.e.,  dodecahedra.  It  is  rarely  the  case,  however, 
that  the  cells  have  a  perfectly  regular  form.  Even  when 
their  diameters  are  approximately  equal,  they  are  generally 
so  much  distorted  that  they  are  best  described  as  irregular 
polyhedra. 

19. — It  much  more  frequently  happens  that  cells  grow 
more  in  some  directions  than  in  others,  and  thus  give  rise 
to  elongated  and  many  irregular  forms.  In  many  of  the 
Thallophytes  the  long  filaments  composing  the  plants 
are  made  up  of  elongated  cylindrical  cells  placed  end  to 
end  ;  while  in  others  the  cells  are  repeatedly  and  iiTCgulai^ly 
branched. 

In  higher  plants  many  elongated  cells  occur,  but  here, 
by  pressure,  they  generally  become  prismatic  in  cross-section. 

{a)  Many  forms  of  cells  have  been  enamerated,  but  they  may  all  be 
arranged  under  the  two  principal  kinds  indicated  above,  viz.,  the 
short,  and  the  elongated.  As  will  be  more  fully  shown  hereafter,  the 
various  kinds  of  short  cells  constitute  what  is  called  Parenchyma; 
hence  the  cells  themselves  are  termed  Parenchymatous  cells,  or  Paren- 
chyma cells.  Similarly,  certain  kinds  of  the  elongated  cells  constitute 
Prosenchyma,  and  hence  such  are  termed  Prosenchymatous  cells,  or 
Prosenchyma  cells.  While  it  is  impossible  to  draw  an  exact  line  be- 
tween parenchymatous  and  prosenchymatous  forms,  yet  the  terms  are 
valuable,  and  are  in  constant  use  to  indicate  the  general  form. 

(p)  Duchartre*  has    made  an    excellent    classification  of  the  prin- 

*  In  his  Elements  de  Botanique,"  second  edition,  a  large  and 
valuable  work,  which  the  student  may  profitably  consult. 


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THE  PLANT^OELL. 


19 


dpal  forms  of  cells,  which  is  given  below  in  a  slightly  modified 
fonn: 

Cell  globular  or 

ovoid,    ia    section 

round  or  oval  ....  SpheraidoL 

Cell  polyhedral  Polyhedral 

Outline  smooth.        Cell  a  parallelo- 

or  without  promi-x  pipedon,  in  section 

nenoes.  rectangular Cttbaidal. 

Cell  tabular, 
with  an  elongated 
rectangular  s  e  c  - 
tion Tabular, 


Cell  short 

(Parenchymch 

tons). 


With  prominences. 


Cell  ramose, 
bavin ff  short  and 
irregular  projec- 
tions  Bamoae, 

Cell  star-shap- 
ed, having:  lonff 
projections  which 
are  more  regular. .  Stellate, 


Cell  elongated. 


Cell  cylindrical,  with  its  ends  at 
right  angles  to  its  axis,  or  but  little 
inclined Cylindrical. 

Cell  prismatic,  with  its  ends  at 
right  angles  to  its  axis,  or  but  little 
inclined Priematie, 

Cell  fusiform  [cylindrical  or  priH- 
matic],  with  its  ends  oblique  and 

pointed Fusiform 

(Prosenchyma- 
tous). 


20. — When  one  or  more  sides  of  a  cell  are  not  in  contact 
with  other  cells,  as  is  the  case  with  those  cells  which  com- 
pose the  surface  of  plants,  the  free  sides  are  generally  con- 
vex, and  they  often  become  more  or  less  prolonged,  sometimes 
in  a  curious  way.  The  velvety  appearance  of  the  petals  of 
many  plants  is  due  to  such  prolongations  of  the  free  sides  of 
the  surface  cells  (Fig.  8).  Of  a  somewhat  similar  nature  are 
the  tubular  extensions  of  the  surface  cells  of  young  roots — 
the  root-hairs.  And  here  we  may  also  place  the  curious  star- 
shaped  cells  which  project  into  the  intercellular  spaces  in  the 
interior  of  the  stem  of  the  water  lily  (Fig.  9),  and  those 
which  compose  the  pith  of  certain  rushes  (Fig.  95). 

21.— In  the  unicellular  plants  each  cell  is  an  independent 


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20 


BOTANY. 


organism  ;  it  absorbs  nourishment,  assimilates,  grows,  and 
reproduces  its  kind.     In  tlie  higher  plants,  although  this 
independence  is  not  so  evident,  it  still 
,  exists  in  a  considerable  degree.      Here 
'  each  cell  is  an  iudividual  in  a  commu- 
nity ;  but  it  still  has  a  life-history  of  its 
own,  a  foimation  (genesis),  growth,  ma- 
turity, and  death.     It  is  the  unit  in  the 
plant.     Upon  its  changes  in  size,  form, 
and  structure  depend  the  volume,  shape, 
x^Xti7^"^f^t^^%il  ^^d  structural  characters  of   the  plant 
of  a  pansy  (Fioto^ricotor),  and  all  its  parts.     It  isthus  the  Morpho- 

Bhowiiig  prolongatioiiB  ol  ,      .     ,   -,    f,     -   ,,         ,       ,  -* 

tbe  free  (upper)  Bides  of  the  logiCOl   Unit  01   the  plant. 

•Lrtre.  *^*  ~  ^  °'  22. — As  the  whole  structure  of  the 
plant  is  an  aggregation  of  cells,  so  the  functions  of  the 
whole,  or  of  any  part  of  a  plant  are  but  the  sum  or  result- 


Fio.  Oft. 


cella  projeci 


chai 


lire. 


».- 


Fio.  9. 

petiole  of  _._^ — ,  -,  -, ,-- 

Into  the  Intercelmlar  spaces  i,  i  ;  9,  a  reduced  flbro-vasciilar  bundle. 

if  Sachs. 

Stellate  cells  from  the  pith  of  Juneus  ^unu,  mag^nifled.^After  Dn- 


Flg.  9.— A  crosB-section  thronsh  the  petiole  of  Nuphar  advenu  ;  »,  «,  star-shaoed 

"    lirojectlng  Into  the  intercella" '  ' j—- ^  -• 1— w — ai^ 

fled.— After  Sachs. 


the  physiological  activities  of  its  individual  cells. 
11  is  thus  also  the  Physiological  Unit  of  the  plant. 


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CHAPTER   III. 

THE  CELL- WALL. 

28.— In  all  but  the  lowest  plants  the  protoplasm  of  every 
cell  surrounds  itself  sooner  or  later  with  a  covering  or  wall 
of  oellulose.  The  substance  of  the  cell- wall  is  a  secretion 
from  the  protoplasm.  Cellulose,  as  such,  does  not  exist  ini 
the  protoplasm  ;  it  is  formed  on  the  surface  when  the  wall  is 
made.  On  its  first  appearance  the  wall  is  an  extremely  thin 
membrane,  but  by  subsequent  additions  it  may  acquire  vary- 
ing degrees  of  thickness.  The  cell-wall  forms  a  complete 
covering  for  the  protoplasm  ;  there  are  at  first  no  openings 
in  it,  at  least  none  that  are  visible ;  later  in  the  life  of  the 
cell  pores  are  formed  in  the  wall  in  some  cases,  while  quite 
frequently  in  dead  cell-walls  there  are  large  perforations  of 
yarious  sizes  and  shapes. 

(a)  Cellulose  is  related  chemically  to  atarcb  and  sugnr.  Its  composi- 
tion is  €i«  Ha*  Oio.  It  is  tough  and  elastic.  It  in  but  slij^htly  soluble 
in  dilute  acids  and  alkalies,  and  not  at  all  in  waiter  and  alcohol.  In 
water,  however,  It  swells  up  from  imbibing  some  of  the  liquid,  but  it 
shrinks  apraiu  in  bulk  when  dried. 

(h)  TesU.-^l.  If  cellulose  is  treated  with  dilute  sulphuric  acid,  and 
shortly  afterward  with  a  weak  solution  of  iodine,  it  is  colored  blue. 

2.  Treated  with  Sctiultz'H  Solution  it  assumes  a  blue  color. 

(c)  In  the  Myxoniycetea,  if  the  larjre  mass  of  protoplasm  composing  a 
plant  is  somewliat  dried,  it  sepn rates  itself  into  smaller  masses,  which 
sarronnd  themselves  with  a  cell- wall.  Upon  apply inj]r  sulphuric  acid 
and  iodine,  the  characteristic  blue  color  of  cellulose  appears,  showing 
that  the  wall  is  a  true  wall  of  cellulose.  If,  however,  any  such  dried 
maM  of  protoplasm  is  subjected  to  the  proper  conditions  of  moisture 
and  temperature,  the  cell-wall  is  dissolved  and  absorbed  into  the  proto- 
plasmic mass.  Tests  applied  now  utterly  fall  to  show  the  presence  of 
oellalose.  These  observations  prove  the  truth  of  the  statement  that 
eellalose  is  a  secretion,  and  that  it  is  not  contained,  as  cellulose,  in  the 
f>iotopla8m. 


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22 


BOTANY, 


24. — After  the  formation  of  the  cell-wall  it  generally 
grows,  and  increases  its  surface  and  thickness.  Usually  the 
surface-growth  at  first  preponderates,  afterward  that  in 
thickness.  Neither  the  one  nor  the  other  is  uniform  over 
all  points  of  the  cell-wall,  hence  each  cell  during  its  growth 
may  also  change  its  form.  As  the  growth  of  the  cell-wall  is 
directly  dependent  upon  the  protoplasm,  it  is  clear  that  it 
can  continue  only  as  long  as  the  protoplasm  is  in  contact 
with  its  inner  surface.  In  the 
growth  of  the  cell-wall  the  new 
cellulose  secreted  by  the  i)rotoplasm 
"^  is  deposited  between  the  molecules 
of  the  membrane  already  formed. 
When  the  new  molecules  are  de- 
posited between  the  previously 
formed  ones  only  in  the  plane  of 
the  cell-wall,  surface-growth  takes 
place;  but  when,  the  planes  of  de- 
position of  the  new  molecules  lie  at 
right  angles  to  the  plane  of  the 
cell-wall,  increase  in  thickness  is 
the  result ;  when  the  molecules  are 
deposited  in  both  planes,  the  wall 
Fig.  ia-Di«grams  to  iiinstrate  mcreascs  both  in  surfacc  and  thick- 

tne  iiitercalarj  growth  of  (Edoso-  Qess. 

iiinm.    A,  internal  ring  of  celln- 

lose  secreted  at  /;   B,  showing        26.  —  SlirflBU3e-grOWth    may     be 

the  way  in  which,  by  the  horizon-  .  .      ,        •    .  i  r     j.v,     ± 

tai  splitting  of  ihe  ringi  the  cell  is  tcrmmal  or  lutcrcalarv.  In  the  lor- 
?heTaiffi>^i?by'rhe^pmun'*g  mcr  case  the  growth  is  greatest  at 
c°^r;the"i2$SifJd'X^fo,^!Sl^  some  point  on  the  surface,  decreas- 
.Te^'Si/ n^nfrJaif^'^^^^^^^  i^g  ^^  intensity  on  all  sides.  The 
Modified  from  8a  h*.  growing  point  thus  comcs  to  pro- 

ject as  a  point  or  knob,  or  it  becomes  the  end  of  a  cylindri- 
cal Siic.  If  several  points  of  growth  occur  in  a  cell  it  may 
become  star-shaped,  and  by  a  continuation  of  the  process 
repeatedly  branched.  The  typical  form  of  intercalary 
growth  takes  place  in  definite  belts  which  surround  the  cell, 
as  is  seen  in  (Edogonium  (Fig.  10).  The  growth  of  the 
whole  of  the  side  wall  of  a  cylindrical  cell,  as  in  Spirogyra, 
is  also  a  form  of  intercalaiy  growth. 


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TEE  CELI^WALL.  23 

26. — Growth  in  thickness  of  the  wall  produces  changes 
in  the  cell  of  even  greater  importance  than  growth  in  sur- 
face.    While  surface-growth  has  but  little  to  do  with  the 
determination  of  the  functions  of  the  cell,  the  thickening  of 
its  wall   generally  results   in  a 
change  in  function,  or  an  entire 
suspension    of    all  physiological 
activities.     Cells  with  extremely 
thin  walls  are  most  active;  only 
such  can  take  part  m  growth. 
(See  Chap.  XI.)     Nutrition  and 
assimilation  are  confined  to  cells 
whose  walls  have  but  slight  thick- 
ness.   Cells  with  moderately  thick 

waUs  may  be  used  as  storehouses  Jjf^/^r^^JlllirlVn'  "^r!^. 
for  food;  starch,  for  example,  is  x 200.- After Dachwiw. 
frequently  found  in  such  cells.     But  as  the  walls  attain  great 
thickness  the  protoplasm  loses  all  activity  save  that  neces- 
sary to  the  secretion  of  cellulose. 

27. — The  thickening  generally  produces  certain  markings 
or  sculpturings  in  the  shape  of  projecting  points,  ridges, 
bands,  etc.,  which  on  the  one  hand  are  on 
the  outside  of  the  wall,  while  on  the 
other  they  are  on  the  inside.  In  some 
pollen  grains  and  spores  we  have  the  best 
examples  of  external  markings.  Here,  in 
some  cases,  certain  isolated  points  in  the 
cell-wall  become  strongly  thickened,  giv- 
^o^diAntnS^.  ing  rise  to  spines  or  prickles  (Fig,  11). 
robrt2*c1.^tht*<Sn.w2i  I"  ^^^^^  c^^s  the  thickening  is  in  cer- 
iflLe%htek^  In  *^  un?^  ^^^  bands,  which  may  rise  into  high 
Into  a  network.  Each  of  walls,  as  in  Fig.  12.     External  markings 

the«e  be'irt  thlckeuings,  '       -  °         n        ,  .  ,  * 

which  project  siui  more,  occur  ouly  upon  ccUs  which  are  free,  or 

in  the  forio  of  spines  ar-  .        t   r^.  x     i.       'ii  iv 

ranffediik«}acumbI-.After  m  Slight  Contact  With  One  another  or 
®**^*  with  other  cells. 

28. — Internal  markings  are  of  essentially  the  same  kind 
as  the  external,  although  of  greater  variety.  When  the 
secretion  of  new  cellulose  is  greatest  at  isolated  points,  knobs 
and  projections  of  various  kinds  are  the  result.     It  more 


f 


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24  BOFANT. 

f reqnently  happens,  however^  that  the  thickening  is  in  bands 
of  greater  or  less  width,  occasionally  extending  over  nearly 
the  whole  inner  surface. 

One  of  the  simplest  cases  is  represented  in  Fig.   13,   where 
new  material  has  been  added  to  all  parts  of  the  wall  ex- 


Fio.  ISA  Fio.  liLl.  Fig.  14. 

Fig.  18.~J,  optical  section  of  a  Klerenchyma-cell  from  beneath  the  epidennie  of 
Che  undergronna  »t«  m  of  PUiis  aquUina^  isolated  by  SchnlzeV  maceration  The 
wall  consists  of  an  inner  very  dense. layer,  and  a  central  less  dense  one  enclosed 
between  two  denser  ones ;  these  layers  are  penetrated  by  pit  channels,  which  are 
seen  in  the  farther  wall  in  transverse  section.  B,  a  similar  cell,  more  thickened. 
The  pits  are  here  long  canals,  which  are  more  or  less  branched,  x  abontSSO.— 
After  Sachs. 

P^.  14.— Brown-walled  cells  in  the  stem  of  Pteris  aguUina.  A,  a  half  cell  iso- 
lated and  rendered  colorless  by  Schnlze's  maceration.  B,  a  piece  more  strongly 
magnified  (X  560).  Theflasore-like  piU  ar^  crossed,  i.e..  theflssare  is  twisted  as 
the  thickening  increases ;  jp.  a  side  view  of  a  fissure  appearing  as  a  simple  channel, 
since  it  shows  the  narrow  diameter.  (7,  cross-section ;  a,  boundary  lamella ;  6,  c. 
Inner  lamvllie.— After  Sachs. 

cepting  in  small  isolated  spots.    As  t^e  wall  thickens  around 
these  spots,  they  become  at  first  pits,  and  finally  channels. 

29. — In  some  cases  the  pits  or  channels  are  simple, 
straight,  or  slightly  bent  extensions  of  the  central  cell-cav- 
ity ;  in  others  they  may  be  branched,  as  shown  in  Fig  135^* 
in  cross-section  they  may  be  round,  as  in  Fig.  ISA,  or  elon- 


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THICKENINGS  OF  THE  WALL,  25 

gated  fissures,  as  in  Fig.  14,  or  of  any  form  intermediate 
between  these.  Pits  with  elongated  fissures  may  be  twisted, 
giving  them,  when  seen  in  front  view,  the  appearance  of  two 
Assures  crossing  one  another  (Fig.  14^,  B), 

30. — In  the  thickening  of  the  cells  of  the  wood  of  the 
ConiferaB  bordered  pits  are  formed  (Fig.  15).  Here  large 
round  areas  of  the  wall  remain  thin,  and  the  thickening 
mass  arches  over  them  on  all 
sides  in  such  a  way  as  to  form 
low  domes  (Fig.  IG,  -^) ;  at  the 
top  of  each  dome  a  small  round 
opening  is  left,  and  this  permits 
free  communication  between  the 
cavity  of  the  cell  and  the  pits 
formed  by  the  dome.  This  pro- 
cess takes  place  in  exactly  the 
same  way  upon  both  sides  of  the 
common  wall  of  contiguous  cells 
(Fig.  16,  5,  ty  ty  and  G).  When 
the  partition  separating  opposite 
pits  breaks  away,  as  it  generally 
does  quite  soon,  the  resulting  cav- 
ity  is  doubly  convex  in  shape 
(Fig.  16,  E).  When  a  pit  of 
this  structure  is  seen  in  front 
view,  it  has  the  appeai-ance  of  two     p,j,  i5.-«nt«  tyivMitU:  lonrf- 

concentric  circles  ^Fio*  15  /"  t»dlnal  radial  i^ection  throngh  the 
concentric    ciroies    yr\^.    lo,    i  ,   ^ood  of  »  rapidly  growing  branch ; 

and  Fiff.  16,  D) ;  the  outer  one  «.^c^bi»iwood-ceijB(tracheTde8); 

_     .  p         \    ,        .  t       ,     . ,  .  a  to «,  older  wood-celln  (tracheTdes); 

bemff  formed  by  the   bottom   of  <',<".<''',  bordered  pit*,  increaulng  in 

,^  •,  J    XI        •  -L       ii  a^c;  #<,  large  pite  where  ells  of  the 

the    pit,    ana    the    inner    by    the  medullary  rays  lle  next  to  the  wood- 

>^»^^«,*^^  «4.  :«.«  4.^^  cel'«-    X  885.— After  Sachs. 

Opening  at  its  top. 

The  bordered  pits  of  pines,  firs,  and  other  ConiferaB  may  be  readily 
examined  by  making  a  longitudinal  radial  section.  They  are  not  foand 
in  abundance  on  the  tanprential  surfaces  of  the  cells. 

The  rep  I  structure  of  tlie  l>ordered  pits  of  the  Conifers  was  not  under- 
stood until  quite  recently.*    Von  Mohl,  apparently  not  noticing  the 

♦  Schacht,  in  1859  (Botanische  Zeitung,  pp.  288, 289),  and  in  a  memoir 
in  1860  ("  De  Maculis  in  PlanUrum  Vasis  Cellulisque  Lignoeis*'),  gave 
the  first  correct  explanation  of  the  structure  of  bordered  pits. 


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26 


BOTANT. 


tliin  partition,  thought  that  the  lenticular  cavity  was  formed  by  the 
separation  of  the  walls  of  the  two  contiguous  cells  at  that  place,  and  con- 
^  ,  sequently  that  they  were 

interee'lular.  This  in- 
terpretation is  still  given 
in  some  Ijooks.* 

81.  _  While  the 
bordered  pits  of  the 
Conifer®  are  never 
crowded  together,  in 
the  cells  of  some 
plants  they  are  so 
numerous  as  to  lie 
closely  side  by  side 
(Fig.  17).  In  such 
case  the  first  thick- 
ening of  the  wall  pre- 
sents itself  as  a  net- 
work of  ridges  en- 
closing elliptical  thin 
places.  As  the  thick- 
ening advances  the 
ridges  increase  in 
height,  but  at  first 
not  in  breadth  ;  later 
they  increase  in 
breadth  at  the  top  and 
overarch  the  thin 
areas,  much  as  in  the 

Pig.  16.— Bordered   plU  of   Pinus  tylv«»tri8.     A,  bordered    pitS    of  the 

traiieverae  section  of  mature  wood;  m,  central  layer  p^„:#^-««  Jn      fViia 

of  ihe  common  wail;  t,  a  matare  pit  cot  through  the  ^oiiiiera;.         lu      uii» 

middle ;  t\  the  «arae,  but  in  a  thlcicer  part  of  the  eec-  f^^^n        Virkwnvo-P       ^Va. 

tion,  the  part  of  the  cavity  of  the  pit  seen  in  perspec-  ^**8L,       uowtjver,      Liit? 

tlve;  V\  a  pit  cut  through  below  it«  openinan;  B,  nnpnino-  at  the  ton  of 

trauBveniesectlonthroughlhecamblum;  c. cambium;  openmg  ai  tae  lop  Ui 

A.  very  young  wood-cells;  U  A  verv  younj?  bordered  the  pit  is  an  cloUffat- 

I,  seen  in  section  ;  C,  diagram  of  sectional  and  lat-  ^        .  ^ 

[  views  of  a  young  bordered  pit;  A  diagram  of  e(J    gljt    instead   of    a 

Lional  and  lateral  views  of  a  mature  bordered  pit ;     . 

section  of  a  mature  pit,  seen  in  perspective;  F.  Circle     (-Clg-     17>     A, 
tion  of  a  younifcr  pit  seen  in  perspective.    A  and         i   >^     \        mi       i  i  • 

(800.-Aher  Sachs.  and  C,  v).     The  thin 

ite  separating  opposite  bordered  pits  of  this  kind  breaks 

^  See  Le  Maout  and  Decaisne's  **  Traits  G6n^rale  de  Botanique,"  1868 
nglish  edition,  1872] ;  Grilfith  and  Henfrey's  "  Micrographic  Die- 


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THICKENINOii  OF  THE  WALL.  27 

away  as  in  the  previous  case,  and  so  free  communication 
between  adjacent  cells  or  vessels  is  established. 


Pig.  17. 


Fio.  18. 
Fig.  17.— Bordered  pits  of  the  thick  root  of  Dahlia  variabUitt.    A.  front  view  of  a 

Siece  of  the  wall  of  a  vee«el,  »een  f^om  without ;  B,  transverse  section  of  thu  rame 
lorlxontal,  and  at  right  aneles  to  the  paper) ;  C,  longltndinal  section  of  A  (vertical, 
and  at  right  angles  to  the  paper) ;  a,  septum ;  a,  the  original  thin  thickening- ridge  ; 
6,  the  expanded  part  of  the  thickening  masses,  formed  later  and  overarching  the  pit ; 
C  the  flssore  through  which  the  cavity  of  the  pit  communicates  with  the  cell  cavity ; 
at  a  and  ^  the  corresponding  front  view  is  appended,  in  order  to  make  the  trana- 
verse  and  longitudinal  sections  more  clear,     x  800.— After  Sachs. 

Fig.  18.— Scalariform  thickening  of  the  walls  of  a  vei>sel  from  the  underground 
•tern  of  PCeris  aauiUna.  A,  half-vessel,  isolnted  hy  8chulze*s  maceration ;  ^  to  2>, 
pieces  obtained  from  stems  hardened  in  absolute  alcohol ;  B,  a  partly  diagrammatic 
▼lew  of  a  vertical  section  of  the  wall,  seen  from  within ;  <?,  c,  plan  of  section  ;  d. 
opening  to  pit ;  C,  front  view  of  young  wall  of  a  vessel ;  s,  nnthlckened  portion  of 
wall ;  0,  thickening-ridge ;  D,  vertical  section  of  C;  E^  section  of  wall  in  a  place 
where  a  vessel  adjoins  a  succulent  cell  p;  the  thickening-ridges  {g)  are  only  on 
one  side,    x  800.~Af ter  Sachs. 

tionaiy,"  third  edition,  1874;  Carpenter's  "The  Microscope,"  fifth  edi- 
tion. 1874 


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28  BOTANY. 

32. — ^The  passage  from  the  mode  of  thickening  just  de- 
scribed to  the  scalariform  manner  (Fig.  18)  is  an  easy  one. 
Here  each  longitudinal  angle  of  the  cell  or  vessel  is  thickened, 
and  from  these  thickened  angles  ridges  run  right  and  left, 
from  one  to  the  other  (Fig.  18,  (7,  v).  The  after  growth 
of  the  ridges  is  essentially  the  same  as  in  the  case  of  crowded 
pits  ;  in  fact,  the  pits  here  are  simply  greatly  elongated  and 
crowded  bordered  pits.  Eventually  the  narrow  plates  be- 
tween the  thickened  ridges  disappear,  as  in  the  other  cases. 
Examples  of  scalariform  thickening  are  common,  especially 
in  the  ferns. 

33. — The  development  of  rings  (Fig.  19,  v)  is  nearly  like 
thAt  of  the  scalariform  thickening.     Instead,  however,  of 


Fig.  19.— Longitudinal  lection  of  a  portion  of  the  stem  of  Impatieru  Baltamina. 
9,  annular  veese].  v',  a  vessel  with  thickenings  which  are  partly  spiral  and  partly  an- 
nular ;t/\  V"',  v""y  several  varieties  of  spiral  vessels ;  t/"",  a  reticulated  vessel— 
After  Duchartre. 

the  ridges  being  short,  they  extend  entirely  around  the  inner 
surface  of  the  wall.  The  transition  from  rings  to  spirals  is 
a  simple  one,  the  thickening  taking  place  in  a  spiral  line, 
instead  of  in  one  passing  directly  around  the  wall  (Fig.  19, 
v'\  v'").  Transitional  forms  are  frequently  found  (Fig.  19, 
v'),  and  many  modifications  and  irregularities  occur — e,g.y 
in  the  figure  at  v'""  is  tlic  form  known  as  the  reticulated. 

34. — In  all  the  foregoing  cases  the  marking  of  the  wall 
has  been  general ;  there  are  some  cases,  however,  where  it 
is  localized.  A  good  example  of  this  is  in  the  formation  of 
the  pits  of  sieve-cells  (Fig.  20).  The  horizontal  walls,  and 
also  areas  upon  the  longitudinal  ones,  become  thickened 
reticulately,  leaving  rather  large  thin  areas,  as  shown  in 
Fig.  20,  q^  q.     After  a  while  the  thin  areas  become  absorbed. 


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THICKENINGS  OF  THE  WALL.  29 

allowing  the  protoplasm  of  contiguous  cells  to  become  struc- 
turally united.  The  sieve- like  appearance  of  these  modified 
portions  of  the  wall  give  to  the  cells  their  name  of  sieve-cells. 

36. — ^The  coUen- 
chjma  cells  which 
are  frequently  found 
beneath  the  epider- 
mis of  the  succulent 
parts  of  higher 
plants  afford  an- 
other instance  of 
localized  thicken-  . 
ing.  Here  only  the 
angles  of  the  cells 
become  tliickened, 
leaving  broad  por- 
tions of  the  wall  un- 
modified (Fig.  21). 

(a)  Examples  of  the 
nniform  thickening  of 
the  cell-wall  m&y  be 
obtained  for  study  by 
making  tliin  sectioos  of 
the  hard  parts  of  man  j 
nuts  and  seeds  (Figs.  58 
to  61) ;  in  many  of  these 
more  or  less  complex 
channels  may  be  found. 
Bordered  pits  are  best 
studied  in  longitudinal 
sections  of  the  yoang 

wood  of  the  pines,  firs,  Fig.  90.— Toung  sieve  tubes  of  CucurbUa  pepo  The 
*»♦/.  tttiH  tlw»  rmwdAd  drawing  made  from  epecimena  which,  bv  having  lain  a 
etc.,  ana  tne  crowuea  long  time  m  absolute  alcohol,  have  allowed  the  prodncs- 
pits  in  the  Ftems  of  tion  of  vxtremely  clear  sections  ;  g,  transverse  view  of 
X       ^1  ni    «^-      rieve-llke  sepu ;  *i,  sieve  plaie  un  side  wall ;  x,  thin- 

most  Other  Fhanero-  ^er  parts  of  the  longitadinal  wall ;  I,  the  same  seen  in 
ffams.  Loniritudinal  section;  ps,  contracted  protoplasmic  contents  (lifted 
"^     .  ^  .  oil  hi  sp  from  the  transverse  septum,  still  In  contact 

sections  of  the  stems  of  at  ^ ;  s,  parenchyma-cells  between  sieve-tubes,  x  fiM). 
most  annuals  will  yield  -^««'  Sachs. 

pood  examples  of  ringed,  spiral,  and  reticulated  thickening.  The 
stems  of  the  Cucurbitacead  (Pumpkin,  Squash,  Gourd,  etc.)  furnish  fine 
examples  of  sieve  cells  and  collenchyma. 

(&)  In  this  place  may  be  mentioned  the  curious  and  sometimes  puz- 


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30 


BOTANY. 


zUng  bernioid  protraBions  to  be  met  witb  in  some  plants.  Wben  tbe 
Borroanding  cells  are  very  active,  it  sometimes  bappens  that  tbe  thin 
membrane  wbicb  closes  up  a  pit  grows  and  is  posbed  tbrougb  into 


aanj 

iiODB 
91,88 

pper 
lebe- 
they 
fill 
y  of 
at  6, 
larffe 
osite 
)t. 


Fio.  tla. 

Pig.  Sl.-^ollenchyma  cells  of  tho  Begonia.  traDirene  flec- 
tion (tf  the  petiole.  «,  epidermis ;  e/,  collendiyma-cells,  with 
thiclcened  angles,  v«  v  ;  chl,  chlorophyll-bodies ;  p,  largecell  of 
parenchyma.    X  650.— After  Sachs. 

Fig.  Sla.— Hemioid  protmsions  into  the  pitted  vessel*  of 
Echinocygtit  lobata :  tho  upper  flgnre  magnified  250,  and  the 
lower  1000.— From  drawings  by  J.  C.  Arthur. 

ories  as  to  the  Mode  of  Thickening.    The  real 
he  process  in  the  growth  in  surface  and  thickness 


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THICKENINQa  OF  THE  WALL,  31 

of  the  cell-wall  was  for  a  long  time  not  fully  understood. 
There  have  been  three  prominent  theories  advanced  to  ex- 
plain the  phenomena  observed.  They  may  be  briefly  stated 
88  follows : 

I.  Von  Mohl  held  that  "the growth  of  the  cell-membrane 
in  thickness  arises  from  a  periodical  apposition  of  new  mem- 
branes upon  the  already  completely  developed  wall."*  Ac- 
cording to  this  theory,  the  marks  of  stratification  usually  seen 
were  supposed  to  be  the  lines  separating  the  added  mem- 
branes. This  deposition  was  supposed  to  proceed  from  with- 
out inwards ;  that  is,  the  newer  layers  were  supposed  to  be 
placed  inside  of  the  previously  existing  ones ;  on  this  ac- 
count this  has  been  called  the  theory  of  centripetal  thicken- 
ing. Until  quite  recently  this  has  been  the  prevailing  theo- 
ry in  English  and  American  books. 

IL  Some  observers,  among  whom  were  llartig  and  Hart- 
ing,  laying  great  stress  upon  the  external  markings,  as  seen 
in  pollen  grains,  spores,  etc.,  opposed  the  foregoing  theory, 
and  propounded  one  which  has  been  termed  the  theory  of 
centrifugal  thickening.  According  to  this  theory,  "  the  cell- 
membrane  increases  in  thickness  in  the  direction  from 
within  outwards  by  the  deposition  of  layers  upon  the  out- 
side of  the  original  membrane."  It  is  thus  the  exact  oppo- 
site of  the  previous  one;  while  in  the  former  the  outer 
membrane  is  supposed  to  be  the  oldest,  in  the  latter  it  is  the 
inner  one. 

III.  The  theory  which  now  generally  prevails  is  that  the 
thickening  of  the  wall  is  a  growth,  due  to  the  formation  or 
deposition  of  new  molecules  between  the  molecules  of  the 
original  membrane.  It  is  called  the  theory  of  intussuscep- 
Hon,  and  was  originated  by  Nageli  in  1858.  f 

*  The  student  will  find  a  condensed  statement  of  this  theorj  in  tbe 
"Principles  of  tlie  Anatomj  and  Physiology  of  the  Vegetable  Cell,"  by 
Hago  Von  Mohl,  translated  by  Henfrey,  1851. 

f  Nfigeli,  **  Die  StftrkekOraer/'  in  "  Pflanzenphysiolo^schen  Unter- 
smchnngen,"  1858.  Dachartre  claims  for  Trecnl  the  first  suggestion  of 
this  theory  in  1854  The  term  intussusception  as  applied  to  the  growth 
of  the  cell-wall  was  used  long  before  this ;  Schleiden,  in  his  "  Contri- 


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33  BOTANY. 

37. — ^Every  part  of  the  living  cell-wall  appears,  from  the 
results  of  N&geli's  researches,  to  be  composed  of  definite 
molecules,  which  are  not  in  contact,  but  separated  from  one 
another  by  layers  of  water,  termed  the  Water  of  Organiza- 
tion. The  thickness  of  these  intermolecular  layers,  and  con- 
sequently the  amount  of  water  in  the  whole  mass  of  any  cell- 
wall,  varies  in  different  cells,  and  even  in  the  same  cell.  In 
the  denser  walls,  or  parts  of  walls,  the  water  is  less ;  in  those 
which  are  less  dense  it  is  greater.     (Fig.  22.) 

Now  it  is  evident  that  young  cell-walls  must  have  rela- 
tively large  amounts  of  water  in  their  substance,  and  here  is 
where  we  find  a  growth  taking  place.  Sachs  supposes*  that 
an  aqueous  solution  derived  from:  the  protoplasm  penetrates 
by  diffusion  between  the  molecules  of  the  cell-wall.  This  is 
not  a  solution  of  protoplasm,  but  probably  some  carbohy- 
drafce  constituent  of  the  protoplasm  which  is  easily  trans- 
formed into  cellulose.  From  this  nutrient  solution  there 
may  be  formed  in  the  spaces  filled  with  water  new  molecules 
of  cellulose,  which  push  aside  and  separate  the  previously 
formed  ones ;  or  the  previously  formed  molecules  may  be 
simply  enlarged  by  the  apposition  of  new  matter. 

According  to  the  tlieory  just  described,  the  formation  of  any  projec- 
tion apon  the  inner  surface  of  the  cell-wall  is  not  bj  the  superficial 
deposition  of  molecules  upon  any  definite  area  of  the  surface  of  the 
wall,  but  by  the  abundant  and  continued  deposition  of  new  molecules 
in  the  wall ;  it  consequently  becomes  thicker  at  the  place  of  deposi- 
tion ;  in  this  thickened  portion  still  more  molecules  are  deposited,  and 
the  thickness  is  further  increased,  and  so  on.  In  the  same  way  projec- 
tions are  formed  upon  the  outside  of  the  wall  by  a  slow  internal  growth. 

88.— Stratifloation  of  the  Wall.  .During  the  increase  of 
the  cell-wall  in  thickness,  an  appearance  of  stratification 
arises  in  it  (Fig.  23).  A  cell-wall  in  which  this  is  strongly 
developed  appears  to  be  made  up  of  concentric  layers,  and 
this  no  doubt  gave  rise  to  the  two  theories  before  men- 

butioDS  to  Phytogenesis/'  1838,  makes  use  of  the  word,  but  it  may  be 
doubted  whether  he  or  Trecul  gave  it  exactly  the  meaning  we  now  do. 
*  '*Lehrbuch,"  fourth  edition,  and  the  English  translation  of  the 
third  edition  ("  Text-Book  of  Botany  ")i  Books  I.  and  III. 


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STRATIFICATION  OF  THE  WALL. 


33 


tioned,  in  which  the  thickening  was  supposed  to  be  due  to 
the  successive  deposition  of  layers,  either  inside  or  outside  of 
the  original  wall.  It  is  now  known  that  stratification  is  due 
to  a  subsequent 
change  in  the 
amount  of  water 
of  organization 
present  in  partic- 
ular parts  of  the 
wall.  When  seen 
with  the  micro- 
scope, those  layers 
which  contain  the 
most  water,   and  "^  '^  "^        ...    ^ 

. ,       ,.,  Fig.  S2.~DiagrammAt!c  ftgare  to  illustrate  NilgolPB  the> 

consequently    tne  ory  or  the  moleciil«r  strocture  of  the  cell-wall ;  m,  m,  m, 

^r^  o^  #>r>11ii1y^oA    t%r^  ^®  crystal  molecules ;  w,  w,  to,  the  layers  of  water  which 

leaSb  CeiiUiOSe,  are  separate  the  molecnles.    The  water  layers  are  represented 

l«oa     a4-«^v«r»1w    "i.^  »»  vcry  thill :  thev  are  frequently  much  thicker  in  propor- 

leSS     Strongly    re-  tlon  \o  the  diameters  of  the  molecules.    (Notk  -It  must 

fractive     than  ^  l>orue  in  mind  t,^  this  figure  is  purely  diagrammatic.) 

those  which  contain  less  water,  or  which,  in  other  words,  are 

denser. 

89.  Striation. — In  many  cases  there  is  also  a  similar  sepa- 
ration into  more  watery  and  less  watery 
layers  at  right  angles  to  those  just 
mentioned.  There  may  be  one  system 
of  such  differentiation,  giving  rise  to  a 
transverse  striation,  which  may  be  an- 
nular (Fig.  24,  c,  d,  e)  or  spiral  (a,  b) ; 
or  there  may  be  two  systems,  and  then 
the  wall  appears  to  be  crossed  by  two- 
sefs  of  spirals  which  run  in  opposite 
directions  around  the  cell. 

Good  examples  of  stratification  may  be  found 
in  the  pitb-cells  of  the  root  of  the  dahlia,  and 
in  the  epidermal  cells  of  most  thick  leaves  ;  and 
of  striation  in  the  bast-cells  of  the  periwinkle 
( Vinea  major),  and  the  wood  of  the  Douglas 
Spruce  {Tmiga  IfougUun).  In  many  cases  it  is  necessary  to  treat  the 
specimens  with  such  acids  {e,g,t  sulphuric  acid)  or  alkalies  {e.g.^  caus- 
tic potash)  as  will  produce  swelling. 


Fig.  98.~TransTerse  sec- 
tion of  a  hA<%  fibre  of  the 
thickened  rout  of  Dahli'i 
vaHabms:  I,  the  cavity; 
JT.  pit  channels  which  pen- 
etrate the  stratification; 
tp^  a  crack  by  which  an  In- 
ner system  of  layers  has 
become  84i>arated.  x  800. 
—After  Sachs. 


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34 


BOTANY. 


40.— Formation  of  Chemically  Difibrent  Layers.    A  stili 
further  differentiation  may  take  place  in  the  thickened  wall, 
by  which  it  comes  to  be  made  up  of  layers  which  differ 
chemically  from  one  another.     This  is  brought  about  by 
the  subsequent  infiltration  of  diverse  mateiials  into  different 
layers.     In  some  eases  the  chemical 
change  is  accompanied  by  so  great  a 
physical  change  that  the  wall  sepa- 
rates readily  into  two  or  more  plates.  * 
Thus,  in  pollen-cells,  the  original  wall 
is  usually  differentiated  into  two  wide- 
ly differing  plates  :  (1)  an  outer  thick 
cuticularized  covering  (the  extine), 
and  (2)  a  thin  inner  membrane  (the 
intine) ;  the  inner  plate  is  shown  by 
tests  to  be  composed  of  pure  cellulose, 
while  the  outer  one  is  generally  so 
filled*  with  other  materials  as  to  hide 
completely  the  cellulose. 

A  similar  differentiation  of  the  wall 
takes  place  in  certain  spores,  and  in 
such  case  the  outer  plate  is  called  the 
exospore  (or  epispore),  and  the  inner 
one  the  endospore  (see  (7,  Dy  E,  Fy 
Fig.  180,  p.  2G2). 

The  outer  walls  of  the  epidermal 
cells  of  many  plants  show  a  remark- 
able separation  into  one  or  more 
plates,  the  outermost  of  which  is 
highly  cuticularized.  In  some  cases, 
as  in  the  cabbage,  for  example,  this 
pjg.  84.— striatton  of  the  outer  plate  may  easily  be  separated  as 

bast  fibres  of  Boya  camoM ;  %  n  •  i        .  i  -n    i 

a  and  b,  crossed  aonular  etri-  a    COntinUOUS  pellicle — the    SO-Called 
atfon  ;  c,  d,  e,  varieties  of  sim-         , .  ■, 

nie  Annular  s'riation.— After  CUtlCle. 

Wood-cells  frequently  show  a  well- 
ed separation  into  plates.  This  may  be  seen  in  Finns 
iris    (Fig.   16,   p.   26),   where  there  are  three  such 

lese  are  the  "  Scbalen  "  of  Sachs,  traDslated  "  Shells  "  in  the  Eng. 
Ition  of  his  "  Lehrbucli." 


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DIFFERENT  LA  TERS  IN  THE  WALL.  35 

plates,  Tiz.,  a  thin  inner  one  (i),  a  thicker  middle  one  («), 
and  a  thin  outer  one  (w).  The  latter  is  apparently  common 
to  the  two  contiguous  cells,  and  is  the  "primary  cell-wall" 
of  some  authors  and  the  "  intercellular  substance"  of  others. 

The  deportment  of  these  lajera  on  the  application  of  reagents  is 
interesting. 

1.  On  treatment  witli  a  solution  of  iodine  the  outer  and  middle  plates 
tarn  yellow. 

2.  On  treatment  with  iodine  and  sulphoric  add  the  outer  and  middle 
plates  turn  yellow  and  the  inner  one  blue. 

8.  On  treatment  with  concentrated  sulphuric  add  the  inner  and 
middle  plates  are  dissolved,  while  the  outer  remains. 

4.  On  boiling  in  nitric  add  with  potassium  chlorate  the  outer  plate 
is  dissolved,  while  the  middle  and  inner  are  not.  By  this  latter  process, 
called  "  Schulze's  Maceration/'  the  cells  may  be  isolated,  but  it  must 
be  borne  in  mind  that  such  isolated  cells  have  lost  by  solution  their 
outer  plate. 

41. — In  some  cases  the  differentiation  is  of  such  a  nature 
that  one  or  more  plates  become  converted  into  mucilage  in 
water.  In  the  dry  state  the  mucilaginous  portions  are  hard 
and  cartilaginous.  Examples  of  the  change  of  the  outer  plates 
into  mucilage  are  common  in  the  FucacesB,  and  of  a  sim- 
ilar change  of  the  inner  ones  in  the  seeds  of  flax  and  quince.* 

42. — ^Inoombtistible  Substanoes,  as  silica  and  lime,  are 
frequently  deposited  between  the  molecules  of  cellulose  in 
the  wall.  Cell-walls  which  are  filled  with  considerable  quan- 
tities of  these  substances,  upon  burning,  leave  ash-skeletons, 
which  retain  the  fonn  and  markings  of  the  cell.  The  Di- 
atoms furnish  excellent  examples  of  highly  silicified  walls. 
Silica  is  abundant  also  in  the  epidermal  cells  of  grasses 
and  scouring-rushes  {BquisetacecB). 

Lime-skeletons  may  be  obtained  by  the  combustion  of  thin  slices  of 
the  tissues  of  many  plants  upon  ^lass  or  platinum-foil.  The  ves^ls  of 
CucurbUa  Pepo  yield  (according  to  Sachs)  beautiful  skeletons  under  this 
treatment. 

Silica-skeletons  may  be  obtained  by  first  soaking:  the  tissue  in  nitric 
or  hydrochloric  add  and  then  burning,  or  by  burning  (upon  platinum- 
foil)  in  a  drop  of  sulphuric  add. 

*  Sachs  attempts  to  reduce  the  chemical  differentiations  of  the  cell- 
wall  to  three  categories,  viz.,  Cuticularizing,  Lignification,  and  Conver 
sion  into  Mucilapre. 


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CHAPTER  IV. 

THE  FORMATION  OF  NEW   CELLS. 

43. — There  are  two  essentially  different  ways  in  which 
cells  originate,  viz.,  (1)  by  the  division  of  a  protoplasmic 
body  into  two  or  more  bodies ;  (2)  by  the  union  of  two  or 
more  protoplasmic  bodies. 

44. — Cell-Formation  by  DiviBion.  The  simplest  cases  of 
the  formation  of  cells  by  division  occur  in  the  Myxomy- 
cetes.  The  swarm-spores  («,  Fig  25),  which  are  naked  masses 
of  freely  moving  protoplasm,  first  lose  their  nuclei  (as  in  b), 
and  then  become  constricted  (as  at  c) ;  the  constriction 
deepens,  and  finally  divides  each  mass 
into  two  parts  {d,  e,f). 

46. — This  may  be  taken  as  the 
type  of  cell-formation  by  division, 
and  in  no  case  does  it  differ  in  any 
essential  particular  from  this.  Most 
plant-cells,  however,  are  surrounded 
by  a  wall,  whose  deportment  during 
division  enables  us  to  distinguish  two 
more  or  less  well-marked  modes  of 
cell-formation  by  division.  On  the 
one  hand  the  wall  divides  as  well  as  the  protoplasm  (Fission), 
while  on  the  other  the  wall  takes  no  part  in  the  division,  and 
it  is  only  the  protoplasm  which  divides  (Internal  Cell-For- 
mation), 

46. — The  best  examples  of  Fission  are  to  be  seen  in  those 
unicellular  plants  which  have  been  frequently  described 
under  the  name  of  Protococcus,*  "The  cell  elongates  and 
the  protoplasm  divides  into  two  across  its  longer  axis,  and 

♦  See  "  Huxley  and  Martin's  Biology."  Chap.  II. 


S 

Fig.  26.— Division  of  the 
8wann-«poreeof  Chondrioder- 
ma  diforme  :  a,  with  nucleus ; 
&,  nucleos  dissolved;  c.  two 
nuclei,  division  of  protopiMm 
begun ;  d,  0,/,  complftion  of 
the  process.—Af  ter  vt  Bary. 


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CELL  FORMATION  BY  DIVISION.  37 

then  a  partition  is  formed  subdividing  the  sac ;  the  halves 
either  separate  at  once  and  each  rounds  itself  off  and  becomes 
an  independent  cell,  or  one  or  both  halves  again  divide  in  a 
similar  way  before  they  separate,  and  so  three  or  four  new 
cells  are  produced." 

47. — In  many  of  the  filamentous  Thallophytes  a  similar  fis- 
sion takes  place,  but  in  these  the  cells  do  not  immediately  sepa- 
rate from  one  another  after  their  formation.  Thus,  in  Nostoc 
and  Oscillatoria  (Fig.  26)  the  cells  do  not  differ  in  any  essen- 
tial way  as  to  their  formation  from  tho'se  which  constitute 
Protococcus,  In  Nostoc  after  fission  the  cells  round  them- 
selves up  and  retain  but  a  slight  and  easily  separable  connec- 
tion with  one  another ;  in 
Oscillatoria,    on   the  con-        ^^^  ^ 

trary,  the  cells  remain  cy- 
lindrical and  are  less  read- 
ily separable. 

48. — In  Spirogyra  (Fig.      Fig.  ae.— -4,  Ulament  of  Nostoc  ;  B,  filament 

36,  p.  45)  new  cells  form  of  ^^^^.  x  m-After  Prenti. 
by  the  partition  of  old  ones.  The  protoplasmic  sac  infolds  all 
around  the  middle  of  the  old  cell  which  is  cylindrioal  in 
shape ;  into  the  circular  channel  thus  formed  the  cell-wall 
extends,  appearing  at  first  as  a  narrow  projection  from  the 
original  waJl,  but  becoming  broader  and  broader,  until  it 
forms  a  complete  partition.  When  the  new  cells  have 
elongated  by  intercalary  growth  the  process  of  fission  may  be 
repeated,  and  so  on.* 

49. — The  cells  which  make  up  the  greater  part  of  the 
tissues  of  the  higher  plants  are  formed  by  fission.  In  the 
apical  cells  of  Equisetum  we  find  a  curious  regularity  in  the 

•  The  student  is  referred  to  Sachs' "  Text-Book,"  pp.  17-18,  for  a  further 
description  of  this  process  in  Spirogyra;  and  to  Von  Mohl's  "  Anatomj 
and  Physiology  of  the  Vegetable  Cell,"  pp.  50-51,  for  a  description  of  the 
similar  fission  of  Cktdophora  ghmerata  {Conferva glomerata,  Linn.).  Von 
Mohl's  description,  which  was  the  result  of  the  first  accurate  investiga- 
tion of  cell-formation,  is  erroneous  in  this— that  he  supposes  that  durin^r 
the  process,  to  quote  his  wortls,  "  a  cellulose  membrane  is  deposited  all 
over  the  outside  of  the  primordial  utricle  "  of  the  whole  cell,  and  th  it 
it  is  a  portion  of  this  new  membrane  which  forms  the  partition. 


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38  BOTANY. 

division.  The  triangular  apical  cells  of  the  growing  stems 
divide  repeatedly  in  the  manner  shown  in  the  diagram  (Fig. 
27).     Here  the  cell  ABC,  bounded  by  the  heavy  black 


HI 


Pig.  27.— DUfcntm  to  show  mode  of  ilBsion  of  the  apical  cell,  as  eeen  from  above. 
/.  the  cell  A^B,  C,  divided  bv  the  paititiun  1 :  //,  the  tame  cell  with  a  second  par- 
tition, 2 ;  III,  the  same  ceU  with  a  ttiird  partition,  & 

lines,  is  first  divided  into  two  unequal  portions  by  the  parti- 
tion 1, 1. ;  next  the  larger  portion  of  the  divided  cell  is  again 

divided  by  the  partition  2,  II.  ; 
later,  a  third  partition  (3,  III.) 
is  formed,  and  so  on.  It  is  no- 
ticeable that  in  this  case  the 
partition  always  forms  parallel 
to  the  oldest  wall  of  the  divid- 
ing cell.  By  continued  gi'owth 
the  apical  cell  retains,  despite 
its  repeated  divisions,  its  origi- 
nal dimensions. 

60. — The  growing  cells  of  the 
stem  of  the  English  bean  ( Vicia 
faha)  furnish  a  good  illustration 
of  fission  in  the  highest  plants. 
In  this  case,  and  in  many 
other,  if  not  all,  Dicotyledons, 
the  division  takec  place  directly 
of^JfeWr^nV'^^^^^  *^^^"g*^   ^^^    centrally    placed 

the  cells  a,  a,  the  process  is  In  its  nuclcUS  (a.  Fig.  28).  After  the 
earlier  stage;  at  6  it  18  completed,    x^  ^••ft  n         i. 

aoa— After  pranu.  formation  of  the  new  wall  each 

new  nucleus  moves  away  and  occupies  a  position  on  the 
opposite  side  of  the  cell  from  where  it  was  formed  (as  at  h 
and  k). 


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CELL  FORMATION  BY  DIVISION.  39 

(a)  The  foregoing  must  saffice  as  examples  of  Fission.  It  occara 
throughout  the  Tegetable  kingdom  and  maj  be  regarded  as  the  great 
means  bj  which  cells  are  multiplied. 

(b)  The  cambium  zone  of  Dicotyledons  may  be  examined  very  profit- 
ably by  the  student.  If  a  thin  cruss-section  of  a  stem  be  soaked  for  a 
short  Ume  in  a  carmine  solution,  the  protoplasm  of  the  cambium  zone 
will  be  colored,  and  the  newly  formed  partitions  made  thus  more 
distinct. 

(e)  The  ends  of  young  roots  are  valuable  for  study  ;  longitudinal  sec- 
tions of  these  should  be  made,  and  treated  as  in  the  previous  case. 

(d)  Another  interesting  study  of  a  special  kind  of  fission  may  be 
taken  up  in  an  examination  of  the  development  of  stomata.   (See  p.  99.) 

(e)  That  slight  variation  of  fission,  whicli  has  sometimes  been  called 
budding,  may  be  very  easily  studied  in  the  Teast  Plant  (Saccharamycfs 
cerenna).*  The  conidia,  stylospores,  and  basidiospores  of  many  fungi, 
which  are  more  difficult  to  study,  are 

very  instructive  examples  of  this  va- 
riety of  fission.  Conidia  may  be 
studied  in  Cystopus;  stylospores  in 
the  Red  Rust  of  the  grasses  (the  so. 
called  uredo-stage  of  Puccinia  gram- 
ini$) ;  and  basidiospores  in  young 
toadstools  {Agaricus), 

e  1        T'U  r»   V^«  n4.    T>l«^4-/^e^^         ^l&-  29— The  Teast  Plant,  8acchar(h 
51. —  Ine    least    riant  (ibaC'    mycet  cerevisia,     a,  roundKl  c^lli 

charomyces  ^er«i;t«>)  furnishes  Jj:S?4r"?.^?ri';T~"«f'o';S 
a  very  simple  example  of  Inter-  f^]^,^  2xS,I.^'C.  t'X^Tt 
nal    CeU- Formation.      Under  ST^/J^  p^'n^Sl^^i"  It  VTr 

certain  conditions  the  cells  Srrow    daaghter-celli :  a  and  b  X  400,  c  and  a 
■    .  .         .  1  ^     -        X  760.— Alter  Reei»a. 

to    a    larger  size  than  usaal ; 

their  protoplasmic  contents  divide  into,  generally,  four 
parts  (two  to  four,  according  to  Sachs),  each  of  which 
rounds  itself  up  and  secretes  a  wall  of  cellulose  on  its  sur- 
face (Fig.  29,  c,  d).  Cells  which  divide  in  this  way  are  called 
mother-cells,  and  the  new  ones  formed  from  them  daughter- 
cells.  In  the  Yeast  Plant  after  the  daughter-cells  are  fully 
formed  the  dead  wall  of  the  mother-cell  breaks  up. 

52. — The  terminal  cells  of  Achlya  (one  of  the  Sapro- 
legniacecB)  form  large  numbers  of  daughter-cells  by  the 
breaking  up  of  the  protoplasm,  as  shown  in  Fig.  30,  A. 
When  the  daughter-cells  escape  they  become  rounded  {B,a)\ 

*  See  "  Huxley  and  Martin's  Biology,"  Chap.  L 


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40  BOTANr. 

after  a  little  while  they  break  their  cellulose  walls  and  be- 
come naked  motile  cells  (zoospores)  {By  e). 

63. — As  the  formation  of  the  spores  of  Bryophytes  and 
Pteridophytes,  and  of  the  pollen- 
cells  in  Phanerogams,  is  essen- 
tially alike,  we  may  take  as  an 
example  the  formation  of  the 
spores  of  a  fern  (Fig.  31).  The 
nucleus  of  the  mother-cell  first 
disappears,  and  two  new  nuclei 
arise  (L,  11. ,  III.) ;  between  the 
nuclei  may  be  seen  a  line  indicat- 
ing the  separation  of  the  proto- 
plasmic mass  into  two  halves. 
Kext  the  nucleus  in  each  half  is 
absorbed  and  replaced  by  two, 
between  which  a  separation  of  the 
protoplasm  soon  takes  place  (IV., 
v.),  thus  dividing  the  cell  into 
four  equal  parts,  which  are  at 
first  angular,  but  soon  rounded 
and  enclosed  in  cell- walls  (VI., 
VII.,  VIIL,  IX.). 

64. — In  the  foregoing  cases  the 
whole  of  tho  protoplasm  of  the 
mother-cell  is  used  in  the  forma- 
tion of  the  daughter-cells.    There 
are  some  cases,  however,  in  which 
only  a  part  of  the  protoplasm  is 
.  used.     One  of  the  beat  known  is 
;  in   the  formation  of  ascospores. 
;  Here  the  mother-cells  are  usually 
\  large  and  elongated  (Fig.  32,  a, 
»  J,  c)  ;  the  nucleus  disappears,  and 
-  the  protoplasm  condenses  in  tho 
upper  portion  of  the  mother-cell ; 
species  figured)  nuclei  appear,  and 
the  protoplasm  gather  to  form  the 
I  (Fig.  32)  the  protoplasm  condenses 


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CELL  FORMATION  BY  DIVISION, 


41 


about  certain  points  without  the  previous  formation  of  nu- 
clei (rf,  e).  In  either  ease  firm  walls  are  secreted  about  the 
spores  while  yet  in  the  mother-cell  and  surrounded  by  the 
unused  part  of  its  protoplasm. 

66. — The  most  striking  example  of  this  variety  of  internal 
cell-formation  is  to  be  found  in  the  development  of  the 
endosperm  cells  in  the  embryo  sac  of  Phanerogams.  The 
protoplasm  which  occupies  the  cavity  of  the  embryo  sac  pre- 
sents here  and  there  points  of  condensation  or  concentration, 
which  in  a  little  time  become  as  many  nuclei  (Fig.  33,  -4,  w,  w), 
each  containing  a  nucleolus.  These  nuclei  are  the  first  in- 
dications of  the  form- 
ing cells.  Protoplasm 
gathers  about  the  nu- 
clei and  forms  globu- 
lar or  ovoid  masses 
{A,  a,  a),  which,  after 
acquiring  a  certain 
size,  secrete  a  thin 
wall  of  cellulose  on 
their  surfaces  (.1,  c,  c\ 
d).  By  the  continued 
production  of  new 
cells  within  the  em- 
bryo sac,  in  this  way, 
they  finally  become 
crowded  together  into 
a  loose  tissue,  in  whose  intercellular  spaces  portions  of  the 
nnconsumed  protoplasm  yet  remain  (B).  After  their  forma- 
tion the  cells  go  on  increasing  in  numbers  by  simple  fission 
{B,  a,  b).* 

(a)  Saclia  f  makes  a  strong  distinction  between  the  cases  of  internal 
cell-formation  where,  on  tlie  one  hand,  a  part  only,  and,  on  the  other, 

*  The  student  is  here  referred  to  the  account  of  the  formation  of 
endosperm  cells  in  Duchartre's  '*  Elements  de  Botanique/'  pp.  37-39 ; 
and  also  to  Hofmeister's  "  Lehre  von  der  Pflanzenzelle/'  Section  17. 

f  '*  Lehrbiicb,"  4te  auf.  In  the  English  translation  of  the  third  edi- 
tion all  cases  of  fission  are  included  under  the  Formation  of  Cells  by 
Division  of  the  Mother-Cell. 


Fig.  81.— Development  of  the  spores  of  Aspidium 
JUiiMna*.  /,  the  epore-mother-cell,  witli  nncleus ; 
//,  the  DQclens  ah»orbed ;  ///.  two  nuclei,  and  the 
division  of  the  protoplasm  into  two  portions ;  IV, 
four  nuclei ;  V.  division  of  the  protoplasm  into  four 
portions ;  F/,  VII,  VIII,  rounding  up  of  the  young 
spores  during  the  secretion  of  their  cell-walls ;  IXl 
mature  epore,  with  thick  and  sculptured  ezospore 
(eplspore).    X  660.— After  Sachs. 


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42  BOTANY. 

the  whole  of  tbe  protoplasm  of  the  mother-cell  is  ased.    The  former  he 
A  h  caWb  Free  Cell  Formation,taid 

the  latter  Formation  of  Cells 
by  DivUfion  of  the  Mother- 
Cell,  and  includes  also  under 
the  last  a  part  of  what  has 
been  described  above  under 
the  head  of  Fission.  It  is 
doubtful,  however,  whether 
such  a  division  is  of  much 
importance. 

9)  What  has  been  called 
the  Rejuvenescence  of  a  cell 
maj  be  mentioned  here.  The 
phenomena  connected  with  it 
are  as  follows:  The  proto- 
plasm of  a  cell  contracts,  ex- 
pels  a  portion  of  the  water 
contained  in  it,  and  escapes 
through  a  slit  in  its  wall  ;  the 
naked  mass  becomes  for  a 
time  a  free-swimming  zoos- 
pore, afler  which  it  secretes  a 
wall  of  cellulose,  and  begins 
to  grow  and  form  new  cells 
by  fission.  Cases  of  this  kind 
occur  in  (Edogonium,  Stigeo- 
clonlum,  and  many  other 
aquatic  Thallophytes.  An 
interesting  fact,  but  proba- 
bly of  no  great  significance, 
is  that  the  axis  of  growth  of 
the  new  cell  is  perpendicular 
to  that  of  the  old  one. 

While  there  can  be  no  doubt 
that    this   process,  as  Sachs 

Pig. 82.-i»<«tea(»nw««te.il, vertical iection  insists.*  "must  be  regarded 
of  the  whole  plant;  A,  hTineniain-i.«..  the  layer  morphologically  as  the  for- 
iiiwhich  the  spore-forming sace  lie, 5. the tiiiene  ^„as«„  ^#  „  „^„  «^ii  »»  ♦i.«,^ 
of  the  fangui^veloplng  the  hymenlum  at  its  mation  of  a  new  cell,  there 
edge  ^  in  a  cup  like  manner ;  at  the  hatte  of  the  can  be  little  question  tliat  it 
tisaue  .9  fine  threads  arise,  which  grow  between  .  .  ,  i  ?  j  ^  .i  r 
the  particles  of  earth.    J5?,  a  small  portion  of  the  is  closely  related  to  the  forma- 

hymonlam;*A,  subhymenial  layer  of  densely  in-  tion    of   zoospores   described 
terwoven  filaments  (hyphie) ;  a  to/,  spore-form-     ,  ,       .^'^      _,,         .._ 

ing  sacs  (a«ji),  with  thin  filaments  q^nraphyses)  above  (p.  40).       Ine    differ- 
between  them.    Ax20,Bx  650.-Af ter  Sachs.  ^^^  jg  ^^j^^  Jq  ^^^  formation 

of  ordinary  zoospores  the  mother-cell  breaks  up    into    more    than 

•  See  "Text-Book,"  p.  9,  and  also  "Lehrbuch,"  4te  Auf.,  where  the 
author  sets  apart  this  as  an  entirely  different  mode  of  cell-formation. 


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CELL  FORMATION  BY  DIVISION.  43 

one  mass  before  escaping ;  while  in  Rejavenescenoe  the  whole  proto* 
plasm  escapes  without  dividing.    Rejavenescence  maj  then  be  regarded 


Fi^.  88b~Bnd08perm-ceU8  of  Pkaseolus  muUkfiorus.  A^  the  production  of  new  cells 
in  the  protoplasm  of  the  embryo  sac ;  n,n^  n,  nuclei ;  a,  a,  a,  masees  of  protoplasm 
gatherer!  around  the  nuclei ;  6,  young  cell,  but  without  a  wall  of  cellulose  ;  c^  young 
cell  with  a  wall ;  <^,  d.  young  cells  with  walls  and  yacuoles.  B^  two  cells  of  the 
endosperm  in  a  much  later  stase ;  the  cells  have  fused  their  walls  so  as  to  form  a 
false  tissne  ;  in  the  angles  between  the  cells  are  Intercellular  spaces  filled  with  some 
of  the  protoplasm  of  the  mother-cell  (embryo  sac) :  the  cell  a  is  in  process  of  fission, 
the  two  nuclei  n.  n,  are  near  together,  as  if  formed  by  the  fi^ssion  or  the  original  nu- 
cleus ;  «,  line  Indicating  the  boundaries  of  the  two  ma^ee^  of  protoplasm ;  the  eel) 
&  is  fully  divided,  and  the  two  parts  are  separated  by  the  wall  d.  x  670.— After 
Dippel. 

as  a  case  of  internal  cell-formation  in  which  there  is  no  diviidon  of  the 
protoplasm. 


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44 


BOTANY. 


66.— Cell-Formation  by  Union.  The  simplest  example 
of  cell-formation  by  the  union  of  cells  is  found  in  the  Myx- 
omycetes.  The  swarm-spores  which  have  been  described  as 
multiplying  by  division  (see  p.  36)  somewhat  later  begin 
the  opposite  process  of  uniting.  Two  or 
moi-e  approach  one  another  and  gradually 
coalesce  into  a  homogeneous  protoplasmic 
mass  (Fig.  34).  During  the  process  the 
nuclei  disaj)pear.  The  union,  at  first 
sight,  appears  to  be  no  more  than  a  mere 
running  together  of  similar  drops;  but  the 
disappearance  of  the  nuclei  shows  that. 
Union  (the  however  much  it  may  resemble  such  a 
oTSSlSr JSf-iJSJi^^Sf  purely  physical  process,  the  coalescing  of 
^r*PeS?TSw^^  the  swarm-spores  of  the  Myxomycetes  is 
something  more.  It  is  possible  that  there 
is  also  some  very  slight  difference  between 
the  uniting  cells. 

57. — In  Cosmarium,  a  genus  of  the 
Desmidiaceae,  the  uniting  cells  have  well- 
develoi>ed  walls,  and  as  a  consequence  the 
process  is  somewhat  different  from  what  it  is  in  the  Myxo- 
mycetes. The  cells,  which  in  this  genus  are  two-lobed  (Fig. 
35),  approach  each  other ;  each  sends  out  from  its  centre  a 
protuberance  which  meets  the  other  (d) ;  the  thin  walls 
separating  the  cavities  of  the  protuberances  are  absorbed,  and 


Fig.  S4.- 
so-ciQled 


liberiianum  6t  D« 
Btry) ;  a,  two  twmnn- 
BporifB;  h,  the  name 
fused  into  one ;  c,  three 
Bwaim-sporet ;  </,  the 
same  a  few  momenta 
afterward,  the  two  up- 
per ones  f  osed  into  on**. 
X  asa— After  Cienkow- 
8kL 


Fig.  as.— Ctomiarivm  MerugMnU,  a,  b,  e.  different  views  of  the  matnre  plants  ; 
<f,  tf,  and/,  three  puges  in  the  formation  of  the  new  cell ;  g^  A,  and  i«  the  aiter-devel- 
opment  of  the  new  cell,     x  475.— After  (Erstcd. 

the  united  protoplasmic  masses  form  a  round  ball  (e)y  which 
soon  becomes  enclosed  in  its  own  proper  coatings  (/). 

68. — The  union  of  cells  in  Spirogyra  is  much  like  that  of 
Cosmarium.     Here  the  cells  are  united  into  long  filaments. 


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CELL  FORMATION  BY  UNION,  45 

instead  of  being  independent,  as  in  the  previous  case.     At 
the  time  of  union  the  filaments  approach  one  another  and  lie 
nearly  parallel ;  protuberances  grow  out  from  the  contiguous 
cells  (Fig.  36,  a,  b) ;  their  extremities  meet,  and  the  walls  are 
absorbed,  making  a  channel  of  communication  from  cell  to 
cell  (Fig.  3G).     Through  this  channel  the  protoplasm  from 
one  of  the  cells  passes  into  the  cav- 
ity of  the  other ;  the  two  masses 
unite  and  form  a  round  or  ovoid 
cell,  which  soon  secretes  a  wall  of 
cellulose  (Fig.  37,  A,  b,  and  B,  c). 

The  particular  kind  of  union  in  wbicli 
the  two  cells  are  of  equal  or  nearly 
equal  size,  and  illustrated  above  by  Cos- 
marium  and  Spirogyra,  lias  received  the 
name  of  Conjugation.  It  is  character- 
istic  of  one  group  of  the  ThaUophytes, 
viz.,  the  ZygosporecB. 

59. — In  Vaucheria,  a  fresh-wa- 
ter Thallophyte,  we  have  an  ex- 
ample of  the  union  of  cells  of  very 
different  sizes.  The  larger  cells 
(called  oospheres)  are  in  lateral 
protuberances  of  the  large  single 
cell  which  composes  the  whole 
plant  (Fig.  38,  A,  and  B,  og).  The 
protoplasm  in  these  is  of  a  spheri- 
cal form,  and  is  much  denser  than 
in  the  main  cell,  from  which  it  is 
separated  in  each  case  by  a  trans- 
verse wall  (shown  in  F).  The  FU?.  86.—Twomament8  of  55pfre>. 
„  11/11  .        'T\     ^yra  tow^ato  about  to  con  jngar« ; 

smaller    cells    (the    sperm  at OZOtas)     ataand  &are  seen  the  protut>er- 

are  produced  by  the  internal  cell-  IpproacWng  each*ottef.°**x*660.— 
division  of  the  protoplasm  of  simi-  -^'^^'S***^***- 
lar  protuberances  (the  antheridia.  A,  and  B,  a).  They  are 
very  small  as  compared  with  the  oospheres,  and  are  naked 
masses  of  protoplasm  provided  with  two  cilia,  by  means  of 
which  they  are  locomotive  (Z>).  Upon  escaping  into  the 
water  by  the  bursting  of  the  old  wall,  they  swim  about,  and 


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46 


BOTANY. 


some  of  them  finally  reach  the  ooephere  (through  a  rupture 
in  its  wall),  and  unite  with  its  protoplasm  {Ey  F).  The  re- 
sult is  at  once  seen  in  its  greater  sliarpness  of  outline,  and 
in  the  development  of  a  cell-wall,  whereby  the  oosphere  is 
transformed  into  an  oospore. 

60.  —Essentially  the  same  kind  of  union  takes  place  in  the 
nearly  related  parasitic  group,  the  PeronosporecB.  The  only 
difference  is  that  here  the  antheridium  (Fig.  39,  n)  comes  in 
direct  contact  with  the  oosphere  (p)  by  means  of  a  project- 
ing tube,  and  through  this  tube  the  protoplasm  masses  of 

the  two  cells  unite. 
The  absence  of  mo- 
tile spermatozoids 
in  this  case  is  profcK 
ably  connected  with 
the  fact  that  these 
plants  live  in  the 
tissues  of  land 
plants,  instead  of 
being  immersed  in 
water. 

61.— The  first  cell 
of  the  embryo  in 
mosses  is  the  result 
of  a  union  of  cells 
differing  greatly  in 
size.  The  larger 
cell  lies  at  the  bot- 
tom of  a  flask-shaped  organ,  the  archegonium  (Fig.  40,  B, 
h) ;  the  smaller,  the  spermatozoids,  are  developed  by  the  in- 
ternal cell-division  of  another  organ,  the  antheridium  (Fig. 
41,-4).  The  spermatozoids,  as. in  Vaucheria,  are  naked 
masses  of  protoplasm,  provided  with  cilia,  by  means  of 
which  they  swim  freely  through  the  water  (Fig.  41,  B). 
Upon  coming  in  contact  with  the  large  cell  in  the  archego- 
nium they  fuse  with  it,  and  thus  make  a  new  cell. 

62. — In  Phanerogams  the  first  cell  of  the  embryo  is  the  re- 
sult of  the  union  of  the  protoplasm  contained  in  the  pollen- 
cell  with  that  in  the  embryo  sac.     Here  again  the  two 


completed:  in  B  the  protoplafmic  mattes  have  se- 
creted thick  walls,  thus  completing  the  formation  of 
the  new  cells.    X  560.— Aft«r  Sachs. 


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CELL  FORMATION  BY  UNION. 


47 


masses  come  in  direct  contact  by  means  of  a  tube  (the  pol- 
len tube)  which  touches  with  its  lower  extremity  the  embry- 
onic vesicle. 

(a)  The  foregoing  classification  of  tbe  modes  of  cellformation  differs 
in  many  respects  from  tliat  given  by  Sachs  in  the  fourth  edition  of  his 
•  •  Leiirbuch."    His  classification  as  there  given  is  as  follows : 


Fig.  Z^—Vancheria  $uiUU.  A,  orUrtn  of  the  lateral  branchet.  oq  {oogonium\  and 
k  ((nUAMdium),  from  the  fllament ;  B,  the  branch  a  (the  same  as  A  In  2)  has  \tA  ter- 
minal portion  cat  off  by  a  partition  ;  in  0(f  the  protoplasm  is  becoming  greatly  con- 
denaed ;  C.  the  same  a»  oa  of  B.  bat  farther  advanced  (now  called  an  ootphert)  and 
tlie  wall  bant  open,  permirting  the  escape  of  a  drop  of  macilage  d  ;  2>,  small  motile 
cells  (spermatozolds)  ftom  the  terminal  cell  of  a  in  B ;  E,  the  same  as  C,  bat  a  little 
later— the  spermatozolds  are  entering  thronsh  the  opening ;  F,  a,  the  branch  a  in  B, 
with  the  terminal  cell  now  empty,  on  account  of  the  escape  of  the  spermatoxoids  ; 
osp,  the  same  as  E,  and  og  in  B,  after  anion  with  the  ppermatozoids— the  protoplasm 
is  rarronnded  by  a  tbick  cell-wall  and  it  is  now  called  an  oospore.    X  100.— After 


A.— Formation  op  Reproductivb  Cells. 

1.  Rejavenescence. 

2.  Conjagation. 

3.  Free  Cell -Formation. 

4.  Formation  of  Reproductive  Cells  by  Division,  which  is  made  to 
mclnde  the  formation  of  pollen,  the  spores  of  mosses  and  ferns,  and 
the  conidia,  stylospores,  and  basidiospores  of  many  fungi. 


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48 


BOTANY. 


Fig.  9i.—Pir<nu)tpora  alHnearum.  A ,  young  ooi^ninm  o,  and  yoong  autheridium 
n,  in  contact  with  it ;  B^  the  antheridiam  n  beginning  to  pierce  theooironiam  o,  whose 
protoplasm  is  becoming  condensed ;  C,  the  line  tube  of  the  antheridlnm  n  has  pt-n- 
etrated  the  oogonium  o,  and  come  in  contact  with  its  condensed  and  rounded  proto- 
plasm, the  ooirpbere.    x  3S0.— After  De  Bary. 


Fio.  40. 


Fio.  41. 


Fig.  40.— Female  reproductive  organs  of  a  moss,  Funaria  hygromelrica.  A^  apex 
of  the  stem ;  a,  srchegonia ;  b,  leaves :  B^  archegonium ;  o,  base :  A,  neck ;  m, 
mouth :  C,  moath  of  fertilized  archegonium.    A  x  100,  B  X  &50.— After  Sachs. 

Fig.  41.— Male  reproductive  organs  of  the  same  moss.  A^  aniherldium  open  and 
permitting  the  ppermatozoids  a  to  escape ;  B,  b.  speim-cell  of  anothfr  moss  {Polytri' 
chum),  with  contained  epermatozoid :  c,  rpermfltuzuid  free,  witli  two  cilia  at  the 
pointed  extremity.    A  X  850,  B  x  800.— After  Suchs. 


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CELL  FORMATION  BT  UNION,  49 

B.— Formation  op  Vegetative  Cells. 

1.  By  tlie  progressive  formation  of  a  division  wall. 

2.  Bj  the  simultaneous  formation  of  a  division  wall. 

Tbe  main  objection  to  this  classification  is  that  its  principal  divis* 
ions  are  based  upon  physiological  distinctions  alone. 

Q>)  Duchartre,  in  bis  **  Elements  de  Botanique/'  makes  a  very  sim- 
ple classification,  as  follows  : 

A.— Free  Cell-Formation. 

1.  Intracellular. 

2.  Extracellular  [Rejuvenescence]. 

B. — Formati6n  op  Cells  by  Division. 

1.  Progressive  division. 

2.  Simultaneous  division. 


Note  on  Paragraph  66.  '*  From  the  researches  of  Schmitz  on  the 
Myzomycetes  (Sitzber.  d.  nieder-rhein.  Qes.  in  Bonn,  1879),  it  appears 
that  the  nuclei  of  the  cells  which  coalesce  to  form  the  plasmodium  do 
not  fuse,  but  remain  distinct :  this  case  of  coalescence  of  cells  cannot, 
therefore,  be  any  long^er  regarded  as  an  instance  of  cell-formation  by 
conjugation."  {8.  K  Vines  in  App,  to  Sachs*  Text-Book  of  Botany, 
Second  English  Edition,  p,  945.) 


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CHAPTER  V, 

PBODUCTS  OF  THE  CELL. 

§  L  Chlorophyll. 

68. — In  many  plant-cells  definite  portions  of  the  proto- 
plasm have  a  green  color,  on  account  of  the  presence  of  a 
peculiar  chemical  compound  known  as  Chlorophyll.*  The 
protoplasmic  bodies  thus  colored  are  called  chlorophyll-bod- 
ies, or  chlorophyll  granules,  while  to  the  coloring-matter 
alone,  distributed  in  small  quantity  through  their  substance, 
the  name  chlorophyll  is  properly  applied. 

64. — The  chlorophyll-bodies  are  of  various  shapes  and 
sizes.  In  some  of  the  lower  plants  nearly  the  whole  of  the 
protoplasm  is  colored,  giving  the  whole  cell  a  uniform  green 
color.  In  others  there  are  stellate  or  band-like  chlorophyll- 
bodies  distinct  from  the  mass  of  the  protoplasm  of  the  cell ; 
the  band-like  bodies  are  straight,  or  more  commonly  spiral 
(Fig.  42).  In  the  great  majority  of  cases,  however,  the 
chlorophyll-bodies  are  simple  rounded  granules  of  such  mi- 
nute size  that  many  are  contained  in  a  single  cell  (Fig.  43). 
The  chlorophyll  may  be  dissolved  out  of  its  protoplasmic 
vehicles,  leaving  the  latter  with  the  appearance  and  chemi- 
cal properties  of  ordinary  protoplasm. 

65. — The  exact  chemical  composition  of  chlorophyll  is  not 
known.  As  obtained  by  the  evaporation  of  its  alcoholic 
solution  it  is  a  green  resin-like  powder,  insoluble  in  water. 
From  the  partial  analyses  of  Kromayer  it  is  probable  that  it 
contains  carbon,  hydrogen,  nitrogen,  and  oxygen,  and  there 
are  good  reasons  for  believing  that  iron  is  also  one  of  its  con- 
stituents. 

*  Chlorophyll  is  also  found  to  a  limited  extent  in  the  animal  king- 
dom. 


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CHLOROPHTLL.  51 

ee. — ^With  few  exceptions  chlorophyll  is  not  found  in  cells 
-which  are  not  exposed  to  the  action  of  light.*    When  ordi- 
nary green  plants  are  removed  for  some  time  fi'om  the  light, 
the  chlorophyll  disappears  from  the  chlorophyll-bodies,  and 
leaves  them  colorless.     The  same  decoloration  also  takes 
place  when  a  plant  is  deprived  of 
iron  as  one  of  the  constituents  of 
its   food.      The  disappearance  of 
chlorophyll  takes  place  normally  in 
higher  plants  when  the  cells  lose 
their  activity.     In  the  case  of  leaf- 
cells,  upon  the  approach  of  autumn 
the  chlorophyll  appears  to  be  re- 
moved to  other    portions  of    the 
plant. 

(a)  The  cells  of  many  PalmeUaeeoB, 
and  many  zoospores— ^.5'.,  of  (Edogo- 
nium  and  Vaiteh&ria — famish  good  ex. 
amples  of  the  coloration  of  nearly  the 
whole  hody  of  protoplasm. 

In  Zygnema  the  cblorophyll-hodies  are 
stellate,  and  in  Spirogyra,  spiral. 

In  Vaueheria  there  are  maltitndes  of 
ronndish  or  slightly  angular  clilorophyll- 
bodies,  which  line  the  interior  of  the 
large  cells.  The  chlorophyll  in  tlie 
leaves  of  many  mosses  may  be  easily 
studied,  even  without  making^  sections ; 
in  them  the  chlorophyll -bodies  are  round- 
ish in  outline.  In  the  higher  plants  thin 
cross^ections  of  the  leaves  afford  the 

best  means  for  the  examination  of  their     pig.  4s.-.Two  fllaments  of  Sjd- 

chlorophyll-bodies,  which  are  uniformly  fWra  lor^ata ;  the  chlorophyll 

,*^  •;  J  J       ^,.  i«  in  eplral  bands;  in  the  centre 

of  a  simple  rounded  outlme.  of  each  cell  is  a  nacleus,  with 

(P)  Chlorophyll  is  soluble  in  alcohol,  ^^^^AftSSTchS.'  P"*^^*"™- 
ether,  chloroform,  benzine,  essential  and 
fatty  oils,  hydrochloric  and  sulphuric  acids,  and  these  may  be  used 

*  The  cotyledons  of  many  Conifer®  acquire  a  green  color  even  in 
total  darkness.  The  embryo  of  Phoradendron  is  green  in  the  unopened 
seed,  and  in  certain  seeds  with  thick  coats,  which  are  impervious  to 
light  (0.  ^.,  in  some  Oucurbitacea),  a  chlorophyll -bearing  layer  of  cells 
surrounds  the  embryo 


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52 


BOTANY. 


for  obtaining  solutiooa    In  transmitted  light  tbe  alcoholic  eolation  is 
firreen,  but  when  viewed  by  reflected  light  it  appears  to  he  red. 

When  an  alcoliolic  solution  of  chlorophyll  is  boiled  for  a  few  minutes 
with  an  alcoholic  solution  of  potash.and  then  neutralized  with  hydrochlo- 
ric acid  two  substances  are  ob- 


\ 


talned  :  the  one  as  a  yellow  pre- 
cipitate, named  PliyUoxaritJune^ 
and  the  other  a  blue  substance 
dissfilved  in  the  supernatant 
liquid  ;  by  evaporation  tlie  lat- 
ter may  be  obtained  as  a  blue 
powder,  named  PhyUocyanine, 
(e)  The  importance  of  iron  in 
^ving  a  green  color  to  plants 
is  easily  demonstrated  by  ^row- 
ing  young  plants  of  Indian  com 
in  solutions  containing  no  iron. 
The  first-formed  leaves  are 
green,  but  subsequently  only 
colorless  ones  are  produced; 
after  the  addition  of  iron  in  the 
form  of  ferric  sulphate  or  ferric 
chloride,  the  colorless  leaves 
become  green  in  the  course  of 
a  few  days. 

The  importance  of  ligfht  in 
the  production  of  chlorophyll  is 
shown  in  the  etiolated  shoots  of 
the  potato  when  grown  in  a 
dark  cellar ;  the  same  thing 
may  be  shown  by  germinating 
the  seeds  of  many  common 
plants  in  dark  boxes. 

((Q  The  disappearance  of  chlo- 
rophyll is  seen  in  the  common 
Pig.  48-ChlorophyU  mnnles  fn  cells  of  oixsration  of  blanching  celery 
the  leaf  of  a  moss,  Funana  hygrometriea.  A^  for  table  use,  and  in  the  blanch- 
granules  of  chlorophyll  with  conuined  8Urch  ,  .  i.    .  , 

KmlnB,  embedded  in  the  protoplasm  of  the  ing  of  grass -blades  under 
cells.  B,  separated  chlorophyll  gTHnulcs  con-  i>«,ard8.  U  pon  gradually  expos- 
talning  starch;  a  and  6,  young  grannlfs;  1/  ,  ,       f    i  i     x    *    ^i. 

5^',  granules  dividing;  e,  d,  and  t,  old  gran-  ing  such  colorless  plants  to  the 
ol^  ;/,  grannie  sw^en  iip  by  the  action  of  jigji^  chlorophyll  is  produced, 
water;  ^,  sUrch  grains  left  after  destruction     «*",,  \    ^        ,\, 

of  chlorophyll  gmnule  by  the  action  of  water,  (e)  Many  plants  which  contain 
xSM—AfterfiMAs.  chlorophyll   have   their  ^rreen 

color  hidden  by  the  presence  of  some  other  coloring-matter.  Some- 
times this  is  dissolved  in  the  water  contained  in  the  vacuoles  ;  this  is 
the  case  in  CoUm,  in  which  the  dissolved  pijjment  is  red.  In  young 
plants  of  AtripUx  the  epidermal  cells  are  filled  with  such  a  red  solu. 
tion,  hiding  the  green  chlorophyll-bearing  cells  underneath.     In  cer. 


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BTAROK  53 

tain  alg»  the  cblorophyll-body  itself  contains  other  coloring-matters— 
solable  in  water,  however — in  addition  to  the  chlorophyli.  In  Ftoridem 
(red  sea- weeds)  this  extra  coloring-matter  is  red  ;  in  Fueacece,  brown  ; 
in  IHat<>macecB,  yellowish  ;  and  in  OsdUatonm,  bine. 

In  the  degradation  of  chlorophyll,  which  takes  place  in  the  walls  of 
the  antheridia  of  mosses,  and  in  the  ripening  of  some  fruits  of  Phanero- 
gams, other  colors  than  gret'n  are  produced. 

(/)  Plants  which  live  parasitical  ly  upon  others,  as  the  Dodder,  and 
those  which  are  saprophytic  in  habit,  as  some  fungi,  are  usually  desti- 
tute of  chlorophyll ;  where  the  parasitism  is  only  partial,  as  in  CasHUeia 
and  Oerardia,  or  where  the  food  used  (stolen)  by  the  parasite  is  onaa* 
nmilated,  as  in  the  Mistletoe,  chlorophyll  is  present.  In  the  true  para- 
tUe$  (found  mainly  amoug  the  f  uugi)  chlorophyll  is  never  present. 

{g)  The  colors  of  flowers  are  produced  in  various  ways.  In  some 
cases  rounded  ma6S*«.  apparently  protoplasmic  in  their  nature,  contain 
a  red  {e.g.,  Adonis),  orange  (e.g. ,  Zinnia),  or  yellow  (e.g. ,  Cucurbita)  color- 
ing-matter. In  other  cases  the  pigment  is  dissolved  in  the  watery  fluid 
of  the  cells  ;  blue  and  violet  colors  are  mostly  produced  in  this  way. 
White  petals  are  so  because  their  external  layers  of  cells  are  filled 
with  air.  An  important  difference  beween  chlorophyll  and  the  pigments 
of  flowers,  is  that  the  latter  appear  not  to  be  dependent  upon  light  for 
their  production  ;  this  may  be  shown  by  enclosing  branches  of  morning- 
glory  (IpanuBa)  bearing  young  flower-buds  in  a  dark  chamber ;  when 
the  flowers  expand  they  will  be  seeu  to  have  their  natural  colors. 


§11.   Starch. 

67. — ^Next  to  chlorophyll,  one  of  the  most  important  pro- 
ducts of  the  plant-cell  is  starch,  an  organic  compound  closely 
related  to  sugar  and  cellulose,  and  represented  by  the  em- 
pirical formula  C„  H^  0,..  It  occurs  in  the  form  of  whitish 
or  semi-transparent,  rounded  or  slightly  angular  stratified 
grains,  and  is  generally  found  closely  packed  in  the  interior 
of  certciin  ceUs. 

68. — The  form  of  starch  grains  varies  greatly  in  different 
plants,  and  considerably  even  in  the  same  plants ;  neverthe- 
less, the  general  appearance  of  the  grains  in  each  plant  is  so 
characteristic  that  the  different  kinds  of  starch  may  be  quite 
easily  distinguished.  In  every  case  the  grains  have  more  or 
less  clearly  defined  lines,  which  are  concentrically  arranged 
about  a  nucleus  *  (Figs.  44  and  45).    In  some  cases  (excep- 

*  The  nucleus  is  called  the  hilum  by  some  authors,  a  term  which 


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54  BOTANY. 

tionally  in  some  plants  and  uniformly  in  others)  two  or  more 
nuclei  occur  in  each  grain ;  by  growth  such  grains  become 
compound  and  may  finally  separate  into  as  many  parts  as 

there  are  nuclei 

60.— The  molecular  structure  of  the  starch  grain  has  been 
determined  to  be  similar  to  that  of  plant-cellulose.  It  is  re- 
garded as  composed  of  molecules,  each  of  which  is  surrounded 
by  a  watery  layer  of  greater  or  less  thickness.  Growth  takes 
place  by  the  intercalation  of  new  molecules  between  the  pre- 
viously formed  onee— in  other  words,  by  intussusception, 

exactly  as  in  the  case  of 

the  cell-wall.    During  the 

formation  of  the  grain,  in 

certain  portions  of  it  the 

watery  layers  surrounding 

the     molecules     become 

thicker.     When  seen  by 

^  transmitted    light     such 

more  watery  parts  appear 

darker  than  those  which 

s  are  less  watery,  and  an  ex- 

)  amination  shows  that  they 

'  surround  the  nucleus  on 

all  sides  in  a  concentric 

manner.     In  this  way  the 

^     . ,  A      #»K-«*»*   starch  grain  comes  to  be 

"Bi<r  44 —Cell*  from  the  cotyledon  of  the  pea,   o*'"*^**  &         .       ,.  i- 

(i2£»^i^m).  ^.Btarchi^^^^  made  up  of    alternating 

ksS^n^"^^"*^-^^"-^^  layers  of  more  and  less 
watery  substance.  Every  watery  layer  is  thus  between  two 
layers  which  contain  less  water,  and  so  every  less  watery  one 
lies  between  two  more  watery  ones.  As  an  increase  m  the 
amount  of  water  in  any  portion  of  the  stanch  grain  de- 
creases the  density  of  that  portion,  the  layers  just  described 
may  be  distinguished  as  of  greater  density  when  having 
less  water  and  of  less  density  when  having  more  water. 


should  be  abandoned,  as  It  was  originally  given  under  the  mistaken 
Suon  that  It  was  the  point  of  attachment  of  the  sUrcU  gram  while 


growing. 


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8TARCK 


55 


70. — There  are  two  kinds  of  starch  in  every  starch  grain. 
The  great  mass  is  made  up  of  a  more  readily  soluble  form, 
the  granuluse,  while  the  remainder,  amounting  to  not  more 
than  from  two  to  six  per  cent  of  the  whole  grain,  is  less  solu- 
ble, and  bears  some  resemblance  to  cellulose ;  it  is  distin- 
guished as  starch-cellulose.  These  two  forms  are  intimately 
combined  throughout  the  whole  starch  grain,  so  that  upon 
the  removal  of  the  granulose  by  solution  a  perfect  skel- 
eton of  the  grain  still  re- 
mains. 

71. — The  first  forma- 
tion of  starch  appears  to 
take  place  in  the  chloro- 
phyll-bodies when  they 
are  exposed  to  the  light 
(Pig.  43,  B,  p.  52,  and 
Fig.  36,  p.  45).  The 
grains  thus  formed  are 
extremely  minute,  and  of 
different  shapes  and  sizes 
in  each  chlorophyll-body ; 
they  do  not  remain  and 
grow  into  larger  grains, 
but  are  dissolved  upon 
the  withdrawal  of  light. 
Thus  the  starch  formed 
during  the  day  disappears  co^L^i„1Sg-p^j;!g^i.f?^»grint  «^«.S^ 

durinST  the    niffllt   and   is  thlu  piateu  of  protoplasm,    in  the  figures  a  to  9, 
,       ,    °  .    1    .        ^1        the  starch  srralns,  taken  ft-om  ft  germinating  In- 

doubtless  carried   to  other  dian  com  grain,  are  becoming  disaolved  and 
J.  ^  xu       1      J.  disintegrated.    X  800.— After  Sachs. 

portions  of  the  plant. 

72. — The  formation  of  ordinary  starch  grains  always  takes 
place  in  protoplasm  ;  in  fact,  they  may  be  said  to  be  secre- 
tions from  the  protoplasm,  just  as  cellulose  is  said  to  be  a 
secretion.  In  a  cell  whose  cavity  is  filled  with  full-grown 
starch  grains  the  protoplasm  has  almost  entirely  disappeared, 
only  small  portions  of  it  remaining  as  thin  plates  or  scales 
between  the  grains  (Fig.  45). 

(a)  Starch  occurs  in  nearly  all  chloroplijll-bearing  plants  ;  it  is  absent 
only  in  No»tocace<B,  OsdUatoricB,  and  other  algae  whose  chlorophyll* 


e  ^^^ 


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56  BOTANY. 

bodies  contain  an  additional  blue  pigment.  It  is  present  in  many 
plants  which  are  destitute  of  chlorophyll ;  this  is  the  case  with  the 
parasitic  Phanerogams ;  it  occurs,  for  example,  in  the  stem  of  Citseuia, 
and  in  the  underground  portions  of  Orcbanche  and  Laihnxa,  From 
chlorophyll.less  Thallophytes  (fungi),  with  rare  exceptions,  it  appears  to 
be  absent  * 

(6)  The  best  common  examples  for  the  study  of  fully  formed  sturch 
grains  are  the  following,  viz.,  tubers  of  the  potato,  seeds  of  the  bean 
and  pea,  grains  of  wheat,  Indian  com,  rice,  etc.  Oat-starch  and  that 
of  the  crocus  corm  exist  in  the  form  of  compound  grains.  Of  those 
named,  the  starch  grains  of  the  potato  and  the  bean  are  the  largest, 
being  about  .07  mm.  (.008  inches)  in  diameter,  while  those  of  rice  are 
the  smallest,  being  about  .007  mm.  (.0003  inches)  in  diameter. 

{c)  The  test  which  is  characteristic  of  starch  is  its  blue  coloration  when 
treated  with  a  weak  solution  of  iodine.  When  the  solution  is  strong 
the  color  is  so  intense  as  to  appear  black.  A  careful  examination  shows 
that  it  is  only  the  granulose  which  is  thus  colored  blue  by  iodine, 
but  on  account  of  its  much  greater  quantity  and  its  intimate  mixture 
with  the  starch-cellulose,  the  blue  granulose  gives  its  color  to  the 
whole  grain. 

(d)  An  indication  of  the  correctness  of  the  present  view  as  to  the 
structure  of  the  starch  grain  and  the  cause  of  stratification  may  be 
obtained  in  two  ways,  as  follows:  1st,  by  thoroughly  drying  the  grain 
by  evaporation  of  its  water  or  by  placing  it  in  absolute  alcohol ;  all 
parts  having  now  equal  amounts  of  water,  the  striao  disappear ;  2d,  by 
rendering  all  parts  of  the  grain  capable  of  absorbing  large  quantities 
of  water,  as  may  be  done  by  means  of  a  weak  solution  of  potash,  as  in 
this  way  the  difference  in  the  amount  of  water  in  different  layers 
being  destroyed,  the  striae  disappear  as  before. 

Thedryingprocess  just  referred  to  reveals  another  structural  pecu- 
liarity, viz.,  that  the  interior  portions  of  the  starch  grain  contain  the 
greatest  amount  of  water.  On  drying,  internal  fissures  appear,  radiating 
from  a  central  cavity  and  having  a  narrower  diameter  as  they  pass  out- 
ward, showing  that  the  loss  of  water  is  greatest  in  the  interior. 

(e)  The  separation  of  the  granulose  from  the  starch-cellulose  may  be 
accomplished  in  the  following  ways :  (1)  by  allowing  the  starch  grains  to 
remain  for  a  long  time  in  a  weak  solution  of  hydrochloric  or  sulphuric 
add  ;  the  acid  solution  must  not  be  strong  enough  to  cause  the  grains 
to  swell ;  (2)  by  the  action  of  saliva  at  a  temperature  of  40**  to  47""  C. 
(105**  to  117°  Fahr.).  In  either  case  the  granulose  is  removed  and  the 
starch  cellulose  remains  as  a  skeleton.  Upon  treatment  with  a  solu- 
tion of  iodine  the  skeleton  is  colored  brown  instead  of  blue.     Other 

♦  Hofmeister,  in  "  Lehre  von  der  Pflanzenzelle,"  from  which  the 
preceding  statements  have  been  mainly  taken,  states  that  starch  gran> 
ules  occur  in  the  oospores  of  JSaprdegnuB, 


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ALEURONE  AND  CBT8TALL0IDa.  5? 

sgents,  as  organic  adds,  diastase,  and  pepsin,  also  are  solvents  of 
granulose. 

(/)  The  natural  solution  of  starch  grains  takes  place  in  the  cells  of 
living  plants  in  a  way  somewhat  similar  to  the  artificial  removal  of 
granolose.  The  process  is  not,  liowever,  so  regular  and  uniform; 
holes  and  irregular  excavations  are  formed  in  the  grains,  sometimes 
with  the  removal  of  the  granulose  only,  and  in  other  cases  with  tlie 
Bolntion  of  the  whole  substance  ;  sooner  or  later  the  grains  break  up 
into  pieces,  and  by  a  continuation  of  the  process  of  solution  they  soon 
disappear  (Fig.  45,  a,  g).  Sachs  maintains  that  starch  may  thus  be 
dissolved  in  the  cotyledons  of  the  bean  and  transferred  to  other  parts 
of  the  plantlet,  reappearinsf  in  the  form  of  grains  without  undergoing 
chemical  change  or  conversion  into  susrar. 

{g)  Observations  upon  the  formation  and  disappearance  of  starch 
grains  in  the  chlorophyll-bodies  are  best  made  with  Spirogyra,  By 
keeping  healthy  filaments  of  this  plant  in  darkness  for  some  time  the 
starch  disappears ;  upon  exposure  to  direct  sunlight  the  formation  of 
ctarch  begins  again  in  about  two  hours ;  in  diffused  daylight  it  begins 
several  hours  later.  Other  plants  with  thin  tissues  may  also  be  used, 
as,  for  example,  the  thin  leaves  of  mosses,  etc 

(A)  The  development  and  growth  of  starch  grains  may  be  studied  io 
the  ripening  grains  of  Indian  corn,  by  making  extremely  thin  sec- 
tions at  difierent  stages  of  the  ripening  process.  They  always  appear 
St  first  as  minute  solid  globular  masses  in  the  protoplasm. 

§  III.  Aleuronb  and  Cbystalloids. 

78. — In  the  ripening  of  seeds  and  the  maturation  of  tnbers 
the  loss  of  water  by  the  protoplasm  gives  rise  to  a  number  of 
poorly  understood  forms  of  albuminous  matter.  Two  of  the 
most  noteworthy  of  these  are  Aleurone,  and  the  crystal-like 
bodies  known  as  Crystalloids. 

74. — ^Aleurone  occurs  in  the  form  of  small  rounded 
grains,  sometimes  occupying  a  great  portion  of  the  cavity  of 
the  cell  (Fig.  44,  a,  p.  54).  They  are  soluble  in  water,*  or 
in  water  containing  a  little  potash ;  but  are  insoluble  in  alco- 
hol, ether,  benzole,  or  chloroform.  They  frequently  contain 
other  bodies  enclosed  in  their  substance,  as  crystaUoids  (de- 
scribed below),  globoids  (composed  of  a  double  calcium  and 
magnesium  phosphate),  and  crystals  of  calcium  oxalate. 


♦  The  aleurone  grains  of  Cynogloisum  officinale  are  stated  by  Sachs 
not  to  be  soluble  in  water. 


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68  BOTANY. 

76. — Aleurone  grains  appear  in  seeds  during  the  last 
stages  of  ripening.  In  the  turbid  cell-contents,  as  the  loss 
of  water  proceeds  small  globular  masses  of  albuminous  mat- 
ter appear,  and  afterward  increase  their  size ;  by  the  con- 
tinued loss  of  water  they  become  hai*der  and  of  a  more  defi- 
nite outline.  In  the  germination  of  the  seed  the  aleurone 
grains  dissolve,  and  the  protoplasmic  contents  of  the  cells 
assume  very  nearly  the  condition  they  held  before  the  final 
changes  in  the  seed  which  produced  the  aleurone. 

Aleurone  may  be.  siadied  in  the  seeds  of  the  bean,  pea,  vetch,  and 
lupine,  and  in  acorns,  chestnuts,  horsechestnuts,  and  the  bran-ceUs  of 
the  oat-grain. 

The  development  of  aleurone  grains  may  be  best  studied  in  the 
ripening  seeds  of  the  peony. 

76. — As  with  the  grains  of  aleurone,  the  nature  of  crystal- 
loids is  not  fully  understood.  They  are  quite  certainly  modifi- 
cations of  protoplasm,  and  not  true  crystals,  although  they 
are  bounded  by  plane  surfaces,  have  sharp  edges  and  angles, 
and  when  viewed  by  polarized  light  bear  a  resemblance 
to  crystals.  Their  deportment  with  reagents,  however, 
is  similar  to  that  of  protoplasm ;  thus,  under  treatment 
with  iodine,  or  nitric  acid  and  potash,  and  in  their  coagula- 
bility, they  show  a  protoplasmic  nature.  They  possess  the 
power  of  imbibing  water,  but  are  not  dissolved  in  it,  and  in 
a  dilute  solution  of  potash  they  swell  greatly,  at  the  same 
time  altering  their  angles.  They  are  insoluble  in  alcohoL 
In  dilute  acids  or  glycerine  one  portion  of  their  substance  is 
removed,  leaving  a  skeleton. 

77. — In  form  they  are  cubical,  tetrahedral,  octahedral, 
rhombohedral,  and  of  other  shapes,  and  there  is  generally 
such  irregularity  in  their  forms  that  it  is  diflficult  to  deter- 
mine to  which  crystal  system  they  belong.  In  most  cases 
they  are  colorless,  but  in  some  plants  they  contain  a  coloring- 
matter  which  may  be  removed  by  alcohol  and  acids. 

(a)  Common  examples  for  study  may  be  obtained  from  the  parenchy- 
ma-cells  beneath  the  skin  of  the  potato  tuber,  in  which  they  are  cubi- 
cal or  tetrahedral,  and  imbedded  in  the  protoplasm. 

They  may  be  obtained  from  the  Brazil-nut  {BerthoUetia  exceUa)  by 
placing  portions  of  the  crushed  seed  in  a  test-tube  and  agitating  it  witlk 
ether ;  the  crystalloids,  which  settle  to  the  bottom,  are  tabular. 


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0BT8TAL8,  59 

niin  sections  of  tbe  seeds  of  the  Castor  Bean  {Ridnus  commun%$\ 
after  the  removal  of  other  substances  by  soaking  in  water  for  some 
time,  show  tetrahedral  or  octohedral  crystalloids. 

(P)  Aleurone  and  the  crystalloids  famish  the  pfreater  part  of  the  al- 
bnminoid  portions  of  edible  grains.  The  amount  of  albuminoids  is 
presumably  an  indication  of  the  amount  of  aleurone  and  crystalloids. 
The  percentage  of  albuminoids  in  some  air-dry  grains  and  seeds  is  given 
below:* 

Bice 7.5 

Barley 9.5 

Indian  Corn 10. 

Oats 12. 

Wheat 18. 

Pea 22.4 

Bean 25.5 

Vetch 27.5 

Lupine 34.5 

Aleurone  and  the  crystalloids  appear  to  be  restinjjr  states  of  proto. 
plasm  analogous  to  the  resting  states  (sclerotla)  of  the  plasmodia  of 
Hyxomycetes. 

§  IV.  Crystals. 

78. — In  many  plants  crystals  of  various  forms  occur  either 
in  the  cavities  of  cells^  or  in  the  substance  of  the  cell-walls, 
or  even  in  intercellular  spaces.  They  are,  in  the  greater 
number  of  cases,  composed  of  calcium  oxalate,  and  are  widely 
distributed  throughout  the  vegetable  kingdom,  but  appear 
to  be  most  numerous  in  the  higher  groups,  and  least  so  in 
Bryophytes  and  Pteridophytes. 

79. — It  is  common  to  distinguish  the  acicular  (needle- 
shaped)  crystals  from  the  other  forms  under  the  name  of 
Raphides  ;  these  have  but  two  equivalents  of  water  of  crys- 
tallization in  their  composition  ([Ca  0],  C,  0.+  2  H,  0). 
They  are  found  in  the  cavities  of  parenchyma-cells,  and  lie 
pandlel  together  in  bundles  of  ten  to  fifty  or  more.  Upon 
slight  pressure  the  crystals  separate  and  escape  (Pig.  46). 

The  other  crystals  of  calcium  oxalate  assume  various 
forms,  such  as  prisms,  octahedra,  etc.    They  have  six  equiv- 

*  These  percentages  are  from  Wolff  and  Knop's  tables,  as  given  by 
Professor  S.  W.  Johnson  in  his  valuable  •*  How  Crops  Grow." 


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60 


BOTANY. 


Fig.  46.— Orydtals  of  calcium  oxalate. 
The  rit(ht*hand  portion  of  the  fl^nre 
ehowB  two  raphis-cells  of  the  Khnbarb, 
with  their  contained  raphidee,  and  one 
"  On  the  left  is  a  crys- 
Hach  magnified. 


crvstal  enlarsed.    On 
tal  from  the  oeet 


alents  of  water  of  crystellization  ([Ca  0],  C^  0,+  6  H,0). 
They  may  be  simple  (Fig.  47)  or  combined  into  compound 

j  crystals  (Fig.  46) ;  many  of 
the  former  are  sometimes 
found  imbedded  in  the  sub- 
stance of  the  cell-wall  of  the 
fibre-cells  of  certain  Gynmo- 
sperms  (Fig. 
47).  Simple 
crystals  oo-J 
cur  also  with- 
in the  cell- 
cavities  of  ' 
many  plants. 
The  com- 
pound forms 
are  very  various ;  they  almost  always 
occur  in  cell-cavities,  as  in  the  beet  (Fig. 
46)  ;  and  it  not  infrequently  happens  that 
both  simple  and  compound  crystals  are 
found  in  the  same  plant,  even  in  contigu- 
ous cells,  as  is  the  case  in  the  onion  bulb. 
80.  —  Crystals  of  calcium  carbonate 
(Ca  CO,)  occur  less  frequently  than  those 
just  described.  Their  most  striking  form 
is  that  seen  in  the  structures  named  cys- 
toliths  (Fig.  48).  These  possess  a  curious 
structure ;  a  club-shaped  or  stalked  out- 
growth of  cellulose  projects  into  the  in- 
terior of  a  cell,  and  upon  and  in  this  mul- 
titudes of  small  crystals  are  grouped. 
Other  forms  of  calcium  carbonate  crys- 
tals are  to  be  found  in  plants — e.g.,  in  the 
Myxomycetes. 

According  to  some  observers,  crystals  ^^^^xTwl!ii^u^ 
of  calcium  phosphate,  calcium  sulphate,  »»ira«/<#.-Aa6r8acht. 
and  silica  are  occasionally  to  be  met  with  in  plants.* 

*  See  an  article  on  plant-crystals  by  Dr.  Lancaster  in  the  Qr-  J'r.  of 
Mie,  Scienee,  1863,  p.  243 ;  also  articles  by  Professor  Galliver  In  the 
same  Journal  for  1R«4, 18«6.  and  1869. 


Fljr.  47.— Crystali  of 


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CRYSTALS.  61 

(a)  In  fltudjing  plant-crystals  it  is  only  necessary  in  most  eases 
to  make  thin  longitudinal  sections,  and  to  mount  in  the  usual  way 
in  water. 

(()  The  calcium  carbonate  crystals  may  be  distinguished  from  those 
of  calcium  oxalate  by  treatment  with  hydrochloric  acid,  which  dissolves 
both,  the  former  with  effervescence,  the  latter  with  none.  Under 
treatment  with  acetic  acid  the  calcium  carbonate  crystals  dissolve  (with 
effervescence,  of  course),  while  those  of  calcium  oxalate  do  not  dissolve. 

(c)  Acicular  crystals,  or  raphides,  may  be  best  obtained  from  the 
Evening  Primrose,  EpiUbiuin,  Fuchsia,  and  other  OnayracesB,  also  from 
the  Balsam  (Impaiiens  BaUamina\  Garden  Rhubarb,  and  the  new 
growths  of  the  Virginia  Creeper,  and  the  grape-vine. 

Raphidea  may  also  be  obtained  from  some  of  the  Monocotyledons 
with  equal  ease,  e.g.t  Tradescantia,  Indian  turnip  {Aiisama),  Calla, 
NarcU9U$t  Lily-of-the- Valley,  etc. 

(d)  The  other  crystal  forms' are  obtainable  from  the  bark  of  the  lo- 
cust (Rotdniu),  elm,  Hoya^  leaves  of  Begonia,  bulb-scales  of  onion, 
garlic,  and  leek,  the  root-stock  of  Iris,  etc 

{e)  Cystoliths  may  be  readily  studied  by  making;  cross-sections  of 
the  leaves  of  Urtica^  mulberry,  hop,  hemp,  fijr,  Celtis,  and  other  Urti* 
eace4B.  Tbey  are  said  by  Sachs  to  occur  only  in  this  order  and  the 
Acanihacfi(B,* 


Fig.  48.— Oystolith  from  the  epldermin  of  the  upper  rarfftce  of  the  leaf  of  UrHea 
tnaerophylla,  from  a  cross  section  of  the  leaf.    X  285.— After  IJe  Bary. 

(/)  Plant-crystals  appear  to  be  surrounded  by  a  thin  layer  of  proto- 
plasm ;  probably  they  are  separated  out  from  the  cell  sap  only  through 
the  influence  of  protoplasm.  It  is  further  probable  that  they  are  resid- 
ual products  of  chemical  actions  in  the  plant,  and,  as  they  appear  never 
to  be  made  use  of  by  the  plant,  we  must  regard  them  as  to  a  certain 
extent  of  the  nature  of  excretions. 

*  "  Lehrbuch,"  4te  auf.,  p.  69.  However,  cystoliths,  or  structures 
very  much  like  them,  may  be  found  in  the  leaves  of  Ceanothui  proHra- 
tus  of  Nevada  and  California.  The  student  is  referred  to  De  Bary's 
"  Vergleichende  Anatomie  der  Vegetationsor^ne  der  Phanero^men 
and  Fame,"  Chapters  I.  and  III.,  for  a  full  discussion  of  the  subject  of 
plant-crystals,  and  for  a  list  of  plants  containing  them.  The  articles 
referred  to  in  ^.  Jour.  Mic.  Science  will  also  prove  helpful. 


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62-  BOTANY. 

§  V.  The  Cell  Sap. 

81. — ^All  parts  of  a  living  cell  are  saturated  with  water.  It 
enters  into  the  structure  of  the  cell-wall ;  it  makes  up  the 
greater  part  of  the  bulk  of  the  protoplasm,  and  it  fills  the 
vacuoles.  It  holds  in  solution  (not  necessarily,  however,  in 
equal  proportions  in  all  its  parts)  the  food-materials  absorbed 
by  the  plant,  and  the  surplus  soluble  products  of  assimila- 
tion and  metastasis. 

82. — Among  the  more  important  substances  dissolved  in 
the  cell  sap  are  Sugar  and  luulin.  Of  the  former  there 
are  two  varieties,  viz.,  sucrose,  or  cane  sugar  (C„  H„  0^,), 
and  glucose  (or  tevulose),  or  fruit  sugar  (C„  H,^  0^,),  which 
differ  in  their  sweetness,  as  well  as  in  other  properties. 

88. — Cane  sugar  exists  in  great  abundance  in  the  cell  sap 
of  sugar  cane,  sugar  maple,  sugar  beet,  Indian  com,  and  in 
greater  or  less  quantity  in  nearly  all  higher  plants.  Fruit 
sugar,  as  its  name  indicates,  is  found  in  many  fruits,  some- 
times mixed  with  cane  sugar ;  thus  in  grapes,  cherries, 
gooseberries,  and  figs  it  is  the  only  sugar  present,  while  in 
apricots,  peaches,  pine-apples,  plums,  and  strawberries  it  is 
mixed  with  cane  sugar. 

84. — Inulin  (C  ,  H,^  0,  J  is  a  substance  related  to  starch 
and  sugar,  and  found  mainly  in  certain  CompositaB,  e.g., 
Dahlia,  Helianthus,  Inula,  Taraxacum,  etc.  It  may  be 
separated  from  the  cell  sap  by  alcohol,  glycerine,  and  other 
agents,  and  it  then  assumes  the  form  of  sphere-crystals.  By 
boiling  in  dilute  hydrochloric  or  sulphuric  acid  inuline  is 
transformed  into  glucose. 

§  VI.   Oils,  Resins,  Gums,  Acids,  and  Alkaloids. 

86. — The  fixed  oils,  as  olive,  castor,  linseed,  and  palm  oil, 
are  secreted  in  many  plant-cells,  particularly  in  the  seeds. 
They  occur  as  separated  drops  among  the  other  contents  of 
the  cells.  In  some  instances  the  tissues  contain  from  thirty- 
five  to  forty  per  cent  of  oil. 

86. — The  essential  oils,  the  resins,  and  gums  are  mainly 
the  products  of  special  cells  in  the  plant.   These  secreting  cells 


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OILS,  BESmS,  ETC.  63 

are  usually  thin-walled  and  filled  with  granular  protoplasm. 
The  secretions  are  in  some  cases  collected  in  drops  in  the 
cell-caYity,  in  others  they  are  caused  to  pass  through  the 
cell-wall^  while  in  still  other  instances  the  cell-wall  ruptures, 
and  permits  the  escape  of  the  secreted  matter. 

87. — There  are  three  classes  of  essential  oils,  distinguished 
by  their  chemical  composition,  as  follows  : 

(a)  The  pure  hydrocarbons ;  these  are  represented  by  the 
formula  C,,  H„.  Oil  of  turpentine,  obtained  from  the  crude 
turpentine  of  various  Conifers,  is  the  type.  Oil  of  lemons, 
oil  of  caraway,  and  oil  of  thyme  are  also  of  this  class. 

(})  The  oxidized  essences,  in  addition  to  carbon  and  hy- 
drogen, have  oxygen  in  their  composition.  Of  this  nature 
are  camphor  (C„H„0),  essence  of  cinnamon,  essence  of 
wintergreen,  etc. 

(c)  The  sulphuretted  essences  contain  sulphur.  To  this 
class  belong  the  essential  oils  in  mustard,  horseradish,  and 
other  CrucifersB,  in  onions,  garlic,  asafcetida,  etc.  That  in 
garlic,  which  may  be  taken  as  the  type,  is  a  sulphide, 
([C,  H  J„  S),  while  that  of  the  mustard  is  a  sulpho-cyanide 
(C.H^CNS). 

88. — ^Eesins  are  much  like  the  essential  oils  in  composition, 
and  are  generally  associated  with  and  dissolved  in  them. 
When  separated  from  the  essential  oils  by  heat,  the  resins  are 
transparent  or  translucent  brittle  solids,  insoluble  in  water, 
but  soluble  in  alcohol.  Common  rosin,  which  is  the  resi- 
due left  when  the  crude  turpentine  derived  from  several  spe- 
cies of  pines  is  distilled  with  water,  may  be  taken  as  the  type. 
It  is  an  oxidized  hydro-carbon,  i.e.,  it  contains  carbon,  hy- 
drogen, and  oxygen. 

80. — Gums.  Under  this  name  many  different  kinds  of 
products  are  commonly  included.  Some  of  them  are  with- 
out doubt  related  to  the  resins,  while  others  are  allied  to 
starch  and  sugar.  Of  the  latter  kind  gum-arabic  (C„  H„  0„) 
is  the  type,  and  allied  to  it  are  cerasin  (from  the  cherry), 
bassorin  (gum  tragacanth),  and  vegetable  mucilage,  which 
is  abundant  in  mallow  roots. 

90. — Pectin,  or  vegetable  jelly  (C„  H,,  0„),  is  related  to 
the  foregoing ;  it  forms,  when  moist,  a  transparent  jelly,  and 


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64  BOTANY. 

dries  into  a  translucent  mass.  It  gives  the  firmness  and  con- 
sistence to  apple,  currant,  and  other  fruit  jellies.  Unripe 
fruits  contain  a  substance  insoluble  in  water,  alcohol,  and 
ether,  which,  during  the  process  of  ripening,  or  under  the 
action  of  heat,  acids,  and  ferments,  is  converted  into  pectin. 

91. — In  addition  to  oxalic  acid  (C,  H,  OJ,  which  is  found 
generally  combined  with  calcium,  there  are  other  vegetable 
acids,  some  of  which  are  even  more  common;  they  occur 
either  free,  or  united  with  organic  or  inorganic  bases. 

(a)  Malic  Acid  (C^  H,  0  J  is  abundant  in  many  sour  fruits 
— e.g.y  apples,  cherries,  strawberries,  currants,  etc.;  it  is 
likewise  abundant  in  rhubarb,  where  it  accompanies  oxalic 
and  phosphoric  acids. 

(J)  Tartaric  Acid  (C^  H,  0,)  occurs  in  the  grape,  tama- 
rind, berries  of  the  mountain  ash  (unripe),  and  other  plants. 

{c)  Citric  Add  (C,  H,  0,)  is  found  in  abundance  in  the 
lime,  lemon,  and  other  fruits  of  the  Aurantiaceae.  It  also 
occurs  in  other  sour  fruits  associated  with  malic  acid,  as  in 
gooseberries,  raspberries,  strawberries,  chemes,  etc. 

{d)  Tannic  Acid  (C„  H„  0„)  occurs  in  the  bark  and 
leaves  of  oak,  elm,  willow,  and  many  other  trees,  in  the 
wood  and  bark  of  sumach  and  whortleberry,  and  the  roots  of 
some  Bosacesd  and  Polygonacese,  and  gives  to  them  their  as- 
tringency. 

Nearly  related  to  tannic  acid  is  quinic  acid,  which  occurs 
in  the  bark  of  Cinchona  (Peruvian  Bark)  in  combination 
with  organic  bases,  of  which  quinia  is  the  most  important. 

There  are  many  other  substances  which  occur  in  plants  as 
the  products  of  cells — e.g.y  the  vegetable  alkaloids,  many 
coloring-matters,  etc.  As,  however,  this  whole  matter  be- 
longs rather  to  Organic  Chemistry,  it  will  not  be  carried 
further  in  this  place. 


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CHAPTER  VI. 

TISSUES. 
§  I.  The  Various  Aggregations  of  Cells. 

In  the  organisms  which  compose  the  vegetable  kingdom 
cells  are  found  principally  under  the  following  conditions  of 
aggregation : 

92. — (1.)  Single  Cells.  A  large  number  of  the  lower 
plants,  during  all  or  a  considerable  part  of  their  existence, 
are  composed  of  single  cells.  They  may  be  round,  as  in 
Sdccharomyces  and  Protococcus,  or  elongated  or  even  filiform, 
as  in  certain  Bacteria.     It  is  only  in  the  lowest  groups  that 

A  B  C 


i5?!.  ^--PediMtntm  granulahtm.  A.  the jronnir  cells  fn  their  motile  ntate,  en- 
cioeea  in  the  membrane  of  the  mother-cell.  B,  the  young  cells  beginning  to  arrange 
themselves  in  a  cell-family.    C,  the  cell-ftunUy  ftilly  developed.— After  Braun. 

adult  plants  are  composed  of  single  cells,   but  it  is  an 
embryonic  condition  of  all  others. 

98 — (2.)  Families,  or  Spurious  Tissues.  There  are 
some  oases  in  which  cells  which  are  at  first  distinct  after- 
wards become  united  more  or  less  closely  into  a  common 
mass,  which  may  be  denominated  a  Cell-Family,  or  Spurious 
Tissue, 

(a)  Pediastrum  and  Bydrodictyon  farnish  the  best  examples  of  true 


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66  BOTANY. 

cell- families ;  in  both  cases  separate  motile  cells  (zoospores)  in  a  mother- 
cell  arrange  themselves  in  a  definite  manner,  and  gradoallj  anite  into 
a  family  resembling  the  parent  plant  (Fig.  49).  Bj  the  breaking  up  of 
the  wall  of  the  mother-cell  the  new  family  is  set  free. 

(6)  In  some  fungi  the  cells  composing  the  vegetative  threads  (hy- 
phflB)  unite  loosely  with  one  another  into  a  mass.  In  some  cases  the 
union  is  so  slight  that  the  hyphae  may  be  separated  with  the  greatest 
ease,  while  in  others  it  approaches  the  density  and  firmness  of  true 
tissues  (Fig.  50).  While  the  term  Gell-Family  may  be  applied  to  such 
aggregations  of  cells,  the  common  one  of  Spurious  Tissue  is  to  be  pre- 
ferred* 

(c)  In  the  embryo  sac  of  Phanerogams  the  cells  are  at  first sepai ate; 


Fig.  60.  —  Rhizomorpha  subeortiealis  (the  compact  myceliam  of  a  f nngns).  The 
left  Hand  flinire  shows  a  longitudinal  section  of  the  growing  end  of  a  yoang  shoot. 
The  right  hand  fi^re  shows  a  cross-section  of  the  ^ame ;  a,  the  central  pith-nke  por^ 
tion :  \  the  cortical  portion  of  smaller  cells ;  A,  the  hairy  coat,  which  is  often 
wanting.    X  100.— After  De  Bary. 

these  afterward  unite  into  a  mass  which  cannot  be  distinguished  by 
any  structural  character  from  a  true  tissue.  (See  Fig.  83,  p.  43.)  As, 
however,  the  component  cells  were  originally  separate,  the  resulting 
mass  must  be  classed  with  the  spurious  tissues. 

94 — (3.)  Fufiions.  It  frequently  happens  that  the  separat- 
ing walls  of  contiguous  cells  are  absorbed  and  their  cell- 
cavities  merged  into  one.     In  this  way  long  tubes  (vessels) 

*  This  is  the  "  Tela  oontezta ' '  of  some  authors. 


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THE  AQOREOATI0N8  OF  CELLS,  67 

are  formed-  These  may  extend  in  any  direction,  but  they 
generally  run  parallel  to  the  axis  of  that  part  of  the  plant  in 
which  they  are  found.  Other  cell-fusions  give  rise  to  irreg- 
ular branching  tubes,  or  they  may  even  form  an  extended 
network  (e.g.y  in  the  laticiferous  tissue  of  Cichoriacese,  Fig. 
65,  p.  75). 

95. — (4.)  Tissues.  A  tissue  may  be  defined  as  an  aggre- 
gation of  similar  cells  (or  cell-derivatives)  connately  united. 
There  are  three  conditions  of  aggregation  : 

(a)  CelUrows.  In  these  the  cells  are  united  by  their  ends 
into  a  row  or  filament.  Such  simple  tissues  result  from  cell- 
fission  in  one  direction  only.     In  some  cases,  as  in  Oscilla- 


Fig.  51.— Succulent  parenchyina  from  the  stem  of  Indian  com ;  transverse  section. 

2ff,  simple  plate  of  ceUnloae,  forming  the  partition-wall  between  two  cell« ;  e, «, 
tercellnlar  spaces  caused  by  splitting  of  the  walls  daring  rapid  growth,    x  650. 
~After  Sachs. 

ioriay  the  cells  are  short  and  broad,  while  in  others — e,g,y 
Spirogyra,  Zygnema,  and  the  hyphse  of  many  fungi — they 
are  cylindrical  or  greatly  elongated.  Numerous  cases  occur 
in  the  higher  plants,  the  most  familiar  being  jointed  hairs. 

(b)  Cell-surfaces  are  composed  of  a  single  layer  of  cells. 
They  result  from  cell-fission  in  two  directions.  Examples 
may  be  found  in  many  Ulvaceae,  and  in  the  leaves  of  some 
Bryophytes. 

(c)  Masses.  Where  the  cell-fission  has  been  in  three  di- 
rections the  result  is  a  mass  of  greater  or  less  solidity.  Fre- 
quently, through  cell-fusions,  the  elements  which  compose 
such  masses  are  cell-derivatives,  instead  of  cells  ;  these  may 
be  r^;arded  as  tissues  of  a  higher  order. 


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68  BOTANY 

06. — The  Cell-wall  in  Tissues.  In  tissues  the  walls  which 
separate  contiguous  cells  are  at  first  simple  and  homogeneous. 
The  plate  of  cellulose  which  first  forms  between  two  sister 
masses  of  protoplasm  in  cell-fission  is  a  single  one,  the  com- 
mon property,  as  it  is  the  common  secretion,  of  the  proto- 
plasm masses.  As  the  wall  becomes  older  and  thicker,  and 
stratification  takes  place,  it  shows  a  line  of  separation  into 
two  halves  ;  this  may  become  so  well  marked  as  actually  to 
result  in  the  splitting  of  the  wall,  as  is  the  case  in  succulent 
tissues  when,  on  account  of  a  particular  kind  of  tension, 
intercellular  spaces  are  formed  in  the  angles  between  the 
cells  (Fig.  51). 

97. — By  a  still  further  differentia- 
'   lion,  after  a  considerable  thickness  of 
the  wall    has    been    attained,    there 
may  arise  a  common  middle  lamella, 
which  appears  at  first  sight   to   lie 
between  the  original  cell-walls  (Fig. 
52).     This  middle  lamella,  which  is 
simply    the    result   of    a    particular 
stratification,  was  long  mistaken  for 
an  intercellular  substance,    and  two 
pan^of  the  Vtmg^  8tem**o?  theories  Were  held  as  to  its  nature.  On 
Bection^°/^*S[?fty  oTSSSTm!  the  ouc  hand,  it  was  supposed  to  be 
^'^tiiwT  wa\/;  'x^'fiSo.-  an  original  common  matrix,  in  which 
After  Sachs.  j^\^q  q^\\^  thcmselves  were  imbedded  ; 

and  on  the  other,  it  was  held  to  be  of  the  nature  of  an  ex- 
cretion from  the  surrounding  cells  into  the  intercellular 
spaces.  The  first  of  these  theories  was  possible  only  so  long 
as  the  knowledge  of  the  origin  and  develoijment  of  cells  was 
exceedingly  defective.  The  second  theory  is  rendered  ex- 
tremely improbable  by  our  present  knowledge  of  the  mode 
of  growth  of  the  cell-wall  by  intussusception. 

Until  recently  another  view  has  been  largely  held,  name- 
ly, that  the  middle  lamella  was  to  be  regarded  as  the  original 
common  wall  of  the  cells,  and  that  the  remaining  portions 
were  after-deposits  upon  it.  TIjIs  view  gave  rise  to  the  terms 
Primary  Cell-wall  and  Secondary  Cell-wall,  which  are  still 
used  to  some  extent.  As  this  explanation  of  the  structure 
rests  upon  the  all-but-abandoned  theory  of  the  thickening 


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THE  PRINCIPAL  TISSUES.  69 

of  the  cell-wall  by  the  addition  of  snccessiye  internal  layers, 
and  is  directly  contradicted  by  the  well-established  doctrine 
of  growth  by  intussusception,  it  must  be  regarded  as  en*oneou8. 
In  some  cases,  as  in  the  wood  of  Pinus  sylvestris,  the  dif- 
ferentiation is  so  great  that  three  lamellaa  are  formed  :  (1) 
the  common  middle  one,  (2)  an  inner,  and  (3)  an  inter- 
mediate one.     (Fig.  16,  p.  26.) 

§  II.   The  Pbincipal  Tissues. 

98. — There  are  very  many  kinds  of  tissues,  distinguished 
from  each  other  by  characters  of 
greater  or  less  importance. 
They  all,  however,  pass  into 
one  another  by  almost  insensi- 
ble gradations ;  hence  by  not- 
ing all  the  slight  differences  we 
may  make  a  long  list  of  tis- 
sues ;  while  by  noting  the  simi- 
larities and  gradations,  all,  or 
nearly  all,  the  forms  may  be  re- 
duced to  one.  The  principal 
varieties  only  will  be  noticed  in 
this  place;  each  one,  as  here 
described,  includes  many  varie- 
ties. 

99.— Parenohyma.  This  is 
the  most  abundant  tissue  in  the 
vegetable  kingdom  ;  it  is  at  once 
the   most   important  and    the  ttSS*  Sc?I®ISJ^"^?'^?'.  f  ®™  °' 

.  ,  ,     ^  ^     ,  Vicia  faba  in  process  of  division,    x 

most  vanable.  As  here  restrict-  aoo.-AfterPranti. 
ed  it  is  composed  of  cells  whose  walls  are  thin,  colorless,  or 
nearly  so,  and  transparent ;  in  outline  they  maybe  rounded, 
cubical,  polyhedral,  prismatic,  cylindrical,  tabular,  stellate, 
and  of  many  other  forms.*  When  the  cells  are  bounded  by 
plane  surfaces,  generally,  but  not  always,  the  end  planes  lie 
at  right  angles  to  the  longer  axis  of  the  cells. 

*  Unfortiinately,  the  terms  parenchyma  and  parenchymatoos  have 
often  been  restricted  in  meaning  to  tissues  composed  of  cells  whose 
three  dimensions  are  equal. 


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70 


BOTANY. 


This  tissue  makes  up  the  whole  of  the  substance  of  many 
of  the  lower  plants.  In  the  higher  plants  the  essential  por- 
tions of  the  assimilative  (green),  vegetative  (growing),  and 
reproductive  parts  are  composed  of  parenchyma. 

Instructive  examples  of  parenchyma  may  be  obtained  in  the  growing 
ends  of  shoots  (Fig.  53)  and  in  the  pith  of  Dicotyledons,  in  the  ends  of 
young  roots-^.  g.,  of  Indian  corn— in  the  green  pulp  of  leaves,  in  the 
pulp  of  fleshy  fruits,  and  in  the  substance  of  young  embryos. 

100. — CoUenchjrma.  The 
cells  of  this  tissue  are  elon- 
gated, usually  prismatic,  and 
their  transverse  walls  are  most 
frequently  horizontal,  rarely 
inclined.  With  few  excep- 
tions* there  are  no  intercellu- 
lar spaces.  The  walls  are 
greatly  thickened  along  their 
longitudinal  angles,  while  the 
remaining  parts  are  thin  (Fig. 
21,  p.  30).  The  cells  con- 
tain chlorophyll,  and  retain 
the  power  of  fission,  f  Wet 
specimens  show  by  transmit- 
ted light  a  characteristic  blu- 
ish white  lustre  (Figs.  54  and 
55). 
^         .      ,    „  Collenchvma  is  found  be- 

chyma  (oo^  of  the  stem  of  E^hinoeyttU     ueath  the  epidermis  01  DlCO- 

S^y^i^oiTeS:  ""Tetf^^^J^^l^  tylcdous  (and  some  ferns), 
K^J.^lSnr.^'^-  ^"*  usually  as  a  mass  Of  conside- 
rable  thickness,  and  is  doubtless  developed  from  parenchyma 
for  the  purpose  of  giving  support  and  strength  to  the  epi- 
dermis. 


*  In  the  collencliyma  of  Saphium  perfoliatum  there  are  many  lon- 
gitudinal intercellular  spaces  of  various  sizes ;  iu  Ipomcsa  purpurea 
there  are  minute  ones. 

fDe  Baiy  states  that  collenchyma-cells  are  capable  of  fission. 
"Vergleichende  Anatomie  der  Vegetationsorgane  der  Phanerogamen 
und  Fame,"  p.  126. 


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TEE  PRINCIPAL   TISSUES. 


71 


(a)  Collencbyma  may  be  stadied  in  the  stems,  petioles,  and  leaf-ribs 
of  berbaoeoas  Dicotyledons— «.^.,  in  species  of  Stiphium,  Rheum, 
Rum^,  Chenopodium — in  many  Labiatat,  Solanaeea,  BegoniacecB,  Cu* 
evrbUacea,  and  many  otbers;  also  in  tbe  petioles  of  tbe  water-lilr 
and  yonng  stems  of  tbe  elder. 

(6)  Upon  soaking  in  water,  or  npon  treatment  with  nitric  or  snlpbu^ 
ric  add,  tbe  tbickened  angles  become  greatly  swollen. 


{c)  Upon  treatment  witb  Scboltz's  Solution  tbe  tbickened  angles  are 
colored  ligbt  blue. 

(d)  Upon  sligbt  warming  In  a  solution  of  potash,  and  then  treating 
witb  a  solution  of  iodine  in  potassium  iodide,  tbe  tbickened  angles  be* 
oome  colored  dark  blue. 

101.— Solerenohyma.    In  many  plants  the  hard  parts  are 
composed  of  cells  whose  walls  are  thickened,  often  to  a  very 


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72  BOTANY. 

considerable  extent.  The  cells  are  usually  short,  but  in  some 
cases  they  are  greatly  elongated ;  they  are  sometimes  regular 
in  outline,  but  more  frequently  they  are  extremely  irregular. 
They  do  not  contain  chlorophyll,  but  in  some  cases  at  least 
{e.g.,  in  the  sclerenchymarcells  in  the  pith  of  apple-twigs) 
they  contain  starch. 

Sclerenchyma  occurs  in  Bryophytes,  Pteridophytes,  and 
Phanerogams. 

{a)  Good  specimenB  of  sclerenchjina  may  be  obtained  for  study  by 
making  longHadinal  sections  of  tbe  rbizome  of  PterU  aquiiina,  in 


Fig.  Sdff.  Fig.  66^1.  Fio.  67. 

Fig.  68.— TwoBclerenchjrma-cells  ftt)m  the  bypodenna  of  the  rhizome  of  PterU 
agumna,  isolated  by  Schnlze's  maceration.  A,  a  very  thick-walled  cell,  with  branch- 
ing pits;  J9,  a  cell  with  walla  leas  thickened— the  wall  of  the  opposite  aide  of  the 
cell  is  aeen  to  be  filled  with  nomerouB  pita,    x  500.— After  Sachs. 

Fig.  67.— Margin  of  leaf  of  Pinus  pinaster,  transverse  station,  e,  caticnlarized  layer 
of  outer  wall  of  epidermis ;  I,  inner  non-cnticnlarized  layer ;  c',  thickened  outer 
wall  of  marginal  cell ;  g,  i\  hypoderma  of  elongated  si-lerenchyma ;  p,  chlorophyll- 
bearing  parenchyma ;  pr^  contracted  protoplasmic  contents,    x  WO.— After  Sachs. 

wbicb  it  occurs  as  a  tbick  hypodermal  mass  ;  by  boiling  in  potassium 
chlorate  and  nitric  acid  (Scbulze's  maceration)  the  ceUs  may  be  com- 
pletely isolated  (Fig.  56,  A  and  B). 

(b)  The  cells  of  the  medullary  rays  of  woody  Dicotyledons — e.g.^ 
Acer,  Pirus,  Ostrya,  LiiHodendnm,  etc— are  generally  thick- walled 
IK  hen  old,  and  in  this  state  must  be  classed  as  sclerenchyma. 

(6)  The  hypoderma  of  the  leaves  of  pines  consists  of  elongated  scle- 
renchyma-cells,  which  at  first  sight  might  easily  be  mistaken  for  bast 
fibres  (Fig.  67,  g,  i).  The  hypoderma  of  many  other  plants  appears  to 
be  of  a  similar  nature. 


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THE  PRINCIPAL  TISSUES.  73 

(d)  The  hard  Uesaes  of  nuts  and  of  stone  fruits  famish  excellent  ex* 
mmples  of  short  and  very  thick-walled  sderenchyma-oells.  In  the 
iiickoTy  nut  {Civrya  aVba)  the  cells  (Figs.  68  and  59)  are  not  more  than 


Fio.  58.  Fio.  59. 

Fig.  6&  —  ScIeronchTxna-cells  of  the  shell  (endocarp)  of  the  hickory-nntC  Cory  a 
-tOba)^  taken  parallel  to  the  surface  of  the  not.    x  400. 

Fig.  SO.— Sclerenchymii-cells  of  the  ehell  (endocarp>  of  the  hickory-nat  {Carya 
'OXbt^  taken  at  right-angles  to  the  surface  of  the  not    x  400. 

two  or  three  times  as  long  as  broad,  and  the  thickening  is  so  great  as 
4Jmoflt  entirely  to  obliterate  their  cavities ;  the  thickened  walls  are 
c  S  a 


Fio.  60. 

Fig.  60.— Sclerenchymacells  of  the  seed-coat  of  EeMnoeyitit  lobata^  firom  a  section 
at  n^t  angles  to  the  surface  of  the  seed  ;  a,  a  cell  cat  directly  throagh  its  centre, 
ahoirbg  the  whole  of  the  cavity— the  three  dark  spots  are  probably  oil ;  ft,  a  ceS 
ait  throagh  at  one  side  of  the  middle ;  c.  a  cell  whose  cayity  was  not  cat  into  In 
making  the  secdon.     x  250.    From  a  drawing  by  J.  C.  Arthur. 

Pie.  61.— Sclerenchyma-cells  of  the  seed-coat  of  Eehinoeyatis  lobata,  ftrom  a  section 
fMrallel  to  the  surface  of  the  seed,    x  850.    From  a  drawing  by  J.  C.  Arthur. 

pierced  by  many  deep  pits.  The  cells  are  arranged  with  their  longer 
axes  perpendicular  to  the  surface  of  the  nut,  and  are  very  closely 
packed  together. 


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74 


BOTANY. 


(0)  The  seed-coat  of  Echinoty^tU  lobcUa  is  composed  almost  entirely 
of  sclerencliyma  (Fig,  tM)).  Tlie  cell-walls  are  greatly  thickened,  and 
the  cells  are  very  closely  packed  together,  so  much  so  that  all  are 
sharply  prismatic  (Fig.  Gl). 

102.— Fibrous  Tissue.  This  is  composed  of  elongated^ 
thick-walled,  and  generally  fusiform  elements,  the  fibres 
(Figs.  62  and  63),  whose  walls  are  usually  marked  with 
simple  or  sometimes  bordered  pits.  These  elements  in  cross- 
section  are  rarely  square  or  round,  but  most  generally  three 
to  many-sided.  They  are  found  in,  or  in  connection  with, 
the  fibro-vascular  bundles  of  Pteridophytes  and  Phanero- 
gams,and  give  strength  and  hardness  to  their  stems  and  leaves. 


Fio.  08.  Fio.  63. 

P!gr.  S8.— Wood  fibres  of  Acer  datyearpwn.  Isolated  by  Schnlse's  miceration.  a, 
four  fibres,  x  U6 ;  6.  a  portion  of  a  fibre,  x  8S0,  showing  the  diagonally  placed  elon- 
gated pits ;  c,  the  ends  of  eleven  united  fibres,  x  95. 

Fig.  63.— Bast  flbreo  of  Ac4^  dasycarpvm,  iK>lated  by  Schnlze's  maceration,  a,  a 
fibre.  X  96 ;  6,  a  portion  of  a  fibre,  X  S80,  showing  the  moch-tbickened  wall. 

Two  varieties  of  fibrous  tissue  may  be  distinguished,  viz., 
(1)  Bast  (Fig.  63),  and  (2)  Wood  (Fig.  62).  The  fibres  of 
the  former  are  usually  thicker  walled,  more  flexible,  and  of 
greater  length  than  those  of  the  latter.  In  both  forms  the 
fibres  are  sometimes  observed  to  be  partitioned.* 

*  These  partitions  have  generally  heen  considered  as  formed  subse* 
quently  to  the  fibres ;  but  it  may  well  be  questioned  whether,  in  some 


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THE  PRINCIPAL   TISSUES.  75 

To  examine  fibrous  tissue  it  is  only  necessary  to  make  thin  longitudi- 
nal slices  of  the  stems  of  woody  plants — e^g,,  Acer,  Pirus,  etc. — and  to 
heat  for  a  minute  or  less  in  nitric  acid  and  potassium  chlorate.     The 


Fig.  64.  Pio.  65. 

PIff.  64.~LatIcIferoiu  tubes  from  Euphorbia.  A.  moderately  magnified:  B,  more 
hiffoly  magnified,  and  Bhowing  the  bone-shaped  or  dnmt>-bell-Bhapea  starch  grains. — 
After  Sachs. 

Fisir.  65.— Laticiferoaa  vessels  of  Seononera  higpaniea.  A,  a  transverse  section  of 
the  pbloCm  of  the  root ;  B.  the  same  more  highly  magnified.— After  Sachs. 

fibres  may  now  be  separated  under  a  disserting:  microscope,  or  the 


I  at  least,  the  fibres  are  not  cell-derivatives,  and  the  partitions  the 
persistent  walls  of  the  original  component  cells. 


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76 


BOTANY. 


specimens  may  be  transferred  to  a  glass  slide  and  dissected  by  tapping 
gently  upon  the  centre  of  the  coyer-glass. 

103. — LatioiferoiiB  Tissue.     In  many  orders  of  Phanero- 
gams tissues  are  found  whose  component  elements  contain  a 
milky  or  colored  fluid — ^the  latex.     To  these,  although  vary- 
ing greatly  in  structure  and  position,  the  general  name  of 
Laticiferous  tissues  has  been  given.     For  the  sake  of  simpli- 
city two  general  forms  may 
be   distinguished :    (1)    that 
composed  of  simple  or  branch- 
ing  elements  (Fig.  64),  which 
are    scattered    through    the 
other  tissues.     As  found  in 
EuphorhiacecBy  where  they  oc- 
cur in  parenchyma,  they  are 
somewhat  simply  branched, 
and    have  very  thick    walls 
(Fig.  64,  B) ;  in  other  orders 
they  are  thin  walled  and  are 
sometimes  inclined  to  anasto- 
'  mose.    From  their  position  it 
is  quite  certain  that  the  ele- 
ments of  this  form  of  laticif- 
!  erous  tissue  frequently  replace 
bast  fibres.      In  such  cases 
«  *-    T  ..'^s  n    **u      I      they  are  said  to  be  metamor- 

Pig.  «6 —Laticiferous  cellB of  the  onion.      ,   •'     ,    ,       ,    «,  ^  .        ,, 

from  a  longitndinal  eeciion  of  a  Kale  of  phoscd  bast  fibres  I*  in  other 
the  bulb.   «,  epidermis  with  cnticle  e  ;  p,  ,  x i 

parenchyma ;  »g,  coagulated  contents  of  CaSCS,  hOWeVCr,  tlicy  appear 
utticiferouB cells,  contracted  so  as  to  show  ,^^.  i^  i  ^  _•  ^\.\a  v>n4-i<.--^  V.1-.4- 
the  porous  waUs;  g.  g,  transyene  wall.-  not  to  be  Of  thlS  nature,  but 

After  Sachs.  ^  ^^^  from  the  parenchyma 

by  the  absorption  of  the  horizontal  partition- walls,  f 

*  There  is  an  objection  to  the  word  metamorpho.«ed  in  this  connec- 
tion, as  it  does  not  exactly  express  the  relation  between  the  laticiferous 
elements  and  the  bast  fibres.  It  most  not  be  understood  that  the 
former  are  made  by  a  transformation  of  the  farmed  bast  fibres ;  the 
relation  is  rather  that  they  develop  from  what  under  other  circum- 
stances would  have  developed  into  bast  fibres.  We  may  express  the 
relation  by  saying  that  laticiferous  elements  and  bast  fibres  are  closely 
related  sister  elements. 

f  **  According  to  Hanstein,  it  is  probable  that  in  some  Aroiden  vesselt 


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THE  PRINCIPAL  TISSUES,  77 

(2.)  The  other  form  is  that  composed  of  reticulately  anas- 
tomosing vessels.  Here  the  tissue  is  the  result  of  the  fusion 
of  great  mimbers  of  short  cells.  The  walls  are  thin  and 
often  irregular  in  outline.  In  Cichoriacem  this  form  of 
laticiferous  tissue  is  very  perfectly  developed  as  a  consti- 
tuent part  of  the  phloem  portion  of  the  fibro-vascular 
bundles  (Fig.  65,  A  and  B). 

(a)  Laticiferous  tissue  has  not  yet  been  shown  to  contain  either  pro- 
toplasm or  nucleus.*  The  latex  is  an  emulsion  of  several  substances, 
some  of  which,  as  caoutchouc  (India-rubber),  gutta-percha,  and  opium, 
are  of  great  economic  importance.  In  some  cases,  as  in  Euphorbia^ 
grains  of  starch  are  contained  in  the  latex  (Fig.  64,  E). 

{b)  The  chemical  composition  of  latex  is  shown  by  the  following 
4UiaIyses,  as  given  by  De  Bary :  f 

Latex  of  Hevea  Ouianensis,  as  determined  by  Faraday  : 

Water  with  an  organic  acid 56.8  per  cent. 

Caoutchouc 31.7    " 

Albumen 1.9    "      ** 

Bitter  nitrogenous  matter,  with  wax.    7.1   **      ** 

Residue  soluble  in  H,  O,  but  insoluble  in  alcohol.  2.9   **      *' 

999 

Latex  of  Oalactodendron  utUe,  as  determined  by  Heintz  : 

Water 57.3  per  cent. 

Albumen 0.4    ** 

Wax  (C,»  H«  O,) 6.8    *' 

Resm  (C,»  H»s  0,) 31.4    " 

Gum  and  sugar 4.7   ** 

Ash 0.4    *' 

100. 

Latex  of  Euphorbia  cyparissian,  determined  by  Weiss  and  Wiesner : 

Water : 72.1  per  cent. 

Resin 15.7  *'      " 

Gum 36  "     " 

Sugar  and  extractive  substances 4.1  *'      *' 

Albumen 0.1  **     " 

Ash 0.9  "      ** 

96.5 

of  the  xylem  assume  the  form  and  function  of  laticiferous  vessels." 
Sachs*  *•  Text-Book  of  Botany,"  English  edition,  p.  110. 

*  The  latex  of  some  Cichoriaceae  coagulates  much  like  protoplasm ; 
possibly  further  investigation  will  show  it  to  be  present. 

t  "Anatomic  der  Vegetationsorgane,"  etc.,  p.  194. 


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78  BOTANY. 

(e)  Examples  of  the  simpler  forms  of  laticiferous  tissue  may  be  ob- 
tained for  study  from  Buphorbiaeea,  UrUcacea,  Asdepiadacea,  Apocy- 
nacea.  Forms  less  simple  occur  in  Araeem,  and  in  the  maple  ;  in  the 
last-mentioned  they  appear  to  replace  the  sieye-Yessels.  Related  to 
these  again  are  the  peculiar  milk-vessels  of  the  onion  (Fig.  66),  which 
consist  of  elongated  cells  separated  by  thin  or  perforated  septa. 


Fig.  67.  —  Longitadin*! 
section  through  the  sieve 
tissfae  of  Cucurbita  P^to. 
g,  q^  section  of  transverse 
sieve  •  plates  ;  H,  lateral 
sieve-plate  ;  cd,  thin  places 
in  wall ;  /,  the  same  seen  in 
section ;  p$^  protoplasmic 
contents  contracted  by  the 
alcohol  in  which  the  speci- 
mens were  soaked  ;  ap,  pro- 
toplasm lifted  oA  from  the 
sieve-plate  by  contraction ; 
d^  protoplasm  still  in  con- 
tact with  the  sieve-plate ;  «, 
parenchyma  between  sieve 
tabes.  X  550.  —After 
Sachs. 


(d)  The  more  complex  or  reticulated  forms  of  laticiferous  tissue 
occur  in  Cichoriaceoi,  Campantdacecg,  Lobeliaeea,  OcmvolvulacecB,  Pct- 
paveraceoB, 

(e)  By  heating  thin  sections  of  any  of  the  foregoing  plants  in  a  di- 
lute solution  of  potash  the  laticiferous  tissues  may  be  readily  isolated 
for  study. 

0)  The  walls  of  the  laticiferous  elements  are  always  rich  in  water, 
and  are  composed  of  cellulose,  as  may  be  shown  by  the  blue  coloration 
which  follows  treatment  with  Schultz's  Solution. 


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THE  PRINCIPAL   TISSUES, 


79 


104. — Sieve  Tissue.  As  found  in  the  Angiosperms  this 
tissue  is  made  up  of  sieye  ducts  and  the  so-called  latticed 
cells.  The  former  (the  sieve  ducts)  consist  of  soft,  not 
lignified,  colorless 
tubes  of  rather  wide 
diameter,  having  at 
long  intervals  horizon- 
tal or  obliquely  placed 
perforated  septa.  The 
lateral  walls  are  also 
perforated  in  restrict- 
ed areas,  called  sieve 
discs,  and  through 
these  perforations  and 
those  in  the  horizontal 
walls  the  protoplasmic 
contents  of  the  con- 
tiguous cells  freely 
unite  (Figs.  67  and 
68).  In  many  plants 
the  sieve  discs  close  up 
in  winter  by  a  thick- 
ening of  their  sub- 
stance (Fig.  69). 

Tlie  tissue  composed 
of  these  ducts  is  gene- 
rally loose,  and  more 
or  less  intermingled 
with  parenchyma;  in 
some  cases  even  single 
ducts  run  longitudin- 
ally through  the  sub- 
stance of  other  tissues. 
In  the  form  described 


Fig.  68.~Longltadlnal  tangential  section  of  the 
. ^^^  ^ 

plat 
tube,  at  the  top  of  tne  ilgare  a  lateral  plate  is 


vinifera)^  taken  In 
beginning  of  Jdly.'  «, «,  sieve  tabes,  with  see- 
ks of  the  transvene  plates— in  the  left-hand  sieye 


young  bark  of  the  grape  ( 

the  beginning  of  Joly.   «,  < . 

lions  of  the  transverfe  platei 


above  it   is  found  only    shown :  m,  m.  medullary  rays,  with  crystals  in 

.     .  "^     some  or  the  cells — between  the  sieve  tubes  them- 

as    one  of  the  COmpo-    selves,  and  between  them  and  the  medullars-  ray«, 

ncnts  of  the  phloSm  «^«»^~^JiJ1^ta.y»«  »"»«>»  J-^-fiy-") 
portion  of  the  fibro- vascular  bundle. 

105.  —  The  so-called  latticed  cells  are  probably  to  be 


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80 


BOTANY. 


regarded  as  undeveloped  sieve  ducts,  and  hence  the  tissue 
they  form  may  be  included  under  sieve  tissue.  Latticed 
cells  are  thin-walled  and  elongated  ;  they  differ  from  true  sieve 
ducts  principally  in  being  of  less  diameter,  and  in  having 
the  markings  but  not  the  perforations 
of  sieve  discs.  Both  of  these  differences 
are  such  as  might  be  looked  for  in  un- 
developed sieve  tissue. 

loe. — In  the  corres- 
ponding parts  of  the  vas- 
cular bundles  of  Gymno- 
sperms  and  Pterido- 
phytes  a  sieve  tissue  is 
found  which  differs 
somewhat  from  that  in 
Angiosperms.  In  Gym- 
nosperms  the  sieve  discs, 
which  are  of  irregular 
outline,  occur  abundant- 
ly upon  the  oblique  ends 
and  radial  faces  of  the 
Pig.  eo.  —  Longitndinti  broad    tubcs  (Fig.    70). 

you?S*  bark  of  the  grape,  In       PteridophjteS      the 

I'SSJrfr^Ve'^S.S  tubes       have      raiying 

Slf??^&SS.'"?S(!rifo™«;      ill    Equisdum 
After  DeBarj.  and   OpMoglossum  they 

are  prismatic,  with  numerous  horizontal  but 
not  vertical  sieve  discs  ;  in  Pteris  and  many 
other  ferns  they  have  pointed  extremities, 
and  are  greatly  elongated,  bearing  the  sieve 
discs  upon  their  sides  (Fig.  71).  In  the 
larger  LycopodiaceAje  the  sieve  tubes  are  pris- 
matic and  of  great  length ;  in  the  smaller  JS^fem^/he rfeve 
species  there  are  tissue  elements  destitute  of  plates  arepiacediat- 

*  ,  eraily  ana  are  com- 

Sieve  discs,  but  which  are  otherwise,  includ-  posed  of  rMnyUuie 

.       ii  .  ^1      1-1       .,       punctured    areas 

mg    position  m  the    stem,  exactly  like  the  grouped  together  ir- 

.  J       i        -    . ,      1  •  regularly,     x  876.— 

Sieve  ducts  of  the  larger  species.  After  De  Bary. 

(a)  Good  epecimens  of  sieye  tissue  may  be  obtained  for  study  by 
making  longitudinal  sections   of  the  stems  of  CucurbUa,  CueiimiSt 


W}i 


Fig.  70.  ~  Radial 
view  of  the  end  of  a 
sieve  tube  of  Seauoia 
qiganUa^  taken 
tram 


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THE  PRINCIPAL   TISSUES.  81 

EMnocyOis,  Ecbalium,  Vitis,  Bignonia,  and  Calnmus  Eotang ;  alao 
Abies  peetinata,  Larxx,  Juniperus,  Sequoia,  And  Ginkgo/  hXeo  Pteris, 
Otmunda,  Equisetum,  and  Lycopodium, 

(&)  By  making  repeated  liorizontal  sections  the  horizontal  sieve  discs 
may  be  found  and  studied. 

(c)  Alcoholic  specimens  afford  much  more  satisfactory  results  than 
firesh  ones ;  especially  is  this  the  case  with  the  more  succulent  plants. 


F!g.  Tl.'Sieve  tlanie  of  Pt4ri»  aquUina.  A,  end  of  a  Bieve  tube  isolated  by  macer- 
ation :  B,  portion«  of  two  tubes  seen  in  vertical  section  ;  in  t'  the  sieve  plates  are 
seen  in  front  view ;  at  c,  c,  they  are  seen  in  section ;  the  tnbe  t*  has  sieve  plates 
on  ita  right  and  left  walls,  but  none  on  its  farther  wall,  which  is  in  contact  with  pa- 
renchymaKsells ;  two  of  the  latter  are  seen  to  have  nuclei  in  them,  x  875.— After  l)e 
Bary. 

107. — ^Tracheary  Tissue.  Under  this  head  are  to  be 
grouped  those  vessels  which,  while  differing  considerably  in 
the  details,  agree  in  having  thickened  walls,  which  are  perfo- 
rated at  the  places  where  similar  vessels  touch  each  other.  The 


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82  BOTANY. 

thickening,  and  as  a  consequence  the  perforations,  are  of 
various  kinds,  but  generally  there  is  a  tendency  in  the  former 
to  the  production  of  spiral  bands ;  this  is  more  or  less  evident 
even  when  the  bands  form  a  network.  The  transverse  parti- 
tions, which  may  be  horizontal  or  oblique,  are  in  some  cases 
perforated  with  small  openings,  in  others  they  are  almost  or 
entirely  absorbed.  The  diameter  of  the  vessels  is  usually 
considerably  greater  than  that  of  the  surrounding  cells  and 
elements  of  other  tissues,  and  this  alone  in  many  cases  may 
serve  to  distinguish  them.  When  young  they  of  course  con- 
tain protoplasm,  but  as  they  become  older  this  disappears, 
and  they  then  contain  air. 

108. — Tracheary  tissue  is  found  only,  in  Pteridophytes 


Fig.  72.— Longitudinal  section  of  a  portion  of  the  8t«m  of  ImpaUeni  BaUamina.  v.  a 
ringed  vessel ;  t/,  a  vessel  with  rings  and  short  spirals ;  r'^  a  vessel  with  two  spirals; 
t/"  and  r"",  vessels  with  branching  spirals ;  «"'",  a  vessel  with  irregolar  thicken- 
ings, forming  the  reticulated  vessel.— After  Doehartre. 

and  Phanerogams.     The  principal  varieties  of  vessels  found 
in  tracheary  tissues  are  the  following  : 

(1.)  Spiral  Vessels,  which  are  usually  long,  with  fusiform 
extremities  ;  their  walls  are  thickened  in  a  spiral  manner 
with  one  or  more  simple  or  branched  bands  or  fibres  (Fig. 
72,  v",  v'",  v"").  This  form  may  be  regarded  as  the  typical 
form  of  the  vessels  of  tracheary  tissue.  In  most  cases  the 
direction  of  the  spiral  is  from  right  to  left  *  It  is  frequent- 
ly in  one  direction  in  the  earlier  formed  spirals  and  the  op- 

*  Right  to  left,  in  speaking  of  these  spirals,  as  also  in  describinfr  the 
twining  of  certain  climbing  plants,  is  passing  up  and  around  in  the  di- 
rection of  the  hands  of  a  watch.  Left  to  right  is  of  course  up  and 
around  opposite  to  the  hands  of  a  watch. 


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THE  PRINCIPAL  TISSUES. 


83 


posite  in  those  formed  later;  while  in  interrupted  spirals 
both  directions  occur  in  the  same  vessel.    Ringed  and  reticu^ 
lated  vessels  are  opposite  modifications  of  the  spiral  form ; 
A 


C3 


Fig.  73.~Scft]arifonn yessels  of  the  rhtzomA  of  Pteris  aquUlna.  A,  longitudinal  sec- 
tion of  en  end  (about  one  third  of  the  whole)  of  a  ehort  veB8el :  /,  the  fasiform  ex- 
tremity, with  longpito  placed  transversely;  B,  a  small  portion  of  ^,  taken  from  a;, 
and  mach  more  higlily  maffiiifled ;  C,  a  longitudinal  section  of  a  portion  of  the  side 
wall  between  two  yessels ;  l)^  a  similar  section  throogh  the  inclined  end  wall  {A,f\ ; 
in  the  npper  part  of  />,  at/ the  wall  between  the  thickening  ridges  Is  broken  through. 
A,  X  143  ;  the  others  x  ^.— After  De  Bary. 

the  first  are  due  to  an  under-development  of  the  thickening 
forces  in  the  young  vessels,  resulting  in  the  production  here 
and  there  of  isolated  rings  (Fig.  72,  v) ;  reticulated  vessels 
are  due,  on  the  contrary,  to  an  over-development,  which 


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84  BOTANY. 

gires  rise  to  a  complex  branching  and  anastomosing  of  the  ■ 

spirals  (Fig.  72,  v'""). 

(2.)  Scalariform  vessels.  These  are  prismatic  vesselawhose 
walls  are  thickened  in  such  a  way  as  to  form  transverse 
ridges,  as  described  in  paragraph  32,  page  28.  They  are  wide 
in  transverse  diameter  and  their  extremities  are  fusiform  or 


Pig.  74.  Pio.  75. 

Pig.  74.-PItted  vewela  of  ArUMoehia  Hpho,  from  a  longltndinal  8«ct!on  of  the 
stem  ;  the  vwmjI  on  ihe  right  Is  seen  in  section,  that  on  the  left  from  withoat ;  a,a, 
rings,  which  are  remnants  of  the  original  transverse  partitions  ;  b,  b,  sections  of  the 
'^^r  '•  i^^^^^'°  the  vessels  are  parenchyma^ells,  highlv  magnified.- After  Dnchartre. 

Fig.  <5.— Tracheldes  of  Cyth-us  laburnum,  from  a  longitudinal  Ungentlal  section 
of  the  i*tem ;  m^m,  a  cross-section  of  a  medullary  ray  :  in  three  of  the  cells  the  pitted 
partitions  are  seen  ;  the  mednllHry  ray  is  surrounded  by  tracheldes,  which  are  spi- 
rally marked  and  |«paringly  pitted  ;  at  a,  two  tracheldes  have  fused  by  the  breaking 
of  the  wall ;  #,  #,  slightly  modified  cauibium-cells.    x  376.— After  Dc  Bary. 

f orated  horizontal  or  inclined  septa  (Fig.   74);    in  other 
forms  they  have  fusiform  extremities. 

(4.)  Tracheldes.     These  consist  for  the  most  part  of  single 
closed  cells,  or  of  elements  which  closely  resemble  cells; 


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THE  PRINCIPAL  TISSUES.  85 

otherwiae  they  possess  the  characters  of  vessels.  In  one  form, 
as  in  the  so-called  wood-cells  of  Oymnosperms  (see  paragraph 
30,  page  25)  they  resemble  on  the  one  hand  the  pitted  ves- 
sels, and  on  the  other  the  fibres  of  the  wood  of  Angio- 
spenns.  Eveiy  gradation  between  these  tracheldes  and  the 
other  forms  of  tracheary  tissue  occur.  In  another  form,  as  in 
Cytisus  and  Celtis,  the  tracheldes  are  shorter  than  in  the 
preceding,  quite  regular  in  their  form,  and  with  tapering 
extremities  (Fig.  75).  Their  walls  are  but  slightly  thickened, 
and  are  marked  with  spirals  and  pits.  When  the  wall  be- 
tween two  contiguous  cells  brejiks  through  or  becomes  ab- 
sorbed the  close  relation  of  such  tracheldes  to  spiral  vessels 
is  readily  seen. 

Tracheldes  may  be  regarded  as  composing  a  less  diflferen- 
tiated  form  of  tissue,  related  on  the  one  hand  to  true  tra- 
^eary  tissue  and  on  the  other  to  fibrous  tissue. 

(a)  Speciuiens  of  spiral  vessels  with  the  spirals  passing  from  right 
to  left  may  be  obtained  by  making  longitudinal  sections  of  the  stems 
of  Malta  Totundifolia,  Impatiens  BaUamina.  and  many  other  plants. 
If  tbe  thin  slices  are  macerated  in  nitric  acid  and  potassium  chlorate 
the  structure  may  be  studied  to  still  better  advantage.  The  spirals  in 
the  yessels  of  Pinus  aylve^ris  pass  from  left  to  right ;  tbey  may  be 
examined  in  longitudinal  sections  of  the  leaves  or  young  twigs.  The 
stems  of  Viti$  tinifera,  Berberis  vulgaris^  Bignonia  eapreolata,  and  Ar* 
tenUtia  ahrotanum  furnish  examples  of  vessels,  the  first  formed  of 
which  have  their  spirals  running  from  right  to  left  and  the  later  ones 
from  left  to  right.  Interrupted  spirals  showing  the  two  directions  may 
be  found  in  stems  of  CucuHnta. 

(b)  Examples  of  scalariform  vessels  may  be  obtained  with  the  greatest 
ease  from  the  rhizomes  of  ferns — eg,,  of  Pteris  ;  it  may  also  be  obtained 
from  many  Dicotyledons — e.g.,  the  stems  of  Vitis, 

(e)  Fine  specimens  of  pitted  vessels  may  be  studied  in  longitudinal 
sections  of  many  kinds  of  wood — e.g. ,  Pints,  Quereus,  and  Liriodendron  ; 
among  herbs,  ImpcUiens  and  Bicintis  furnish  good  examples. 

(d)  In  order  to  study  the  tracheldes  of  the  Oymnosperms  thin  slices 
of  the  wood— of  Pinus,  for  example— should  be  heated  for  some  time  in 
nitric  add  and  potassium  chlorate.  By  this  means,  after  transferring 
to  a  glass  slide  and  covering  in  the  usual  way,  the  tracheldes  may  be 
easUy  isolated  by  gently  tapping  upon  the  cover-glass. 

(«)  Tracheldes  of  the  second  form  are  easily  studied  in  horizontal  and 
longitudinal  sections  of  the  wood  of  Celtis, 


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86  BOTANY. 

%  III.   The  Primary  Meristem.* 

100. — Under  this  name  are  grouped  the  unformed  and 
growing  tissues  found  at  the  ends  of  young  stems,  leaves,  and 
roots.  In  these  parts  the  tissues  described  above  (paragraphs 
99  to  108)  have  not  yet  formed  ;  they  are,  on  the  contrary, 
composed  entirely  of  a  mass  of  thin-walled,  growing,  and 
dividing  cells  containing  an  abundance  of  non-granular  pro- 
toplasm. In  the  lower  plants  the  meristem-cells  do  not 
change  much  in  their  configuration  or  general  structure  as 
they  develop  into  the  ordinary  plant-cells ;  but  the  higher 
the  type  of  plant,  the  greater  are  the  changes  which  take 
place  during  the  development  of  meristem  into  permanent 
tissues. 

110. — In  most  of  the  plants  outside  of  the  Phanerogams 
the  primary  meristem  is  the  result  of  the  continually  repeated 
division  of  a  single  mother-cell  situated  at  the  apex  of  the 
growing  organ.  In  the  simplest  forms  this  apical  cell  is  the 
terminal  one  of  a  row  of  cells,  as  in  many  alg»  and  fungi. 
The  apical  cell,  in  such  cases,  keeps  on  growing  in  length, 
and  at  the  same  time  horizontal  partitions  are  forming  in  its 
proximal  portion.  In  this  way  long  lines  of  cells  may 
originate. 

In  the  more  complicated  cases  the  segments  cut  off  from 
the  apical  cell  grow  and  subdivide  in  different  planes,  so  as 
to  give  rise  to  masses  of  cells.  The  partitions  which  succes- 
sively divide  the  apical  cell  are  sometimes  perpendicular  to 
its  axis,  but  more  frequently  they  are  oblique  to  it.  In  most 
mosses,  for  example  (Fig.  76),  the  apical  cell  is  a  triangular, 
convex-based  pyramid,  whose  apex  is  its  proximal  portion. 
The  successive  segments  are  cut  off  from  the  apical  cell  by 
alternate  partitions  parallel  to  its  sides,  thus  giving  rise  to 
three  longitudinal  rows  of  cells.  Most  Pteridophytes  have 
an  apical  cell  not  much  different  from  that  of  the  ma- 
jority of  mosses.  In  Equisetum,  for  example,  it  is  an  in- 
verted triangular  pyramid,  having  a  convex  base  (Fig.  77  ; 

*  From  the  Greek  fiipoi,  part,  and  rifiviev,  to  cut  off.  This  tissue  is 
sometimes  called  Proto-meristem. 


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PRIMARY  MERISTEM,  87 

Ay  side  yiew,  By  a  section).  The  segments  (daughter-cells) 
are  cut  oflf  by  alternating  partitions  parallel  to  the  plane 
sides  of  the  pyramid,  as  in  the  mosses.  In  some  of  the 
Bryophytes  and  Pteridophytes  the  apical  cell  is  wedge-shaped 
— i.e.y  with  only  two  surfaces — and  in  such  cases  two  instead 
of  three  rows  of  meristem-cells  are  formed. 

111. — In  the  Phanerogams  the  Primary  Meristem  is  de- 
veloped from  a  group  of  cells,  instead  of  from  a  single  one  ; 
they  therefore  have  no  apical  cell.      This  group  of  cells 


Fig.  76.— Lon^tndinal  section  of  ap«x  of  Ptem  of  a  moss  {Fontinalit  anUpyrttiodS. 
V,  w^aiX  cell,  forming  eeffments-  (8  rows),  each  Begmeut  divided  into  an  outer  cell, 
a,  and  an  inner  one— the  former  develops  cortex  of  the  8tem  and  a  leaf,  the  latter 
the  inner  timae  of  the  stem ;  t,  apical  cell  of  lateral  leaf-forming  shoot,  arising 
below  a  leal ;  c,  first  cell  of  leaf ;  6,  cells  forming  cortex.— After  Leitgeb. 

occupies  approximately  the  same  position  in  the  organs  of 
Phanerogams  a»  the  apical  cell  does  in  the  Bryophytes  and 
Pteridophytes ;  it  is  composed  of  cells  which  have  the  power 
of  indefinite  division  and  subdivision. 

112. — The  a])ical  cell,  and  its  actively  growing  daughter- 
cells  in  its  immediate  vicinity,  or  in  the  case  of  the  Phanero- 
gams the  apical  group  of  cells,  with  their  daughter-cells, 
constitute  the  Growing  Point  or  Vegetative  Point  (Punctum 
vegetaiionis)  of  the  organ.  When  this  active  portion  is 
conical  in  shape  it  is  the  Vegetative  Cone  of  some  authors. 


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88 


BOTANY. 


(a)  Primary  Meristem  tissue  may  be  readily  obtained  for  study  by 
making  tbin  longitudinal  sections  of  tbe  tips  of  growing  abocts  of 
Equisetum,  PhaseoluB,  Hippuris,  and  tbe  roots  of  Pteris,  Zea,  Impa- 
tiens,  etc,  or  by  carefully  dissecting  out  tbe  youngest  rudiments  of  tbe 
leaves  of  many  Monocotyledons. 

Tbe  value  of  tbe  specimen  will  often  be  increased  by  staining  it 
witb  carmine. 

(b)  Tbe  apical  cell,  wbicb  may  be  seen  in  tbe  best  of  tbe  above-men. 


Fig  77.— The  growing  point  of  the  stem  of  BqtUteium  sHrpokUi.  A^  ieen  from 
without,  showing  the  apical  cell  at  the  top  ;  the  mmierals  1,  8, 4,  etc,  indicate  the 
order  or  the  formation  of  the  partitions  of  the  apical  cell;  that  marked  1  is  the  laat 
formed,  8  the  third  from  the  last,  etc  ;  between  4  and  7  on  the  right,  and  6  and  9  on 
the  left,  are  the  partitions  which  form  after  the  primary  ones;  B,  a  vertical  section  of  A, 

tioned  sections  of  EquUetum  and  PUrU,  sbould  also  be  studied  by 
making  extremely  tbin  cross-sections  of  tbe  apical  portion  of  tbe 
Vegetative  Ck>ne ;  tbe  triangular  sbape  of  tbe  apical  cell  can  tbus  be 
made  out. 

Tbe  simple  side  view  of  tbe  isolated  Vegetative  Cone  is  also  instruo 
tive  wben  so  prepared  tbat  it  can  be  rotated  under  tbe  microscope. 


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CHAPTER  VII. 

TISSUE  SYSTEMS. 
§  L — ^Thb  Differbktiatiox  of  Tissues  into  Systems, 

113. — It  rarely  happens  that  the  tissues  which  compose 
the  body  of  a  plant  are  uniform.  In  the  great  majority  of 
cases  the  cells  of  the  Primary  Meristem  become  differently 
modified,  so  as  to  give  rise  to  several  kinds  of  tissues.  The 
outer  cells  of  the  plant  become  more  or  less  modified  into  a 
boundary  tissue,  and  the  degree  of  modification  has  relation 
to  its  environment  Certain  inner  cells,  or  lines  of  cells,  be- 
come modified  into  sclerenchyma,  or  some  other  supporting 
tissue  (collenchyma,  or  fibrous  tissue),  and  here  again  there 
is  a  manifest  relation  to  the  environment  of  the  plant.  Cer- 
tain other  inner  cells,  or  rows  of  cells,  become  modified  into 
tubes  affording  a  ready  means  for  conduction,  and  appear  to 
have  a  relation  to  the  physical  dissociation  of  the  organs  of 
the  higher  plants,  in  which  only  they  occur.  Thus,  in  phy- 
siological terms,  there  may  be  a  boundary  tissue,  a  support- 
ing tissue,  and  a  conducting  tissue,  lying  in  the  mass  of  less 
differentiated  ground  tissue. 

114. — In  different  groups  of  plants  the  elementary  tissues 
described  in  previous  paragraphs  (99  to  108)  are  aggregated 
in  different  ways,  and  are  variously  modified  to  form  these 
bounding,  supporting,  and  conducting  parts  of  the  plant. 
Several  tissues,  or  varieties  of  tissue,  are  regularly  united  or 
tiggregaieA  in  particular  ways  in  each  plant,  constituting 
what  may  be  called  Groups  or  Systems  of  Tissues.  A  Tis- 
sue System  may  then  be  described  as  an  aggregation  of  ele- 
mentary tissues,  forming  a  definite  portion  of  the  internal 
structure  of  the  plant.     From  what  has  already  been  said,  it 


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90  BOTANY. 

is  clear  that  systems  of  tissue  do  not  exist  in  the  lowest 
plants,  and  that  they  reach  their  fullest  development  only 
in  the  highest  orders.  It  is  evident  also  that  these  systems 
have  no  existence  in  the  youngest  parts  of  plants,  but  that 
they  result  from  a  subsequent  development. 

116. — Many  systems  of  tissue  might  be  enumerated  and 
described ;  but  here  again,  as  with  the  elementary  tissues, 
while  there  are  many  variations,  there  ai*e  also  many  grada- 
tions, having  on  the  one  hand  a  tendency  to  give  us  a  long 
list  of  special  forms,  and  on  the  other  to  reduce  them  to  one, 
or  at  most  to  two  or  three.  The  three  systems  proposed 
by  Sachs  are  instructive,  and  will  be  followed  here  ;  they 
are :  (1)  the  Fundamental  System,  which  includes  the  mass 
of  unmodified  or  slightly  modified  tissues  found  in  greater  or 
less  abundance  in  all  plants  (except  the  lowest) ;  (2)  the 
Epidermal  System,  composed  mainly  of  the  boundary  cells 
and  their  appendages  (hairs,  scales,  stomata,  etc.)  ;  (3)  the 
Fibro-vascular  System,  comprising  those  varying  aggrega- 
tions of  tissues  which  make  up  the  string-like  masses  found 
in  the  organs  of  the  higher  plants. 

§  II. — The  Epidermal  System  of  Tissues. 

lie. — ^This  is  the  simplest  tissue  system,  as  it  is  the  ear- 
liest to  make  its  appearance,  in  passing  from  the  lower  forms 
to  the  higher.  It  is  also  (in  general)  the  first  to  appear  in 
the  individual  development  of  the  plant.  It  is  sometimes 
scarcely  to  be  separated  from  the  underlying  mass,  as  in 
most  higher  Thallophytes  and  Bryophytes ;  and  here  it  is 
composed  of  but  one  tissue — ^parenchyma — or  of  two  or  more 
slight  variations  of  it.  In  Pteridophytes  and  Phanerogams, 
while  it  may  be  very  simple  in  some  (aquatic)  plants,  it  fre- 
quently attains  some  degree  of  complexity,  and  is  sharply 
separated  from  the  underlying  ground  tissues. 

117. — In  the  simpler  epidermal  structures  of  the  Thallo- 
phytes the  cells  are  generally  darker  colored,  smaller,  and 
more  closely  approximated  than  they  are  in  the  subjacent 
mass  ;  in  some  higher  fungi  a  boundary  tissue  may  be  easily 
separated  as  a  thickish  sheet,  but  probably  in  such  case  a 


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THE  EPIDERMAL  SYSTEM.  91 

portion  of  tlie  underlying  mass  is  also  removed.  In  many 
of  the  Thallophytes  there  is  absolutely  no  differentiation  of 
an  epidermal  portion. 

118. — In  the  Bryoi)liytes  there  is  in  general  a  poor  epider- 
mal development ;  it  is  composed  for  the  most  part  of  one 
or  more  weakly  defined  layers  of  smaller  cells,  which,  how- 
ever, pass  by  insensible  gradations  into  the  inner  tissue 
mass.  Here,  however,  the  first  true  epidermal  hairs  make 
their  appearance. 

119. — In  one  group  of  the  Liverworts — the  MarchaniiacecB 


Fig.  Ta—Longitadliial  section  of  erect  portion  of  thallos  of  Marchantia  pnlymor- 
-pha.  o,  epidermis ;  ^  walls  beiweea  uir-spaces,  the  latter  filled  with  rowsof  cnloro- 
phyll-bearing  cells,  efU ;  sp,  a  stoma ;  ^,  a  large  parenchyma-cell,  x  fiSO.— After  Sachs. 

— there  is  an  epidermal  system  of  a  high  degree  of  perfection, 
and  composed  of  epidermis  proper  and  stomata  (Fig.  78). 
The  epidermis  consists  of  a  single  layer  of  somewhat  tabu- 
lar cells  arching  over  the  air-cavities  which  occupy  the  upper 
surface  of  the  plants  ;  it  is  perforated  here  and  there  by  sto- 
mata or  breathing  pores,  composed  of  four  to  eight  circular 
rows  of  cells  placed  one  above  the  other  {sp  in  the  figure). 
These  chimney-like  structures  originate  by  the  division  of  a 
single  cell  into  four  or  six  radiating  daughter-cells  ;  in  the 
centre  of  this  group  an  intercellular  pore  is  formed  by  the 
lateral  growth  of  the  cells  (Fig.  79)  ;  and  by  a  subsequent 


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92  BOTANY. 

horizontal  division  the  several  saperimposed  circular  rows 
of  cells  arc  formed. 

120. — In  true  mosses  the  sporangia  possess  an  epidermal 
system  which  is  composed  of  a  layer  of  strongly  cuticular- 
ized  cells — the  epidermis — sometimes  provided  with  stomata. 
Other  portions  of  the  plant,  aside  from  the  eixirangia,  are 
destitute  of  a  true  epidermis  or  of  stomata. 

121. — The  epidermal  systems  of  Pteridophytes  and  Phaner- 
ogams are  so  much  alike  that  they  may  be  described  together, 
although  it  must  be  remembered  that  in  the  latter  group 
they  are,  in  general,  somewhat  more  perfect  than  in  the  for- 
mer.    In  these  groups  the  epidermal 
structures  consist  usually  of  three  por- 
tions :   (1)  a  layer  of  more  or   less 
modified   parenchyma — the  epidermis 
proper — bearing  two   other  kinds  of 
structures  which  develop  from  it,  viz., 
(2)  trichomes,  and  (3)  stomata. 

122.— Epidermis.    The   differentia- 
tion of  parenchyma  in  the  formation 
p  of  epidermis,  when  carried  to  its  ut- 
most extent,  involves  three  different 
^  -  modifications   of    the   cells,   viz.,   (1) 

rt^taorIS?«i!Siapo5'-  change  of  form,  (2)  thickening  of  the 
3fgSiSi  ^xi.Tc%m^  walls,  (3)  disappearance  of  the  proto- 
StniV/^'tiSLch'T^^  Pl«*™'^  contents.  These  three  modi- 
«/,  gua^-cefiB —After  Sachs,  fications  may  occur  in  varying  de- 
grees of  intensity ;  they  may  all  be  slight,  as  in  many  aquatic 
plants  and  in  the  young  roots  of  ordinary  plants ;  or  the  cells 
may  change  their  form,  while  there  may  be  little  thickening 
of  their  walls,  q&  in  other  aquatic  plants,  and  some  land  plants 
which  live  in  damp  and  shady  places  ;  or  on  the  other  hand, 
the  change  of  form  of  the  cells  may  be  but  little,  while 
their  walls  may  have  greatly  thickened,  resulting  in  a  disap- 
pearance of  their  protoplasm,  as  may  be  seen  in  parts  of 
some  land  plants  which  grow  slowly  and  uniformly.  When 
the  differentiation  of  epidermis  is  considerable,  it  can  usu- 
ally be  readily  removed  as  a  thin  transparent  sheet  of  color- 
less cells. 


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TEE  EPIDERMAL  STSTEM:  93 

128. — ^The  change  in  tho  form  ot  the  epidermal  cells  is 
due  to  the  mode  of  growth  of  the  organ  of  which  they  form 
a  part ;  the  lateral  and  longitudinal  growth  of  an  organ 
causes  a  corresponding  extension  and  consequent  flattening 
of  the  cells ;  if  the  growth  has  been  mainly  in  one  direction, 
as  in  the  leaves  of  many  Monocotyledons,  and  the  young 
shoots  of  many  Dicotyledons,  or  if  the  grovirth  in  two  direc- 
tions has  been  regular  and  uniform,  as  in  the  leaves  of  some 
Dicotyledons,  the  cells  are  quite  regular  in  outline ;  where, 
however,  the  growth  is  not  uniform  the  cells  become  irregu- 
lar, often  extremely  so  (Fig.  89,  page  100). 

124. — ^The  thickening  of  the  walls  is  greatest  in  those 
plants  and  parts  of  plants  which  are  most  exposed  to  the  dry- 
ing effects  of  the  atmosphere.  It  consists  of  a  thickening  of 
the  outer  walls,  and  frequently  of  the  lateral  ones  also.  The 
outer  portion  of  the  thickened  walls  is  cuticularized,  and 
this,  by  a  subsequent  stratification  and  lamellation,  is  separ- 
ated as  a  continuous  pellicle,  the  so-called  cuticle. 

125. — ^The  cuticle  extends  uninterruptedly  over  the  cells, 
and  maybe  readily  distinguished  from  the  other  portions 
of  the  outer  epideimal  walls.  It  is  insoluble  in  concen- 
trated sulphuric  acid,  but  may  be  dissolved  in  boiling 
caustic  potash.  Treated  with  iodine  it  turns  a  yellow  or 
yellowish  brown  color.  A  waxy  or  resinous  matter  is  fre- 
quently developed  upon  the  surface  of  the  cuticle,  constitut- 
ing what  is  called  the  bloom  of  some  leaves  and  fruits.  De 
Bary*  distinguishes  four  kinds  of  waxy  coating,  as  follows  : 
(I)  continuous  layers  or  incrustations  of  wax — e.g.,  on  the 
leaves  and  stems  of  purslane,  the  leaves  of  Fuchsia,  yew,  the 
stems  of  the  wax  palms  {Ceroxylon),  etc.  ;  (2)  coatings  com- 
posed of  multitudes  of  minute  rods  placed  vertically  side  by 
side  upon  the  cuticle — e.g.,  on  the  stems  of  sugar  cane, 
Coxx  lachryma,  and  some  other  grasses ;  (3)  coatings  made 
up  of  minute  rounded  grains  in  a  single  layer — e.g.,  on  the 
leaves  of  the  cabbage,  onion,  tulip,  clove-pink  {Dianthus 

*  *'  Verf^leicbeDde  Anatomie  der  Vegetationsorgane  der  Phaneroga- 
men  und  Fame/'  1877,  p.  87,  where  figures  of  several  of  these  kinds 
are  given. 


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94  BOTANY, 

Caryophyllus),  etc. ;  (4)  coatings  of  minute  needles  or  grains 
irregularly  covering  the  surface  with  several  layers — e.g.,  on 
the  leaves  of  Eucalyptus  globulus,  rye,  etc. 

126. — The  protoplasm  of  the  epidermal  cells  generally 
disappears  in  those  cases  where  there  is  much  thickening  of 
the  walls  ;  it  is  always  present  in  young  plants  and  parts  of 
plants ;  it  is  also  frequently  present  in  older  portions,  which 
are  not  so  much  exposed  to  the  drying  action  of  the  atmos- 
phere, as  in  roots,  and  the  leaves  and  shoots  of  aquatic  plants, 
and  of  those  growing  in  humid  places.  In  few  cases,  how- 
ever, are  granular  protoplasmic  bodies  {e.g.,  chlorophyll)  pres- 
ent in  epidermal  cells.* 

127. — While  the  epidermis  always  consists  at  first  of  but 
one  layer  of  cells,  it  may  become  split  into  two  or  more  lay- 
ers by  subsequent  divisions  parallel  to  its  surface.  These 
layers  may  resemble  the  outer  one  and  have  their  walls 
thickened,  as  in  the  leaves  of  the  Oleander,  or  they  may  con- 
sist of  thin-walled  cells  with  watery  contents  (constituting 
the  so-called  Aqueous  Tissue),  as  in  the  leaves  of  Ficus  and 
Begonia. 

(a)  Epidermis  may  be  Btudied  with  comparatively  little  difficulty. 
In  many  cases  It  may  be  etripped  off  in  thin  sheets  and  mounted  in 
the  usual  way ;  such  preparations,  with  thin  cross-sections  (which  are 
readily  made  by  placing  a  piece  of  leaf  between  pieces  of  elder  pith), 
are  sufficient,  in  most  cases,  to  give  a  jrood  knowledge  of  the  structure. 
The  leaves  of  many  Liliacem  (hyacinths,  lilies,  etc.)  and  Graminea  may 
be  examined  for  regular  cells,  and  those  of  many  Dicotyledons,  as  bal- 
sams, primroses,  and  fuchsias,  for  irregular  ones. 

(6)  Thickened  epidermal  walls  may  be  found  in  leaves  of  a  hard  tex- 
ture, as  those  of  the  pines,  holly,  oleander,  mistletoe,  many  ComponUB, 
and  in  the  stems  of  many  CactacecB,  The  siraiificaUon  of  the  thickened 
walls  may  be  brought  out  in  the  cross-sections  by  heating  in  a  solution 
of  potash. 

(r)  A  series  of  specimens  of  the  epidermis,  taken  from  leaves  of  all 
ajres.from  their  younjrest  and  smallest  rudiments  in  the  bud  up  to  full- 
grown  ones,  is  instructive. 


•  In  the  leaves  of  PrimtUa  sineruis,  grown  in  the  green-house,  the 
epidermal  cells  contain  many  chlorophyll-bodies ;  the  leaves  of  Fuchsias, 
under  similar  conditions,  possess  a  few  chlorophyll-bodies  in  the  epider- 
mal  layer. 


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THE  EPIDERMAL  SYSTEM. 


95 


las.—Triohomes.  Under  this  term  are  to  be  included  the 
outgrowths  which  arise  from  the  epidermis  ;  they  may  have 
the  form  of  hairs,  scales,  glands,  bristles,  prickles,  etc.,  and 
may  be  composed  of  single  cells,  or  of  masses  of  cells. 

They  originate  mostly  from  the  growth  of  single  epidermal 
cells,*  and  on  their  first  appearance  consist  of  slightly  en- 


Fie.  81. 


Fie.80. 


Pig.  80.— TranBverte  lectlon  of  epidermis  and  underlying  tlesne  of  orary  of  Oi$' 
0ifrMto.  a.  hair  of  a  row  of  cells  :  b  and  rf,  glandular  hairs  of  different  ages ;  «,/, 
e,  hairs  in  the  yoangest  stages  of  their  development,    x  100.— After  Prantl. 

Fig.  81.— A  seedling  mnstard  plant  with  its  single  root  clothed  with  root-hairs* 
the  newest  (lowermost)  portion  of  the  root  is  not  yet  provided  with  root-hairs. 

larged  and  protruding  cells  (Fig.  80,  e,  /,  c).  These  may 
elongate  and  form  single-celled  hairs,  which  may  be  simple 
or  variously  branched.  The  most  important  of  these  hairs 
are  those  which  clothe  so  abundantly  the  young  roots  of  most 
of  the  higher  plants,  and  to  which  the  name  of  Eoot-hairs 

*  It  is  probable  that  the  common  Btatemeot  that  tricbomes  al wajs 
deyelop  ftom.  single  cells  must  be  modified. 


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96  BOTANT. 

has  been  applied  (Fig.  81).  These  are  composed  of  single 
cells,  which  have  very  thin  and  delicate  walls  (Fig.  82),  and 
are  the  active  agents  in  the  absorption  of  nutritive  matters 
for  the  plant 


mt.  A^  the  ends  of  three  haira,  one  mnch 
lave  particIeB  of  sand  adhering  to  and  im- 
r  growing  from  the  rooi-cell,  r.    X  900. 

)f  the  hairs  on  aerial  parts  of 
hat  the  terminal  cell  becomes 
in  which  gummy,  resinous,  or 
[ :  sometimes  several  terminal 


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TEE  EPIDERMAL  SX81\bM. 


97 


cells  are  bo  transformed  into  a  secreting  organ, 
tion  appears  as  a  rounded 
pustule,  partly  surround- 
ing the  secreting  cell 
(Figs.  83  to  87),  and 
which  is  removed  upon 
the  slightest  touch.  Tri- 
chomes  of  this  nature  are 
called  glandular  hairs ; 
they  are  exceedingly  vari- 
able in  form,  and  are  not 
infrequently  short  and 
depressed,  when  they  are 
known  as  surface  glands, 
or  glandular  scales  (Fig. 
87). 


The  secro* 


Fig.  88.— Glandular  hairs  from  the  petiole  of 
Primula  atnenHs,  in  several  stages  of  develop* 
mcnt  a,  the  bejrinning  of  the  secretion  iu  tae 
terminal  cell;  6,  nair  with  a  large  mass  of  se- 
creted matter ;  <f,  an  old  hair  after  the  removal 
of  the  secreted  matter,    x  149.— After  De  Bary. 


(a)  Trichomee  are,  in  gene- 
Tal,  easy  objects  of  study. 
In  many  cases  they  may  be 
simply  scraped  off  and  mounted  in  alcohol,  or  in  a  solution  of  potash 


Fka.84. 


Fio.  85. 


Fie.  86. 


Fig.  87. 


Fig.  84.  -of,  the  cell  a  of  Fig.  88  more  highly  magnified ;  a''  the  same  after  removal 
of  the  secretion  by  treatment  with  alcohol.    X  876.— After  De  Bary. 

Fig.  86.— &  end  of  a  hair  with  large  mass  of  secreted  matter  ;  c',  the  same  after 
treatment  with  alcohol,    x  875.— After  De  Bary. 

Fig.  86.— The  end  of  the  hair  d,  in  Fig.  88,  more  hlflihly  magnified,  showing  the  Arag- 
ments  of  the  secretion  pustule  surrounding  the  terminal  cell,  which  still  contains  pro- 
to^asm.    x  875.— After  De  Bary. 

Fig.  87.— Olandnlar  scale  from  the  hop.  A,  in  Its  young  stage ;  B,  the  same  some 
time  afterward— the  secretion  fhim  the  cells  has  pushed  out  the  cuticle  and  filled  the 
■pace  between  it  and  the  cells  (in  the  specimen  from  which  these  were  drawn  the 
secretion  was  removed  by  solution  in  alcohol),  x  142.— After  De  Bary. 

after  wetting  them  with  alcohol  to  free  them  from  entangled  and  en* 
closed  air. 


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98 


BOTANY. 


(&)  One-celled  simple  hairs  may  be  obtained  from  the  vegetatiTe 
organs  of  species  of  (Enothera  and  Brauica  and  many  grasses — 0.^., 
species  of  Panieum — and  from  the  seeds  of  the  cotton  plant ;  the  last 
constitute  the  '*  cotton"  of  commerce. 

{c)  Many-celled  simple  hairs  occur  on  the  filaments  of  Tradeteantia, 
on  leaves  of  the  Primrose,  Ageratum,  Ertgeron  Canadense,  pumpkin, 
and  very  many  others. 

(d)  Branched  one-celled  hairs  occur  in  Capsella,  Braba,  SUymbryum^ 
Alysum,  and  many  other  Cmeifera. 

(e)  Branched  many.celled  hairs  may  be  found  on  the  Mullein  and 
Ivy. 


m  Thistle  (Cnicuf  nlHtHmvt).  A^  yonng  hair  ftom  the  ftem 
iwn  out ;  B^  an  older  hair  more  highly  magniiied,  after  ita  ex- 
wu  ont  into  a  thread-like  laeh ;  (7,  hair  with  a  long  laah  from 
lU-grown  leaf.    Highly  magniiied.— After  Beal. 

r  tufted  hairs  are  found  on  many  Maltaee^B,  and  the 
les  or  peltate  hairs  on  STiepherdia,  ' 

re  best  obtained  for  study  by  growing  seeds  of  mustard, 
s.,  on  damp  cotton  or  blotting-paper,  and  then  mak- 
udinal  sections  of  the  terminal  portion  of  the  root  at 
le  hairs  are  just  appearing  (usually  several  millimetres 
the  root).  By  making  preparations  in  this  way  all 
(lopment  of  these  hairs  may  be  studied  in  the  same 

liairs  are  found  in  many  groups  of  plants  ;  they  may 
inia.  Verbena,  Primula,  Martynia,  and  the  tomato, 
related  to  glandular  hairs  are  the  curious  hairs  from 


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THE  EPIDERMAL  SYSTEM.  99 

which,  as  pointed  out  by  Professor  Beal,*  are  drawn  ont  the  long 
thread*llke  lashes  which  are  so  abundant  on  the  leaves  of  some  thistles 
and  other  CompotUcB  (Fig.  88).  These  lashes  appear  to  be  of  the  na- 
ture of  secretions,  and  they  are  capable  of  being  drawn  out  to  an  aston- 
ishing length.  These  are,  in  turn,  much  like  the  glandular  hairs  on 
the  leaves  of  Dipsaeiu  tyhestris,  discovered  by  Francis  Darwin.f 
and  from  which  motile  protoplasmic  filaments  protrude.  Mr.  Darwin 
oondudes  that  they  have  the  power  of  absorbing  nitrogenous  matter. 

130. — Stomata  (singular,  Stoma).  These  structures  con- 
sist, in  most  cases,  of  two  specially  modified  chlorophyll- 
bearing  cells,  called  the  Guaixi-cells,  which  have  between 
them  a  cleft  or  slit  passing  through  the  epidermis  (Figs.  89, 
90).  These  openings  are  always  placed  directly  over  interior 
intercellular  spaces.  Stomata  are  developed  from,  and  in 
their  distribution  always  have  a  relation  to,  the  epidermal 
cells;  in  an  epidermis  composed  of  regular  cells  there  is 
more  or  less  regularity  in  the  arrangement  of  the  stomata  ; 
but  when  tne  epidermal  cells  are  irregular  the  stomata  are 
also  irregularly  placed. 

They  occur  on  aerial  leaves  and  stems  most  abundantly, 
being  sometimes  exceedingly  numerous,  and  are  exception- 
ally found  on  other  parts,  as  the  sepals,  petals,  and  carpels 
of  the  flowers.  On  submerged  or  underground  stems  and 
leaves  they  are  found  in  less  numbers,  and  from  true  roots 
they  are  always  absent.  The  stomata  on  leaves  are  generally 
confined  to  the  lower  surface,  and  when  present  on  the  up- 
per they  are  usually  much  fewer  in  number ;  there  are,  how- 
ever, some  exceptions  to  this. 

131. — Their  development  genemlly  takes  place  in  the  fol- 
lowing way :  in  a  young  epidermis-cell  a  partition  forms  at 
right  angles  to  the  plane  of  the  epidermis,  cutting  off  a  por- 
tion of  the  cell ;  this  in  one  series  of  cases  becomes  the 
mother-cell  of  the  stoma ;  in  another  series  of  cases,  how- 
ever, it  is  divided  one  or  more  times  by  subsequent  partitions 
before  the  mother-cell  is  formed.     In  either  case,  when  once 

*  In  an  article  entitled  **  How  Thistles  Spin,"  in  the  American  Nat- 
uraHst,  1878,  page  648.  See  also  an  article  by  the  same  writer  on 
**  Hairs  and  Glandular  Hairs  of  Plants  :  their  Forms  and  Uses,"  in  the 
same  volume  of  the  journal  named,  on  page  271. 

f  See  his  account,  with  a  plate,  in  Qr.  Jour,  of  Mic.  Science,  1877,  p.  245. 


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100 


BOTANY. 


the  mother-cell   is  formed  a   median  partition- wall  forms 
in  it,  and  gradually  becomes  separated  into  two  plates,  which 

eventually  sepa- 
rate and  form  a 
pore  through 
the  epidermis. 
The  two  halves  of 
the  mother-cell  be- 
come symmetrical- 
ly rounded  off  into 
semilunar  or  semi- 
circular forms, 
and  constitute  the 
guard-cells  before 
mentioned.  The 
details  of  the  fore- 
going process  in 
one  of  its  more 
complex    forms 

_  #,«.  stomata;  ^.  a,  irregular  eplder-  are    illustrated  in 

mie-cells  between  the  veins  of  the  leaf ;  v,  elongated  and  -ri*       n-i      a        j  z> 

regular  epidermis-cells  over  a  vein.     X  860.— From  a  1^  Ig.  S7l,  A.  and  />• 

drawing  by  J.  C.  Arthur.  ^j^^     Splitting  of 

the  middle  partition- wall  of  the  mother-cell  is  shown  in  the 
successive  sections  (Fig.  92). 

132. — In  the  light,  under  certain  conditions  of  moisture 
and  temperature,  the 
guard-cells  become 
curved  away  from  each 
other  in  their  central 
portions,  thus  opening 
the  slit  and  allowing 
free  communication 
between  the  external 
air  and  that  in  the  in- 
tercellular spaces  and 
passages  of  the  leaf. 

(a)  A  Buperfici&I  examination  of  stomata  may  be  easily  made  by 
stripping  off  the  epidermis,  and  mounting  it  in  water  or  alcohol.  Good 
sections  of  stomata  are  more  difficalt  to  make  ;  they  may  be  obtained, 


Fig.  89.— stomata  from  the  under  surface  of  the  leaf  of 
Schfnooyttis  lobtUa.  t, «.  stomata ;  g,  g^  irregular  epider- 


FIg.90.- 
of  the  leaf  of 
drawing  by  J.  C. 


Double  stomata  from  the  under  snrface 
lobata,    X  600.— From  a 
nr. 


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101 


Tg,  91^— The  deTdopment  of  the  »toiiuiU  of  the  leaf  of  Sedum  purpuratctnt.  A, 
t  piece  of  rery  young  epidermis,  showing  the  early  stages  of  the  process.  The  no- 
menls  indicate  the  order  of  formation  of  the  partitions ;  that  marlied  1, 1«  1,  was 
formed  first,  then  S,  t,  and  last  8, 8 ;  the  cell  enclosed  by  these  three  partitions  is  the 
stoma-mother-cell ;  B,  a  folly  completed  stoma ;  «,  «,  two  original  epidermis-oells— 
in  the  rtj^t  hand  one  the  new  partition  1, 1, 1,  first  appeared ;  this  was  followed  by 
t,  3. 1  then  by  8, 8,  and  4. 4 ;  Uwtly  the  cell  thns  formed  became  divided  by  a  middle 
partition,  which  soon  soUt,  and  thus  formed  the  opening  of  the  stonuL^After  Sachs. 


Fio.  9Sd.  Fio.  99i. 

Tig.  98.— Development  of  the  stonuta  of  the  leaf  of  ffyadnthtu  orUnkUiij  seen  in 
trsDfverie  section.  A^  the  division  of  the  mother-cell  S;  e,  «,  epidermis>celis ;  p  p, 
PsrachTina-cells ;  i,  small  intercellular  ppace :  B  and  C  the  same  a  little  later ;  2>, 
int  Nparation  of  the  two  gnard-cells  by  tiie  splitting  of  the  partition  between  them, 
fonnbg  the  opening  t ;  E,  the  folly  formed  stoma,    x  800.— Alter  Sachs. 


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102 


BOTANY. 


however,  by  making  a  large  number  of  very  thin  sections  of  the  whole 
leaf  (bj  placiug  it  between  two  pieces  of  elder  pith),  when  it  will  be 
found  that  in  some  cases  stomata  have  been  cat  through  in  the  man* 
ner  shown  in  Fig.  92. 

(&)  Examples  may  be  obtained  from  any  of  tiie  higher  plants,  bat 
those  which  are  of  a  firm  texture  and  have  a  smooth  epidermis  are 
best  to  begin  with — t.g,,  the  hyacinth,  tulip,  the  lilies,  many  grasses, 
fuchsia,  UIrc,  etc. 

(c)  Weiss*  determined  the  number  of  stomata  on  the  epidermis  of 
both  surfaces  of  167  leaves  of  plants  ;  some  of  his  results  are  given 
below : 


In  one  square  millimetre. 

Upper  side. 

Under  side. 

0 

625 

0 

477 

0 

461 

0 

886 

0 

8{<0 

175 

825 

188 

802 

0 

278 

55 

270 

60 

268 

0 

259 

0 

251 

0 

237 

0 

229 

101 

216 

0 

208 

0 

204 

67 

191 

114 

189 

0 

166 

94 

158 

184 

156 

0 

145 

0 

145 

89 

181 

50 

71 

0 

67 

0 

62 

65 

58 

48 

27 

In  one  square  inch. 


Upper  side.  Under  side. 


Olea  Europea 

Vinca  minor 

Jufflans  nigra. 

Ailanthus  glandulosa 

Svringa  vufgaris 

Helianthus  annuus 

Brassica  oleracea 

Platan  us  occiden talis 

Populus  dilatata 

Solanum  dulcamara. 

Euphorbia  cyparissias 

Maclura  aurantiaca 

Betula  alba 

Berberis  vulgaris 

Pisum  sativum 

Buxus  sempervirens 

Prnnus  Mahaleb 

Asdepias  incarnaia. 

Datura  stramonium 

Taxns  baccata 

Zea  mais 

Chenopodium  ambrosioides.. 

Ficus  elastica 

Ribesaureum 

Populus  monilifera 

Pinus  sylvestris 

Anemone  nemorosa 

Lilium  bulbiferum 

Iris  Germanica 

Avena  sativa 


0 

0 

0 

0 

0 

112,875 

88,910 

0 

85,475 

88,700 

0 

0 

0 

0 

65,145 

0 

0 

48,215 

78,580 

0 

60.680 

118,680 

0 

0 

57,405 

82,250 

0 

0 

41,925 

80,960 


408,125 

808,665 

298.845 

248,970 

212,850 

209,625 

194,790 

179,810 

174,150 

169,685 

167,055 

161,895 

152,865 

147,706 

189,820 

184,160 

181,580 

128,195 

121,905 

107,070 

101,910 

100,620 

98.525 

98,525 

84,495 

45,895 

48,215 

89,990 

88,410 

17,415 


*In  a  paper  on  the  Number  and  Size  of  Stomata,  published  in 
Fringsheim's  '*  JahrbUcher  fUr  Wissenschaftliche  Botanik,"  1865. 


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THE  EPIDERMAL  SYSTEM. 


loa 


(d)  In  the  plants  he  examined  he  found  that  there  were 


54  ipedes  with  from     1  to  100  stomaU  per  sq.  mm.  : 


645  to   64.500  per  sq.  Inch 


S8 

«« 

«« 

lootoaoo     ** 

♦* 

"     =    64,50010  129,0:0 

• 

8» 

M 

*t 

200  to  800       " 

•* 

'     =  129,000  to  198,500 

M                    4 

23 

•• 

44 

300to400       *» 

(t 

"     =198,500  to  268,000 

*'         " 

9 

•* 

»» 

400  to  600 

•• 

'      =  256,000  to  822,500 

44                 «4 

1 

4* 

•♦ 

600to600       " 

«*                 4 

'     =822,500  to  887,000 

44                 44 

3 

«• 

«4 

eootoToo     " 

44 

'     =387,000  to  451,500 

44                «4 

ie)  Morren's  measurementa*  vary  somewhat  from  those  given  by 
Weiss.  The  following,  not  given  by  Weiss,  are  taken  from  Morren's 
table: 


In  one  sqaare  millimetre, 


In  one  square  inch. 


Under  side.  Upper  ride. 

835 

133,515 

256 

0 

253 

0 

246 

0 

196 

0 

155 

0 

115 

48.875 

91 

0 

86 

0 

42 

81,605 

Under  side. 


Trifolium  pratense  . . . .   . 

Hamulus  Lupulus 

Pranus  domesiica 

Pirus  Mains 

Hedera  helix 

Vitis  vinifera 

Beta  vulgaris 

Pirus  communis. , 

Philadelphus  coronarius. 
Secale  c^reale 


216,075 

165,120 

163,185 

158,670 

126,420 

99,975 

74,175 

58,695 

55,470 

27,090 


ij)  The  stomata  of  the  so-called  Compass  Plant  {SUphium  tadnia^ 
turn)  are  nearly  equal  in  number  on  the  two  sides  of  the  vertical  leaves ; 
there  are  on  the  true  upper  surface  82  per  sq.  mm.  (=  52,700  per  sq. 
inch),  and  on  the  under  surface,  87  per  sq.  mm.  (=  57,800  per  sq. 
inch).f 

{£)  On  most  leaves  the  stomata  are  not  distributed  equally  over  all 
portiona  of  either  surface  ;  they  are  not  found  on  the  veins,  but  are 
restricted  to  the  areas  between  them.  In  some  plants  this  restriction 
is  accompanied  by  a  further  modification,  as  in  Ceanothtis  pro8tratus, 
where  the  stomata  are  confined  to  tlie  bottoms  of  sunken  pits  which 
occur  on  the  under  side  of  the  leaves.  In  the  long  harsh  leaves  of 
SHpa  iparUa  the  stomata  of  the  upper  surface  are  restricted  to  the 
sides  of  the  deep  longitudinal  channels  which  lie  between  the  promi- 
nent nerves.    (See  Figs.    185-^,  pa^e  158.) 

*  Pnblished  first  in  BuUetin  de  VAcctdemie  royale  de  Belgique,  vol. 
16«  number  12,  1864,  and  also  in  part  in  Pringsheim's  '*  Jahrbiicher,'' 
etc,  L  c 

f  See  an  article  in  American  NaturcUUt,  1877,  p.  486  :  "  Observations 
on  SUphium  laciniatum,  the  so-called  Compass  Plant,"  by  C.  E.  Bessey; 


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104  BOTANY. 

(A)  Water-p<yr€»,  De  Bary*  doBcribes  under  this  name  some  carious 
stoma-like  stractureii  which  occur  on  many  plants.  These,  instead  of 
containing  air  in  their  cavities,  normally  contain  water.  Their  guard- 
cells,  which  are,  in  some  cases  at  least,  much  like  those  of  ordinary 
stomata,  are  immovable,  and  as  a  consequence  the  pore  is  incapable  of 
enlargement  or  contraction.  They  are  always  found  over  the  ends  of 
small  bundles  of  spiral  vessels,  which  appear  to  pass  into  the  pore  cav- 
iUes. 

One  form  of  these  may  be  readily  examined  in  the  leaves  of  the  f  uch- 


Fio.  98.  Fio.  94. 


Fig.  98.— Surface  view  of  the  water-pore  on  the  extremity  of  the  leaf-tooth  of  Fuch' 

3od09a,    X  600.— After  Arthar. 
.  94.— Traneverse  section  of  leaf-tooth  of  Fuefuia  globoM ;    cp,  chlorophyll- 
Off  parenchyma,  within  which  ia  the  flbro-vaacular  handle ;  m,  raphia-cella.    x 

sia,  and  the  primrose  {PrimtUa  ainenns).  In  the  fuchsia  they  are  found 
in  the  papillie  or  small  teeth  on  the  margins  of  the  leaves,  and  in  the 
primrose,  in  the  papillie  terminating  the  lobes  and  lobules.  In  Fuchna 
globasa  each  leaf-tooth  is  provided  with  a  single  terminal  pore  (in  some 
of  the  dark  colored  varieties  there  are  several),  which  resembles  an 
ordinary  stoma  (Fig.  93).  Beneath  the  pore  is  a  cavity,  commonly  filled 
with  water  (Fig.  95,  6),  which,  by  evaporation,  deposits  calcium  car- 
bonate upon  the  walls  of  the  lining  cells,  thereby  discoloring  them.  A 
fibro-vascular  bundle  is  continued  from  the  veins  of  the  leaf  through 

♦In  •' Vergleichende  Anatomie  der  Vegetationsorgane,"  etc,  1877, 
on  page  54,  et  seq.  References  are  there  given  to  the  literature  of  the 
subject,  which  is  both  recent  and  limited.  After  Mettenius'  paper  in 
Filiees  harti  LipiienM,  others  appeared  by  other  writers  in  Botaniaehe 
ZeUunff,  1809,  1870,  and  1871. 


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THE  EPIDERMAL  BT8TEM,  105 

the  tooth  to  the  water-cavitj ;  in  the  tooth  it  becomee  greatly  enlarged, 
and  ia  there  oompoeed  of  spiral  cells  (tracheldefl),  which  surround  a 
central  mass  of  narrow  elongated  parenchymatous  cells  (Fig.  95,  e,  g\ 
The  handle  tenninat^fS  by  the  free  ends  of  the  parenchyma-cells  extend- 


Fig.  95.— Vertical  Bection  of  a  leaf-tooth  of  PuehHa  (Hoboga.  a,  vertical  longltadl- 
ml  eection  of  water-pore  ;  b,  water-cavit v ;  o,  tracheldes ;  cT,  chlorophyll-bearing 
pareDChyma  :  «,  large  cell  containinff  raphlde^ ;  /,  hair ;  g,  parenchyma  of  the  flbro- 
Tucalar  handle.  The  lower  part  of  the  figure  passes  into  the  leaf -blade,  x  12&.~ 
After  Arthur. 

iDjr  loosely  into  the  water-cavity.  Between  the  bundle  and  the  epider- 
mis  of  the  leaf-tooth  lie  two  or  three  cell  layers  of  ordinary  chlorophyll- 
bearing  parenchyma,  in  which  there  are  occasionally  large  cells  con- 
taining  raphides  (Fig.  94,  ep  and  ra)* 

*  The  foregoing  account  of  the  water-pores  of  Fuchsia  gUbosa,  and 
the  drawings  for  Figs.  93-4-5,  are  taken  from  an  unpublished  paper 
Oft  "The  Water-Pores  of  Fuchna globosa"  by  J.  C.  Arthur. 


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106  BOTANY, 

Water.pores  nearly  like  those  of  the  fuchsia  occur  on  eome  species  of 
Sacnfraga,  Heuehera,  MUella,  AeonUum,  Delphinium,  Sambueui,  and 
many  other  plants. 

Another  form,  more  closely  resembling  the  ordinary  stomata  (but  of 
much  larj^er  size),  occurs  on  TropcMlum  Lobbianum,  Boehea  eocdnea, 
and  others. 

§  III.  The  Fibro-vascular  System. 

133. — In  most  of  the  higher  plants  portions  of  the  pri- 
mary meristem  early  become  greatly  differentiated  into 
firm  elongated  bundles,  whicH  traverse  the  other  tissues. 
They  are  composed  for  the  most  part  of  tracheary,  sieve, 
and  fibrous  tissues,  together  with  a  varying  amount  of  pa- 
renchyma. These  elementary  tissues  have,  with  some  con- 
siderable variations  in  the  different  groups  of  plants,  a  gen- 
eral similarity  of  arrangement  and  aggregation  throughout 
the  Pteridophytes  and  Phanerogams.  In  a  comparatively 
small  number  of  cases  laticiferous  tissue  is  associated  with 
the  above-mentioned  tissues.  To  these  aggregations  of  tis- 
sues the  name  of  Fibro-vascular  Bundles  has  been  given.  ♦ 

134. — In  many  plants  the  fibro-vascular  bundles  admit  of 
easy  separation  from  the  surrounding  tissues;  thus  in  the 
Plantain  (Plmitago  major)  they  may  readily  be  pulled  out 
upon  breaking  the  petioles.  In  the  leaves  of  plants,  where 
they  constitute  the  framework,  they  are,  by  maceration, 
readily  separated  from  the  other  tissues  as  a  delicate  net- 
work. In  the  stems  of  Indian  com  the  bundles  run  through 
the  internodes  as  separate  threads  of  a  considerable  thick- 
ness. 

136. — It  is  impossible  to  fix  upon  a  particular  form  as  the 
type  of  the  fibro-vascular  bundle.  It  should  be  understood 
at  the  outset  that  the  similarity  between  the  bundles  of 
widely  separated  groups  of  plants  is  only  a  general  one,  and 
that  there  are  great  differences  in  the  details  of  their  struc- 
ture. It  must  further  be  borne  in  mind  that  these  bundles 
are  not  themselves  tissues,  but  aggregations  of  dissimilar  tis- 

♦  They  are  also  called  Vascular  Bundles ;  this  term  ought,  however, 
to  he  retained  for  those  reduced  hundles  in  wlilch  only  vessels  are  prefik> 
ent — e.g.,  in  the  veinlets  of  leaves. 


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THE  FIBRO-VASCULAB  SYSTEM. 


107 


sues,  any  of  which  may  be  wanting  in,  or  separated  a  little 
space  from,  the  bundle.  In  short,  the  elementary  tissues, 
particularly  tracheary,  sieve,  fibrous,  and  parenchymatous 
tissues,  are  to  be  considered  as  the  units,  and  the  term  Fibro- 
vascular  Bundle  as  little  more  than  a  convenient  expression 
of  the  usual  condition  of  aggregation  of  these  units.* 

The  general  structure  of  fibro-vascular  bundles  will  be 
more  readily  un- 
derstood after 
the  examination 
of  a  number  of 
examples.  Those 
which  follow  are 
not  in  any  sense 
typical ;  they  are 
only  illustrative. 

136.— The  fi- 
bro-vascular bun- 
dle of  the  stem  of 
Pteris  aquilina 
is  composed  of 
tracheary  and 
sieve  tissues,  par- 
enchyma, and  a 
small  amount  of 
poorly  developed 
fibrous  tissue.  In 
transverse  b  e  c  - 
tion  the  bundle 
has  usually  an 
elliptical  outline. 
The  great  mass 
of  the  bundle  is  made  up  of  large  scalariform  vessels, 
which  occupy  its  interior  {g^gyg,  Fig.  96).  Enclosed  in 
the  scalariform  tissue  are  masses  of  parenchyma  and  a  few 

*  By  considering  the  Fibro-vascular  Bundle  to  be  one  of  the  struc* 
tanl  units  of  the  higher  plants  a  serious  mistake  has  been  made, 
leading  to  profitless  discussions  and  speculations  as  to  its  typical  struc- 
ture, and  divertinp^  attention  from  the  study  of  its  actual  structure. 


Fig.  96.— Part  of  a  transverpe  pcctlon  of  the  flbro-vas- 
cQlar  bundle  of  the  stem  of  Pteris  aquilina  ;  «,  spiral  ves- 
sel ;  g,  g^  scalariform  vessels ;  ^/>,  sieve  tissue ;  o,  fibrous 
tissue  (protophloSm  of  Russow)  ;  «^,  bundle  sheath ;  p. 
Htarch -bearing  parenchTma :  K^  A,  thickened  angles  of 
scalariform  vessels.— After  Sachs. 


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108  BOTANY. 

spiral  vessels,  the  latter  occurring  near  the  foci  of  the  el- 
liptical cross-section  of  the  bundle  (5,  Fig.  96).  Surround- 
ing, or  partly  surrounding,  the  tracheary  portion  of  the  bun- 
dle is  a  layer  of  sieve  tubes  {sp,  Fig.  96),  separated  from  the 
large  scalariform  vessels  by  a  layer  of  parenchyma.  Outside 
of  the  sieve  tissue  is  a  mass  of  fibrous  tissue  (J,  Fig.  96), 
which  is  itself  bounded  externally  by  another  layer  of  paren- 
chyma.  The  whole  bundle  is  surrounded  by  a  layer  of  paren- 


WHf.  07.— TransTerse  oection  of  the  flbro-vagcnlar  bnndle  of  the  rhizome  of  Polyp(h 
dium  vtilgare ;  sp,  477,  narrow  spiral  veseelA  in  the  e^ge  of  the  mass  of  scalariform  yes- 
eels ;  «,  region  of  the  sieve  tissue  filled  with  parenchyma  and  poorly  developed  sieve 
tisane  ;  u,  bundle  sheath,  outside  of  virhich  U  parenchyma.    X  2S5.— After  De  Bary. 

chyma  differing  from  the  other  parenchymatous  tissues  in 
not  containing  starch  in  its  cells ;  to  this  the  name  of  Bun- 
dle Sheath  has  been  given. 

A  noticeable  feature  in  the  structure  of  this  fibro-vascular 
bundle  is  that  the  tissues  have  a  concentric  arrangement ; 
the  tracheary  tissue  is  encircled  by  a  layer  of  parenchyma  ; 

See,  in  this  connection,  an  article  on  *'  Some  recent  views  as  to  the  com- 
position  of  the  Fibro-vascular  Bundles  of  Plants,"  by  S.  H.  Vines,  in 
Or.  Jour.  Jtic.  Science,  1876,  p.  388. 


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THE  F1BR0-VA8CULAR  SYSTEM. 


109 


this  by  one  of  sieve  tissue  ;  this  again  by  fibrous  tissue,  and 
60  on. 
187. — A  similar  but  not  identical  structure  is  found  in  the 


Vlg.  WL«-Pwt  of  the  cro88-0ectlon  of  an  old  root  of  Adiantvm  MoHtMianum,  A,  A. 
hainof  the  root  forfttce;  «,v,  handle  sheath  (endodermU) ;  between  A  and  ti.pa- 
renehyma ;  pc^  perlcambiam ;  or,  a  plate  of  tracheary  tissue,  which  is  boondea  on 
each  side  l^  sieye  tiasoe.    x  2».— After  De  Bary. 

bundle  of  the  rhizome  of  Polypodium  vulgare.  Here  the 
central  portion  of  the  stem  is  made  up  of  scalarif orm  tissue 
(Fig.  97,  the  larger,  thicker-walled  tissue),  and  this  is  sur* 
rounded  by  a  tissue  which  may  be  regarded  as  but  partly 


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110 


BOTANY. 


differentiated,  being  composed  of  parenchyma  and  poorly 
developed  sieve  tubes  («,  Fig.  97).  The  whole  bundle  is  sur- 
rounded,  as  in  Pteris  aquilina,  by  a  bundle  sheath  (u,  Fig. 
97).  In  the  outer  part  of  the  mass  of  scalariform  tissue  are 
a  few  narrow  spiral  vessels  {sp,  sp,  Fig.  97),  but  they  are 
not  sufficiently  numerous  to  constitute  a  ring  or  layer. 
138. — In  the  root  of  Adiantum  Moritzianum  the  bundle 

consists  of  a  cen- 
tral plate  of  tra- 
cheary  tissue  (jt?r, 
Fig.  98),  with  a 
mass  of  sieve 
tissue  on  each 
side  of  but  not 
quite  enveloping 
it.  Next  outside 
of  this  is  a  layer 
of  active  paren- 
chyma, the  peri- 
cambium  {pcy 
Fig.  98),  and  sur- 
rounding  the 
whole  is  a  poorly 
developed  bundle 
sheath  (w.  Fig. 
98). 

189.  —  In  the 
stem  of  Equise* 
turn  palustre   it 


Fie.  99.— Transveree  section  of  a  flbro-yaacnlar  bundle  of 
Equuetwn  palusfre,  r ,  ^  ringed  vesMle  on  the  border  of  a 

large  intercellular  canal;  «,  sieve  tisane;  ff^ff.  groups  of   •  ^  g^t^arr  na 

annular  and  reticulated  vessels ;  t#,  the  so-called  general  *8  nOb  BO  easy  as 
bnndle  sheath,  which  snrronnds  all  the  bundles :  i,l,  axial 
air  camJs  ;    x ,  x ,  fragments  of  the  ruptured  cells,    x  146. 
~Af ter  De  Bary. 


in  the  foregoing 
cases  to  mark  the 
limits  of  the  bundles,  which  are  arranged  in  a  circle  about 
the  axis.*  On  the  axial  side  of  each  bundle  there  are  at 
first  a  few  spiral  and  annular  vessels,  most  of  which, 
along    with  a   considerable    amount    of    parenchyma,   are 

*  In  Equmtum  limomim,  however,  there  is  a  bundle  sheath  about 
each  bnndle,  consequentlj  there  is  in  that  species  do  difficulty  as  to 
the  limits  of  the  bundle. 


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THE  FIBRO-VASCULAB  8T8TEM.  HI 

destroyed  shortly  after  their  formation,   thus  forming  a 

wide    canal    (Fig.   99;    t,   spiral,   and  r,   annular  vessels 

on  the  border  of  the  canal).     Immediately  in  front  of  or 

outside  of  the  canal  is  a  considerable  mass  of  sieve  tissue, 

made  up  of  true  sieve  tubes  and  the  nearly  allied  cambiform 

or  latticed  cells 

(«,  Fig.  99). 
Bight  and  left  of 

the  sieve  tissue 
lie  a  few  annular 
and  reticulated 
vessels  {g,  g.  Pig. 
99).  Exterior  to 
all  the  bundles 
(in  this  species) 
is  a  cellular  lay- 
er, which  has  i-e- 
ceived  the  name 
of  bundle  sheath, 
but  which,  prob- 
ably, has  no  rela- 
tion to  the  lay- 
er 80  named  that 
surrounds  each 
fibro  -  vascular 
bundle  of  some 
plants. 

140.  — The 

structure  of  the  Fig.  lOO.— C^O8»-«ectionofthettemoriSitfa0in«tfaifla!^i- 
v  ji  •  o  7  *  yM<a«  Bbowing  three  bandlee;  in  each  bundle  the  inner 
bunaie  m  oelaffl-  thicker  wallea  tissae  is  compoeed  of  scalariform  veesela, 

77     .    ^ .^r^i:^  with  a  few  narrow  apiral  vessels  on  each  extreme  margin: 

neUa  tnoqutjona  sorronnding  the  scalariform  tissae  is  the  thinner  wSled 

l^Aa««  t%  r*rxr\atAaf  sieve  tlssue,  and  aTOond  this  again  is  a  layer  of  cclU,  which 

Dears  a  COnSiaer-  nj^y  be  caUed  the  bundle  sheath ;  /,  I,  intercellular  epacet 

able  resemblance  8<irroandlng  the  bundles.    xl60.-After  Sachs. 

to  that  of  Pteris  aqtiilina.  There  is  in  each  bundle  a 
central  plato  of  tracheary  tissue,  consisting  of  a  few  narrow 
spiral  vessels  in  its  two  edges  and  a  remaining  mass  of  scala- 
liform  vessels  (Fig.  100).  The  tracheary  portion  is  sur- 
rounded by  a  tissue  of  elongated,  thin-walled  tissue  which 
is,  at  least  in  part,  a  sieve  tissue.     In  this  and  allied  species 


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112  BOTANY. 

the  bundles  are  curiously  isolated  from  the  surrounding 
ground  tissues  of  the  stem. 

141. — The  bundle  of  the  nearly  related  Lycopodium  com" 
planatum  is  much  more  complex  in  its  structure  (Fig.  101). 
Here  thei*e  are  four  parallel  plates  of  tracheary  tissue^  each 
having  a  structure  like  the  single  plate  of  the  bundle  of 
Selaginella  inmquifolia.  Between  the  tracheary  plates  there 
is  in  each  case  a  row  of  sieve  tubes  imbedded  in  a  lignified 
tissue  composed  of  elongated  cells  (sclerenchyma,  or  fibrous 


Fig.  101.— Croefi-eectlon  of  the  Btem  of  Lvoopodivm  compUmntttm.  The  flhro-yaa* 
cnlar  bundle  is  composed  of  four  plates  or  tracht- ary  tissue  (darker  in  the  figure), 
between  which  are  nuiHses  of  Ugnffled  tissue  composed  of  elongated  cells  ;  each  or 
these  latter  masses  encloses  a  row  of  sieve  tubes  (larger  and  thicker  walled  in  the 
figure) ;  the  bundle  sheath  is  seen  to  bound  on  iu  inner  side  a  tbkk  mass  of  very  thick 
waUed  fibrous  tissue ;  exterior  to  this  (toward  B)  is  a  laver  of  chlorophyll-bearing 
parenchyma,  bounded  by  a  well-developed  epidermis.  The  small  vessels  at  the  ex- 
treme edges  of  the  plates  of  tracheary  ti^ue  are  narrow  and  npirally  marked ;  the 
remainder  of  each  plate  is  composed  of  scalariform  vessels,    x  100.— After  Sacha. 

tissue?).  Around  this  central  fibro-vascular  portion  there  is 
a  layer  of  parenchyma,  and  outside  of  this  a  bundle  sheath^ 
which  is  commonly  regarded  as  marking  the  boundary  of 
the  bundle  ;  it  is  doubtful,  however,  whether  it  should  be  so 
considered,  as  exterior  to  it  lies  a  thick  mass  of  fibrous  tissue 
which  completely  envelops  all  the  previously  described 
tissues.* 

*  Sachs  ("Text-Book,**  p.  418)  repfards  the  Btem  of  Ljcopodiam  as 
oompoeed  of  four  united  bundles  and  compares  them  to  the  separate 
bundles  of  SelagineUa.     De  Bary  ("  Anatomie/'  etc.,  p.  8^),  on  the 


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THE  FIBRO-  VASCULAR  BT8TEM.  113 

142. — In  the  fibro-Yascular  bundle  of  the  stem  of  Indian 
com  {Zea  mats)  the  central  portion  is  composed  of  tracheary 


FIff.  lOS.— Tnnevene  section  of  flbro-TascnIar  bnndle  of  Indian  corn  {Zea  maU), 
a,  Bioe  of  bandie  looking  toward  the  circomference  of  the  stem;  i,  side  of  handle  look- 
ing toward  the  centre  of  the  stem ;  0,  thin-walled  parenchyma  of  the  fundamental 
timet  of  the  stem;  a,  g^  large  pitted  Teasels;  #,  spiral  vessel;  r,  rin?  of  an  annular 
▼easel ;  I,  air-cavity  formed  oy  the  breaking  apart  of  the  surrounding  cells ;  v,  v, 
latticed  cells,  or  soft  bast,  a  form  of  sieve  tissue,    x  550.— After  Sachs. 

tissue^  consisting  of  pitted,  spiral,  ringed,  and  reticulated 
vessels  (Fig.  102,^,  </,  8,  r,  and  the  tissue  between  v — Syg — -g) 

other  hand,  considers  the  cylindrical  portion  in  the  centre  as  but  one 
bundle,  belonging^  to  what  he  terms  the  Radial  type.  Both  agree  in  con- 
sidering the  fibrous  tissue  outside  of  the  bundle  sheath  as  not  belong- 
ing to  the  bundles  ;  but  certainly  if  this  is  one  bundle,  there  is  as  good 
reason  for  including  the  fibrous  cylinder  in  it  as  there  is  in  the  case  of 
the  bundle  of  Indian  com. 


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114  BOTANY. 

Lying  by  the  side  of  the  tracheary  tissue  (on  its  outer  side  as 
it  is  placed  in  the  stem)  is  a  mass  of  sieve  tissue,  composed  of 
latticed  cells  (v,  v.  Fig.  102).  Surrounding  the  whole  is  a 
thick  mass  of  fibrous  tissue  composed  of  elongated,  thick- 
walled  cells  (the  shaded  ones  in  the  figure). 

143. — The  fibro-vascular  bundle  of  the  flowering-stalk  of 
Acorus  calamus  bears  a  close  resemblance  to  that  of  Indian 
corn.  Like  that,  it  has  a  central  tracheary  portion  {g,  Fig. 
103),  which  has  lying  exterior  to  it  a  mass  of  sieve  tissue  {w, 

Fig.  103).  On  the  inner 
side  there  is  a  larga  in- 
tercellular canal,  evi- 
dently holding  the  same 
relation  to  the  other 
tissues  that  the  smaller 
canal  does  in  the  bundle 
of  Indian  corn.  The 
exterior  of  the  bundle 
is  here  also  made  np  of 
a  thick  mass  of  fibrous 
tissue. 

144.  —  In  the  fibro- 
vascular  bundle  of  the 
adventitious  roots  of 
Acorus  calamus  the  ar- 
rangement  of    the  tis- 

Plff.  108.— Traniiyerw  section  of  a  portion  of  ^    ^„     '^     „^«„      ;i;4V^wx««4- 

the  general  peduncle  of  Acorw  co/omw.   €,epi-  SUeS     IS     Very      aitterent 

dennis ;  b,  tmall  flbro-vaBcolar  bundle  ;  in  the  #--,.„    fliof   rlacnriKotfl 

large  bundle  w  is  the  sieve  tls^ue,  a  the  trache-  irom   tnat   aeSCriDCa 

ary  tisane, /an  intercellular  canal ;  the  periphery  aVtnvA         TTprA   fhprA   ata 

of  the  bundle  is  composed  of  thick- walled  flbroua  aoovc.      xiere  tnere  ar© 

tissue  (figured  dark),    x  145.— Alter  De  Bary.        many  radially    placed 

plates  of  tracheary  tissue  {pp,  Fig.  104),  which  alternate 
with  thick  masses  of  sieve  tissue  (ph,  Fig.  104).  Between 
these  alternating  tissues,  and  within  the  circle  formed  by 
them,  there  is  a  mass  of  parenchymatous  tissue.  The 
whole  bundle  is  separated  from  the  large-celled  parenchyma 
of  the  root  by  a  well-marked  bundle  sheath  («,  Fig.  104) ; 
the  latter  is  bounded  interiorly  by  a  layer  of  active  thin- 
walled  cells  —  the  pericambium  —  from  which  new  roots 
originate.    In  the  older  root,  the  central  cell  mass  (which. 


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THE  FIBR0VA8CULAB  SYSTEM,  115 

as  described  aboye,  is  in  younger  specimens  composed 
of    parenchyma)   is  transformed    into  sclerenchyma  (Fig. 

105). 

X45^ The  fibro-vascular  bundles  of  Ricinus  communis 

have  an  arrangement  in  the  stem,  and  a  general  structure 
somewhat  similar  to  those  of  Equisetum  palustre,  described 
above.     The  limits  of  the  bundles  are  so  poorly  marked  that 


Fig.  104.— TituiBverae  Mction  of  the  flbro-Taaenlar  handle  of  the  root  of  Aeorut 
cakmmM.    «,  hondle-ebeath  (also  called  endodermis),  with  parenchyma  outride  and  a 


single  layer  of  perlcambiam-cells   inside :  pp.  platen  of  radial ly-plac  d  trachearj 
tiasae;  pfi^  bundles  of  sieve  tissue;  pp,  narrow  peripheral  (and  linj'  '         ' 
sels ;  g,  large  and  still  young  Te«sel.~  After  Sachs. 


in  places  it  is  impossible  to  tell  whether  the  tissues  belong 
to  them  or  to  the  surrounding  ground  tissues. 

The  inner  portion  of  the  bundle  (g,  g,  t,  /,  Fig.  106,  and  s 
to  /,  Fig.  107)  is  made  up  of  tracheary  tissue  of  several  varieties; 
on  the  inner  edge  of  this  tracheary  portion  lie  several  spiral  ves- 
sels {s,  8,  Pig.  107)  ;  next  to  these,  on  their  outer  side,  are  sca- 
lariform  and  pitted  vessels  (/,  /,  g,  g.  Fig.  106,  Z,  ty  t',  Fig. 
107),  intermingled  with  elongated  cells,  whose  walls  are  pitted 


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116  BOTANY. 

(A,  h\  h'\  h"\  Fig.  107).  The  last-named  are  clearly  related 
to  the  vessels  which  surround  them,  and  from  which  they 
differ  only  in  their  less  diameter,  and  in  having  imperforate 
horizontal  or  oblique  septa.  They  are  doubtless  properly 
classed  with  the  Trachetdes  (see  p.  84).  On  the  outer  side  of 
the  tracheary  portion  just  described  lies  a  mass  of  narrow, 
somewhat  elongated,  thin-walled  cells,  which  constitute  a 
true  meristem  tissue,  to  which  the  name  of  Cambium*  has 
been  given  {c,  c,  Figs.  106  and  107).    Next  to  the  cambium 


Fig.  lOB.— A  very  thin  cros«-f«ctioii  of  the  radial  flbro-vawsnlar  bnndle  of  an  old 
adventitloiLB  root  of  Aoorus  calamuf.  g,  the  radial  plates  of  tracheary  tisone ;  tr,  the 
sieve  tissue  alternating  with  the  plates  of  tracheary  tissue  ;  «,  the  bnndle^beath ; 
the  tissue  in  the  centre  of  the  bundle  is  sclerenchyma.    x  145.— After  De  Bary. 

lie,  in  order,  sieve  tissue  and  parenchyma;  these  do  not  occupy 
separate  zones,  but  are  more  or  less  intermingled,  forming 
a  mass  sometimes  called  the  Soft  Bast  (y,  y,  y,  Fig.  106,  and 
p,  Fig.  107).  The  sieve  tissue  includes  sieve  tubes  and 
cambif orm  or  latticed  cells.  In  the  extreme  outer  border  of 
the  bundle  is  a  mass  of  fibrous  tissue  (J,  J,  Figs.  106  and  107). 
The  layer  of  starch-bearing  cells  just  outside  of  the  last- 
named  tissue  is  the  so-called  bundle  sheath. 

*  Cambiam,  a  low  Latin  word,  meaning  a  liquid  which  becomes 
glutinous.  Tlie  term  was  introduced  when  the  real  stractore  of  the 
part  to  which  it  was  applied  was  not  understood. 


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THE  FIBR0VA8CULAR  SYSTEM.  117 

146. — The  bundle  of  the  adventitious  root  of  Ranunculus 
repens  is  very  different  from  the  one  just  described.  It  may 
be  briefly  described  as  composed  of  a  mass  of  tracheary  tis- 


Flf(.  106.— Transyerae  vection  of  hjpocotyledonarj  portion  of  ttem  of  Bicinw  com  - 
m%mi».  r,  r,  parenchyma  of  the  primary  cortex  ;  m,  parenchyma  of  the  pith  *,  6, 
bast  fibres  ;  y.  y,  soft  bast ;  c,  cambium  :  g,  g,  larse  pitted  Teasels  ;  ^,  ^,  smaller  pit- 
ted Teseels  ;  CO,  continuation  of  the  cambium  into  ttie  parenchyma  lying  between  the 
bondlee— the  parenchyma-cells  are  repeatedly  divided  by  tangential  walla.  Between 
the  primary  cortex  r  and  the  flbrons  tissue  of  the  phloem  lies  a  layer,  the  so-called 
bandle-eheath,  filled  with  compound  starch  grains.   Highly  magnified.— After  Sachs. 

sue,  which  is  cross-shaped,  as  seen  in  transverse  section  (g, 
^y  99  -^g*  108),  and  four  masses  of  sieve  tissue,  which  lie  in 
the  angles  between  the  projecting  portions  of  the  tracheary 
tissue.    Around  the  whole  is  a  layer  of  pericambium  {p, 


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118  BOTANY, 

Fig.  108),  and  exterior  to  this  is  the  bundle  sheath  (u.  Fig. 
108). 

147. — In  Gymnosperms  and  Dicotyledons  the  fibro-vascu- 
lar  bundles  of  the  stems  have  a  structure  essentially  like  that 
of  Ricinus  communis,  described  above.  In  them  it  is  evi- 
dent at  a  glance  that  the  bundle  is  divided  into  two  some- 
what similar  portions,  an  inner  and  an  outer,  by  the  cam- 


Fig.  107.— Longitudinal  radial  section  of  the  flbro-vaernlar  handle  of  the  hrpocot- 
yledonary  stem  of  RMnw  eommunU  (the  transverse  section  being  shown  in  Fig. 
100).  r,  paranchTma  of  the  primary  cortex  ;  g^,  bundle  sheath  :  m,  parenchyma  of 
the  pith ;  &,  bast  fibres  ;  p,  phloem  parenchyma  :  c,  cambium ;  the  row  of  cells  be- 
tween e  and  0  is  afterward  developed  into  a  sieve-tnbe — ^this  and  e  constitute  the 
soft  bast ;  «,  the  flret-formed  narrow  spiral  vessel ;  from  t  the  development  of  the 
zylem  portion  of  the  bundle  is  toward  t ;  y.  wide  sptral  vessel ;  /,  scalariform  ves- 
sel ;  /,  r,  wide  pitted  vessels  ;  9,  the  absorbed  septum  ;  A'^  A''^  tracheTdes  (?) ;  h^kft 
forms  of  cells  apparently  intermediate  between  pitted  vessels  and  tracheldes.  Highly 
magnified.— After  Sachs. 

bium  zone.  Nftgeli,*  who  first  pointed  out  these  divisions, 
named  the  inner  one  the  Xylem  portion,  because  from  it  the 
wood  of  the  stem  is  formed  ;  the  outer  he  named  the  Phloem 
portion,  for  the  reason  that  it  develops  into  bark.f  In 
some  cases  the  similarity  between  the  stnicture  of  xylem 

*  "  Beitrftge  zur  WiflflenBchaftliclien  Botanik,"  1858. 

f  Xylem  from  ^vXov,  wood  ;  Phloem  from  Greek  ^^016;  ^  bark. 


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THE  FIBBO-VASVULAR  8T8TEM,  119 

and  phloem  is  so  marked  that  they  are  said  to  be  composed 
of  corresponding  tissues,  (1)  Vascular,  (2)  Fibrous,  and  (3) 
Parenchymatous.*  The  vascular  tissues  are,  on  the  one 
hand,  the  tracheary  tissue  found  only  in  the  xylem,  and  on 
the  other,  the  sieve  tissue  of  the  phloem.  The  fibrous  tissue 
of  the  xylem  is  the  variety  with  the  shorter  and  harden 


Fig.  106.— Cross-section  of  the  flbro-TMcalsr  bnndle  of  an  old  adventitious  root  of 
Banuneuliurepsns.  g^  a,  g,  the  oater  marine  of  the  radial  plates  of  tracheary  tissae ; 
r,  a  large  otntral  pitted  vessel ;  x ,  septnm  in  pitted  vessel,  with  its  central  portion 
absorbed  ;  p,  pericambinm  ;  u,  handle  sheath ;  betwe     "*^    ' '    " "    " 


the  tracheary  portion  of  the  baodle,  and  jast  within  the  pericambiam,  lies  the  sieve 
•ae.    X  146.— After  De  Bary. 


fibres,  known  as  wood  fibres ;  that  of  the  phloSm  is  com- 
posed of  the  longer  and  tougher  bast  fibres.  The  paren- 
chjrma  of  the  two  portions  is  much  alike. 

*  Attention  sboald  be  called  here  to  the  fact  that  in  a  good  many 
orders  of  Phanerogams  the  laticiferous  vessels  are  constituent  parts  of 
the  fibro-vascalar  bundles.  Thus  in  Cichoriaceie,  CampanuIacesB, 
PapaveracesB,  Asclepiadacee,  Apocjnaceie,  and  Acerineao  they  occur  in 
the  phloSm;  in  Papayaoe®  and  Aroideee  thej  occur  in  the  xjlem. 


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120  BOTANY. 

148. — K&geli  extended  this  classification  of  the  tissues  to 
the  fibro-vascalar  bundles  of  Monocotyledons,  and  subse- 
quently it  has  been  still  further  extended  so  as  to  include  all 
kinds  of  fibro-vascular  bundles.  In  every  case  the  tracheary 
portion  is  the  essential,  or  most  constant,  characteristic  of 
the  xylem,  as  the  sieve  tissue  is  of  the  phloem. 

These  terms  are  valuable  when  used  in  reference  to  the 
fibro-vascular  bundles  of  the  stems  of  Phanerogams ;  they 
may  also  be  valuable,  if  pi-operly  used  and  understood,  when 
applied  to  other  forms  of  the  fibro-vascular  bundle.  The 
zylem  portions  of  the  stem  bundles  of  different  plants 
among  the  Phanerogams  are  homologous  parts  of  the  tissue 
systems — the  bundles  ;  but  when  the  term  xylem  is  applied 
to  certain  parts  of  two  dissimilar  bundles — e.g.,  of  Ricinus 
(Fig.  106)  and  Lycopodium  (Fig.  101) — no  homology  of  parts 
should  be  understood.  The  tissues  themselves,  in  some 
cases  of  dissimilar  bundles,  may  be  homologous,  but  they  are 
homologous  tissues ,  and  not  homologous  parts  of  a  system 
of  tissues.*  When,  therefore,  these  terms  are  used  in  the 
present  work,  it  must  be  borne  in  mind  that  they  do  not 
necessarily  convey  the  idea  of  homology  of  parts. 

149. — De  Bary's  f  recent  structural  classification  of  fibro- 
vascular  bundles  is  useful  in  designating  their  general  plan. 
He  includes  all  forms  under  three  kinds,  viz.,  (1)  the  Col- 
lateral bundle,  which  has  one  mass  of  xylem  by  the  side  of 
a  single  mass  of  phloem  ;  this  is  the  form  of  all  bundles  of 
the  stems  of  Equisetum,  and  of  the  stems  and  leaves  of  Pha- 
nerogams I  (Figs.  99,  102, 103, 106, 107) ;  (2)  the  Concentric 


*  This  point,  which  is  an  important  one,  may  be  made  clearer  bj  an 
illustration  from  zoolo^.  The  nervous  iisme  of  one  animal  is  the 
homologue  of  tliat  found  in  any  other,  but  the  nervous  iystem  of  one 
may  or  may  not  l>e  the  homologue  of  tlie  other.  The  nervous  system 
of  the  hee,  for  example,  is  not  the  homologue,  but  the  analogue,  of 
that  of  the  ox ;  it  is,  however,  the  homolopfue  of  the  nervous  system 
of  the  lobster.  The  brain  of  the  ox  and  tlie  brain  of  the  bee  are  not 
homologues  m  parts  of  a  tyitem,  but  they  are  homologues  as  tiuusi. 

t  "  Vergleichende  Anatomie,"  etc.,  p.  331.  et  seq. 

X  In  the  Cucurbitaceas  and  some  other  orders  there  is  a  mass  of  sieve 
tissue  on  the  inner  side  of  the  xylem,  so  that  tlie  latter  is  between  two 


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THE  FJBBO-VASCULAE  SYSTEM,  121 

bundle,  which  has  its  tissues  arranged  concentrically  around 
one  another ;  this  is  the  bundle  of  the  stems  and  leaves  of 
ferns  (with  a  few  exceptions),  Selaginellae,  and  a  few  excep- 
tional cases  in  Phanerogams  (Figs.  96,  97,  98,  100) ;  (3)  the 
Badial  bundle,  which  has  its  tissues  arranged  radially  about 
its  axis  ;  such  a  bundle  occurs  in  the  stems  of  Lycopodium, 
and  it  is  the  primary  bundle  of  the  roots  of  most  Pterido- 
phytes  and  Phanerogams  (Figs.  101,  104,  105,  108). 

150a — The  development  of  the  fibro- vascular  bundle  takes 
place  in  this  wise:  in  the  previously  uniform  Primary  Meris- 
tern  there  arises  an  elongated  mass  of  cells,  constituting  the 
Procambium  of  the  bundle ;  as  it  grows  older  the  cells, 
which  were  at  first  alike,  become  changed  into  the  vessels, 
£bres,  and  other  elements  of  the  bundle  tissues.  In  ^  the 
£bro-vascular  bundle  of  the  stems  and  leaves  of  Oymno- 
43perm8  and  Dicotyledons  this  change  begins  on  the  two  sides 
of  the  bundle— I.e.,  on  the  outer  edge  of  the  phlofim  and 
the  inner  edge  of  the  xylem  ;  from  these  points  the  cTiange 
into  permanent  tissue  advances  from  both  sides  toward  the 
oentre  of  the  bundle.  In  some  cases  {e.g,y  in  the  leaves) 
all  of  the  procambium  is  changed  into  permanent  tissue, 
forming  what  is  termed  the  closed  bundle;  in  other  cases 
there  is  left  between  the  phloem  and  xylem  a  narrow  zone 
of  the  procambium  (now  called  the  Cambium),  forming 
what  is  known  as  the  open  bundle. 

151. — In  the  stem  and  leaf  bundles  of  Monocotyledons 
the  development  of  procambium  into  permanent  tissue  is 
•essentially  as  in  Dicotyledons  and  Gymnosperms,  with  this 
difference,  that  here  they  all  become  closed.  In  Pteridophytes 
and  the  roots  of  Phanerogams, the  development,  while  agree- 
ing in  general  with  the  foregoing,  is  quite  different  as  to  de- 
tails; all  are  closed,  unless  those  in  the  roots  of  Dicotyledons 
and  Gymnosperms  should  be  shown  to  be  exceptions. 

152. — The  fibro-vascular  bundles  of  leaves  and  the  re- 
productive organs  are  quite  generally  reduced  by  the  absence 

•o-called  phloSm  portions.  Sach  bandlee  are  considered  by  De  Bary  to 
be  variations  of  the  collateral  form,  and  be  designates  tliem  as  bi-ool- 
lateral  bundles. 


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122  BOTANY. 

of  one  or  more  tissues;  this  reduction  may  be  so  great  as  to 
leave  but  a  single  tissue,  which  in  many  cases  is  composed  of 
only  a  few  spiral  vessels  or  tracheldes  (Fig.  109).  In  other 
cases,  instead  of  spiral  vessels  the  bundle  may  consist  of  a  few 
fibres  of  bast ;  or  of  elongated,  thin- walled  cells,  which  are 
doubtless  to  be  regarded  as  meristem-cells  which  failed  to 

fully  change  into  one  of  the  or- 
dinary permanent  tissues ;  this 
last  is  a  very  common  accom- 
paniment of  reduced  bundles. 

(a)  In  tbe  stadj  of  the  Btracture 
of  fibro-vascular  bundles  much  care 
is  required  in  tbe  preparation  of  the 
specimens.  The  thin  transverse  sec- 
tions are  obtained  bj  ordinary  pro- 
cesses with  no  great  diificultj,  but 
such  is  not  the  case  with  the  lon^ 
gitudinal  sections  ;  thej  must  not 
only  be  extremely  thin,  but  must  run. 
^  parallel   with   the  cells  and  fibres, 

and  moreover,  must  be  sufficieDtly 
large  to  show  all,  or  a  considerable 
part,  of  the  bundle.  It  is  necessary 
also  to  have  several  lon^ntudinal 
sections,  and  to  know  the  exact  posi- 
tion of  each  one  wlien  compared 
witli  the  transverse  section. 

(&)  The  most  satisfactory  results 

can  be  obtained  only  by  the  use  of 

Y\g.  109.-Termlntl  ramWcatlona  of   some  mechanical  section-cutter.*    In 

the  reduced  flbro-vasciilar  bnudlei)  of   most  cases  the   sections  are    made 

the  leaf  of  PwroUa  bituminoM;  the ^.,     „*»^,  „^«ir:««  ♦!»«  <>»<»«»« 

ends  X ,  X .  are  cut  off  In  making  the    mor©  easily  after  soakmfi:  the  stems, 
preparation,  the  others  are  the  actual    roots  or  leaves  used  in  alcohol, 
termini ;  the  bundles  are  seen  to  be        .  ,  .  ...  ca  ui 

composed  of  spiral    tracheldes,  and        (c)  In  many  cases  it  is  profitable 
spiral  vessels  resulting  fn)m  their  fu-    ^  macerate  some  of  tlie  lonjritudi- 
sion ;  around  the  bundles  are  seen  the         ,         .        ,        .    ,        . ,       <.    ^      . 
cells  of  the  chlorophyll-i)earfng  paren-    nal  sectioiks  in  nitric  acid  and  potassi- 
chyma.    x  225.-Arter  De  Bary.  ^^  chlorate  (Schulze's  maceration), 

so  as  to  permit  of  an  isolation  of  the  fibres,  cells,  and  vessels. 

(d)  Good  specimens  for  study  may   be  obtained  from  any  of  the 
■     "    r  plants,  but  the  examination  will  be  most  profitable  if  tlie  order 

or  the  various  contrivances  used  for  cutting  sections  see  tbe  com- 
books  on  microscopy,  also  American  NaturaliH,  1874,  p.  59 ; 
iean  Quarterly  Microscapieal  Journal,  1879,  p.  181,  and  several 
^  in  Qr,  Jour.  Mie.  Science,  1870. 1874, 1875,  1877. 


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THE  FUNDAMENTAL  SYSTEM.  123 

fn  the  followinpr  list  of  examples  is  observed :  (1)  the  rhisomes  and 
roots  of  ferns ;  (2)  stems  of  SelagineUa  and  Lycopodium  ;  (3)  stems  of 
Monocotyledons ;  (4)  stems  of  Eqviuium  ;  (5)  young  stems  of  Gymno- 
spenns  and  Dicotyledons;  (6)  roots  of  Phanerogams;  (7)  reduced 
bundles  of  leaves. 

{€)  The  discussion  of  the  disposition  of  the  bundles  in  the  stem,  and 
their  relation  to  the  leaf  bundles,  together  with  the  development  and 
structure  of  secondary  bundles,  belongs  properly  to  the  special  anatomy 
of  the  Phanerogams.    (See  Chapter  XX.) 

§  IV.  The  Fundamental  System,  or  the  System  of 
Ground  Tissues. 

158.— These  terms  refer  to  the  mass  of  various  tissues 
lying  within  the  epidermis,  and  not  included  in  the  fibro- 
yascular  bundles,  when  they  are  present.  In  passing  down 
through  the  lower  plants  this  inner  mass  becomes  more  and 
more  simple,  until  it  is  composed  of  but  one  homogeneous 
tissue,  when  the  term  system  can  no  longer  bo  profitably 
applied  to  it ;  in  passing  to  the  higher  plants,  on  the  other 
hand,  there  is  in  this  portion  of  their  structure  an  increasing 
complexity,  which  comes  at  last  to  more  than  equal  that  of 
either  the  epidermal  or  fibro- vascular  systems. 

154.— In  its  fullest  development,  the  fundamental  system 
may  contain  parenchyma  of  various  forms,  coUenchyma, 
sclerenchyma,  laticiferous  tissue,  and  possibly  also  fibrous 
tissue.*  Their  arrangement,  within  certain  limits,  presents 
a  considerable  degree  of  similarity  in  nearly  related  groups 
of  plants,  but  this  is  by  no  means  as  marked  as  in  the  case  of 
the  fibro-vascular  system. 

*  It  is  a  question  whether  fibrous  tissne  occnrs  in  the  fundamental 
system  ;  there  are  some  cases  (e.g.y  in  Ferns,  Ljoopodiact^.  etc.) 
which  appear  to  phow  that  it  does,  but  possibly  they  admit  of  other  in- 
terpretation.  It  should  be  mentioned  here  that  many  eminent  botanists 
(noubly  Schwenden^r,  Russow.  Falconberg,  and  De  Bary)  hold  that  aU 
fibrous  tissue  belongs  to  the  fundamental  system,  and  as  a  consequence, 
that  it  in  no  case  is  a  proper  constituent  of  the  fibro-vascular  IJundle. 
This  is,  however,  nothing  more  than  making  a  typical  form  of  bundle 
(composed of  tracheary  and  sieve  tissues),  and  then  insisting  that  all  tis. 
sues  not  found  in  tlie  type  are  extra-fasdcnlar,  a  course  which  cannot 
be  followed  in  this  book. 


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124  BOTANY, 

(1.)  Parenchyma  is  the  most  constant  of  the  fundamental 
tissues  ;  it  makes  up  the  whole  of  the  interior  plant-body  in 
those  cases  where  there  has  been  no  differentiation  into  more 
than  one  tissue,  and  from  here,  it  is  present  in  varying 
amount  in  nearly  all  (if  not  all)  cases  up  to  and  including 
the  highest  plants.  In  stems  of  Monocotyledons  it  makes  up 
the  mass  of  tissue  lying  between  the  scattered  bundles,  and 
in  stems  of  Gymnosperms  and  Dicotyledons  it  constitutes 
the  pith  and  portions  of  the  bark. 

(2.)  Collenchyma,  when  present,  as  it  frequently  is  in  the 

stems  and  leaves  of  Dicotyle- 
dons, is  always  either  in  con- 
tjict  with  or  near  to  the  epi- 
dermis. 

(3.)  Sclerenchyma  is  com- 
mon beneath  the  epidermis 
of  the  stems  and  leaves  of  Bry- 
ophytes,  Pteridophytes,  and 
Phanerogams.  It  appears  to 
replace  collenchyma  in  parts 
having  greater  firmness  than 
that  riven  by  the  latter.    Some 

Fig.  110.— Margin  of  letf  of  Plnia  pin-     -         °       -     "^     ,  , 

a»UT,  transverse  section ;  o.  cnticoiar-  lorms    01     sclerenchyma    are 

ixed  layer  of  oater  wall  of  epidermis  ;  i>     «^„^«^i„     4.^    u«    j:«4.: :^1>«J 

Inner  nonK5uticalatiJ!ed  layer ;  C.  thick-    SCarCCly     tO     DC    aiStingUlShea 

•h^^era^o^io^n^pS^e?^^^^^^^  from  fibrous    tissuc-e../.,   in 

feS?S^^JI;^fcmr^^^^^^^  the  hypoderma  of  pine  leaves 

80o.-Afterfachs.  (Fig.   110,  g,  {').     It  may  be 

that  the  supposed  cases  of  fibrous  tissue  among  the  funda- 
mental tissues  will  turn  out  to  be  sclerenchyma  instead. 

(4.)  Laticiferous  tissue  may  occur,  apparently,  in  any  por- 
tion of  the  fundamental  system  of  Phanerogamous  plants. 

155.— It  is  thus  seen  that  in  general  the  tissues  of  the 
fundamental  system  are  so  disposed  that  the  periphery  is 
harder  and  firmer  than  the  usually  soft  interior,  although 
there  are  many  exceptions.  This  geneml  structure  has  given 
rise  to  the  term  Hypoderma  for  those  portions  of  the  funda- 
mental system  which  lie  immediately  beneath,  or  near  to  the 
epidermis.  Hypoderma  is  not  a  distinctly  limited  portion — 
in  fact,  it  is  of t^n  difficult  to  say  how  far  it  does  extend ; 


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THE  FUNDAMENTAL  8T8TEM, 


125 


however,  it  usually  includes  several,  or  even  many,  layers  of 
oells,  or  the  whole  of  each  of  the  tissue-masses  {e.g.y  collen- 
ohyma,  sclerenchyma,  etc.)  which  immediately  underlie  the 
epidermis  (Fig.  110,  ^,  t). 

The  remaining  portion  of  the  fundamental  system,  inside 
of  the  hypoderma,  is  designated  by  Sachs  as  the  Intermediate 
tissue.  The  term  is  of  but  little  value  in  many  of  the  higher 
plants,  where  more  particular  names  may  be  applied  ;  but  in 
flome  Monocotyledons,  most  Pteridophytes,  and  in  Bryo- 
phytes  it  is  very 
serviceable. 

156.  — Cork. 
Within  the  zone 
which  the  hypo- 
derma  includes 
there  frequently 
takes  place  a  pe- 
culiar develop- 
ment  of  the 
young  parenchy- 
ma, giving  rise 
to  layers  of  dead 
celfe,  whose  cav- 
ities are  filled 
with  air  only. 
The  walls  in 
some  cases  (c.^'., ^ y.«,.„-^«,.  „  ^p.«^.„..»,  », ^w.«^..., ,, ^. 

fVio  /»/\i-lr_/\uV\  aTtx  RToen  c«ll«t  the  phelloderma  ;  between  *  and  r  a  layer  of 
me  COrK-oaK  j  are  ^\\^  f^^  ^^  protoplamn,  called  the  phellogen  or  cork 
thin    and    weak,    cwiblum.    x  SSO.-After  Prantl. 

while  in  others  {e,g,,  the  beech)  they  are  much  thickened, 
and  in  all  cases  they  are  nearly  impermeable  to  water.  True 
cork  is  destitute  of  intercellular  spaces,  its  cells  being  of 
regular  shape  (generally  cuboidal)  and  fitted  closely  to  each 
other  (Fig.  111). 

157. — Cork  substance  Is  formed  by  the  repeated  subdivis- 
ion of  the  cells  of  a  meristem  layer  of  the  fundamental  tissue 
(Fig.  Ill) ;  these  continue  to  grow  and  divide  by  parti- 
tions parallel  to  the  epidermis,  forming  layers  of  cork  with 
its  cells  disposed  in  radial  rows  (Fig.  Ill,  k).     Shortly  after 


Ffff.  111.— Transverne  section  of  one-year  old  stem  of  Ai- 
lanihtu  glanduUmu.    «j  epidermis  ;  A,  cork-cells ;  r,  inner 


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126  BOTANY, 

their  formation  the  cork-cells  lose  their  protoplasmic  con* 
tents,  while  beneath  them  new  cells  are  constantly  being  cut 
off  from  the  cells  of  the  generating  layer ;  in  this  way  tho 
mass  of  dead  cork  tissue  is  formed  and  pushed  out  from  its 
living  base. 

158.— The  generating  tissue  is  called  the  Phellogen,*  or 
Cork-cambium ;  it  occurs  not  only  in  the  hypoderma,  but  in 
any  other  part  of  the  fundamental  system,  and,  as  will  be 
shown  hereafter,  in  the  secondary  fibro-yascular  bundles. 
When  a  living  portion  of  a  plant  is  injured,  as  by  cutting, 
the  uninjured  parenchyma-cells  beneath  the  wound  often 
change  into  a  layer  of  phellogen,  from  which  a  protecting 

-     mass  of  cork  is  then 
developed. 

159. — LenticeU 
are  in  many  cases  the 
result  of  a  restricted 
corky  growth  just  be- 
neath a  stoma.  Phel- 
logen consisting  of  a 

«..-^'^                ^-         ^       »    ^  few  cells  of  the  hypo- 
Fig.  112.— Tmntrene  ■ection  of  a  portion  of  the  ,  .    ^  j*'f 
Intemode  of  a  yonnfr  twig  of  Bttula  alba,  c,  caticle,  derma,  IS  lOrmecl  im- 

eoraewhat  separated  fh>m  the  epidermis ;  c,  «,  epider-  , j,*i.i         i.i 

mis ;  a,  cavity  ander  the  stoma  seen  in  crow-MCtion  meaiatCly      DCiOW      a 

above  :  a,  a;,  cells  which  are  beginning  the  process  of  of/\*«*i    /!?;/»     ii  o    ^\  . 

maUipIication  by  fission,  constftntlng  the  phellogen  Stoma   \r\g.    11^,  X)  , 

of  the  future  lenlicel.    x  876. -After  De  Bary.  by  the  growth  of  COrk 

from  this  phellogen  the  epidermis  is  pushed  out  and  finally 
ruptured,  exposing  the  roundish  or  elongated  mass  of  corkf 
(Fig.  113).  Lenticels  are  of  frequent  occuri'ence  on  the  young 
branches  of  birch,  beech,  cherry,  elder,  lilac,  etc.,  and  may  be 
distinguished  by  the  naked  eye  as  slightly  elevated  roughish 
snots,  usually  of  a  different  color  from  the  epidermis. 

e  examination  of  the  tissnes  of  the  fundamental  system  maj 
il  be  made  with  considerable  ease,  by  making  transverse^tan. 
Qd  radial  sections. 

\  the  Greek  ^eA^oc,  cork. 

>pear8  quite  certain  that  not  all  lenticels  develop  from  the 
sa  beneath  stomata ;  phellogen  forms  beneath  the  epider- 
ber  points,  and  gives  rise  to  lenticels  in  a  way  essentiijly  as 
ler  cases. 


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THE  FUNDAMENTAL  BT8TEM.  127 

(&)  Oidinarj  herbaceous  Dicotyledons  furnish  the  best  examples  of 
fully  developed  fundamental  tissues ;  tbej  can  be  most  easily  exam- 
ined after  soaking  for  some  time  in  alcohol. 

(e)  Examples  of  thin- walled  oork  are,  of  course,  best  obtained  from 


Flc.  118.— Transrerae  ■ection  through  a  lentieel  of  Betxda  alba.  «,  e,  epidermis ;  «, 
old  noma ;  under  this  !»  a  mass  of  cork  which  develops  from  the  phellosen  layer 
lyinc  next  to  the  ordinary  parenchyma  (flgared  darker) ;  the  great  multiplioatioB  of 
eork-cells  has  poshed  oat  the  epidermis,    x  S8l).— After  De  Bary. 

the  ordinary  commercial  article  ;  the  thick -walled  form  may  be  obtained 
from  the  bark  of  the  beech,  willow,  prickly  ash  (XarUhoxylum  Amer" 
kanum),  Vibumum  optUtu,  etc.  Its  development  may  be  observed  by 
making  successive  sections  of  the  shoots  at  different  heights. 


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CHAPTER  VIII. 

INTERCELLULAR  SPACES  AND  SECRETION  RES- 
ERVOIRS. 

160. — In  addition  to  the  cayities  and  passages  wliich  are 
formed  in  the  plant  from  cells  and  their  modifications,  there 
are  many  important  one^s  which  are  intercellular,  and  which 
at  no  time  were  composed  of  cells.  In  some  cases  they  so 
closely  resemble  the  cavities  derived  from  cells  that  it  is  with 
the  greatest  difSculty  that  their  real  nature  can  be  made  ont. 
In  their  simplest  form  they  are  the  small  irregular  spaces 
which  appear  during  the  rapid  growth  of  parenchyma-cells 
(Fig.  51,  p.  67) ;  from  these  to  the  large  regular  canals 
which  are  common  in  many  water  plants  there  are  all  inter- 
mediate gradations. 

161. — In  leaves,  especially  in  the  parenchyma  of  the  under 
portion,  there  are  usually  many  large  irregular  spaces  be- 
tween the  cells  ;  they  are  in  communication  with  the  exter- 
nal air  through  the  stomata,  and  contain  only  air  and  watery 
vapor.  The  petioles  and  stems  of  many  aquatic  plants  con- 
tain exceedingly  large  air-conducting  intercellular  canals, 
which  occupy  even  more  space  than  the  surrounding  tissues 
(Fig.  9,  page  20).  In  the  Water-lilies  {NyrnphcBacm)  and 
Water-plantains  (AlismacecB)  they  are  so  large  as  to  be  read- 
ily seen  by  the  naked  eye,  and  in  the  Naiads  (Naiadacem) 
they  are  almost  equally  large  (Fig.  114).  In  the  fibro- vascu- 
lar bundles  of  Fquiseium,  and  of  many  Monocotyledons  and 
some  Dicotyledons,  there  are  intercellular  canals,  sometimes 
of  very  considerable  diameter  (Figs.  99,  102,  103).  Lastly, 
in  the  medullary  parenchyma  (pith)  of  many  plants  there  is 
a  large  central  cavity  (although  formed  in  part  by  the  rup- 
ture of  some  cell-walls),  which  must  be  considered  as  inter- 


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INTERCELLULAR  SPACES.  129 

cellular ;  of  this  nature  are  the  cavities  in  many  hollow  stems 
— e.g.,  in  many  UmbellifersB  and  Gramineae. 

162. — There  are  in  many  plants  intercellular  spaces  and 
canals,  which  are  made  the  receptacles  for  special  secretions, 
and  to  which  the 
name  of  Secretion 
Beservoirs  may  be 
applied.  They  are 
surrounded  ( at 
first,  at  least)  by 
secreting  cells, 
which  furnish  the 
oil,  gum,  resin,  and 
other  substances 
(seep.  62)  found  in 
the  reservoirs. 
Their  stmcture 
and  mode  of  de- 
velopment may  be 

illustrated  by  the  i 

gum-canals  of  the 
Ivy  {ffedera  helix). 
Each  at  first  con- 
sists of  a  long  col- 
umn developed  in 
the  phloem,  and 
composed  of  four 
or  five  rows  of  thin- 
walled  cells  arrang- 
ed radially  about  a 

common  axis.    The  Vlg.  114.— Part  of  the  tmnsverw  wctlon  throuTh  the 

n^lla  erxr^n    oat^othi^a  Jnteniode  of  the  stem  of  Potamogeton  peetinatut,  ehow- 

ceilS  soon   separai/e  jne  the  large  intercellnlar  npnces  botween  the  central 

fmm  oa/»Vi  rfcfh<»r  in  Ahro-vaecular  bnndle  and  the  circnmferenre  of  the  etem  : 

iromeacil  ouier  in  ^  «,  epidermis:  a,  a  small  bnndle.  consipHnjrof  surronnd- 

thft  axis  of  fhft  f»nl-  *"?  ^Ihrons  tissne  and  a  very  small  central  msseof  sieve 

uie  aiia  ui  me  cui  xxB%xkt\  6,  b,  h,  small  bnndlw  containlnjr  only  flbrons  rt«- 

Umn,      and        thus  ™®'  «,  bnndle  sheath  of  principal  handle  in  the  axis  of 
the  stem,  within  which  is  a  mass  of  sieve  tissne  snrronnd- 

lOrm  a  small  canal  *"^  ^^*  Intercellnlar  canal,  g.    x  80.— After  De  Bary. 

(Fig.  116,  A),  which  is  afterward  increased  in  diameter  by 
the  formation  of  radial  partitions,  and  the  tangential  growth 
of  the  surrounding  cells  (Fig.  115,  E).     The  surrounding 


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130  BOTANY, 

cells  secrete  a  peculiar  sap  or  gum,  which  passes  into  and 
fills  up  the  canal. 

In  the  Coniferae  the  turpentine  canals  have  essentially  the 
same  structure.  They  are  found  in  the  bark, wood  and  pith  ; 
they  occasionally  unite  with  one  another,  or  change  their 
direction  through  some  of  the  medullary  rays,  the  cells  of 
which  have  apparently  become  transformed  into  resin-secret- 
ing tissue. 

163. — Allied  to  the  foregoing,  although  formed  in  a 
slightly  different  way,  are  the  small  secretion  reservoirs  of 
many  plants,  and  in  which  oils,  resins,  gums,  and  other 


Pig.  116.— Traniverse  sectionfi  of  yonoe  stem  of  Ivy  (ffedera  helix).  A,  young  In- 
tercellalar  gum  amal,  sarroanded  by  roar  cells ;  «,  cambium ;  tcb,  soft  bast ;  S, 
fully  developed  canal,  ff ;  6,  bast ;  rp,  cortical  parenohyma.    x  800.— After  Sachs. 

odorous  substances  are  collected.    The  fragrance  of  many 

fruits — e.g.  9  oranges  and  lemons — is  due  to  the  oils  and  other 

matters  contained  in  such  receptacles.     In  Dictamn'us  frax- 

inella  these  are  developed  as  follows  :  two  mother-cells  (/?,  /;, 

Pig.  116)  appear  in  the  hypoderma  and  divide  by  several 

partitions,  forming  a  mass  of  thin-walled  secreting  cells 

L6,  B) ;  these,  by  a  degeneration  of  their  walls,  fuse 

ommon  cavity  filled  with  oil  and  watery  matter  (Fig. 

I.     It  appears  that  the  outer  layer  of  secreting  cells 

s  developed  from  the  epidermis  (Fig.  116,  -4,  rf,  c); 

bis  is  partly  an  epidermal  structure. 

i&  nature  are  the  reservoirs  in  the  "  glandular  hairs  " 

ame  plant ;  in  fact,  the  two  structures  are  apparently 


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BEOBETION  RESERVOIRS, 


181 


but  slightly  different  deyelopments  of  the  same  organ  (Fig. 
117). 

(a)  The  omaller  and  more  irregular  intercellular  spaces  may  be 
flta^ed  in  the  fundamental  tissue  of  the  stem  of  Indian  com,  in  the 
Darenchyma  of  most  leaves,  and  the  stems  of  Juncus. 


Fro.  117. 

VlflT.  118.— Inlenial  elands  of  the  leaf  of  DUstamnut  fraoAneUa.  A  and  2?,  early 
•taf^  of  development;  (7,  matare  gland  ;  d,  epidermia ;  <%  p^  molher-cella  of  ihe  ue- 
creting  cells :  o,  drop  of  ethereal  oil.— After  Kanter. 

Fig.  117.— Glandular  hair  of  the  Inflorescence  of  ZHetamwut  fraadneUa;  A  and  B^ 
earlieet  stages,  showing  the  origin  to  be  similar  to  that  of  the  internal  glands ;  C,  fully 
developed  hair ;  the  part  A  is  the  true  hair,  while  all  below  it,  incladmg  the  oil  cav- 
ity, is  to  be  regarded  as  an  outgrowth  of  the  sub-epidermal  cells.  X  about  S20.— After 
Banter. 


Qt)  Thin  cross-sections  of  the  stems  and  petioles  of  Npmphaa, 
Nitphar,  Ndutiibium,  8agUt€ma,  Potamogetont  and  many  other  water 
plants,  afford  excellent  specimens  for  the  study  of  intercellular  c:inala 


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132  BOTANY. 

Tbe  relation  of  tlie  intercellular  spaces  of  the  leaves  to  the  canals  of 
the  petioles  may  be  studied  by  carefully  made  longitudinal  sections. 

(e)  The  resin  canals  of  SUphium  laeinialum  and  8.  perfoliatum,  and 
the  turpentine  canals  of  Coni ferae,  furnish  excellent  examples  of  the 
larger  secretion  reservoirs,  while  the  smaller  ones  may  be  studied  in 
the  cavities  in  the  rind  of  the  orange  and  lemon,  the  leaves  of  Dictam* 
nus,  XanthosB*tUim^  Rue  (i2t<to),  Hypericum,  and  many  Labiatse. 


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CHAPTER  IX. 

THE    PLANT-BOD  Y. 
§  I.   Generalized  Forms. 

164. — The  cells^  tissues,  and  tissue  systems  described  in 
the  preceding  pages  are  variously  arranged  in  the  different 
groups  of  the  vegetable  kingdom  to  form  the  plant-body. 
The  simplest  plants  are  single  cells  or  undifferentiated 
masses  of  cells ;  in  those  next  higher  the  cells  are  aggre- 
gated into  simple  tissues,  while  still  above  these  the  tissues 
are  grouped  into  tissue  systems.  With  this  internal  differ- 
entiation there  is  a  corresponding  differentiation  of  the  ex- 
ternal plant-body.  The  lower  plants  are  not  only  simpler  as 
to  their  internal  structure,  but  they  are  so  as  to  their  exter- 
nal form  as  well.  The  higher  plants  are  as  much  more 
complex  than  the  lower  ones  as  to  their  external  parts  as 
they  are  in  regard  to  their  tissues  and  tissue  systems. 

166. — In  the  lowest  groups  of  plants  the  simple  plant- 
body  has  no  members  ;  the  single-or  few-celled  alga  has  no 
parts  like  root,  stem,  or  leaf  ;  it  is  a  unit  as  to  its  external 
form.  In  the  higher  groups,  on  the  contrary,  the  plant- 
body  is  composed  of  several  to  many  less  or  more  distinct 
members.  In  those  plants  in  which  they  first  appear,  the 
members  are  not  clearly  or  certainly  to  be  distinguished  from 
the  general  plant-body ;  but  in  the  higher  groups  they  be- 
come distinctly  set  off,  and  are  eventually  differentiated  into 
a  multitude  of  structural  and  functional  forms. 

lee. — As  will  be  seen  in  the  future  chapters,  every  plant, 
in  its  earliest  (embryonic)  stages,  is  simple  and  memberless  j 
and  every  member  of  any  of  the  higher  plants  is  at  first  indis- 
tinguishable from  the  rest  of  the  plant-body ;  it  is  only  in 


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134  BOTANY. 

the  later  growth  of  any  member  that  it  becomes  distinct ;  in. 
other  words,  every  member  is  a  modification  of,  and  develop- 
ment from,  the  general  plant-body.  Likewise,  where  equiva- 
lent members  have  a  different  particular  form  or  function, 
it  is  only  in  the  later  stages  of  growth  that  the  differences 
appear.  All  equivalent  members  are  alike  in  their  earlier 
st^es,  whether,  for  example,  they  eventually  become  broad 
green  surfaces  (foliage  leaves),  bracts,  scales,  floral  envelopes, 
or  the  essential  organs  of  the  flower. 

167. — These  facts  make  it  necessary  to  have  some  general 
terms  for  the  parts  of  the  plant-body,  which  are  applicable 
to  them  in  all  their  forms.  We  must  have,  for  example,  a 
term  so  generalized  as  to  include  foliage  leaves,  bi'acts,  scales, 
floral  envelopes,  and  all  the  other  forms  of  the  so-called  leaf- 
series.  So,  too,  there  is  need  of  a  term  to  include  stems, 
bulbs,  bud,  and  flower  axes,  root-stocks,  corms,  tubers,  and 
the  other  forms  of  the  so-called  stem-series. 

168. — By  a  careful  study  of  the  members  of  the  more 
perfect  plants  we  find  that  they  may  be  reduced  to  four 
general  forms,  viz.,  (1)  Caulome,  which  includes  the  stem 
and  the  many  other  members  which  are  found  to  be  its 
equivalent ;  (2)  Fhyllome,  including  the  leaf  and  its  equiva- 
lents; (3)  Trichome,  which  includes  all  outgrowths  or  ap- 
pendages of  the  surface  of  the  plant,  as  hairs,  bristles,  root- 
hairs,  etc.  ;  (4)  the  Root,  which  includes,  besides  ordinary 
subterranean  roots,  those  of  epiphytes,  parasites,  etc. 

160. — As  indicated  above,  in  the  lower  plants  the  differ- 
entiation into  members  is  not  so  marked  as  in  the  higher, 
and  in  passing  downward  in  the  vegetable  kingdom  groups 
are  reached  in  which  it  is  inappreciable,  and  finally  in  which 
it  is  entirely  wanting ;  such  an  undifferentiated  plant-body 
is  called  a  Thallome,  and  may  properly  be  regarded  as  the 
original  form,  or  prototype. 

170. — Thallome.*  The  simplest  thallome  is  the  single 
cell ;  this,  though  generally  rounded,  is,  in  some  cases 
{Botrydiumy  Caulerpa,  etc.),  irregularly  extended  into 
branch-like  or  leaf -like  portions,  which  must  not  be  mistaken 

•  From  tbe  Greek  i^oAA<Js,  a  yoang  shoot,  branch ,  or  frond. 


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GENERALIZED  FORMS.  135 

lor  members  coordinate  with  those  mentioned  above,  as  they 
are  only  parts  of  a  unit,  instead  of  members  of  a  body ;  they 
may  be  regarded  as,  to  a  certain  extent,  f  oreshadowings  or 
anticipations  of  the  members  of  the  higher  plants.  Plants 
composed  of  rows  of  cells  or  cell  surfaces  frequently  show 
no  indication  whatever  of  a  division  into  members  ;  but,  in 
some  cases,  there  is  a  little  differentiation,  which,  though 
not  carried  far  enough  to  give  rise  to  members,  is  the  same 
in  kind.  In  the  larger  algae  there  is  sometimes  so  much  of 
a  differentiation  that  it  becomes  difficult  to  say  why  certain 
parts  ought  not  to  be  called  members.  Caulome  and  phyl- 
lome,  at  least,  are  strongly  hinted  at  in  the  Fucaceae,  and 
in  this  group,  although  the  term  thallome  is  applied  to  the 
plant-body,  it  must  be  admitted  as  not  fully  applicable. 
Structures  of  this  kind  are  instructive,  as  showing  that  the 
passage  from  the  thallome  plant-body  to  that  in  which 
members  are  differentiated  is  by  no  means  an  abrupt  or 
sudden  one. 

171.— Mutual  Belations  of  Thallome^  Caulome,  and 
Phyllome.  The  caulome  is  the  phyllome-bearing  axis  of  the 
plant,  and  phyllomes  are  the  members  developed  upon  the 
caulome.  The  two  have  a  reciprocal  relation,  and  in  no 
case  is  the  one  present  without  the  other.  The  definition  of 
the  one  involves  that  of  the  other.  Both  are  derived 
directly  from  the  thallome,  and  that  differentiation  which 
gives  rise  to  one  necessarily  produces  the  other.  The  differ- 
entiation of  thallome  into  caulome  and  phyllome  is  simply 
a  lobing  and  contraction  of  the  marginal  portions  into  sepa* 
rable  phyllomes,  and  a  rounding  and  contraction  of  the 
central  or  axial  portion  into  a  caulome. 

172. — Caulome.*  By  this  general  name  we  designate 
all  axial  members  of  the  plant.  In  the  more  obvious  cases 
the  caulome  is  the  axis  which  bears  leaves  (foliage),  and  in 
this  form  it  constitutes  (1)  the  Stem;  branches  are  only  stems 
which  originate  laterally  upon  other  stems. 

The  other  caulome  forms  are  : 

(2.)  Runners^  which  are  bract-bearing,  slender,  weak,  and 
trailing. 

*  From  the  Greek  xavAoS,  stem. 


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136  BOTANY. 

(3.)  Root-stocks,  which  are  bract  or  scale-bearing,  usually 
weak,  and  subterranean. 

(4.)  Tubers,  which  are  bract  or  scale-bearing,  short  and 
thickened,  and  subterranean. 

(5.)  Corms,  which  are  leaf-bearing,  short  and  thickened, 
and  subterranean. 

(6.)  Bulb-axes,  which  are  leaf -bearing,  short  and  conical, 
and  subterranean. 

(7.)  Flower-axes,  which  are  bract,  perianth,  stamen,  and 
pistil-bearing,  short,  and  usually  conical  and  aerial. 

(8.)  Tendrils,  which  are  degraded,  slender,  aerial  cau- 
lomes,  nearly  destitute  of  phyllomes. 

(9.)  Thorns,  which  are  degraded,  thick,  conical,  aerial 
caulomes,  nearly  destitute  of  phyllomes. 

173. — ^Phyllome.*  The  phyllome  is  always  a  lateral 
member  upon  a  caulome.  It  is  usually  a  flat  expansion  and 
extension  of  some  of  the  tissues  of  the  caulome.  Its  most 
common  form  is  (1)  the  Leaf  (foliage),  which  is  usually  large, 
broad,  and  mainly  made  up  of  chlorophyll-bearing  paren- 
chyma. 

The  other  phyllome  forms  are  : 

(2.)  Bracts,  which  are  smaller  than  leaves,  generally  green. 

(3.)  Scales,  which  are  usually  smaller  than  leaves,  wanting 
in  chlorophyll-bearing  parenchyma,  and  with  generally  a 
firm  texture. 

(4.)  Floral  envelopes,  which  are  variously  modified,  but 
generally  wanting  in  chlorophyll-bearing  parenchyma,  and 
with  generally  a  more  delicate  texture. 

(5.)  Stamens,  in  which  a  portion  of  the  parenchyma  de- 
velops male  reproductive  cells  (pollen). 

(6.)  Carpels,  bearing  or  enclosing  female  reproductive 
organs  (ovules). 

(7.)  Tendrils  and  Spines,  which  are  reduced  or  degraded 
forms,  composed  of  the  modified  fibro-vascular  bundles,  and 
a  very  little  parenchyma  ;  in  the  first  the  structures  are  weak 
and  pliable,  in  the  latter  stout  and  rigid. 

The  altogether  special  modifications  of  the  phyllome,  as  in 
pitchers  and  cups,  will  be  noticed  hereafter. 

♦  From  the  Greek  ^^\ov,  leaf. 


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GENERALIZED  FORMS.  137 

174. — ^Trichome.*  The  trichome  is  a  surface  appendage 
consisting  of  one  or  more  cells  usually  arranged  in  a  row  or 
a  column^  sometimes  in  a  mass.  Its  most  common  forms  are 
met  with  in  (1)  the  Hairs  of  many  plants.     (See  page  95.) 

The  other  trichome  forms  are  : 

(2.)  Bristles,  each  consisting  of  a  single  pointed  cell  or 
a  row  of  cells,  whose  walls  are  much  thickened  and  hardened. 

(3.)  Prickles,  like  the  last,  but  stouter,  and  usually  com- 
posed of  a  mass  of  cells  below. 

(4.)  Scales,  in  which  the  terminal  cell  gives  rise  by  fission 
to  a  flat  scale,  which  soon  becomes  dry. 

(5.)  Glands,  which  are  generally  short,  bearing  one  or 
more  secreting  cells. 

(6.)  Root-hairs,  which  are  long,  thin,  single-celled  (in 
mosses  a  row  of  cells),  and  subterranean. 

(7.)  Sporangia  of  Pteridophytes,  some  of  whose  interior 
cells  develop  into  reproductive  cells  (spores). 

(8.)  Ovules  of  Phanerogams,  one  or  more  of  whose  cells 
develop  into  reproductive  cells  (embryo  sacs).t 

175.— Boot.  The  root  is  that  portion  of  the  plant-body 
which  is  clothed  at  its  growing  point  with  a  root-cap.  In 
ascending  through  the  vegetable  kingdom  roots  are  the 
latest  of  the  generalized  forms  to  make  their  appearance, 
and  in  the  embryo  they  appear  to  be  formed  later  than 
caulome  and  phyllome.  They  present  fewer  variations  than 
any  of  the  other  generalized  forms.  The  ordinary  (1)  Sub- 
terranean roots  of  plants  are  typical.  They  differ  but  little 
from  one  another  in  all  the  groups  of  the  Pteridophytes  and 
Phanerogams. 

The  other  root  forms  are  : 

(2.)  Aerial  roots,  which  project  into  the  air,  and  often  have 
their  epidermis  peculiarly  thickened,  as  in  the  epiphytic 
orchids. 

(3.)  Roots  of  Parasites,  which  are  usually  quite  short,  and 


*  From  the  Greek  ■&pl^,  rpixoi,  a  hair. 

t  It  iB  held  bj  some  botanists  that  in  some  plants  the  ovale  is  *'  the 
terminal  portion  of  the  axis/'  and  that  in  others  it  is  a  leaf  or  part  of  a 
leaf. 


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138 


BOTANY, 


in  some  cases  provided  with  sucker-like  organs,  by  means  of 
which  they  come  into  a  more  intimate  relation  to  their  hosts. 

176.— Fartioiilar  Belations  of  Fhyllome  to  CaiQome. 
Sachs*  has  formulated  the  relations  of  phyllome  to  caulome 
in  substance  as  follows : 

(1.)  Phyllomes  always  originate  from  the  Primary  Meris- 
tem  of  the  punctum  vegetationis  ;  fully  differentiated  tissues 
are  incapable  of  producing  them. 

(2.)  They  are  always  exogenous  formations ;  that  is,  they 


Fio.  119. 


Pio.  118. 

Fig.  118.— Diagrams  of  dictaotomoas  branching.  A,  normal  dichotomy,  in  which 
each  branch  is  again  dichotomoa«lT  branched  ;  B^  helicoid  dichotomy,  in  which  the 
right-hand  branch,  r,  does  not  develop  farther,  while  the  left-hand  one,  /,  is  in  every 
case  again  brunched  ;  (7,  ecorpioid  dichotomy,  in  which  the  branches  are  alternately 
fhrther  developed.— After  Sachs. 

Fig.  119.— Diagram  of  botryoee  monopodial  branching.  The  nnmerals  indicate  the 
'*  generations.** 

develop  from  outer  and  not  inner  tissues,  consequently  their 
tissues  are  externally  continuous  with  those  of  the  caulome. 
(3.)  They  always  originate  below  the  growing  apex  of  the 
caulome  as  lateral  outgrowths  ;  they  may  appear  singly,  so 
that  no  two  are  situated  at  the  same  height  on  the  stem,  or 
two  or  more  may  grow  at  once,  generally  at  equal  distances 
from  one  another  in  the  circumference  of  the  caulome. 

♦"Text-Book,"  p.  131. 


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GENERALIZED  FORMS. 


139 


(4.)  They  always  arise  in  acropetal*  order. 

(5.)  They  grow  more  rapidly  than  the  eaulome  does  above 
their  insertion.  When  they  are  numerous  their  rapid  growth 
gives  rise  to  the  accumulation  of  phyllomes  known  as  a  Bud. 

(6.)  The  phyllomes  of  any  plant  are  always  of  a  different 
form  than  the  caulomes. 

177.— General  Modes  of  Branching  of  Members.  There 
are  two  general  modes  of  the  branching  of  the  members  of 
the  plant-body.  In  the  one,  the  apex  of  the  growing  mem- 
ber divides  into  two  new  growing  points,  from  which  branches 
proceed ;  this  is  the  Dichotomous  mode  of  branching  (Pig. 

(f 

V 


F!g.  190.— Diagrams  of  cymoee  monopodial  branching.  A  and  B,  ecorpfoid  vy  u.^  ^ 
C^  forked  CTino^e  moDopodlom,  the  compound  or  falsely  dichotomous  cyme  (called 
also  the  dUAoHum):  />,  hellcold  cyme.— After  Sachs. 

118).  In  the  other,  the  new  growing  points  arise  as  lateral 
members,  while  the  original  apex  of  the  parent  stem  still 
retains  its  place  and  often  its  growth  ;  this  is  the  Jfowo- 
podial  mode  of  branching  (Fig.  119).  Both  modes  are  sub-  i 
ject  to  many  modifications,  the  most  important  of  which  are 
briefly  indicated  in  the  following  table  : 

A.— DICHOTOMOUS. 
1.  Forked  dichotomy,  in  which  both  branches  of  each  bifurcation  are 
equally  developed  (Fig.  118,  A). 

*  Acropetal,  tending  toward  the  Bummit ;  from  the  Qreekdtcpa, 
summit,  and  neraij,  to  move  toward. 


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140  BOTANY, 

2.  Bympodial  dichoUm^y,  in  which  one  of  the  branches  of  each  bifur- 
cation develops  more  than  the  other. 

a.  Hdicoid  sympodial  dichotomy,  in  which  the  greater  development 

is  always  on  one  side  (Fig.  118,  B), 
6.  Scorpioid  Bympodial  dichotomy ,  in  which  the  greater  develop- 
ment is  alternately  on  one  side  and  the  other  (Fig.  118,  O), 

B.— MONOPODIAL. 

1.  Botryose  monopodium,  in  which,  as  a  rale,  the  axis  continues  to 
grow,  and  retains  its  ascendency  over  its  lateral  branches  (Fig.  119). 

2.  Cymose  monopodium,  in  which  the  axis  soon  ceases  to  grow,  and  is 
overtopped  by  one  or  more  of  its  lateral  branches. 

a.  Forked  cymose  monopodium,  in  which  the  lateral  branches  are 

all  developed  (Fig.  120,  (7). 
6.  Sympodial  cymose  monopodium,  in  which  some  of  the  lateral 
brauches  are  suppressed  ;  this  may  be 
I/,  Heliooid,  when  the  sappression  is  all  on  one  side  (Fig.  120, 

D);or 
y^.  Scorpioid,  when  the  suppression  is  alternately  on  one  side 
and  the  other  (Fig.  120.  A  and  B). 

Dichotomous  branching  takes  place  in  many  Thallophytes ;  it  is 
beautifully  seen  in  the  appendages  to  the  perithecia  of  many  Erysipha- 
ceae  (e.g.,  lilac-blight,  cherry- blight,  etc.)  It  occurs  also  in  the  roots, 
stems,  and  leaves  of  many  Pteridophytes,  and  the  leaves  and  other 
phyllome  structures  of  some  Phanerogams. 

Monopodial  branching  is,  on  the  other  hand,  the  general  rule  for  all 
members  of  the  plant-body  in  Phanerogams,  and  in  Pteridophytes, 
Bryophytes,  and  Thallophytes  very  much  of  the  branching  is  also  of 
this  kind.* 

§  II.   Stems. 

178. — The  primary  stem  of  a  plant  first  develops  from  the 
meristem  tissue  of  the  embryo ;  its  subsequent  growth  is  a 
growth  from  the  meristem  of  the  punctum  vegetationis,  to- 
gether with  an  intercalary  growth  of  its  newer  parts.  Oa 
account  of  the  more  rapid  growth  of  its  young  leaves,  it  usu- 
ally happens  that  the  stem  is  terminated  by,  and  appears  to 
grow  from,  a  bud  ;  in  fact,  it  is  a  common  statement  that 
stems  grow  from  buds.  It  will  be  necessary  to  examine  the 
bud  in  detail. 

*  A  full  discussion  of  this  subject  would  occupy  more  space  than  can 
be  allotted  to  it  in  tliis  book,  and  any  attempt  to  cover  the  subject  in  a 
few  pages  would  tend  rather  to  confuse  the  student  than  to  enlighten 
him.  For  a  good  account,  the  student  is  referred  to  Sachs* "  Text-Book 
of  Botany,"  p.  155 ;  Hofmeister's  **A1]gemeine  Morphologie  der  Ge» 


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STEMS.  141 

179. — The  punctum  vegetationis  (growing  point)  of  a  stem 
is  generally  a  conical  point ;  upon  its  curved  surface  a  little 
below  its  apex  the  rudiments  of  leaves  appear  as  slight  swell- 
ings or  papillae ;  as  the  growing  point  elongates,  and  the 
rudimentary  leaves  grow,  new  ones  appear  above  the  pre- 
viously formed   ones.     By  the  more  rapid  growth  of  the 
leaves  than  the  newer  part  of  the  stem,  the  latter  comes  to 
be  covered  with  many  closely  approximated  young  leaves. 
This  is  the  usual  condition  of  the  ends  of  growing  stems  in 
summer,  hence  such  an  aggre- 
gation of  rudimentary  leaves 
may  be    termed   a  summer 
bud.     While  in  the  apex  of 
the  bud  the  leaves  grow  more 
rapidly  than  the  stem,  in  its 
base  the  growth  of  the  stem 
is  much  the  most  rapid.  This 
later  stem-growth  is  an  inter- 
calary one,  and  it  results  in 
separating  the  previously  ap- 
proximated leaves  a  consid- 
erable   distance    from    one 
another,   forming  the  inter- 
nodes  of  the  stem. 

180.  —  Winter  buds  have 
essentially  the  same  struc- 
ture, and  the  sjime  mode  of 

formation.        In    these,    how-  p,g.,2i._Ext«mltyof  abranchof  the 

ever,    most    of    the    phyllome  Howe-chestnut  (^oujwj«p/»o^^^^ 

/                                  .       "^  a  large  terminal  bud  with  two  smaller  lat- 

rudimeuts  develop  mtO  more  ^ral  buds  ;  a,  a,  a,  scars  of  fallen  leaves. 

-        ,        ,         -    *    ,            ,  .   ,  Natural  size.— After  Duchartre. 

or  less  hardened  scales,  which 

grow  rapidly  and  overtop  the  punctum  vegetationis.  The 
basal  growth  of  the  bud  ceases,  and  soon  its  apical  growth 
also,  and  thus  the  scaly  phyllomes  are  left  in  close  approxi- 
mation (Fig.  121).  Such  a  bud  is  but  a  state  of  the  ter- 
minal portion  of  the  leaf -bearing  stem,  and  not  a  new  for- 
mation or  member ;  it  cannot  even  be  called  an  organ. 
181. — Upon  the  return  of  warm  weather  in  the  spring 

wlchse,"  p.  482.  and  Eichler's  '*  BlUthendiapramme,"  page  33  et  aeq. 
In  eacli  there  are  many  references  given  to  the  literature  of  the  subject. 


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142  BOTANY. 

the  basal  growth  of  the  bud  is  resumed^  and  shortly  after- 
wardy  or  simaltaneously,  the  apical  growth  also.  The  thick 
scales  separate  by  the  slight  elongation  of  the  stem^  and  being 
of  no  further  use  to  the  plant  they  soon  fall  off.  The  inter- 
calary growth  of  the  scale-bearing  portion  of  the  stem  is  gen- 
erally much  less  than  of  that  which  bears  leaves^  hence  the 
fii-st  intemodes  which  appear  in  the  spring  of  the  year  are 
quite  short.  The  punctum  vegetationis  of  such  a  winter 
bud,'  after  resuming  its  activity,  goes  on  developing  leaves  as 
lateral  members  exactly  as  if  there  had  been  no  interruption 
in  its  activity.     Upon  the  approach  of  autumn  again  the 


Fig.  122.— Lonffitndinal  section  of  the  ipex  of  tlie  stem  of  a  moss  {FonUna^  anU» 
ptfrOiea).  v,  apical  cell ;  a,  outer  t>ait  or  one  of  the  seinnentB  cot  off  from  apical 
cell ;  «,  apical  cell  of  a  lateral  leaf-Dearing  shoot  arising  below  a  leaf;  e,  first  cell  of 
a  leaf ;  &,  b,  cells  forming  cortex.  —After  Leitgeb. 

same  process  of  bud-formation  takes  place  by  the  decrease  in 
the  rapidity  of  extension,  and  its  final  cessation  ;  this  is  fol- 
lowed again  by  the  resumption  of  growth  upon  the  advent  of 
spring.  Thus  the  stem  exhibits  a  periodicity  in  its  growth, 
and  one  of  its  phases  is  the  so-called  winter  bud. 

182. — Branches  of  stems  (lateral  stems)  normally  originate 
in  the  punctum  vegetationis  as  lateral  outgrowths  (Pig. 
122,  z) ;  each  develops  first  into  a  conical  mass,  which  then 
becomes  the  punctum  vegetationis  of  a  new  stem,  and  upon 
it  lateral  members  arise,  as  in  the  case  of  the  principal  stem. 
The  new  stem  may  elongate  at  once  into  a  leafy  shoot,  as 


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STEMS, 


143 


takes  place  in  annuals ;  on  the  other  hand^  it  may  make  but 
little  growth  in  extension,  so  forming  a  bud,  as  is  common 
in  perennials  (Fig.  123).  Buds  like  the  last,  which  are 
apparently  sessile  upon  the  parent  axis,  are  said  to  be  lateral, 
although,  strictly  speaking,  they  are 
terminal  upon  very  short  stems. 

188. — It  most  frequently  hap- 
pens that  new  stems  arise  near  to 
certain  leaves.  The  origin  of  the 
stem  may  be  below  the  leaf,  as  in  | 

many  Bryophytes  {z,  Fig.  122) ;  or 
beside  it,  as  in  EquisetacesB ;  or 
above  it  in  its  axil,  as  in  Monocoty- 
ledons and  Dicotyledons  (Fig.  121), 
and  it  appears  that  in  each  case  the  V 

new  stem  originates  shortly  after 
the  leaf. 

184. — In  Monocotyledons  and 
Dicotyledons  there  are  usually  as 
many  new  stems  formed  as  there 
are  leaves  ;  exceptionally  there  may 
be  several  new  stems  (supernumer- 
ary stems  or  buds)  formed  in  the 
axil  of  each  leaf  (Fig.  123.)  In 
mosses,  ferns,  and  Conifers,  on  the 
contrary,  there  are  by  no  means  as  , 

many  new  stems  as  there  are  leaves.       ^ 

186. — Rarely,  new  stems  (adven- 
titious stems  or  buds)  arise  from 
the  older  parts  of  plants  ;  thus  they 
may  arise  from  petioles  and  ribs  of 

some  leaves — e.g,y   Begonia,   Bryo-  

phyllum,  etc. ;  from  the  cambium  of 
the  cut  surfaces  of  stems  —  e.g,, 
elm,  willow,  etc. ;  and  sometimes  in 
abundance  from  the  fibro-vascular 
bundles  of  roots — e.g.,  Populus  alba,  cherry,  sweet  potato, 
etc.  Such  structures  are  always  endogenous,  as  in  all  cases 
they  spring  from  some  portion  of,  or  near  to,  the  fibro-vas- 
cular bundles,  and  break  through  the  overlying  tissues. 


Pig.  193.— Branch  of  the  Cher- 
ry bearing  lateral  buds :  y,  I/,  I/. 
buds  from  which  leafy  branches 
will  develop  ;  b,  b,  6.  onds  ftom 
which  flowerx  will  develop.  Nat- 
ural size.— After  Dnchartre. 


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144  BOTANY. 

186. — Frequently  the  new  stems  which  are  normally  formed 
make  but  a  very  little  growth^  and  in  perennials  become 
covered  by  the  subsequently  formed  tissues  ;  they  thus  become 
the  so-called  dormant  buds.  Under  favorable  conditions  they 
may  resume  their  growth  long  afterward,  and  they  are  then 
liable  to  be  mistaken  for  adventitious  stems.  Probably  very 
many  of  the  supposed  cases  of  adventitious  stems  upon  the 
older  stems  of  Dicotyledons  are  in  reality  only  the  late 
growths  of  stems  which  have  been  dormant  for  a  long  time. 

(a)  The  development  of  stems  may  be  studied  in  almost  any  plant. 
Those  which  have  large  winter  buds,  however,  offer  some  advantages 
to  the  beginner.  Sach  are  the  bads  of  hickory,  horse-chestnut,  lilac, 
etc. 

(6)  Vertical  sections  should  be  made  of  the  buds  before  they  resume 
their  growth  in  the  spring,  and  these  should  be  compared  with  similar 
sections  made  after  some  growth  has  taken  place. 

(c)  Many  of  the  common  annuals  with  a  continued  growth — e.g,, 
balsam,  mallow,  etc.— may  be  profitably  studied  for  making  out  the 
growth  of  summer  buds.  The  young  shoots  of  many  shrubs — e.g,^ 
elder  and  lilac — are  also  excellent  for  study. 

(d)  Thin  enough  longitudinal  sections  should  be  made  to  show  the 
punctum  vegetationis.  The  specimens  may  often  be  made  much  more 
instructive  by  coloring  with  carmine,  or  other  staining  fluids. 

§  III.   Of  Leaves  ik  Gekeral. 

187. — Every  leaf  originates  in  the  Primary  Meristem  of 
the  punctum  vegetationis.  It  is  at  first  a  small  projection 
or  papilla,  composed  of  one  or  more  cells,  which  undergo  a 
rapid  division,  thereby  producing  the  quick  early  growth 
before  mentioned  (p.  139).  Generally  the  multiplication  of  the 
cells  is  such  as  to  give  rise  to  a  surface  whose  plane  cuts  the 
stem  transversely.  In  many  cases  the  apex  of  the  leaf  soon 
becomes  changed  into  permanent  tissue  while  the  base  con- 
tinues to  grow,  indefinitely  in  grasses  and  many  other 
Monocotyledons,  and  definitely  in  most  Dicotyledons.  In 
other  cases  the  base  passes  over  into  permanent  tissue,  while 
the  apical  portions  keep  on  growing,  as  in  ferns  and  some 
pinnate  leaves  of  Dicotyledons. 

188. — Many  leaves  are  raised  upon  a  stalk  by  a  subsequent 
growth  between  the  stem  and  the  base  of  the  leaf ;  this  leaf- 


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OF  LEAVES  IN  GENERAL,  145 

stalk  (petiole)  is  much  extended  in  the  lower  leaves  Of  many 
plants,  especially  of  those  which  grow  in  the  shade  or  are 
intermixed  with  other  plants.  Structurally  the  petiole  is  the 
extension  of  the  fibre- vascular  and  parenchymatous  connec- 
tion between  the  leaf  and  the  stem ;  and  it  generally  forms 
an  articulation  or  joint  with  the  stem  at  its  lower  extremity ; 
physiologically  it  is  a  support  for  the  leaf,  and  it  is  longer  or 
shorter  just  as  elongation  or  want  of  it  places  the  leaf  under 
the  best  physiological  conditions. 

189. — The  leaf  is,  when  first  formed,  destitute  of  fibro-vas- 
cular  bundles,  and  this  is  the  permanent  condition  of  the  leaves 
of  Bryophytes,  and  the  leaf -like  portions  of  the  Thallophytes. 
In  most  higher  plants,  however,  portions  of  the  leaf  tissue 
early  become  differentiated  into  one  or  more  fibro-vascular 
bundles,  which  pass  downward  into  the  stem  and  unite 
with  the  older  bundles ;  the  upper  parts  of  the  bundles  grow 
with  the  leaf,  and  form  lateral  branches  and  branchlets, 
giving  rise  to  the  complicated  system  of  so-called  veins  so 
often  to  be  seen  (especially  in  Dicotyledons).  In  many  of 
the  smaller  phyllome  structures,  as  scales,  bracts,  etc.,  which 
may  be  regarded  as  rudimentary  leaves,  there  are  no  fibro- 
vascular  bundles,  just  as  in  the  rudiments  of  actual  leaves. 

190.— Venation,  In  mosses  and  other  plants  destitute  of 
fibro-vascular  bundles,  the  veins,  when  present,  are  composed 
of  but  slightly  modified  parenchyma  ;  in  higher  plants  they 
are  composed  of  fibro-vascular  bundles  and,  in  the  larger 
veins,  of  one  or  more  surrounding  layers  of  modified  paren- 
chyma in  addition.  The  disposition  of  the  veins  in  a  leaf 
depends  largely  upon  its  mode  of  growth.  Usually  several 
veins  form  early ;  if  they  grow  from  a  common  point,  an 
arrangement  like  that  in  the  maple  (radiate  venation)  is  the 
result ;  if  the  veins  grow  from  points  on  an  axis,  the  various 
modifications  of  the  pinnate  venation  are  produced,  depend- 
ing upon  the  amount  of  elongation  of  the  axis. 

In  many  Monocotyledons  the  leaves  continue  to  grow  at 
their  bases  ;  their  veins  are,  as  a  consequence,  parallel  with 
the  leaf  axis  ;  in  other  Monocotyledons  and  most  Dicoty- 
ledons the  veins  originate  on  an  extending  axis,  and  pass 
outward  to  or  near  to  the  margins. 


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146 


BOTANY. 


101. — Leaves  are  for  the  most  pai-t  bilaterally  symmetrical, 
a  vertical  plane  passing  from  base  to  apex  generally  dividing 
them  into  two  equal  and  corresponding  halves.  In  the  elm, 
linden,  begonia,  etc.,  and  the  leaflets  of  many  compound 
leaves,  the  two  halves  are  unequal.  The  asymmetry  is  ap- 
parently related  in  some  way  to  the  position  of  the  leaves  on 
the  stem,  as  it  is  more  frequently  noticed  on  plants  whose 
leaves  are  two-ranked,  with  the  leaf  planes  parallel,  or 
nearly  so,  to  the  axis  of  the  stem  (or  in  compound  leaves,  to 
the  central  leaf  axis).  In  some  two-ranked  leaves  the  upper 
half  of  each  leaf  (/.e.,  that  nearer  to  the  apex  of  the  stem) 
is  the  larger,  while  in  others  the  opposite  is  the  case.* 

102. — In  form  leaves  are  very 
variable  ;  even  in  the  same  plant 
it  rarely  happens  that  all  have 
the  same  form.  In  general, 
elongated  forms  (t.e.,  linear  and 
oblong)  prevail  in  the  Monocoty- 
ledons, while  as  a  rule  they  are 
considerably  broadened  (t.e., 
lanceolate,  elliptical,  cordate, 
etc.)  in  mosses,  ferns,  and  Di- 
cotyledons; many  exceptions, 
however,  occur. 

103. — The  absolute  size  of 
leaves  varies  greatly  also.  The 
largest  leaves — as,  for  example,  those  of  palms,  tree-ferns,  ba- 
nana, Victoria  regia^  etc. — occur  in  the  warmer  portions  of 
the  earth  ;  in  frigid  regions  the  leaves  are  small ;  in  tem- 
perate climates  perennial  leaves  are,  as  a  rule,  smaller  than 
annual  ones. 


ABC 
Fig.  124.—^,  leaf  with  serrate  mar 
g\n ;  S,  leaf  with  dentate  or  toothea 
marffin  ;  C,  leaf  with  crenate  or  scal- 
loped margin. 


♦  See  an  article  on  this  subject  by  Professor  Beal  in  Ameriean^ 
Naturalist,  1871,  p.  571,  and  a  still  earlier  one  by  Dr.  Wilder.  Both 
writers  show  that  in  many  cases  the  upper  half  of  the  leaf  is  the  most 
deyeloped,  in  opposition  to  De  Candolle,  who  makes  the  statement 
that  "  the  side  most  developed  is  always  the  lower."  Herbert  Spencer's 
supposition  that  the  want  of  symmetry  is  (in  some  cases)  due  to  the 
shading:  of  tlie  smaller  half  of  the  leaf,  they  show  not  to  be  correct,  as 
the  apymmetry  is  observable  in  the  vounjr  leaves  in  the  unespanded 
bud! 


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OF  LEAVES  IN  GENERAL.  147 

194.— Leaves,  like  other  members  of  the  plant-body,  may 
braiK)h  during  their  growth.   At  first  they  are  always  simple, 
and  if  the  growth  is  uniform  the  result  is  a  simple  leaf  ;  if, 
however,  as  frequently  happens,  the  growth  is  more  rapid  at 
certain  points,  branches  may  arise,  as  in  the  so-called  com- 
pound  leaves.      All   grada- 
tions are  observable  between 
simple  leaves,  in  which  the 
growth  has  been   absolutely 
uniform    (producing  entire 
margins),      to      compound 
leaves  with  jointed  leaflets. 
The  differentiation  is   here 
much  like  that  which  takes 

place    in    passing    from    the       Fig.ias.-Three-lobedleafof  Hepatlca. 

thallome  to  the  form  of  plant-body  with  distinct  caulome 
and  phyllome. 

The  simplest  cases  are  those  in  which  the  branches  are 
rudimentary,  as  in  the  serrate  (Fig.  124,  A),  dentate  (Fig. 
124,  jB),  crenate  (Fig.  124,  G),  and  other  similar  forms. 
When  the  branches  are  more  prominent  they  give  rise  to 
lobes  of  various  kinds  (Figs.  125,  126).  Where  the  longitu- 
dinal growth  of  the  leaf  (not  of  its 
branches)  is  but  little,  the  lobes  ap- 
pear to  radiate  from  a  common 
point,  as  in  hepatica,  mallow,  maple, 
etc. ;  such  are  called  radiately,  pal- 
Diately,  or  digitately  lobed.  Where, 
as  in  the  oak,  the  longitudinal 
growth  of  the  leaf  is  considerable, 
the  lobes  are  laterally  arranged  upon 
itSSiSri;  thJ^iob^  hil:  a  central  portion  ;  such  leaves  are 
^^*«^-  said  to  he  pifinately  lobed. 

106. — Leaf -branches  frequently  become  so  developed  that 
they  themselves  form  distinct  leaves,  and  thus  we  have  what 
is  termed  the  compound  leaf  (Figs..  127  and  128).  Terms 
similar  to  those  used  in  the  case  of  lobed  leaves  are  here 
used  also  ;  thus  where  the  secondary  leaves  (leaflets)  grow 
from  an  extremely  short  axis,  so  that  they  radiate  from  a 


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148  BOTANY, 

common  point,  the  leaf  is  said  to  be  radiately,  palmately,  or 
digitately  compound  (Fig.  127,  A  and  B).  In  those  cases 
where  the  leaflets  grow  from  an  axis  which  lengthens  more 


Fig.  127.—^,  palmately  componnd  leaf  of  Horae-chestDUt;  i?,  palmately  trifoliate 
compound  leaf. 

or  less,  the  leaf  is  termed  a  pinnately  compound  one  (Fig. 
128,  A  and  B).  It  not  infrequently  happens  that  in  the 
growth  of  leaflets  they  also  produce  branches,  giving  rise 
thus  to  doubly  compound  leaves. 


Ffff.  188.~ji,  pinnately  componnd  leaf  ;  JB,  pinnately  componnd  leaf,  with  common 
midrib  prolonged  and  metamorphosed  into  a  tendril.    (See  page  186.) 

196. — The  stipules  which  occur  as  lateral  appendages  upon 
the  petioles  of  many  leaves  of  Dicotyledons  are  early  leaf- 
branches  which  were  not  carried  up  by  the  subsequent  elon- 


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THE  ARRANGEMENT  OF  LEAVES.  149 

gation  of   the   petiole;  as  in  the  pea^   yetch^  agrimony, 
qnince,  etc. 

§  rv.   The  AKRANGEMEin'  of  Leaves  (Phyllotaxis). 

197. — Leaves  are  disposed  on  stems  in  various  ways  : 

(1.)  They  may  be  in  whorls  of  three  or  more  encircling 
the  stem  at  intervals.  In  this  case  each  whorl  was  formed  as 
a  ring  of  rudimentary  leaves  about  the  punctum  vegetationis.* 
The  leaves  o|  each  succeeding  whorl  usually  appear  just 
above  and  between  the  preceding  ones^  so  that  the  whorls 
alternate  with  one  another. 

(2.)  Where  two  leaves  originate  on  exactly  opposite  sides 
ofy  and  at  the  same  height  on^  the  punctum  vegetationis,  the 
opposite  arrangement  is  produced.  Here,  as  in  whorled 
leaves,  the  new  ones  usually  arise  in  the  intervals  between 
the  previously  formed  ones,  so  that  the  pairs  of  leaves  decus- 
sate. 

(3.)  If  the  leaves  originate  singly  (scattered  or  alternate 
leaves),  the  simplest  case  is  that  in  which  each  succeeding 
leaf  appears  a  little  above  the  preceding  and  on  the  opposite 
side  of  the  punctum  vegetationis.  In  this  case,  where  the 
stems  elongate,  the  leaves  are  arranged  in  two  opposite  lon- 
gitudinal rows  or  ranks  (orthostichies)y\  hence  this  is  called 
a  two-ranked  arrangement. 

(4.)  If,  instead  of  each  new  leaf  forming  at  a  point  half 
of  the  circumference  of  the  punctum  vegetationis  from  the 
last,  it  appears  at  a  point  distant  (always  in  the  same  direc- 
tion) one  third  of  the  circumference,  there  will  be  three  ver- 
tical rows  of  leaves  upon  the  stem ;  this  is  the  three-ranked 
arrangement. 

(5.)  In  rare  cases  the  succeeding  leaf  is  in  each  case  distant 
one  fourth  of  the  circumference  from  the  last,  always  meas- 
uring in  the  same  direction ;  this  gives  rise  to  the  four- 
ranked  arrangement, 

*  There  are  some  cases  of  false  whorls,  in  which  the  leaves  are  first 
formed  at  different  heights,  and  onlj  later  by  irregularities  in  the 
growth  of  the  stem  become  whorled. 

t  From  the  Greek  6p^6%,  straight,  and  orixoi,  a  row. 


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150  BOTANY. 

(6.)  It  is  very  common  for  the  young  leaves  to  appear  in 
succession  on  the  punctum  vegetationis  at  a  distance  equal 
to  two  fifths  of  the  circumference  from  each,  producing  a 
five-ranked  arrangement. 

(7.)  A  seven-ranked  arrangement  is  rarely  seen ;  it  is  pro- 
duced by  the  leaves  following  each  other  at  a  distance  of  two 
sevenths  of  the  circumference. 

(8.)  An  eight-ranked  arrangement,  which  is  a  very  common 
one,  results  from  the  leaves  appearing  at  the  constant  distance 
of  three  eighths  of  the  circumference. 

(9.)  In  like  manner  there  may  be  formed  9,  11, 13, 14, 18, 
21,  23,  29,  34,  37,  47,  55,  and  144  ranks. 

198. — The  distance  between  any  two  succeeding  leaves  is 
called  the  angular  divergence;  it  may  geneitdly  (but  not  always) 
be  deduced  directly  from  the  number  of  ranks  (orthostichies); 
thus  in  the  2-ranked  leaves  it  is  \  :  in  the  3-ranked,  ^^ ;  in  4- 
ranked,  \  ;  in  5-rauked,  f  (rarely  |) ;  in  7-ranked,  f ;  in  8- 
ranked,  f  (rarely^);  in  9-ranked,  f ;  in  11-ranked,  t^;  in 
13-ranked,  ^  ;  in  14-ranked,  ^^ ;  in  18-ranked,  -f^  ;  in  21- 
ranked,  ^;  in  23-ranked,  t^;  in  29-ranked,  ^;  in  34- 
ranked,  ^ ;  in  3  7-ranked,  ^  ;  in  47-ranked,  J4  y  ^^  ^^" 
ranked,  \\  ;  in  144-ranked,  ^^. 

Examples  of  the  more  common  of  these  arrangements  are  to  be 
found  as  foHows  .* 

(a.)  2-ranked  in  Fagu$,  CeUis,  Ulmus,  Vit's,  THia,  most  ViciecB^  and 
all  grasses. 

(6.)  8-ranked  in  Carex,  Seirpus,  and  most  JungermannuB. 

{c),  4- ranked  in  the  bracts  of  the  principal  axis  of  inflorescence  of 
BmUo  erectui  and  Thamnoehortus  seariosus. 

((2.)  5-ranked  in  Quercu»,  PopuliiSf  Robinia,  most  RosacecB^  Borra- 
ginacea^  etc. ;  this  is  the  most  common  arrangement  in  Dicotyledons. 

{e.)  7-ranked  in  Melaleuca  erieafolia,  Euphorbia  Tieptdgmia,  Sedum 
iexanffulare,  etc. 

(/.)  8-ranked  in  Polytrichum,  Pai'ietaria  erecta,  Antirrhinum  ma- 
jus,  Baphanus,  Brassiea,  Hieracium  pHoseUa,  etc. 

(g.)  9-ranked  in  Lycopodium  selago. 

{h.)  11-ranked  not  rarelj  in  Sedum  reflexum  and  Opuntia  vulgaris. 

(k.)  18-ranked  in  Ve^'lKUCum,  Bhus  typhina,  Tsuga  canadensis. 

*  This  list  of  examples  is  from  Hofmeister's  "  Allgemeine  Morphol- 
ogie  der  Gewftchse,"  p.  448  et  seq. 


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ARRANGEMENT  OF  LEA  VE8. 


151 


({.)  21-raDked  in  the  weak  branches  of  AUea  pectinata  and  Pieea 
txedsa,  and  in  most  cones  of  these  species. 

(m.)  34-ranked  on  strong  branches  of  AHei  pectinata  and  Pice>2 
txeelta,  cones  of  Pintis  larido,  and  the  interfloral 
bracts 'of  the  inflorescence  of  Hudbeckia,  JV        V         ,^ 

(n.)  55-ranked  in  the  uppermost  shoots  of  many 
pines  and  firs,  in  manj  MamiUaria,  etc. 

{o.)  144>ranked  in  the  interfloral  bracts  of 
strong-grown  flower-heads  of  Hdianthus  annuus, 

199. — By  an  examination  of  various 
leaf-arrangements,  the  following  interest- 
ing but  not  very  important  facts  may  be 
noted  (Fig.  129)  : 

(1.)  If  we  draw  a  line  from  the  inser- 
tion of  one  leaf  to  the  one  next  above  and 
nearest  to  it,  and  continue  this  around  the 
stem  to  the  next,  and  so  on,  a  spiral  will 
be  obtained  agreeing  with  the  order  of 
development  of  the  young  leaves  on  the 
punctum  vegetationis.  To  this  line,  so 
drawn,  the  name  of  Generating  Spiral 
has  been  given, 

(2.)  In  most  cases  the  spiral  passes  more 
than  once  around  the  stem  before  inter- 
secting leaves  of  all  the  ranks. 

(3.)  The  number  of  turns  of  the  spiral 
about  the  stem  in  intersecting  leaves  of 
all  the  ranks  equals  the  numerator  of  the     v\g.  i89.~Diagram  or 
fraction  which  indicates  the  angular  di-  meni."  The  orthoSShSs 
Yergence  of  the  leaves  from  each  other.       ^  bottom  in  RomaS 

(4)  Two  sets  of  secondary  spirals  {Far-  ^^^t:A^^Si/^ 
astichies)*  crossing  each  other  at  an  acute  f^",J  leat  ^h«  iIuS 
angle  may  be  observed  on  the  stem  when  iSw^Sp^^!^Ait^i 
the  leaves  are  close  together,  as  in  Fig.   Pranti. 
129 ;  the  leaves  numbered  1,  6, 11,  and  16  form  one  of  the 


*  It  is  of  great  importance  that  the  student  should  not  regard  these 
ipir&ls  (genentin^  spirals  and  parastichies)  as  anything  more  than 
convenient  means  for  describing  any  particular  leaf-arrangement.  En- 
tirely t<io  much  attention  has  been  given  to  working  out  all  kinds  of  curi- 
008  mathematical  laws,  which  are»  to  say  the  least,  al>8olutel7  worthless 


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152 


BOTANY. 


parastichies  passing  to  the  right,  while  leaves  3,  6,  9,  12, 

15,  18  belong  to  the  parastichies  which  pass  to  the  left. 

(5.)  Upon  counting, 
in  Fig.  129,  it  is  found 
that  there  are  three 
parastichies  passing  to 
the  left  and  five  to  the 
right ;  the  smaller 
number  is  the  same  as 
the  numerator  of  the 
fraction  expressing  the 
angular  divergence, 
while  the  sum  of  the 
two  equals  the  denomi- 
nator ;  similar  rela- 
tions may  be  shown  to 
exist  in  other  cases. 

200.  —  If    now   we 
study  the  several   ar- 
rangements by  projecting  the  stem  upon  a  flat  surface  in 

such  a  way  that  the  successive 

nodes,  in  ascending  the  stem, 

are    represented    by   smaller 

and  smaller  concentric  circles 

(Fig.  130)  (as  would,  in  fact, 

be  the  case  if  we  made  sections 

through    the    nodes   of    the 

punctum  vegetationis),  it  is 

at  once  evident  that  each  leaf 

is  so  placed  as  to  stand  over 

the  vacant  space  between  the 

previously  formed  ones,  and 

that   as   regards   the    leaves 

formed  after  it,  it  is  equally 

well  situated. 

Hofmeister  formulates  this 


Fig.  180. —  Diagram  of  eight-ranked  ai 
ment,  viewed  from  above.  The  orthoetichiee,  which 
htre  appear  to  be  radial  lines,  are  nombered,  at)  in 
Fig.  129,  from  /.  to  VIJI.  The  leaves  are  number- 
ed from  1  to  16.— After  Sachs. 


Fig.  ISOa.— Crwis-section  of  a  leaf-bnd 
of  the  Hemlock  Sprnce  {Tmga  Canada^ 
tis).    Magnified.— After  Hofmeister.    • 


to  tbe  morphologlBt.  So  much  has  this  been  done,  thnt  tbe  study  of 
Phjllotaxis  bae  in  some  quarters  become  little  more  tban  a  species  of 
mathematical  frjmnastics. 


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AnHANOEMENT  OF  LEAVES,  153 

as  follows  :*  "  New  lateral  members  have  their  origin  aboYO 
the  centre  of  the  widest  gaps  which  are  left  at  the  cir- 
cumference of  the  punctum  vegetationis  between  the  in- 
sertions of  the  nearest  older  members  of  the  same  kind  f 
and  no  doubt  this  is  one  of  the  most  important  immediate 
causes  which  determine  where  each  new  leaf  is  to  arise.  If  it 
be  asked  why,  then,  are  not  all  leaves  arranged  alike,  the 
answer  must  be  looked  for  in  the  differences  in  structure  of 
the  puncta  vegetationes.  In  cases  where  there  is  an  apical 
cell,  the  arrangement  of  the  leaves  may  be  directly  traced  to 
its  mode  of  division.     In  Phanerogams  it  is  often  clearly  due 


Pig.  180&.— CrosB-RectSon  of  the  leaf-bad  of  the  chcfltnnt  (Coitansa  vesca).  «>,  «•, 
tte  Bcal».like  leaves  ;/>,/«,/»,  etc.,  the  rndiracntary  leayen  ;  ti-^».  t«H»«,  etc,  the 
mpoles  belonging  to  the  correBpoudinglr  numbered  leaves.  Magniiled.  —  After 
Honnei«ter. 

to  a  difference  in  the  size  and  form  of  the  punctum  vegeta- 
tionis ;  in  Conifers  and  Composites,  for  example,  it  is  com- 
mon for  a  change  in  the  arrangement  to  take  place  in  pass- 
ing from  the  foliage  leaves  to  the  bracts  of  the  inflorescence 
upon  the  same  stem,  the  number  of  ranks  in  such  cases 
being  greater  on  the  larger  axes.  Doubtless  some  of  the  dif- 
ferences can  be  explained  only  by  taking  into  account,  also, 
the  inherited  peculiarities  of  the  plant. 


*"Allgem.  Morphol.,"  p.  482,  and  quoted  in  Sachs'  "  Text-Book," 

I*.  177. 


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154  BOTANY 


A  study  of  actual  cross-sections  of  leaf -buds  will  make  the 
truth  of  the  previous  statements  more  clearly  evident    Hof- 


Pig.  180c.— Crosfrsection  of  a  lateral  bnd  of  the  Vlrelnia  Creeper  {An 


Fig.  laoc.— Crosfrsectlon  of  a  lateral  unci  or  tne  vireinia  ureeper  KAmpwmn»  ^^ 
gw/wia)^  showing  arrangemeiii  of  parib  In  a  double  bud.  Magnified.— After  not- 
xneister. 

meister's  figures,*  several  of  which  are  here  reproduced  (Figs. 

130,  a,  to  130,  d),  show 
that  in  all  cases  the  leaf 
rudiments  occupy  in 
the  bud  the  positions  in 
which  they  meet  with 
the  least  resistance. 
This  is  beautifully 
shown  in  the  leaf-bud 
of  the  Hemlock  Spruce 
(Fig.  130,  a).  In  the 
leaf-bud  of  the  chest- 
nut (Fig.  130,  b),  the 
.      •  .V   1   *K  ^    *     large  stipules  form  the 

Pie.  laorf.—  Cro8«u»ection  of  the  leaf-bud  of  a         »         ^       ,      i  i 

young  plant  of  Indian  corn  (Zea  mais).    /.,  the  bud-SCalcS  ;  DUt  here,  as 

cotyledon^with  its  two  flbro-vascular  bundles,  1,1';  .  «^«^^;v»«.  />oan 

7/,/7/.,i7..  F.,  the  succeselve  leaver,  their  mid-  m    the    preceding   CaSC, 

ribamarkedWadot.    Magnifled.-Af ter Hofineia-  ^^owth appears tofoUoW 

the  "lines  of  least  resistance,"  the  yonng  leaves  occupying 
the  interspa<;es  between  the  stipules.   The  double  lateral  bud 

♦  In  "  Allffem.  Morphol." 


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INTERNAL  STRUCTURE  OF  LEAVES.  165 

of  the  Virginia  Creeper  (Fig.  130,  c)  may  also  be  studied  with 
profit,  and  it  is  curious  to  see  how  the  positions  of  some  of  the 
leaves  are  altered  by  the  fact  that  the  bud  is  a  double  one. 
The  bud  of  the  Indian  corn  (Fig.  130,  d)  shows  that  the  same 
law  holds  in  the  Monocotyledons  as  in  the  Dicotyledons, 

§  V.  The  Internal  Structure  of  Leaves, 

201. — The  internal  structure  of  leaves  varies  considerably. 
In  all  cases,  however,  the  leaf  is  composed  mainly  of  thin- 
walled,  chlorophyll-bearing  parenchyma,  and  this  is  to  be  re- 
garded as  the  proper  leaf  tissue.  The  fibro-vascular  bundles 
constitute  little  more  than  the  framework  of  the  leaf  and 
its  connection  with  the 
stem,  while  the  epider- 
mis is  here,  as  elsewhere 

in  the  plant,  a  covering  n 

tissue.  In  the  related 
members  of  the  plant, 
such  as  bracts,  scales, 
floral  envelopes,  and 
other  phyllome  struc- 
tures, chlorophyll-bear- 
ing parenchyma  is  gen- 
erally    wanting,     but  ^ 

from  true  leaves  it  is  Fig.  m.-Venicalsectlonof*  portion  of  the  leaf 
mrplv  pvpr  ah«»pnf  l[^\\a  ot  Echinocustia  lobata.  «,  epidermis  of  the  upper 
rareiy  ever  aosent.     ±  ne  ^^^^^^  .  ^^  ep,^enni8  of  th£  lower  surface  ;  /the 

shape    of     the   leaf,    its  Paf«°c*»yni*  constituting  the  "palisade "tissae; 
.    '^  .  .  '  i/,  the  loose  and  Irregular  parenchyma  of  the  lower 

Size,  position,  and  re-  part  of  the  leaf,  in  a  part  of  the  section  the  chlo- 
T   ,.      ^ ,  ,,  rophyll  granules  are  shown,      x  860.— From  a 

lation    to     other    mem-  drawing  by  J.  C.  AiUiur. 

bers,  all  have  somewhat  to  do  with  securing  the  best  disposi- 
tion of  the  essential  leaf  tissue. 

202. — In  leaves  composed  of  one  layer  of  cells,  as  in  many 
mosses  and  some  ferns,  obviously  there  is  no  need  of  any 
special  arrangement  of  the  cells  in  order  to  secure  their  best 
exposure  to  light,  heat,  gases,  etc.  In  thick  leaves,  however, 
the  internal  cells  are  clearly  not  so  well  situated  as  the 
external  ones  are,  hence  we  find  such  leaves  possessing  some 
})eculiarities  in  their  structure  which  obviate  this  difficulty. 
Instead  of  being  composed  of  solid  tissues,  their  cells  are 


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156 


BOTANY, 


generally  loosely  arranged,  with  large  intercellular  spaces  be- 
tween them  (Figs.  131  and  133),  and  these  are  in  free  com- 
munication with  the  external  air  by  means  of  the  stomata. 
It  most  frequently  happens  that  this  loose  tissue  is  in  the 
under  part  of  the  leaf,  while  the 
upper  portion  is  composed  of  one  or 
more  layers  of  closely  placed  cells  ; 
and  this  agrees  with   the  general 
distribution  of    the  stomata,  there 
being  usually  numy  more    on  the 
under  than  the  upper  surface. 

203. — The  upper  denser  tissue, 
termed  palisade  tissue,  is  composed 
of  elongated  cells,  which  stand  at 
right  angles  to  the  surface  of  the 
leaf  (Fig.  131).  In  cross-section  the 
palisade-cells  are  cylindrical,  with 
small  intercellular  spaces  between 
them  (Fig.  132),  or  in  some  cases 
they  are  more  or  less  compressed  and  angular. 

In  general,  palisade  tissue  is  confined  to  the  upper  surface 
of  the  leaf,  the  lower  being  occu- 
pied by  the  loose  tissue  previously 
mentioned  ;  but  there  are  some  cu- 
rious exceptions  to  this  rule.  The 
most  notable  of  these  is  found  in 
the  leaf  of  SilpMum  laciniatum — 
the  so-called  Compass  Plant* — of 
the  Mississippi  Valley ;  its  chloro- 
phyll-bearing parenchyma  is  almost 
entirely  arranged  as  palisade  tissue, 
80  that  the  upper  and  lower  por-  pJUcil^^SU'oVUSS^ 
tions  are  almost  exactly  identical  &'J±!Si''^S?^tt^^^ 

ir»  a^^Tjture  (FifiT     134)        The  Ver-    ^^  drawn  showing  their  chloro- 
^  .  o*.        -/'  -  -    phyll  granules.      X  «50.— From  • 

aves    of    the    Manzanita    of    drawlngbyJ.C.  Arthur. 

jific  Coast  {Arctostaphylos  pungens,  var.  platyphylla) 
similar  structure. 


Pig.  l».-Section  of  tne  ** 
sade^'  tissue  of  the  leaf  of  ^ 
noeyitig  iobaf/i^  taken  parallel  to 
the  leaf  surface.  A  few  of  the 
cells  drawn  with  their  contained 
chlorophyll  ffrannle«.  x  S80.— 
From  a  drawing  by  J.  C.  Arthur. 


deBcriptloDB  of  this  curiouB  plant,  whose  leaves  have  a  marked 
r  to  stand  with  one  edge  to  the  north  and  the  other  to  the 


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INTERNAL  8TBUCTUBE  OF  LEAVES.  157 

204. — Another  curious  leaf  structure  is  to  be  seen  in 
Stipa  spartea,  the  Porcupine  Grass  of  the  interior ;  each  long 
harsh  leaf  is  longi- 
tudinally channel- 
led on  its  upper 
surface,  which,  by 
the  twisting  of  the 
basal  portion  of 
the  leafy  becomes 
apparently  the  low- 
er, and  the  chlo- 
rophyll-bearing pa- 
renchyma is  con- 
fined to  the  sides  of 
the  channels  (Figs. 
135  and  136).  At 
the  bottom  of  each 
channel  the  epider- 
mal cells  are  pe- 
cuUarly  developed 
into  a  hygroscopic 
tissue,  which,  by 
contracting,  closes 
the  channels  and 
rolls  the  leaf  to- 
gether, as  always 
takes  place  in  dry 
air. 

(a)  Many  MonoootjT- 
ledons— as,  for  ezain- 

pie,  Iris  and   Indian  ' 

Aoni.^ffoTd  tmnA  awA-  '^'  184.— TraniroTPe  McHon  of  the  leaf  of  SUphlum 

com— anoM  gooa  spe-  jadniatum,    «,  cpidennis  of  the  upper  nurface  ;  #',  epl- 

cimena  of  very  yoang  dermia  of  the  lower  surface  ;  p,  palisade  tisnae  of  the 

Imvm      Dw  ^Mk*A#nii»  upper  portion  of  the  leaf;  j/,  paliMde  tiseae  of  the 

leayea.    JJy  carefully  j^^,  f^  ^f  ^^^  y^  .  ,/a  Ptoma  eeeu  in  transTerae 

removing    the     outer  section,    x  285.  -From  a  drawing  by  the  author, 
leaves  in  succession  all  stages  of  leaf-development  may  be  obtained. 

aooth— {.0.,w]th  the  leaf-planes  parallel  to  the  plane  of  the  meridian— 
tMe  articles  in  tL^  American  Naturalist:  1870;  p.  495;  1871,  p.  1; 
1877,  p.  48d. 


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158 


BOTANY. 


In  tbis  way  often  mach  light  will  be  tbiown  upon  tbe  morphology 

of  leaf  parts  * 
(&)  Among  Dicotyledons  it  is  generally  best  to  select  those  whose 
yoang  leaves  are  least  downy  or  hairy, 
otherwise  tbe  difficulties  of  tbe  examina- 
tion are  greatly  increased.  The  lilac  is 
one  of  tbe  best  for  this  purpose.  Longi. 
tudinal  sections,  prepared  as  in  the  ex- 
amination of  young  stems,  should  be 
made. 

(e)  The  young  leaves  in  the  winter  buds 
of  tbe  hickory  are  instructive,  as  showing 
how  compound  leaves  are  formed. 

(d)  The  study  of  the  arrangement  of 
leaves  is  most  interesting  in  the  twigs 

and  cones  of  the  Conifers,  and  the  stems  and  heads  of  the  Composites. 

The  student  should,  however,  before  spending  much  time  in  the 


Fig.  185.— A  part  of  a  trans- 
veree  section  of  the  leaf  of  Stipa 
tpariea  in  the  position  it  as- 
snmee— i.«.,  with  what  is  really 
the  upper  surface  turned  toward 
the  earth.  /,/,  rib^  each  con- 
taining a  flbro-vascular  bundle  ; 
between  these  are  the  mas»ee  of 
chlorophyll-bearing  parenchyma 
(figured  darli  in  the  cut),    x  18. 


Fig.  186.— Transverse  section  of  one  of  the  ribs  of  the  leaf  of  Siipa  tparUa.  tp^ 
ll-beaiing  parenchyma ; «,  ^,  portions  of  the  epidermis  containiug  etomata ; 
^roscoplc  cells,  which  contract  when  the  leaf  rolls  up.  The  blanic  space  on 
lows  the  extent  of  the  cavity  occupied  by  chlorophyll-bearing  parenchyma. 
h>m  a  drawing  by  the  author. 

tion  of  the  more  difficult  forms,  study  tbe  twenty-sixth  section 

B*  '•  Text-Book  of   Botany,"  and  the  wbole  subject  of  the 

llustration  of  this,  the  Iris  itself  may  be  cited.     Its  leaf  is 
spoken  of  as  made  by  the  folding  of  its  upper  surface  upon 


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THE  ROOTS  OF  PLANTS.  159 

arrangement  of  lateral  members  as  given  in  Hofmeister*s  "General 
Morphology,"  ♦ 

(0)  The  internal  stractare  of  the  leaf  may  be  easily  studied.  The 
most  important  sections  are  those  made  at  right  angles  to  the  surface ; 
but  some  should  be  made  also  parallel  to  it,  so  as  to  show  the  form  of 
the  palisade  cells  and  the  dispositions  of  the  cells  in  the  loose  tissue  of 
the  nnder  surface.  The  leaves  of  the  lilac,  apple,  cherry,  Impatiens, 
SOp^unht  sunflower,  etc.,  are  very  good  for  this  study.  The  more 
difficult  sections  can  be  more  easily  made  after  soaking  the  leaves  for 
some  time  in  strong  alcohol,  thus  hardening  them. 

§  VI.   Op  the  Roots  of  Plants. 

206. — The  root  differs  from  all  other  members  of  the 
plant  in  being  tipped  with  a  peculiar  mass  of  cells — the  Root- 
cap  {pileorhiza\) — and  in  originating  endogenously ;  from 
stems  it  differs  in  never  producing  leaves  or  other  phyllome 
structures.  There  is  some  doubt  as  to  whether  the  Primary 
Root — Le,,  the  first  root  of  the  embryo — is  not  in  many  cases 
formed  otherwise  than  endogenously ;  J  but  all  common  roots 
certainly  are  developed  from  beneath  the  surface  of  other 
parts  of  the  plant. 

206. — Roots  may  develop  from  any  part  of  a  plant  which 
contains  fibro-vascular  bundles,  so  that  it  is  no  uncommon 
thing  for  them  to  issue  from  stems  (particularly  their  nodes) 
and  leaves,  as  well  as  from  other  roots.  Whatever  their 
origin,  they  are  essentially  alike,  the  differences,  as  before 
intimated,  being  of  minor  importance.    They  all  agree  in  hav- 

iteelf,  so  tbat  the  two  sides  exposed  to  the  air  and  light  are  said  to  be 
in  reality  the  under  surface.  A  study  of  the  very  young  leaf  of  the 
Iritf  along  with  that  of  IlemerocaUis^  shows  them  to  be  alike ;  both  are 
composed  of  an  upper  laterally  flattened  portion  and  a  lower  channelled 
one ;  in  the  Iris  the  upper  portion  grows  fully  as  much  as  the  lower, 
while  in  ffemerocaUisihe  growth  is  almost  entirely  confined  to  the  lower 
portion,  the  upper  extending  but  little  and  forming  the  small  extremity 
of  the  leaf.  The  small  tip  of  the  leaf  in  the  latter  case  is  clearly  the 
homologue  of  the'whole  of  the  so-called  ensiform  leaf  of  the  former. 

*  "  Allgemeine  Morphologie  der  GewSchse,"  von  Wilhelm  Hofmeis- 
ter ;  Leipsig,  1868. 

f  From  the  Greek  9r/?.eoS,  a  cap,  and  fii^a,  a  root. 

X  The  mode  of  formation  of  the  Primary  Root  will  be  taken  up  for  each 
group  of  plants  in  Part  II. 


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160  BOTANY. 

ing  less  perfectly  developed  tissues  and  tissue  systems.   Their 
epidermal  system  is  more  feebly  developed,  and  they  bear  very 


Fig.  187.-^Longltudina1  tection  throagh  the  apex  of  a  root  of  Indian  corn  {Zea 
maU).  All  within  and  above  the  line  r.  «,  r,  la  the  loot  proper,  all  below  and  ontside 
of  it  ie  the  root-cap,  or  pikorhiza ;  «,  apex  of  root ;  e^ «« epidermiis  continaed  into 
the  dermatogen  at  trie  apex ;  v,  v,  the  thickened  outer  wail  of  the  epidennlB  (the 
origin  of  the  root-cap  from  the  dermatogen  is  not  shown  in  this  flgnre) ;  as.  r.  the  cor- 
tex which  ie  produced  from  the  pcriblem  at  the  apex  ;  m,  g.f^  the  plerome ;  m  be- 
comes the  pith,  g  a  vessel,  /,  wood  ;  a,  a,  outer  ana  older  portion  of  the  root-cap ;  i, 
inner  and  younger  portion  of  the  root-cap.— After  Sachs. 


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THE  BOOTS  OF  PLANTS,  161 

simple  trichomes — the  root-hairs.  The  fibro-vascular  bun- 
dles are,  especially  in  the  higher  plants,  of  a  much  lower 
type  than  those  in  the  stems  and  leaves.  The  fundamental 
system  is  also  poorly  developed,  and  has  not  that  vai'iety  of 
tissues  found  in  other  portions  of  the  plant. 

207. — Another  remarkable  peculiarity  of  roots  is  that  they 
differ  much  less  from  one  another  in  structure  than  do  their 
stems.  The  young  roots  of  Monocotyledons  have  very  nearly 
the  same  structure  that  those  of  Dicotyledons  have,  and  those 
of  Pteridophytes  do  not  differ  much  from  either.  The  older 
roots  of  Monocotyledons  and  Dicotyledons  differ  considerably, 
on  account  of  changes  in  their  structure  which  take  place 
later,  and  then  each  root  bears  a  closer  resemblance  to  the 
stem  from  which  it  grows,  or  to  which  it  belongs. 

208. — The  general  structure  of  the  root-cap  may  be  easily 
understood  from  the  accompanying  figure  (Fig.  137).  It  is 
a  cap-like  mass  of  parenchymatous  cells  which  surrounds 
the  end  of  the  root ;  its  outer  cells  are  loose,  and  in  some 
cases  are  more  or  less  changed  into  a  mucilaginous  mass; 
in  any  event  they  gradually  lose  their  protoplasm  and  become 
detached  and  destroyed.  The  inner  layers  (t,  s.  Fig.  137)  are 
constantly  developing  from  a  deep-lying  tissue,  the  Dermato- 
gen*  (not  shown  in  the  figure),  so  that  as  the  cap  is  destroyed 
on  the  outside  it  is  renewed  from  the  interior.  By  its  lat- 
eral growth  it  in  some  cases  ensheathes  the  terminal  part  of 
the  root  for  a  considerable  distance. 

209. — Back  of  the  root-cap  lies  the  primary  meristem  of 
the  root,  composed,  in  Phanerogams,  of  a  mass  of  small  and 
actively  dividing  cells.  In  this  meristem  there  is  as  yet  no 
differentiation,  but  as  it  is  prolonged  by  rapid  cell-multipli- 
cation the  cells  become  modified  in  its  posterior  portion. 
There  is  thus  a  constantly  advancing  formation  of  meristem, 
followed  at  a  little  distance  by  as  constant  a  modification 
into  other  tissues.  The  usual  course  of  this  differentiation 
is  first  into  a  central  cylindrical  mass,  the  Plerome\  (Fig. 

*  From  the  Greek  dipfia^  Sepfiaroi,  skin,  and  yiwdu,  to  bring  forth  or 
generate. 

f  So  named  by  Hanstein  ("  Scheitelzellegrappe  im  Vegetationapunkt 
der  Phanerogamen/'  1868),  from  the  Greek  nXripufia,  a  fiUing  up. 


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162  BOTANY, 

137,  m,/,  g),  which  is  ensheathed  by  the  Peribleniy*  which 
soon  becomes  transformed  into  the  cortical  portion  of  the 
root  {x,  r,  Fig.  137).  The  epidermis  is  developed  from  the 
region  from  which  the  root-cap  grows,  and,  in  fact,  as  will 
be  shown  below,  it  is  a  continuation  and  modification  of  the 
generating  tissue  of  the  root-cap. 

210. — In  Fig.  138  the  relation  of  the  parts  is  even  better 
shown  than  in  iie  previous  figure.  The  central  plerome 
column  is  surrounded  by  a  layer  of  active  cells,  the  pericam- 


Flg.  188.— Median  longltadlnftl  section  of  the  apex  of  the  root  of  the  buckwheat 
(FaffOpyrumeMulentum).  pc^  pericamblam,  constitating  the  boandary  of  the  plerome 
column ;  «,  dermatogen ;  between  e  and/v,  periblem  ;  A,  root-cap.— After  De  Bary. 

bium  (pc) ;  outside  of  the  latter  lies  the  periblem,  or  young 
cortical  portion,  and  still  outside  of  this  the  dermatogen 
{e),  which  further  back  on  the  root  becomes  the  epidermis. 
The  root-cap  {h)  lies  entirely  outside  of,  and  is  quite  distinct 
from,  the  back  portions  of  the  dermatogen,  but  near  the 
apex  of  the  root  there  is  a  tract  in  which  dermatogen  and 
root-cap  apparently  fuse  into  one.     At  this  point  the  layers 

*  Another  of  Hanstein's  tenna,  from  the  Greek  nepiSXufjui,  a  cloak. 


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THE  BOOTS  OF  PLANTS.  163 

of  the  root-cap  originate  by  the  successive  divisions  of  the 
dermatogen  cells  by  partitions  parallel  to  the  curved  surface 
of  the  root-tip.  As  the  dermatogen  is  continuous  with  the 
epidermis,  we  may  regard  the  root-cap  as  morphologically 
a  greatly  thickened  and  somewhat  modified  epidermis. 


Pig.  189.— Mode  of  fonnation  of  the  Iftteral  roots  in  a  mother-root  of  Trapa  naiara, 
A^  a  portionof  the  pericambiam  fr.  bounded  externally  by  the  innermost  layer  of  cor> 
ticalceUa,  r;  d.  dermatogen  ;  n,  the  inner  layer  of  the  pericambium  after  Bplitting  ; 
By  the  same  advanced  wmewhat,  the  inner  layer  is  beginninj;  to  divide ;  (7,  young 
root  enclosed  in  the  tissue  of  the  mother-root ;  J?,  r,  cortex  ormother-root ;  tt,  pen- 
cambium  of  mof  her-root,  from  which  the  new  root  has  been  formed ;  A,  first  layer  of 
tha  rootrcap  of  the  new  root,  formed  bv  the  splitting  of  its  dermatogen  o ;  i,  n,  mass 
of  cell4>  resulting  from  the  division  of  the  layer  i»  hi  ^  ;  Z>,  new  root  further  devel- 
oped (the  thick  cortical  tissues  of  the  mother-root  are  not  shown ;  r,  inner  layer  of 
cortical  tissue  of  mother-root) ;  p,  p.  periblem  of  new  root ;  m,  m,  the  tissue  which 
connects  the  new  root  with  the  tissues  of  the  mother-root.  Magnified.— After 
Keinke. 

The  plerome  column  is  a  mass  of  nascent  fibro- vascular 
elements,  and  in  it,  somewhat  further  back  from  the  root-tip, 
a  differentiation  into  the  bundle  takes  place. 


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164  BOTANY. 

211. — The  formation  and  development  of  a  new  root  is 
interesting  and  suggestive.  It  usually  takes  place  at  some 
distance  from  the  primary  meristem,  in  the  cambium  or  peri- 
cambium.  In  the  root  of  Trapa  iiatans  it  takes  place  as  fol- 
lows :  The  cells  of  a  restricted  portion  of  the  pericambium 
divide  by  tangential  walls  into  an  outer  layer,  which  becomes 
the  dermatogeu  of  the  new  root  (J,  Fig.  139),  and  an  inner 
layer,  from  which  develops  its  primary  meristem  (»,  Fig. 
139).  The  inner  cells  multiply  by  divisions  in  several  direc- 
tions, and  as  their  mass  increases  they  push  out  the  young 
dermatogen  (B,  (7,  and  2>,  Fig.  139).  From  the  dermato- 
gen  the  first  layer  of  the  root-cap  is  formed  by  the  tangen- 
tial division  of  its  cells  (C,  A,  Fig.  139).  These  growing 
tissues  push  out  the  overlying  portions  of  the  mother-root, 
and  finally  break  through  them.  The  root  is  thus  seen  to 
be  a  strictly  endogenous  fonnation  ;  there  is  no  connection 
between  its  tissues  and  the  epidermal  and  cortical  portions 
of  the  mother-root,  the  sole  connection  being  with  the  deep- 
lying  tissues  in,  or  in  connection  with,  the  fibro-vascular 
bundles.  Herein  roots  present  a  marked  contrast  to  stems 
and  leaves,  which,  as  a  rule,  develop  from  the  exterior  of 
the  plant-body,  or,  in  other  words,  are  exogenous  in  their 
origin. 

212. — Roots  are  rarely  arranged  in  as  regular  an  order  as 
are  stems.  In  general  they  arise  in  acropetal  order  upon  the 
mother-roots  of  Pteridophytes  and  the  primary  roots  of  Pha- 
nerogams, but  this  order  is  subject  to  many  more  disturbing 
influences  than  in  the  case  of  the  origin  of  stems.  As  to 
position,  they  may  arise  in  rows  or  ranks,  or  in  particular 
spots,  dependent  upon  the  disposition  of  the  fibro-vascular 
bundles,  or  the  generating  tissues  in  the  root  or  stem.  Thus 
it  may  happen  that  on  a  root  or  stem  there  may  be  as  many 
rows  of  roots  as  there  are  fibro-vascular  bundles.  Boots 
which  develop  from  stems  are  generally  much  more  affected 
by  external  influences  than  those  which  grow  from  othei 
roots.  The  degree  of  moisture  of  the  different  parts  of  the 
stem  appears  to  have  much  to  do  in  determining  the  point 
of  the  appearance  of  roots ;  this  is  seen  in  stems  which  touch 
the  ground,  as  in  the  tomato,  and  in  climbing  plants,  as  the 


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THE  ROOTS  OF  PLANTS.  165 

Ivy  {ffedera),  Poison  Ivy  {Rhus)^  the  Virginia  Creeper  {Am- 
pelopsis),  etc. 

218. — In  form  roots  are  generally  fibrous,  and  this  is 
manifestly  their  best  form,  in  so  far  as  they  are  organs  for 
obtaining  dissolved  matters  from  the  soil.  In  perennials, 
however,  as  the  stems  become  larger  the  roots  increase  cor- 
respondingly to  support  the  additional  weight;  they  thus 
become  hold-fasts  or  mechanical  supports.  In  other  cases 
they  are  made  the  recipients  of  assimilated  matters,  as  starch, 
sugar,  etc.,  and  thus  become  thickened  storehouses. 

In  many  cases  the  latter  are  capable  of  forming  buds  and 
of  sending  out  new  stems  from  the  meristem  tissue  in,  or  in 
the  vicinity  of,  the  fibro-vascular  bundles,  as  is  notably  the 
case  in  the  tuberous  root  of  the  sweet  potato. 

(a)  The  root-cap  may  be  studied  with  the  least  difficulty  in  roots 
which  are  ^rown  in  water.  Tliose  of  Lemna  may  be  easily  obtained^ 
and  are  excellent. 

(6)  Roots  of  Indian  corn.  Hyacinth,  Impaiiens,  etc.,  also  famish 
easily  made  and  g(X)d  specimens. 

(c)  lu  prepuruig  specimens  for  examination  tliin  longitudinal  sections 
should  be  made,  and  these  should  be  supplemented  by  transverse  sec- 
tions taken  at  various  heights  on  a  root-tip. 

(d)  By  the  use  of  staining  fluids,  as  carmine,  magenta,  etc.,  some 
points  in  the  structure  will  be  made  more  evident.  Iodine  should  also 
be  used  ;  by  treatment  with  it,  tlie  starch  which  is  present  in  the  root* 
tip  in  many,  if  not  all,  cases  may  be  seen. 

(e)  For  studying  the  formation  and  development  of  new  mots  suc- 
culent plants  should  be  chosen,  as  the  sections  of  their  tissues  are  more 
transparent  than  those  of  other  plants.  On  this  account  many  water 
plants  are  to  be  preferred.  Amon^  land  plants,  Impatiem  is  one  of 
the  beet ;  it  always  has  a  large  number  of  forming  roots  on  its  stem 
near  or  at  the  surface  of  the  ground. 

{/)  Vertical  sections  of  the  papille,  showing  the  point  of  appearance 
of  new  roots,  should  be  made.  If  many  longitudinal  slices  of  the 
lower  part  of  the  stem  of  ImpalieM  are  made  in  a  section-cntter,  it  will 
almost  certainly  happen  tiiat  some  good  specimens  will  be  found. 


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CHAPTER    X. 

THE  CONSTITUENTS  OP  PLANTa 

§  L  The  Water  in  the  Plant. 

214.— Amount  ofWater  in  Plants.  All  living  parts  of 
plants  are  abundantly  supplied  with  water.  It  is  always 
present  in  living  protoplasm,  and  the  greater  its  activity  the 
more  watery  is  its  composition.  The  cell-walls  of  living 
tissues  also  contain  large  quantities  of  water ;  and  in  plants 
composed  of  many  cells  (as  the  larger  flowering  plants)  even 
those  cells  and  tissues  which  have  lost  their  activity  generally 
have  their  walls  saturated  with  water.  In  ordinary  herbace- 
ous land  plants  the  amount  of  water  is  not  far  from  75  per 
cent  of  their  whole  weight ;  thus  in  growing  rye  it  is  about 
73  per  cent ;  in  meadow  grass,  before  blossoming,  75— after 
blossoming,  69  ;  in  lucerne,  when  young,  81 — in  blossom,  74 ; 
in  white  clover,  80 ;  in  red  clover,  before  blossoming,  83— 
after  blossoming,  78 ;  in  oats,  in  blossom,  81 ;  in  Indian 
com,  in  blossom,  84.  In  certain  parts  of  plants  the  per- 
centage is  still  higher ;  for  example,  in  the  leaves  of  the  field 
beet  it  is  90 ;  in  tubers  of  the  potato,  75 ;  in  the  thickened 
root  of  the  parsnip,  88;  in  the  similar  root  of  the  turnip, 
92.  In  aquatic  plants  the  percentage  is  much  higher,  often 
exceeding  95;  it  is  so  abundant  in  many  of  the  simpler 
forms  that  upon  drying  nothing  but  an  exceedingly  thin  and 
delicate  film  is  left. 

215.— Water  in  the  Protoplasm.  As  explained  in  para- 
graphs 4  and  5  (page  5),  living  protoplasm  has  the  power 
of  imbibing  water,  and  thereby  of  increasing  its  fluidity. 
Even  after  it  has  imbibed  all  the  water  which  it  can  retain 
it  continues  the  process,  and  separates  the  surplus  in  drops 


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THE  WATER  IN  THE  PLANT.  167 

in  its  interior,  the  so-called  vacuoles.  Now  an  examination 
of  the  cells  of  rapidly  growing  tissues  shows  that  their  pro- 
toplasm is  much  more  watery  than  that  of  living,  but  dor- 
mant tissues — e.g.,  those  of  seeds — and  one  of  the  first  signs 
of  activity  in  the  latter  is  the  imbibition  of  water. 

This  avidity  of  protoplasm  for  water  plays  an  important 
part  in  the  general  economy  of  the  plant.  By  it  all  the  cells 
which  contain  protoplasm  are  kept  turgid,  and  by  the  ten- 
sion thus  created  the  soft  parts  of  plants  are  made  rigid. 
It  plays  no  small  part  also  in  keeping  up  the  supply  of 
moisture  in  living  tissues  when  wasted  by  evaporation.  (See 
paragraph  220  ec  seq. ) 

216.— Water  in  the  Cell-walls.  In  the  cell-walls,  accord- 
ing to  Nageli's  theory,  the  water  forms  thinner  or  thicker 
layers  surrounding  the  crystalline  molecules  of  cellulose.  (See 
para^aph  37,  p.  32.)  The  wall  of  the  cell  is  thus  not  a 
membrane  which  separates  the  water  of  one  cell  cavity  from 
that  in  the  next,  but  rather  a  pervious  stratum,  composed  of 
solid  particles  which  are  not  in  contact,  and  between  which 
the  water  freely  passes.  In  a  living  tissue  the  water  is  con- 
tinuous from  cell  to  cell,  and  constantly  tends  to  be  in  equi- 
librium— i.e.,  the  turgidity  of  the  cells  is  approximately 
equal  throughout  the  tissue,  and  likewise  the  wateriness  of 
both  cell-walls  and  cell-contents. 

In  the  simpler  aquatic  plants  the  water  of  the  cells  and 
their  walls  is  continuous  with  that  in  which  they  grow. 
Likewise  the  water  in  the  tissues  of  roots  or  other  absorbing 
organs  of  the  higher  aquatic  plants  is  continuous  with  that 
which  surrounds  them;  and  even  in  ordinary  terrestrial  plants 
there  is  a  perfect  continuity  of  the  water  in  the  root  tissues 
with  the  moisture  of  the  soil. 

217.— Water  in  Intercellular  Spaces.  In  some  cases  the 
intercellular  spaces  and  passages,  and  even  the  vessels  of  the 
more  succulent  plants,  are  filled  with  water,  thus  increasing 
its  amount  in  the  whole  plant  very  considerably.  More 
commonly,  however,  these  cavities  are  filled  with  air  and 
gases,  the  vessels  having  early  lost  the  protoplasm  which 
they  contained  at  first.     It  is  probable,  moreover,  that  the 


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168  BOTANY. 

water  which  is  occasionally  found  in  their  cavities  has  little 
or  no  physiological  relation. 

218.— The  Equilibrium  of  the  Water  in  the  Plant.  The 
water  in  the  tissues  of  every  plant  tends  constantly  to  become 
in  equilibrium,  and  this  state  would  soon  be  reached  were  it 
not  for  certain  disturbing  causes  which  are  almost  as  con- 
stantly in  action.  In  any  cell  an  equilibrium  may  soon  be 
reached  between  the  two  forces  which  reside  respectively  in 
the  cell-wall  and  the  protoplasm,  viz.,  (1)  the  attraction  of 
the  surfaces  of  tlie  molecules  for  the  water,  and  (2)  the 
*Mmbibition  power"  of  protoplasm.  This  equilibrium  once 
attained,  all  motion  of  the  water  must  cease,  and  it  must 
remain  at  rest  until  disturbed  by  some  other  force  or  forces. 
This  condition,  or  one  approximating  very  closely  to  it,  is 
reached  by  paany  of  the  perennial  plants  during  the  winter 
or  i)eriod  of  rest. 

219.— Disturbance  of  Equilibrium.  During  the  growing 
stages  of  plants  the  equilibrium  of  the  water  is  constantly 
disturbed  in  one  or  more  ways,  viz.,  (1)  by  the  chemical 
processes  within  the  cells  ;  (2)  by  the  "  imbibition  power"  of 
the  protoplasm  and  walls  of  newly  formed  cells ;  (3)  by  the 
evaporation  of  a  portion  of  the  water. 

The  chemical  processes  within  the  cell  include :  (1)  the 
actual  use  of  water  by  breaking  it  up  into  hydrogen  and 
oxygen ;  every  molecule  which  is  so  broken  up  leaves  a 
vacancy  which,  sooner  or  later,  must  be  replaced ;  (2)  the 
formation  of  substances  which  are  more  soluble  than  those 
from  which  they  were  formed;  (3)  the  formation  of  sub- 
stances which  are  less  soluble  than  those  from  which  they 
were  formed.  These  processes  take  place  in  all  cells,  even 
those  of  the  simplest  plants. 

In  plants  composed  of  tissues,  wherever  new  cells  are 
forming  and  developing,  the  new  protoplasm  and  cell-walls 
require  considerable  quantities  of  water  to  satisfy  their 
molecular  attraction  (paragraphs  215  and  216  above) ;  this 
supply  is  always  made  in  part  or  entirely  at  the  expense 
of  the  adjacent  cells.  In  many  aquatic  plants  there  can 
be  little  doubt  that  the  needed  water  in  meristem  tissues 
is  obtained  partly  by  direct  absorption  from  the  surround- 


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THE  WATER  IN  THE  PLANT.  169 

ing  water,  but  this  can  only  be  the  case  with  the  external 
cells ;  the  deep-lying  ones  must  obtain  their  supply  from  the 
cells  which  surround  them.  In  aerial  parts  of  plants  the 
newly  formed  cells  obtain  all  their  water  from  the  adjacent 
cells, 

220.— Evaporation  of  Water.  In  the  aerial  parts  of  plants 
the  evaporation  of  water  from  their  surfaces  is  a  far  more 
powerful  disturbing  cause  than  either  of  the  two  preceding. 
Whenever  a  cell  is  exposed  to  dry  air  at  ordinary  tempera- 
tures a  portion  of  its  water  passes  off  by  evaporation ;  this 
immediately  disturbs  the  equilibrium  of  water  throughout 
the  tissue,  and  the  more  rapid  or  the  longer  continued  the 
evaporation,  the  greater  the  disturbance. 

Evaporation  (called  also  transpiration  and  exhalation) 
from  living  cells  or  tissues  is  dependent  upon  a  number  of 
conditions,  some  of  which  are  entirely  exterior,  while  others 
Are  connected  with  the  structure  of  the  plant  itself.  Among 
the  former,  the  most  important  is  the  condition  of  the  air  as 
to  the  amount  of  moisture  which  it  contains.  In  air  satu- 
rated with  moisture  no  evaporation  can  take  place  ;*  but 
whenever  the  amount  of  moisture  falls  below  the  point  of 
saturation,  if  the  other  conditions  are  favorable,  evaporation 
takes  place.  The  temperature  of  the  air  (and,  as  a  conse- 
quence, that  of  the  plant  also)  has  some  effect  upon  the 
rapidity  of  evaporation.  It  appears  that  there  is  an  increase 
in  the  amount  of  water  given  ofE  as  the  temperature  rises ; 
this  may  be  due,  however,  to  the  fact  that  with  such  increase 
of  the  temperature  of  the  air  there  is  generally  a  considerable 
decrease  in  its  moisture.  The  direct  influence  of  light  upon 
evaporation  is  also  somewhat  doubtful.  While  there  can  be 
no  doubt  that  plants  generally  lose  more  water  in  the  light 
than  in  darkness,  it  may  be  questioned  whether  this  is  not 


*  Manj  experiments,  at  first  sight,  seem  to  show  that  plants  evapo- 
jate  water  in  air  saturated  with  moistare ;  but  Enop  has  found 
(~  Versuchs-Sutionen,"  Vol.  VI.,  p.  255)  that,  under  similar  conditions, 
moist  pieces  of  paper  or  wood  also  evaporate  water,  thus  showing  that 
the  idr,  instead  of  being  saturated,  lacked  somewhat  of  being  so. 


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ITO  BOTANY, 

mainly  due  to  tlie  increased  heat  and  dryness  which  are 
common  accompaniments  of  the  increase  of  light.* 

221. — In  enumerating  the  internal  conditions  one  general 
one  must  not  be  forgotten,  which  is,  that  the  water  in  plant- 
cells  contains  many  substances  in  solution,  and  consequently 
evaporates  less  rapidly  than  pure  water,  in  accordance  with 
well-known  physical  laws.  Moi'eover,  the  attraction  of  the 
molecules  of  the  cell-walls  for  the  water  layers  counteracts, 
to  a  considerable  extent,  the  tendency  to  evaporation  ;  and 
in  the  same  manner,  even  to  a  greater  extent,  the  water  is 
prevented  from  passing  off  by  the  **  imbibition  power  "of 
protoplasm.  It  is,  in  fact,  impossible  to  deprive  cellulose 
and  protoplasm  of  their  intermolecular  water  in  dry  air  at 
ordinary  temperatures. 

In  all  the  aerial  parts  of  higher  plants  the  epidermis 
offers  more  or  less  resistance  to  the  escape  of  the  water  of  the 
underlying  tissues.  This  is  mainly  accomplished  by  the 
thick  and  cuticularized  outer  wall  of  the  epidermal  layer ;  in 
many  cases,  especially  in  plants  growing  naturally  in  very 
dry  regions,  the  epidermis  consists  of  several  layera  of  cells, 
which  offer  still  more  resistance  to  evaporation  by  being 
themselves  filled  with  moist  air  only.  Among  the  lower 
plants,  the  single  reproductive  cells  (spores)  are  guarded 
against  the  loss  of  water  by  having  their  walls  greatly  thick- 
ened and  cuticularized.  Even  in  the  lowest  plants,  the  Slime 
Moulds  (Myxomycetes),  the  naked  masses  of  protoplasm, 
when  placed  in  dry  air,  will  contract  into  rounded  masses, 
which  then  become  covered  with  a  somewhat  impervious 
envelope  (paragraph  23,  c  :  page  21). 

222. — The  stomata  of  the  green  and  succulent  parts  of 
higher  plants  control  to  a  great  extent  the  amount  and 
rapidity  of  their  exhalation.  In  leaves,  for  example,  where, 
on  account  of  its  cuticularization,  there  can  be  but  little 
evaporation  through  the  epidermis,  it  is  dependent  upon  the 

*  I  am  aware  that  aome  experiments  made  wiih  plants  in  saturated 
and  in  dry  air  appear  to  show  that  in  direct  sunlight  there  is  a  rapid 
evaporation.  I  cannot,  however,  regard  these  experiments  as  con* 
elusive. 


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THE  WATER  IN  THE  PLANT,  171 

nnmber,  size,  and  condition  {i.e.,  whether  open  or  closed) 
of  the  stomata.  As  previously  described  (paragraph  130,  p. 
99),  the  stomata  are  placed  over  intercellular  spaces,  which 
are  in  communication  with  the  intercellular  pjissages  of  the 
plant  These  spaces  and  passages  are  filled  with  moist  air 
and  gases,  which,  when  the  stomata  are  open,  expand  and 
contract  with  every  change  of  temperature  or  atmospheric 
pressure,  and  thus  permit  the  escape  of  considerable  amounts 
of  water  ;  when,  on  the  other  hand,  the  stomata  are  closed, 
little  or  no  escape  of  moisture  is  possible.  The  opening  and 
closing  of  the  stomata  appear  to  depend  upon  the  amount  of 
light ;  they  open  more  widely  the  greater  the  amount  of 
light,  and  close  almost  completely  in  darkness.  The  amount 
of  moisture  on  the  surface  of  the  epidermis  appears  also  to 
affect  somewhat  the  opening  and  closing  of  the  stomata  ; 
when  the  epidermis  is  very  dry  the  stomata  are  generally 
closed,  and  vice  versa. 

223.— The  Amount  of  Evaporation.  The  conditions  con- 
trolling evaporation  are  thus  seen  to  be  many  and  various. 
They  never,  or  but  very  rarely,  act  singly,  two  or  more  of 
them  usually  acting  together  with  varying  intensity,  so  that 
the  problem  of  the  amount  of  evaporation  taking  place  at 
any  particular  time  is  a  complex  and  difficult  one.  All  the 
observations  yet  made,  and  which  have  necessarily  been  upon 
a  very  small  scale,  indicate  that  the  rate  of  evaporation  is 
actually  very  slow.  Thus  Hales  long  ago  found  that  the 
amount  of  water  evaporated  from  a  vine  in  twelve  hours  of 
daylight  equalled  a  film  only  .13  mm.  (.005  in.)  thick,  and 
having  an  extent  as  great  as  that  of  the  evaporating  surfnce  ; 
the  amount  from  a  cabbage  in  the  same  time  equalled  a  film 
.31  mm.  (.012  in.)  thick  ;  from  an  apple  tree,  .25  mm.  (.01 
in.)  thick  ;  from  a  sunflower  in  a  day  and  a  night,  equal  to 
a  film  .15  mm.  (.006  in.)  thick.*  Mftller  found  the  rate  of 
evaporation  from  the  leaves  of  Hwmanthus  puniceus  to  be 
only  one  seventeenth  as  rapid  as  that  from  an  equal  area  of 
water  during  the  same  time.     Sachs  found  the  evaporation 

*  "  Statical  Essays :  Vegetable  Statics/'  by  Stephen  Hales.  1727. 
Foarth  edition.     1769.    p.  21. 


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172  BOTANY, 

from  the  leaves  of  the  White  Poplar  to  be  about  one  third  as 
rapid  as  from  water,  linger  places  the  evaporation  from 
most  leaves  at  about  one  third  that  from  equal  areas  of 
water ;  in  some  cases,  however,  running  as  low  as  one  fifth 
and  one  sixth.* 

224.  — Pfaff  calculated  the  amount  of  water  evaporated 
from  an  isolated  oak  tree  during  the  growing  season.  The 
tree  selected  was  a  close-topped  one  6f  metres  (20  ft. )  high, 
bearing  about  700,000  leaves.     The  results  were  as  follows : 

May  (14  days) 888  kilograms  =  (  1,944  lbs.) 

June 26,028         "         =(57,250  " 

July 28.757         "*         =(63,265   - 

August. 21.745         '•  =(47389   ^ 

September 17,674         "         =  (38,882  " 

October 17,028         "  =  (37,450  " 

The  evaporation  from  each  leaf  was  for  the  season  of  five 
and  a  half  months  (one  hundred  and  sixty-seven  days)  .16 
kilograms  (.36  lbs.) ;  allowing  forty-eight  square  centimetres 
of  surface  to  each  leaf,  this  amounted  to  a  layer  of  water 
3.33  centimetres  (1.31  in.)  deep  over  the  whole  evaporating 
surface,  f 

225.— The  Moyement  of  Water  in  the  Plant.  It  is  clear, 
from  what  has  been  said,  that  in  polycellular  plants  there 
must  be  a  considerable  movement  of  water  in  some  parts,  to 
supply  the  loss  by  evaporation.  Thus  in  trees  there  must  be 
a  movement  of  water  through  the  roots,  stems,  and  branches 
to  the  leaves,  to  replace  the  loss  in  the  latter.  This  is  so 
evident  that  it  scarcely  needs  demonstration ;  it  can,  how- 
ever, be  shown  by  cutting  oflF  a  leafy  shoot  at  a  time  when 

*The  three  last  Btatements  and  the  following  are  given  on  the 
authority  of  Duchartre  (*'  Elements  de  Botanique/'  second  edition,  1877, 
pp.  844  and  846). 

f  Pfaff  found  that  the  water  evaporated  duriDff  the  season,  when  con- 
sidered with  reference  to  the  area  of  ground  covered  by  the  tree  top, 
was  equal  to  a  layer  5.89  metres  high  (212  indies)  Observation  had 
shown  the  annual  rain-fall  to  be  .65  metres  (25.6  incites) ;  so  that  the 
water  evaporated  from  the  tree  was  ei$rht  times  the  amount  which  fell 
upon  the  earth  under  it.  The  evaporation  is  very  much  less  in  dense 
forests  than  in  isolated  trees,  but  with  every  allowance  it  is  sufficient 
in  dry,  hot  seasons  to  quickly  exhaust  the  moisture  of  the  soil. 


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THE  WATER  IN  THE  PLANT.  173 

evaporation  is  rapid ;  in  a  short  time  the  loaves  wither  and 
become  dried  up^  unless  the  cut  portion  of  the  shoot  be 
placed  in  a  vessel  of  water ;  in  the  latter  case  the  water  will 
pass  rapidly  into  the  shoot,  and  the  leaves  will  retain  their 
normal  condition.  If  in  such  an  experiment  a  colored  watery 
solution  (as  of  the  juice  of  Poke  berries)  be  used  instead  of 
pure  water,  it  will  be  seen  that  the  liquid  has  passed  more 
abundantly  through  certain  tracts  than  through  others,  in- 
dicating that  the  tissues  are  not  equally  good  as  conductors 
of  watery  solutions.  As  would  readily  be  surmised,  the 
tissues  in  ordinary  plants  which  appear  to  be  the  best  con- 
ductors are  those  composed  of  elongated  wood-cells,  and  it  is 
doubtless  through  them  that  the  greater  part  of  the  water 
passes.  Furthermore,  it  is  probable  that  the  movement  of 
the  water  is  through  the  substance  of  the  cell-walls,  and  not, 
at  least  to  any  great  extent,  through  the  cell  cavities.  Ac- 
cording to  this  view,  the  force  which  raises  the  water,  in 
some  cases  to  the  height  of  a  hundred  metres  or  more,  is  the 
attraction  of  the  surfaces  of  the  crystal  molecules  for  the 
layers  of  water  which  surround  them. 

226. — The  rapidity  of  the  upward  movement  of  water  evi- 
dently varies  directly  as  the  rapidity  of  evaporation,  and  in- 
versely ais  the  area  of  the  conducting  tissue  in  transverse  sec- 
tion. As  both  these  factors  are  variable,  it  is  impossible  to 
give  an  average  rate  of  movement.  Sachs  estimated  the 
rate  of  ascent  in  a  branch  of  the  Silver  Poplar,  from  which 
there  was  strong  evaporation,  at  23  cm.  (9  in.)  per  hour. 
McNab,  by  watering  plants  with  a  solution  of  lithium  citrate 
and  then  examining  the  ashes  at  successive  points,  found  the 
rate  in  a  Cherry  Laurel  to  be  101  cm.  (40  in.)  per  hour.  Pfit- 
zer  obtained  the  astonishing  result  of  22  metres  (72  ft.)  per 
hour  in  the  Sunflower  ;  there  is  but  little  doubt,  however, 
that  this  is  entirely  too  high. 

(a)  In  addition  to  the  movements  of  the  water  described  above,  that 
which  has  been  called  root  pressure  requires  a  brief  mention.  If  the 
root  of  a  vigorously  growing  plant  be  cut  off  near  the  surface  of  the 
ground  and  a  glass  tube  attached  to  its  upper  end,  the  water  of  the  root 
wUl  be  forced  out,  often  to  a  considerable  height.  Hales*  noted  a  pressure 

*  Statical  Essays,  p.  114. 


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174  BOTANY. 

upon  a  mercurial  gauge  equal  to  11  metres  (86.5  ft.)  of  water  when  at- 
tached to  the  root  of  a  vine  ( VUU).  Clark,*  in  a  similar  mamier,  foand 
the  pressure  from  a  root  of  the  birch  (Betula  lutea)  t«>  be  equal  to  25.8 
metres  (84.7  ft.)  of  water.  This  root  pressure  appears  to  be  greatest 
when  the  evaporation  from  the  leaves  is  least ;  in  fact,  if  the  experi- 
ment is  made  while  transpiration  is  verj  active,  there  is  always  for  a 
while  a  considerable  absorption  of  water  hj  the  cut  end  of  the  root, 
due  probably  to  the  fact  that  the  celLwalls  had  been  to  a  certain  ex- 
tent robbed  of  their  water  by  the  evaporation  from  above.  Root  pres- 
sure is  probably  a  purely  physical  phenomenon,  due  to  a  kind  of  en- 
dosmotic  action  taking  place  in  ilie  r<iotcf]ls. 

(&)  The  flow  of  water  (sap)  from  the  stems  aud  branches  of  certain 
trees,  notably  from  the  Sugar  Maple,  appears  to  be  due  to  the  quick 
alternate  expannion  and  contraction  of  the  air  and  other  gases  In  the 
tissues  from  the  quick  changes  of  temperature.  The  water  is  forced  out 
of  openings  in  the  stem  when  the  temperature  suddenly  rises  ,*  when 
the  temperature  suddenly  falls,  as  at  night,  there  is  a  suction  of  water 
or  air  into  the  stem.  When  the  temperature  is  nearly  uniform,  whether 
in  winter  or  summer,  there  is  no  flow  of  sap. 

§  IL    As  TO   SOLUTIOXS. 

227. — The  water  in  the  plant  holds  in  solutit)n  several 
substances,  so  that  it  is  not  water  alone,  but  in  reality  a 
complex  solution.  Some  of  the  substances  in  solution  are 
solids,  as  the  inorganic  salts  taken  up  from  the  soil  or  water, 
while  others  are  gaseous,  as  the  air  and  carbon  dioxide  taken 
up  in  the  water  by  the  roots,  or  absorbed  by  the  leaves  and 
there  entering  into  solution  in  the  water.  The  final  use  of 
these  solutions  will  be  spoken  of  further  on  ;  here  it  is  only 
necessary  to  point  out  some  of  tlie  more  important  general 
facts  as  to  solution  and  diffusion  : 

1st.  When  a  substance  has  entered  into  solution  it  still 
exists  as  that  substance,  and  the  water  in  which  it  is  dis- 
solved is  in  one  sense  pure.  This  is  readily  shown  by  driving 
off  the  water  by  lieat,  when  the  dissolved  substance  is  again 
obtained  in  its  original  solid  state. 

2d.  As  soon  as  solution  begins  the  process  of  difihision 

♦  In  1873,  recorded  in  the  Twenty-first  Report  of  the  Secretary  of 
the  Massachusetts  State  Board  of  Agriculture.  See  also  farther  re- 
sults by  the  same  observer  In  the  Twenty-second  Report. 


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PLANT  FOOD,  175 

necessarily  commences  also ;  this  is  the  passage  of  the  mole- 
cnlee  of  the  dissolved  substance  through  the  water  without  a 
movement  of  the  latter.  Thus  in  perfectly  quiescent  water 
a  substance  may  diffuse  itself  between  the  molecules  of  the 
latter  to  considerable  distances,  and  this  muy  take  place  in 
any  direction,  even  when  the  substance  is  heavier  than  water ; 
thus  common  salt  placed  in  the  bottom  of  a  tall  vessel  of 
water  will  dissolve  and  gradually  diffuse  throughout  the 
whole. 

3d.  The  rapidity  of  diffusion  varies  for  different  sub- 
stances ;  thus  the  diffusion  rate  of  sugar  is  more  than  three 
times  that  of  common  salt  (exactly  as  365  to  116). 

4th.  Two  or  more  diffusions  may  take  place  at  the  same 
time  in  the  same  fluid,  and  they  may  move  in  the  same  or  in 
opposite  directions. 

5th.  Diffusion  continues  until  all  parts  of  the  solution 
contain  equal  quantities  of  the  dissolved  substance. 

6th.  If  at  any  point  in  a  solution  the  dissolved  substance 
be  removed  in  some  way,  as,  for  example,  by  the  formation 
of  a  new  salt  by  chemical  reaction,  there  will  be,  as  a  conse- 
quence, a  continued  diffusion  toward  that  point ;  and  if  the 
new  salt  be  a  soluble  one  it  must  diffuse  in  every  direction 
from  the  point  of  its  formation.  Thus  the  molecular  move- 
ments may  become  quite  complex. 

§  III.  Plant  Food. 

228.— The  most  important  elements  which  are  used  in 
the  nutrition  of  plants,  or  which,  in  other  words,  enter  into 
their  food,  are  Carbon,  Hydrogen,  Oxygen,  Nitrogen,  Sul- 
phur, Iron,  and  Potassium.  These  all  appear  to  be  necessary 
to  the  life  and  growth  of  the  plant,  and  if  any  of  them  are 
wanting  in  the  water,  soil,  or  air  from  which  the  plant  de- 
rives its  nourishment,  death  from  starvation  will  soon  follow. 
There  are  other  elements  which  are  made  use  of  by  plants, 
but  as  life  may  be  prolonged  without  them,  they  are  regarded 
as  of  secondary  importance.  In  this  list  are  Phosphorus, 
Calcium,  Sodium,  Magnesium,  Chlorine,  and  Silicon. 


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176  BOTANY. 

229.— The  Compounds  Used.  With  the  single  exceptioa 
of  oxygen,  the  elementary  constituents  named  above  do 
not  enter  into  the  food  of  plants  in  an  uneombined  state ; 
on  the  contrary,  they  are  always  absorbed  in  the  condition 
of  compounds,  as  water,  carbon  dioxide,  and  the 


Nitrates 

Sulphates 

(.'arbonatee 

Phosphates 

Silicates,  oi 

Chlorides 


of 


Ammonia. 

Potash. 

Lime. 

Iron. 

Soda,  or 

Magnesia. 


In  addition  to  these,  many  organic  compounds  are  ab- 
sorbed in  particular  cases,  as  in  those  plants  which  live  in 
decaying  animal  or  vegetable  matter  (saprophytes),  as  well 
as  those  which  absorb  the  juices  from  living  plants  (para- 
sites). 

230. — ^How  the  Food  is  Obtained. — In  the  case  of  aquatic 
plants,  these  compounds  are  taken  into  the  plant-body  by  a 
process  of  difihision  from  the  surrounding  water ;  in  terres- 
trial plants  the  gaseous  compounds,  as  carbon  dioxide  and 
carbonate  of  ammonia,  are  absorbed — at  least  in  part — ^by  the 
leaves  directly  from  the  surrounding  air,  while  the  solutions 
of  these  and  the  other  compounds  in  the  water  in  the  soil 
find  their  way  into  the  plant  by  diffusion. 

2dOa.— How  tlie  Food  is  Transported  in  the  Plant. 
Once  within  the  plant-body,  the  food  materials  diffuse  to  all 
watery  parts,  in  the  case  of  the  larger  terrestrial  plants  ris- 
ing through  the  stem  to  the  leaves.  By  diffusion,  there  is  a 
constant  tendency  toward  an  equal  distribution  throughout 
the  plant  of  the  solutions  which  enter  it,  and  if  there  were 
no  disturbing  chemical  reactions  taking  place,  such  a  condi- 
tion would  in  most  plants  be  soon  reached.  It  is  quite 
probable,  indeed,  that  this  actually  happens  for  certain  sub- 
stances which  are  found  in  solution  in  the  soil  or  water,  and 
which,  entering  plants,  diffuse  through  them  to  all  parts, 
but  not  being  used  they  soon  reach  a  state  of  equal  diffusion, 
which  is  only  slightly  disturbed  by  the  extension  of  the 
plant-body  by  growth.  Doubtless  the  rapid  diffusion  of 
food  materials  throughout  terrestrial  plan^  is  aided  by  the 


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PLANT  FOOD.  177 

eraporation  of  water  from  the  leaves,  thus  causing  a  strong 
upward  movement  of  the  water  which  contains  the  various 
solutions  of  food  matter.  Moreover,  there  can  be  no  doubt 
that  the  movement  of  the  water  in  terrestrial  plants,  caused 
by  the  swaying  and  bending  of  the  stems  and  branches^ 
faciUtates  and  hastens  the  diffusion  of  food  materials. 


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CHAPTER    XL 

CHEMICAL  PROCESSES  IN  THE  PLANT. 

§  I.    ASSIMILATIOK. 

231. — In  many  plants  the  food  materials  which  are  taken 
into  the  plant-body  are  of  such  a  nature  that  they  can  be 
directly  used  by  the  protoplasm ;  thus  in  the  saprophytes 
the  solutions  of  organic  compounds  derived  from  the  decay 
of  animal  or  vegetable  tissues  are  imbibed  by  the  protoplasm 
and  used  by  it  as  true  food  ;  and  in  the  parasites  the  proto- 
plasm and  the  juices  of  living  tissues  are  directly  used  in  a 
similar  way.  It  is,  furthermore,  probable  that  in  some  of 
the  lowest  forms  of  vegetation,  as  in  the  Myxomycetes  and 
Schizomycetes,  the  protoplasm  is  capable  of  making,  to  a 
limited  extent,  a  direct  use  of  some  of  the  inorganic  sub- 
stances absorbed  by  them.  For  the  most  part,  however,  the 
principal  food  materials  taken  in  by  plants  are  such  as  can- 
not be  directly  used  by  protoplasm  in  either  its  vegetative 
or  reproductive  activity ;  thus  neither  water  nor  carbon 
dioxide  is  directly  used  as  food  by  the  protoplasm  of  ordi- 
nary green  plants,  but  in  all  cases  they  undergo  certain 
chemical  changes,  by  which  they  are  made  suitable  for  use 
by  protoplasm.  To  these  preparatory  changes,  which  fit  the 
crude  food  materials  for  protoplasmic  food,  the  general  name 
of  Assimilation  has  been  given. 

232. — It  is  impossible  as  yet  to  give  a  complete  statement 
of  all  the  processes  in  assimilation  ;  the  principal  facts  now 
made  out  appear  to  be  as  follows :  In  the  chlorophyll- 
bearing  portions  of  plants,  carbon  dioxide  and  water  are  de- 
composed, and  from  their  component  elements  carbohydrates 
are  at  once  formed.  This  decomposition  and  subsequent 
combination  take  place  only  in  the  granules  or  masses  of 


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METASTASIS.  179 

chlorophyll,  and  only  in  sunlight.  Those  parts  of  ordinary 
plants  which  are  destitute  of  chlorophyll  are  entirely  want- 
ing in  the  power  of  assimilation,  and  likewise  the  chloro- 
phyll-bearing portions  are  unable  to  assimilate  in  darkness. 
Carbon  dioxide  is  probably  decomposed  into  carbon  oxide 
and  free  oxygen  :  CO,  =  CO  +  0.  At  the  same  time  water 
is  decomposed  into  hydrogen  and  oxygen  :  H,  0  =  2  H  + 
0.  The  free  oxygen  atoms  are  exhaled,  and  by  the  union 
of  carbon  oxide  and  hydrogen,  starch  is  in  most  cases 
formed ;  this  appears  as  minute  granules  imbedded  in  the 
chlorophyll-bodies  (Fig.  43,  p.  52).  In  some  plants  no 
starch  is  formed  in  the  chlorophyll,  but  oily  or  sugary  mat- 
ters which  have  nearly  the  same  chemical  significance. 
Assimilation  is  thus  a  deoxidizing  process.  Both  water  and 
carbon  dioxide  contain  large  quantities  of  oxygen,  while  in 
starch  it  is  much  less  ;  consequently,  in  the  formation  of  the 
latter  from  the  former,  there  must  be  a  surplus  of  oxygen. 
This  may  be  shown  as  follows  : 


12C0,   = 
12H,0  = 


13C0 1         BtarcU 

;i2o[  =240  set  free.  1=  C,  H,oO,o  +  2H,0 


24H. 


Here  twelve  molecules  of  carbon  dioxide  and  twelve  mole- 
cules of  water  produce  one  molecule  of  starch  and  two  mole- 
cules of  water  (water  of  organization),  while  twenty-four 
atoms  of  oxygen  are  set  free  and  permitted  to  escape  from 
the  cells  into  the  surrounding  air  or  water. 

§  II.  Metastasis. 

283.— Its  General  Nature.  The  chemical  changes  just 
described,  which  constitute  assimilation,  take  place  only  in 
chlorophyll-bearing  plants,  or  parts  of  plants,  and  in  these 
only  in  the  sunlight.  In  cells  which  are  destitute  of  chloro- 
phyll, and  in  the  chlorophyll-bearing  ones  in  the  absence  of 
light,  other  chemical  changes  take  place  ;  these,  while  differ- 
ing much  among  themselves,  agree  in  always  being  processes 
of  oxidation,  and  changes  of  one  organic  compound  into  an- 
other.    To  these  chemical  changes,  in  order  to  distinguish 


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182  BOTANY. 

Bimilar  to  those  which  follow  the  transfprmation  of  the 
starch  of  the  chlorophyll. 

288.— The  Nutrition  of  Parasites  and  Saprophytes  is 
similar  to  that  of  embryos,  buds,  bulbs,  etc.  Here  assimi- 
lated materials  are  drawn  from  some  other  organism,  and 
subsequently  undergo  metastatic  changes.  In  some  cases  the 
parasitism  is  only  partial,  as  in  the  mistletoe,  where  a  part 
of  the  assimilated  matter  is  formed  in  the  parasite  (which, 
therefore,  contains  chlorophyll),  while  a  portion, seems  to  be 
taken  along  with  the  mineral  salts  from  the  host  plant.  So, 
too,  there  are  plants  which  are  partially  saprophytic  in  habit, 
deriving  a  part  of  their  nourishment  as  saprophjrtes,  while 
the  remainder  is  elaborated  by  their  chlorophyll.  Many  cul- 
tivated plants,  as  we  grow  them,  are  partially  saprophytic, 
deriving  a  portion  of  their  nourishment  from  decaying  or- 
ganic matter  in  the  soil.  The  so-called  Carnivorous  plants, 
as  Drosera,  DionaBa,  Sarracenia,  Darlingtonia,  Nepenthes, 
Utricularia,  etc.,  are  in  reality  partially  saprophytic,  obtain- 
ing a  considerable  part  of  their  food  materials  from  de- 
caying animal  matter. 

289.— The  Formation  of  Alkaloids.  Among  the  most 
obscure  of  the  metastatic  changes  are  those  which  give  rise 
to  the  alkaloids.  These  are  compounds  of  carbon,  hydro- 
gen, nitrogen,  and  generally  oxygen,  in  which  the  first  two 
elements  have  approximately  an  equal  number  of  atoms, 
while  the  last  two  have  also  a  nearly  equal  but  much  smaller 
number. 

The  more  important  ones  are  the  following  : 

Conia  (Ct  Hi$N,)  from  Conium. 
Nicotine  (d.  Hi 4  N,)  from  Tobacco, 
dncbonla  (C,«  Ha«  NjO)  from  Peruvian  Bark. 

Morphia  (Cn  Hi»  N  Ot  +  H,  O)  from  the  Opium  Poppy. 
Strychnia  (Cn  Hj»  N«  O.)  from  the  seeds  of  Strjchnoa. 
Cafielne  (Cb  Hi©  N4  O,  +  H,  O)  from  Coffee  and  Tea. 

These  and  many  others  occur  in  plants  in  combination 
with  organic  acids,  such  as  :  malic  acid  (C,  H,  0  J  ;  tartaric 
acid  (C,H,0,);  citric  acid  (C,H,0,);  oxalic  acid  (C,H 
0,);  tannic  acid  (C„H„0„);  quinic  acid  (C,H„0,); 
meconic  acid  (C,  H,  0.)-     These  acids  are  probably  formed 


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METASTASIS.  183 

by  the  oxidation  of  some  of  the  saccharine  or  amylaceous 
substances  in  the  plant,  while  the  alkaloids  with  which  they 
are  combined  appear  to  have  some  relation  to  the  nitrogenous 
constituents  of  the  protoplasm,  and  are  possibly  derived  from 
them.  From  the  fact  that  the  alkaloids  are  formed  more 
abundantly  in  those  tissues  which  have  passed  the  period  of 
their  greatest  activity,  it  may  be  surmised  that  they  are 
either  compounds  of  a  lower  grade  which  are  formed  instead 
of  the  ordinary  albuminoids,  or  the  first  results  of  the  incip- 
ient decay  of  the  cells. 

240.~Be8tat8  of  Metastasis.  In  the  preceding  para- 
graphs it  is  seen  that  chlorophyll-bearing  plants  absorb 
carbon  dioxide  and  exhale  free  oxygen,  the  former  being  de- 
composed in  the  chlorophyll  granules  in  sunlight  and  the 
oxygen  being  set  free  as  a  consequence.  In  other  words,  the 
absorption  of  carbon  dioxide  and  the  exhalation  of  oxygen 
are  connected  with  the  process  of  assimilation.  It  is  further 
seen  that  oxygen  is  absorbed  and  carbon  dioxide  evolved,  as 
results  of  certain  metastatic  processes  which  take  place  in 
any  tissues,  whether  possessing  chlorophyll  or  not,  and  inde- 
pendently of  the  presence  or  absence  of  sunlight.  In  the 
sunlight  the  absorption  of  carbon  dioxide  to  supply  assimila- 
tion is  so  greatly  in  excess  of  its  exhalation  as  a  result  of 
metastatic  action,  that  the  latter  is  unnoticed.  In  dark- 
ness, however,  when  assimilation  is  stopped,  the  exhalation 
of  carbon  dioxide  becomes  quite  evident  So,  too,  with 
oxygen ;  in  the  sunlight  the  excess  of  its  evolution  is  so 
great  over  its  absorption  that  the  latter  was  long  unknown ; 
but  in  the  absence  of  light  its  absorption  becomes  manifest. 
Parasites  and  saprophytes,  as  well  as  those  parts  of  ordinary 
plants  which  are  wanting  in  chlorophyll,  as  flowers  and  many 
fruits,  deport  themselves  in  this  regard  exactly  as  chloro- 
phyU-bearing  organs  do  in  darkness. 


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CHAPTER   XII. 

THE    RELATIONS    OF    PLANTS    TO    EXTERNAL 
AGENTS. 

§  L  Tempeeaturb. 

241.— General  Belations.  The  functions  of  plants  are 
possible  only  between  certain  limits  of  temperature  of  the 
air,  water,  or  soil,  varying  considerably  for  each  species.  In 
every  plant  there  is  a  certain  minimum  temperature,  below 
which  all  functional  activity  ceases  ;  thus  in  most  instances 
plants  become  inactive  when  the  temperature  approaches 
O""  Cent  (32''  Fahr.).  On  the  other  hand,  there  is  a  maxi- 
mum beyond  which  activity  ceases ;  this  ranges  in  different 
plants  from  about  35°  to  50°  Cent.  (95°  to  122°  Fahr.).  Be- 
tween these  two  extremes  is  tlie  temperature  at  which  the 
greatest  activity  takes  place ;  this  has  been  termed  the  opti" 
mum. 

In  any  particular  plant,  the  maxima,  optima,  and  minima 
are  not  exactly  alike  for  all  functions,  some  being  performed 
at  temperatures  considerably  above  or  below  those  at  which 
others  cease.  It  is  furthermore  to  be  observed  that,  in  gen- 
ersU,  there  is  a  simple  suspension  of  activity  at  temperatures 
a  few  degrees  below  the  minimum,  whereas  above  the  max- 
imum the  death  of  the  organ  ensues  ;  in  the  former  a  resto- 
ration of  the  normal  temperature  is  soon  followed  by  a  re- 
sumption of  activity;  In  the  latter  the  activity  cannot  be 
restored,  even  under  the  most  favorable  conditions. 

242.— Absorption  of  Water  as  Af^ted  by  Temperature. 
The  absorption  of  water  and  watery  solutions  is  greatly 
affected  by  changes  in  the  temperature  of  the  absorbing 
organs,  as  the  roots  of  the  higher  plants.  Thus  Sachs 
found  ''that  the  roots  of  the  tobacco-plant  and  gourd  no 


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TBMPEBATUBK  185 

longer  absorb  suflScient  water  to  replace  a  small  loss  by  evap- 
oration in  a  moist  soil,  having  a  temperature  of  from  3°  to 
5°  Cent  (37''  to  41**  Fahr.) ;  the  heating  of  the  soil  to  a  tem- 
perature of  from  12°  to  18°  Cent.  (53°  to  64°  Fahr.)  sufficed 
to  raise  their  activity  to  the  needful  extent."*  According 
to  the  same  investigator,  the  roots  of  the  turnip  and  cabbage 
continue  to  absorb  water,  even  when  the  temperature  of  the 
soil  is  reduced  very  nearly  to  0°  Cent.  (32°  Fahr.).  In  the 
winter  and  early  spring,  when  the  temperature  of  the  soil  is 
low,  the  roots  of  trees  and  other  perennials  cannot  absorb 
moisture  unless  they  extend  deep  enough  to  reach  the 
warmer  strata  beneath  ;  under  such  circumstances,  it  not  in- 
frequently happens  that  if  the  air  temperature  rise  high 
enough  to  allow  evaporation,  evergreen  trees  and  shrubs  are 
killed  by  too  great  loss  of  moisture. 

243.— Evaporation  or  Transpiration.  In  aerial  plants, 
when  the  temperature  of  the  air  is  low,  but  little  evaporation 
takes  place  from  the  leaves  or  other  living  organs,  while  an 
increase  of  temperature  is. followed  by  an  increase  in  the 
rapidity  of  evaporation.  It  is  probable  that  this  is  due  (Ist) 
to  the  closing  of  the  stomata  in  the  lower,  and  their  opening 
m  the  higher  temperature,  and  (2d)  to  the  fact  that  in  all 
ordinary  cases,  as  the  temperature  of  the  air  is  lowered  its 
degree  of  saturation  is  increased,  and  as  its  temperature  is 
raised  its  degree  of  saturation  is  decreased.  As  transpiration 
appears  to  be  a  purely  physical  phenomenon,  we  scarcely 
need  expect  it  to  be  as  definitely  or  certainly  affected  by 
changes  of  temperature  as  are  the  proper  functions  of  the 
plant. 

244.— Assunilation.  The  lower  limit  of  the  temperature 
in  which  assimilation  is  possible  varies  much  in  different 
plants.  The  "Bed-snow  Plant"  {Protococcus,  sp.)  of  the 
Arctic  regions  grows  rapidly  upon  the  surface  of  the  snow  in 
a  temperature  which  must  be  little,  if  any,  above  0°  Cent. 
(32°  Fahr.) ;  in  the  larch,  assimilation  takes  place  at  from 
0.5°  to  2.5°  Cent.  (33°  to  36°  Fahr.),  and  in  meadow-grasses 
at  from  1.5°  to  3.5°  Cent.  (35°  to  38°  Fahr.).     In  water- 

♦  -  Lelirbucli,"  English  ediUon,  p.  052. 


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186  BOTANY. 

plants  the  lower  temperature  limit  is  apparently  somewhat 
higher  than  in  aerial  ones  ;  thus  in  Hottonia  palustris  it  is 
2.7^  Cent  (37°  Fahr.) ;  in  Vallisneria,  6°  Cent,  or  more  (42* 
Fahr.) ;  in  Potamogeton  from  10°  to  16°  Cent  (60°  to  69* 
Fahr.). 

Neither  the  maximum  nor  the  optimum  temperature  has 
been  determined  for  ordinary  land  plants  ;  in  Hottonia 
palustris,  an  aquatic  plant,  the  maximum  temperature  for 
assimilation  is,  according  to  Sachs,  between  60°  and  66* 
Cent  (122°  and  132°  Fahr.). 

246 .— Metastasis.  But  little  is  accurately  known  as  to 
the  effect  of  an  increase  or  decrease  of  temperature,  within 
moderate  ranges,  upon  those  metastatic  changes  which  take 
place  in  the  ordinary  growth  of  plants  or  the  storing  of  reserve 
material.  It  is  well  known,  however,  that  some  plants  live 
wholly  in  low  temperatures,  performing  all  their  functions 
in  air  or  water  little,  if  any,  above  the  freezing  point 
Thus  in  the  "  Eed-snow  Plant,"  above  cited,  the  metas- 
tatic changes  must  take  place  very  near  0°  Cent 

In  the  polar  waters,  where  the  temperature  is  from  3°  ta 
5°  Cent  (37°  to  41°  Fahr.),  or  even  less,  myriads  of  diatoms 
flourish,  and  in  seas  but  little  warmer  many  of  the  higher 
sea-weeds  (Fucaceae  and  Florideae)  abound.  In  all  these 
cases  the  metastatic  changes  (as  well  as  all  others)  must  take 
place  at  these  low  temperatures.  In  ordinary  land-plants  it 
is  to  be  observed  that  whereas  assimilation  takes  place  only 
during  the  light  part  of  the  day,  when  it  is  warmer,  metasta- 
sis takes  place  not  only  in  daylight,  but  even  more  rapidly  in. 
darkness,  when  the  temperature  is  considerably  lower.* 

Sachs  measured  the  length  of  plumule  developed  upon 
different  plants  of  the  same  species  subjected  to  different 
temperatures,  and  in  this  way  found  the  approximate  optima 
for  several  species,  as  follows  :t 

*  It  must  not  be  forgotten,  however,  that  assimilation  is  dependent 
upon  light,  while  metastasis  is  somewhat  checked  hy  it,  and  this  is 
doubtless  by  far  the  most  important  relation  ;  and  still  it  is  a  significant 
fact  that  in  ordinary  land-plants  metastasis  continues  when  assimi- 
lation has  stopped. 

fin  " Physiologische  Untersuchungen  Aber  die  Abhftng^gkeit  der 


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TEMPERATURE. 


187 


Pea 26°  Cent.  (78.8'  Pahr.). 

Wheat  (winter  var.) 34^*     **     (93.7°     " 

Indlancorn 84'*     "     (92.7**     " 

ScarletBean 84*     *'     (92.7'»     « 

In  Sachs'  and  others'  observations  upon  the  growth  of 
roots,  it  waa  found  that  the  most  rapid  growth  took  place 
for  different  plants  at  the  following  temperatures  : 

Scarlet  Bean 26**  Cent.  (78.8*  Fahr.). 

Pea 26.6*'  '•     (79.9**     " 

Flax 27.4"  "     (SLS**     " 

Wheat  (winter  var.) 28.5°  **     (83.8°     " 

Barley  (summer  var.) 28.5°  **     (83.8°     " 

Indlancorn 84°      **     (92.7°     - 

In  the  deposit  of  reserve  material  there  can  be  no  doubt 
that  metastasis  often  takes  place  at  lower  temperatures  than 
assimilation  ;  thus  the  storing  of  starch  in  the  potato  tubers, 
and  in  many  other  subterranean  stems  and  roots,  takes  place 
in  the  soil  which,  at  the  time,  is  much  cooler  than  the  air. 

In  the  growth  of  many  plants  in  early  spring,  at  the  ex- 
pense of  reserve  material  in  the  roots  or  stems,  the  metas- 
tatic changes  often  take  place  at  quite  low  temperatures. 
Thus  perennial  and  biennial  rooted  plants,  as  many  grasses, 
thistles,  parsnips,  etc.,  begin  to  grow  almost  as  soon  as  the 
snow  has  disappeared,  and  the  flower  buds  of  many  perenni- 
als develop  equally  early — e,g.y  the  hazel,  elm,  maple,  liver- 
leaf  {Hepatica)y  Mayflower,  etc. 

As  regards  the  metastatic  changes  which  take  place  in  the 
germination  of  seeds,  we  have  much  more  definite  informa- 
tion. Sachs  has  determined  the  minimum,  optimum,  and 
maximum  temperatures  for  the  germination  of  the  seeds  of 
the  following  plants  :* 


Ind.  com. 
Scar.  B*n.. 
Pumpkin. 
Wheat... 
Barley... 


MiNIMTTM. 


9.4°  C.=  (48.8°  P.). 
9.4°  C.=  (48.8°  F.). 
14°  C.=  (56.7°F.). 
6°  C.=  (41°  F.). 
5°    C.=  (4r    F.). 


OpmcuH. 


34°  C.  =  (92  7° 
34°  C.  =  (92.7° 
34°  C.  =(92.7° 
29°  C.  =  (88.7° 
29°  C.  =  (83.7° 


F.). 
F.). 
F). 
F.). 


Maximum. 


46°  C.  =  (116.2°  F). 
46°  C.  ^(116.2'F.). 
46°  C.  =  (115.2°  F.). 
42°  C.  =  (108.5°  F.). 


F.).37°C.  =(  99.5°  F.). 


Keimung  yon  der  Temperature,"  in  '*  Pringshelm's  JahrbQcher  fOr 
Wiasenschaftliche  Botanik,"  Vol.  II.,  1860,  p.  854. 
*  "  Physiologische  Untereuchungen,"  etc.,  op.  cit.,  p.  865. 


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188  BOTANF. 

According  to  seyeral  observers,  the  minima  and  optima 
for  the  germination  of  the  seeds  of  the  following  plants  are : 


MiKIMIJM. 

Optimum. 

Lepidiam  sativum 

Flax 

White  Mustard 

Pea 

Pole  Bean 

1.8*  C.  =  (35*  Fahr.). 
1.8*  C.  =  (85*      ** 
0.0°  C.  =  (32*      " 
0.7^  C.  =  (43*      " 

27.4*  C.   =  (81*  Fi 
27.4*  C.   =  (81* 
27.4*  C,   =  (81* 
26.6*  C.   =  (80* 
31.5*  •  .   =  (88.7* 
31.5*  C    =  (88.7* 
31.5*  C.   =  (88.r 
37.5*  C.  =  (99.5*  ' 

ibr.). 
(( 

ft 

• 
< 

Sunflower 

Hemp, 

It 

tt 

Watermelon.. 

t 

246.~Death  Caused  by  High  Temperature.  When  the 
temperature  rises  above  a  certain  point  the  death  of  the 
plant  takes  place.  Those  plants,  or  parts  of  plants,  which 
contain  the  least  water  are  capable  of  enduring  higher  tem- 
peratures than  those  which  are  more  watery.  Thus  at  from 
66^  to  80°  Cent.  (149°  to  177°  Fahr.)  many  dry  spores  and 
seeds  are  uninjured,  while  in  water  they  are  generally  killed 
when  the  temperature  exceeds  50°  or  55°  Cent.  (122°  or  131° 
Fahr.).  For  ordinary  growing  parts  of  plants  the  tempera- 
ture must  be,  as  a  rule,  considerably  lower  than  those  given 
above.  Few  aquatic  plants  can  endure  a  prolonged  tempera- 
ture much,  if  any,  above  40°  Cent.  (104°  Fahr.),  and  at  50° 
Cent.  (122°  Fahr.)  most  terrestrial  plants  are  soon  killed. 
It  appears,  also,  that  at  temperatures  much  lower  than  these 
some  plants  arc  killed ;  thus,  according  to  Hofmeister,*  the 
organization  of  the  protoplasm  of  the  plasmodium  of  Didy- 
mium  serpula  (one  of  the  Slime  Moulds)  is  destroyed  by 
heating  it,  in  air,  to  35°  Cent.  (95°  Fahr.),  and  in  the  nearly 
related  Fuligo  variaiis  the  same  destruction  follows  at  39° 
Cent.  (102°  Fahr.). 

The  immediate  cause  of  death  appears  to  be  the  coagula- 
tion of  the  albuminoids  of  the  protoplasm.  The  protoplasm 
thus  loses  its  power  of  imbibing  water,  and  the  cells  conse- 
quently lose  their  turgidity.  In  watery  tissues  chemical 
changes  at  once  begin,  resulting  in  the  rapid  disintegration 

♦  "  Die  Lehre  von  der  Pflanzenzelle,"  1867,  p.  27. 


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TEMPERATURE,  189 

of  the  substances  in  the  cells,  accompanied  by  an  evolution 
of  carbon  dioxide. 

247.— Death  Caused  by  Iiow  Temperature.  In  many 
respects  the  results  of  too  great  a  reduction  of  temperature 
are  similar  to  those  produced  by  too  great  an  elevation. 
There  is  observed  the  same  coagulation  of  the  albuminoids, 
resulting  in  the  destruction  of  the  power  of  the  protoplasm 
to  imbibe  water,  and,  as  a  consequence,  in  the  loss  of  the  tur- 
gidity  of  the  cells.  Moreover,  as  in  the  case  of  injury  from 
high  temperature,  those  cells  which  are  the  most  watery  are 
the  ones  which,  other  things  being  equal,  are  injured  most 
quickly  by  a  i*eduction  of  temperature.  Embryo  plants  in 
seeds,  when  dry,  are  able  to  endure  almost  any  degree  of  low 
temperature  ;  but  after  they  have  germinated,  and  the  cells 
have  become  watery,  they  are  generally  killed  by  a  reduction 
to,  or  a  few  degrees  below,  0°  Cent.  (32''  Fahr.).  So,  too, 
the  comparatively  dry  tissues  of  the  winter  buds  and  ripened 
stems  of  the  native  trees  and  shrubs  in  cold  countries  are 
rarely  injured  even  in  the  severest  winters,  while  the  young 
leaves  and  shoots  in  the  spring  are  often  killed  by  slight 
frosts. 

Death  from  low  temperature  is  always  accompanied  by  the 
formation  of  ice-crystals  in  the  succulent  tissues  ;  these  are 
formed  from  the  water  of  the  plant,  which  is  abstracted  from 
it  in  the  process  of  congelation.  Much  of  the  water  thus 
frozen  is  that  which  fills  the  cavities  (vacuoles)  of  the  cells, 
while  some  of  it  is  that  which  moistens  the  protoplasm  and 
cell-walls.  Now  it  is  evident  that  the  water  in  the  large 
vacuoles  is  much  more  easily  congealed  than  that  in  the  pro- 
toplasm and  cell- walls ;  for  in  the  latter  the  force  of  adhesion 
between  the  molecules  of  protoplasm  or  cellulose  and  the 
imbibed  water  offers  a  considerable  resistance  to  the  separa- 
tion of  the  water  in  ice-crystals,  and  this  resistance  is  greater 
as  the  contained  water  is  less.  As  the  liquid  in  the  vacuoles 
is  not  pure  water,  but  a  mixture  of  several  solutions,  it  freezes 
at  a  lower  temperature  than  water,  and  then,  according  to  a 
well-known  law  of  physics,  separates  into  pure  ice-crystals 
and  a  denser  unfrozen  solution.  By  a  greater  reduction  of 
temperature  more  ice-crystals  may  be  separated  out,  and  the 


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190  BOTANY. 

remaining  solution  made  denser  stilL  These  adhesive  forces 
tend  to  retard  the  formation  of  ice-crystals,  and  it  is  prob- 
able that  it  is  only  in  extremely  low  temperatures,  if  at  all, 
that  the  liquids  in  the  plant  are  completely  solidified. 

248. — A  plant  which  has  been  frozen  may  survive  in  many 
instances  if  thawed  slowly,  whereas  if  thawed  quickly  its 
vitality  is  generally  destroyed.  Thus  many  herbaceous 
plants  will  endure  quite  severe  freezing  if  they  are  afterward 
covered  so  as  to  secure  a  slow  rise  of  the  temperature,  and 
many  bulbs,  tubers,  and  roots  will  survive  the  severest  win- 
ters if  covered  deeply  enough  to  prevent  sudden  thawing. 
Likewise  turgid  tissues,  which  are  not  living,  as  those  of 
many  succulent  fruits,  are  injured  or  not  by  freezing,  accord- 
ing as  the  thawing  has  been  rapid  or  slow.  From  these  facts 
it  may  be  inferred  that  the  injury  in  freezing  is  primarily  of 
a  physical  instead  of  a  chemical  nature,  and  that  it  is  mainly 
the  withdrawal  of  water  from  its  physical  union  with  the 
solids  of  the  cell.  According  to  this  view,  the  difference  be- 
tween slow  and  rapid  thawing  is  that  in  the  former  the 
slowly  liquefying  water  is  reabsorbed  by  the  same  solids  from 
which  it  had  been  abstracted,  while  in  the  latter  the  large 
amount  of  water  set  free  is  imperfectly  absorbed,  forming 
solutions  which  are  unstable  and  subject  to  subsequent  fer- 
mentive  changes.  It  is  probable  that  to  these  fermentive 
changes  is  due  the  coagulation  of  the  albuminoids  and 
the  rapid  disorganization  of  the  protoplasm  which  accom- 
pany injury  from  freezing. 

While  the  sketch  given  above  is  doubtless  true  in  a  large 
number  of  cases,  it  appears  that  in  many  other  cases  death 
follows  freezing  whether  the  thawing  be  rapid  or  not ;  and 
this  indicates  that  besides  the  immediate  causes  of  death  al- 
ready indicated,  there  are  others  which  are  as  yet  unknown 
to  us. 

§  II.  Light. 

249.— Qeneral  Belations.  Directly  or  indirectly  plant- 
life,  as  indeed  all  life,  whether  vegetable  or  animal,  is  de- 
pendent upon  light.     Parasites  and  saprophytes  may  grow 


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LIGHT.  191 

in  complete  darkness,  but  they  do  so  at  the  expense  of  ma- 
terial which  has  been  elaborated  in  light.  So,  too,  some 
parts  of  many  ordinary  plants  grow  in  total  darkness,  as 
roots,  tubers,  bulbs,  etc.,  but  these  depend  for  their  carbo- 
hydrates upon  the  aerial,  chlorophyll-bearing  parts  which 
are  in  the  light.  As  will  be  shown  in  the  sequel,  this  depen- 
dence of  all  life  upon  light  is  due  to  its  relation  to  chloro- 
phyll in  the  processes  of  assimilation  ;  and  while  other  func- 
tions than  that  of  assimilation  and  other  orgars  than  those 
which  contain  chlorophyll  are  somewhat  affected  by  the 
presence  or  absence  of  light,  or  its  greater  or  less  intensity, 
yet  these  latter  are  of  comparatively  little  moment  when  com- 
pared with  the  former. 

The  absorption  of  water  by  the  plant  appears  to  be  entirely 
independent  of  light,  and  in  most  plants  it  takes  place  in  its 
entire  absence.  Likewise  it  is  probable  that  light  itself  does 
not  directly  affect  the  rate  of  evaporation  of  water  from  the 
leaves  of  higher  plants.  As,  however,  the  stomata  are  gen- 
erally opened  more  widely  in  light  than  in  darkness,  evapo- 
ration may  be  promoted  by  it  in  some  cases. 

260.— Light  and  Assimilation.  It  is  first  of  all  to  be 
observed  that  chlorophyll  itself  is  dependent  upon  light. 
Those  parts  of  plants  (with  rare  exceptions)  which  grow  in 
darkness  are  destitute  of  chlorophyll,  and  even  parts  which 
contain  chlorophyll  lose  it  when  placed  for  some  time  in  com- 
plete darkness.  When  such  a  colorless  plant  is  brought  into 
the  light  it  soon  becomes  green  from  the  formation  of  chlo- 
rophyll in  its  protoplasm. 

The  decomposition  of  carbon  dioxide,  and  the  consequent 
evolution  of  oxygen,  only  take  place  in  the  light.  As  the 
light  decreases  in  intensity  from  a  certain  point  the  amount 
of  assimilation  decreases  ;  on  the  other  hand,  there  is  a  de- 
crease in  assimilation  as  the  intensity  increases  unduly,  and 
beyond  certain  points  in  either  direction  assimilation  ceases. 
Thus  there  are  here,  as  in  the  case  of  temperature,  a  mini- 
mum, optimum,  and  maximum  ;  but  we  cannot  define  their 
limits  as  readily,  for  want  of  a  proper  instrument. 

261. — Experiments  have  often  been  made  upon  plants 
when  placed  in  rays  of  different  refrangibility,  and  it  has 


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192  BOTANY. 

been  sliown  (1)  that  the  assimilation  is  greater  in  the  whole 
beam  (white  light)  than  in  any  one  of  its  constituent  rays, 
and  (2)  that  the  amount  of  assimilation  varies  greatly  in  the 
different  rays.*  When  plants  are  grown  in  the  different 
rays  of  the  spectnim,  and  properly  protected,  so  tliat  each 
receives  but  one  kind  of  light,  the  amount  of  assimilation  in 
each  case  is  about  as  follows,  that  for  white  light  being  100  : 

Red.      Orange,      Yellow,      Green,      Blue,      Indigo,      Violet, 
9.5  28.5  87.3  14.  8.2  5.  2.5 

The  less  refrangible  rays  are  thus  seen  to  be  far  more  effica- 
cious than  the  more  refrangible  ones,  and  in  the  yellow  and 
orange  rays,  which  are  the  brightest  to  the  eye,  the  greatest 
amount  of  assimilation  takes  place.  From  these  rays  there 
is  a  decrease  toward  each  end  of  the  visible  spectrum,  and  in 
the  so-called  heat  rays  and  chemical  rays,  found  respectively 
beyond  the  red  on  the  one  hand  and  the  violet  on  the  other, 
there  is  no  assimilation  whatever. 

262.— Light  and  Metastasis.  Many  of  the  metastatic 
changes  in  the  plant  take  place  in  complete  darkness,  such 
as  those  connected  with  the  growth  of  roots  and  other  sub- 
terranean organs.  In  trees  and  thick-barked  shrubs  the  metas- 
tatic changes  which  occur  in  the  stems  are  in  total  darkness, 
and  even  in  many  herbs  the  thick  cortical  tissues  must  cut 
off  the  greater  part  of  the  light  from  the  active  interior  cells. 
On  the  other  hand,  in  a  great  number  of  aquatic  plants  their 
translucency  is  so  great  that  every  internal  change  must  be 
in  bright  light,  and  in  a  few  terrestrial  plants — as,  for  ex- 
ample, in  Impatiem  Bahamhm — the  cortical  tissues  permit 
most  of  the  light  to  penetrate  to  the  inner  active  cells.  These 
facts  indicate  a  marked  indifference  of  the  metastatic  changes 
to  light,  as  compared  with  those  of  assimilation. 

This  indifference  is  further  illustrated  in  the  gix)wth  of 
flowers  in  the  dark,  where,  with  few  exceptions,  they  develop 
as  perfectly  as  in  the  light  So  the  colorless  parasites — tf.^r., 
Monotropay  AphylloUy  Corallorhiza,  etc. — and  all  the  fungi 

*  The  earliest  experiments  of  much  value  were  those  of  Charles 
Daubeny,  "  On  the  Action  of  Li^ht  upon  Plants,  and  of  Plants  upon 
the  Atmosphere,"  pub.  in  PhU,  Tram.,  1886. 


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HELIOTBOPISM.  193 

glow  either  in  light  or  darkness.  It  must  not  be  inf  erred, 
however,  that  there  is  a  complete  indifference  to  the  presence 
or  absence  of  light,  for  careful  experiments  show  that  light 
favors  some  metastatic  changes,  while  in  many  cases  it  actu- 
ally exerts  a  retarding  influence.  Thus  if  aU  other  condi- 
tions, as  temperature,  moisture,  etc.,  are  made  constant,  the 
rapidity  of  growth  of  most  aerial  stems  is  considerably  greater 
in  darkness  than  in  light ;  while  under  similar  conditions 
the  growth  of  the  leaves  of  most  plants  is  less.  Experiments 
show  that  the  retardation  of  growth  is  due  to  the  rays  of 
high  refrangibility,  blue,  indigo,  violet,  and  ultra  violet,  and 
that,  60  far  aa  the  metastatic  changes  under  consideration 
are  concerned,  the  less  refi*angible  rays  are  equivalent  to 
darkness. 

§IIL  Heliotropism. 

268. — The  retarding  influence  of  light  upon  the  growth 
of  stems  gives  rise  to  a  curvature  when  the  illumination  is 
stronger  upon  one  side  than  upon  the  other.  Thus,  as  is 
well  known,  most  plants,  when  grown  in  windows,  bend 
strongly  toward  the  light,  and  if  their  position  be  afterward 
reversed  they  soon  bend  again  toward  the  side  of  greatest 
illumination.  To  this  phenomenon,  which  is  an  exceedingly 
common  one  throughout  the  vegetable  kingdom,  the  name 
Heliotropism*  has  been  given.  The  explanation  which  is 
commonly  given  is  that  the  light  retards  the  growth  on  the 
illuminated  side,  while  the  shaded  side  elongates,  resulting 
in  a  tension  which  necessarily  produces  a  curvature. 

264. — ^Evidently  allied  in  some  way  to  heliotropism  is  the 
bending  of  certain  organs  away  from  the  light.  Thus  the 
leafless  stems  (runners)  of  Saxifraga  sarmentosa,  when  grown 
in  a  window  so  that  they  are  illuminated  upon  one  side  more 
strongly  than  upon  the  other,  curve  toward  the  darker  side. 
This  opposite  bending  has  been  called  Negative  Heliotro- 
pism, and  is  supposed  to  be  caused  by  light  in  some  way  not 
yet  understood.      The  tendrils  of  the  Vine  and  Virginia 

*  From  the  Greek  i^^oS,  the  bud,  and  rpeireiv,  to  turn. 


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194  BOTANY. 

Creeper  (Ampehpsis)  are  negatively  heliotropic,  and  they 
are  thus  enabled  to  reach  and  attach  themselves  to  the  sur- 
faces— e.g.,  walls,  tree-trunks,  etc. — which  give  them  sup- 
port. The  same  organ  may  be  positively  heliotropic  in  one 
stage  of  its  growth  and  negatively  so  in  another  ;  thus  the 
younger  intemodes  of  the  ivy  {Hedera)  bend  toward  the 
light,  and  the  older  ones  away  from  it ;  and  the  runners  of 
Saxifraga  sarmentosa,  mentioned  above,  are  positively  he- 
liotropic as  soon  as  they  develop  tufts  of  leaves  upon  their 
free  extremities. 

The  rays  of  light  which  cause  the  curvature  are  those 
having  the  greatest  refrangibility.  Sachs'  experiment  shows 
this  conclusively ;  he  grew  plants  in  light  which  had  passed, 
on  the  one  hand,  through  a  solution  of  potassium  bichro- 
mate, and,  on  the  other,  through  one  of  ammoniacal  copper 
oxide ;  in  the  light  passed  through  the  first  solution  (red, 
orange,  and  yellow  rays,  and  a  portion  of  the  green)  there 
was  no  curvature  whatever,  while  in  the  blue,  indigo,  and 
violet  rays  passed  through  the  second  solution  the  heliotro- 
pic curvature  was  strongly  shown. 

§  rV.  Geotropism. 

266. — ^Nearly  all  organs  of  plants  have  a  definite,  normal 
direction  of  growth,  which  is  in  general  terms,  either  toward 
or  away  from  the  earth.  Thus  the  Plasmodium  of  Fuligo 
varians  creeps  upward ;  the  conidia-bearing  hyphae  of  moulds 
grow  upward,  while  the  root-like  hyphae  grow  downward  ;  the 
stems  of  many  mosses  grow  upward,  and  their  rhizoids  down- 
ward ;  in  the  higher  plants  the  stems,  as  a  rule,  grow  upward, 
some  root-stocks  and  other  stems  growing  downward,  how- 
ever, while  the  roots,  as  a  rule,  grow  downward.  To  these 
phenomena  of  growth  the  name  Geotropism*  has  been 
given  ;  when  the  direction  of  growth  is  downward,  the  organ 
is  said  to  be  positively  geotropic,  when  upward,  negatively 
geotropic. 

Knight  long  ago  proved  gravitation  to  be  the  cause  of 

*  From  the  Greek  yii,  yia,  the  earth,  and  rpiiresv,  to  tarn. 


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OE0TB0PI8M.  195 

geoiaropism.*  He  placed  germinating  seeds  upon  wheels, 
which  were  made  to  rotate  rapidly,  in  one  series  of  experi- 
ments in  a  vertical,  and  in  the  other  in  a  horizontal  direction. 
In  the  first  case  he  found  that  the  roots  grew  directly  away 
from  the  centre  of  the  wheel,  and  the  stems  toward  it — ^that 
is,  haying  in  his  experiment  substituted  centrifugal  force  for 
grayitation,  leaving  all  other  condition^  unchanged,  he  found 
that  the  root  grew  in  the  direction  of  that  force,  and  the 
stem  opposite  to  it.  In  the  second  series  of  experiments,  in 
which  grayitation  and  centrifugal  force  were  made  to  act  at 
right  angles  to  each  other  upon  the  growing  plantlets,  the 
direction  of  growth  coincided  with  that  of  the  diagonal  of 
the  two  forces,  the  roots  growing  diagonally  outward  and 
downward,  the  stems  inward  and  upward.  Dutrochet  after- 
ward showed,  by  similar  experiments,  that  many  leaves  are 
geotropic,  turning  their  under  surfaces  toward  the  circum- 
ference, and  their  upper  toward  the  centre  of  the  wheel,  f 

256. — ^If  positively  and  negatively  geotropic  organs  are 
placed  in  what  may  be  termed  their  normal  positions,  they 
grow  on  the  one  hand  downward  and  on  the  other  upward, 
without  any  curvature,  and  in  such  case  the  cells  in  all  parts 
of  any  section  of  either  the  ascending  or  descending  portions 
ahow  a  symmetrical  development.  But  if  such  symmetrically 
developed  positively  and  negatively  geotropic  organs  are  af- 
terward placed  in  a  reversed  or  horizontal  position,  they 
will  become  considerably  curved  in  order  to  assume  their 
normal  positions.  Thus  the  first  roots  of  most  young  plants, 
if  placed  horizontally,  soon  become  curved  downward  near 
their  tips  ;  this  takes  place  even  when  there  is  considerable 
resistance  to  the  curvature,  as  is  shown  by  the  penetration 
of  roots  into  mercury.  A  similar  curvature  in  an  upward 
direction,  however,  takes  place  in  most  stems  when  placed 
horizontally ;  in  grasses  the  curvature  is  almost  entirely  con- 
fined to  the  nodes.  In  such  curved  parts  of  roots  and  stems 
the  cells  are  more  elongated  upon  the  convex  than  upon 

*  "On  the  Direction  of  tlie  Radicle  and  Plumule  daring  the  Vegeta- 
tion of  Seeds."    PhUosophieal  TransaeUom,  1806. 
t "  Memoiree,"  Paris,  1887. 


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196  BOTANY. 

ihe  concave  side,  and  it  is  evident  that  this  is  the  immediate 
cause  of  the  bending.  We  do  not,  however,  know  how  grav- 
itation causes  this  inequality  in  the  growth  of  the  cells, 
and  the  problem  is  the  more  difficult  from  the  fact  that  the 
more  rapid  elongation  of  the  cells  is  in  one  case  upon  the 
upper  and  in  the  other  upon  the  under  side  of  the  organ. 
Moreover,  in  "  weeping  trees  "  the  branches  are  positively,  in- 
stead of  negatively,  geotropic,  although  we  know  of  no  struc- 
tural diflEerence  between  these  and  the  branches  of  ordinary 
trees. 

§  V.  Certain  Movements  of  Plants. 

257. — ^Under  this  head  are  to  be  considered  a  few  only  of 
the  more  important  movements  in  plants.  It  must  be  remem- 
bered that  living  protoplasm  has  everywhere,  under  proper 
conditions,  the  power  of  spontaneous  movement.  In  the 
lower  forms  of  vegetation  this  results  in  visible  movements, 
which  are  of  common  occurrence  ;  but  in  the  greater  part 
of  the  vegetable  kingdom,  while  the  protoplasm  is  doubt- 
less as  active,  the  cell-walls  which  enclose  it  are  so  rigid  that 
its  physical  activity  is  incapable  of  producing  external  move- 
ment. Thus  most  parts  of  ordinary  plants  do  not  perform 
movements  which  are  the  direct  results  of  the  physical  activ- 
ity of  the  protoplasm  ;  but  this  is  not  because  of  a  want  of 
activity  in  the  protoplasm,  but  mainly  from  the  rigidity  of 
the  walls  surrounding  it.  In  a  comparatively  small  number 
of  instances,  however,  the  structure  of  the  organs  of  even 
the  higher  plants  is  such  that  movements  directly  due  to  pro- 
toplasmic activity  are  performed.  Such  are  the  so-called 
spontaneous  movements  of  the  leaves  of  some  plants,  and 
those  dependent  upon  external  stimuli,  as  light,  heat,  me- 
chanical irritation,  etc.,  which  have  been  called  paratonio 
movements. 

268.— SpontaneouB  Movements.  The  most  remarkable 
case  of  movements  apparently  not  dependent  upon  external 
agents  is  that  of  the  leaves  of  Desmodium  gyrans^  an  Indian 
plant.  The  small  lateral  leaflets  of  the  trifoliate  leaf  bend 
upon  their  slender  stalks  (petiolules)  in  such  a  way  that  their 


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MOVBMENTti  OF  PLANTS.  197 

apices  describe  nearly  a  circle.  A  reyolution  occapies  from 
two  to  five  minutes  if  the  temperature  is  above  22°  Gent. 
(73®  Fahr.).  This  continues,  when  the  conditions  are  other- 
wise favorable,  in  darkness  as  well  as  in  the  light  Other  less 
noticeable  movements  of  this  nature  occur  in  many  plants — 
$.g.y  Clover,  Mimosa,  Oxalis — but  they  are  often  hidden  by  the 
more  marked  movements  due  to  other  causes.  The  active 
portion  of  the  moving  organ  (in  the  cases  cited  above,  a  por- 
tion of  the  leaf -stalk)  consists  of  a  tissue  composed  of  thin- 
walled  cells,  forming,  in  many  cases,  a  thickened  **  pulvinus.** 
The  cells  are  targid  and  the  tissues  are  in  a  state  of  tension. 
When  movements  occur,  it  appears  that  the  protoplasm  in 
certain  layers  of  cells  permits  the  escape  into  the  intercellu- 
lar spaces  of  a  portion  of  the  water  of  the  vacuoles ;  it  is, 
however,  quickly  absorbed  again  and  the  cells  rendered 
thereby  turgid,  while  the  escape  of  water  takes  place  in 
contiguous  layers,  to  be  quickly  absorbed  again,  and  so  on 
regularly  around  the  axis  of  the  contracting  organ. 

269.— Movements  Dependent  upon  External  Stimuli* 
These  are  exhibited  by  many  parts  of  the  higher  plants — e.g., 
leaves  in  Mimosa  (the  Sensitive  Plant),  Cassia,  Clover^ 
Oxalis,  Dionsea,  etc.,  stamens  of  many  CompositsB,  of  Bar* 
berry,  Portulaca,  etc.,  stigmas  of  Martynia,  Mimulus,  etc* 
In  the  Sensitive  Plant,  the  leaves,  when  touched  roughly  or 
jarred,  close  up  quickly  by  the  secondary  leaflets  moving 
upward  and  forward,  so  that  the  upper  surfaces  of  the 
pairs  are  approximated  to  each  other;  next,  the  primary 
leaflets  bend  downward,  and  at  the  same  time  approach  each 
other,  and  finally  the  whole  leaf  bends  downward.  The 
movements  are  in  all  cases  at  the  bases  of  the  organs,  where 
tissues  are  developed  similar  to  those  in  the  spontaneously 
moving  organs  (paragraph  258).  In  the  other  cases  essen- 
tially the  same  movements  and  mechanism  are  found.  When 
the  movements  occur,  there  is  an  escape  of  the  water  of  the 
vacuoles  from  the  cells  in  one  side  of  the  organ,  and  this 
side  is,  as  a  consequence,  shortened  and  made  concave. 
After  a  time  the  water  is  reabsorbed  and  the  organ  resumes 
its  normal  position.  In  addition  to  the  mechanical  stimuli 
of  jarring,  concussion,  etc.,  greater  or  less  amounts  of  lights 


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198  BOTANT. 

increase  or  decree  of  temperature^  and  electrical  discharges, 
may  cause  movements.  Those  movements  which  are  brought 
about  by  changes  in  the  amount  of  light  constitute  what  are 
known  as  the  "  sleep"  and  **  waking"  of  plants.  Thus  the 
leaves  of  the  Sensitive  Plant  close  up  in  darkness  exactly  as 
from  a  concussion,  but  they  remain  closed  until  the  reap- 
pearance of  the  light 

260. — The  power  of  movement,  whether  spontaneous  or 
paratonic,  may  be  temporarily  suspended  by  certain  external 
conditions.  Thus,  according  to  Sachs,  transitory  rigidity 
or  immobility  takes  place  under  the  following  conditions  : 

1.  Low  Temperature.  In  Mimosa  pudica  rigidity  com- 
mences at  about  15°  Cent.  (59°  Fahr.),  in  Desmodium  gyrans 
at  about  22°  Cent  (72°  Fahr.). 

2.  High  Temperature.  Mimosa  slowly  becomes  rigid  at 
40°  Cent  (104°  Fahr.),  and  very  quickly  at  50°  Cent  (122° 
Fuhr.). 

3.  Darkness.  Long  exposure  to  darkness  (twenty-four 
hours  or  more)  produces  a  rigidity  which  is  only  removed  by 
a  long  exposure  to  light 

4.  Insufficient  Moisture.  When  the  supply  of  water  to 
the  roots  of  the  Sensitive  Plant  is  too  little,  a  partial,  and 
sometimes  almost  complete,  immobility  is  produced,  which  is 
soon  removed,  however,  by  copious  watering. 

5.  hisufficient  Supply  of  Oxygen.  In  a  vacuum,  or  in  an 
atmosphere  of  nitrogen,  hydrogen,  ammoniacal  gas,  etc.^ 
motile  organs  become  immobile.  On  the  other  hand,  in 
pure  oxygen  rigidity  takes  place  also. 

6.  Ancesthetics.  In  the  vapor  of  ether  or  chloroform  the 
leaves  of  the  Sensitive  Plant  become  immobile,  but  in  the 
air  they  soon  regain  their  motility. 

Mr.  Darwin's  experiments*  upon  the  leaves  of  Drosera  and 
Dionaea  are  confirmatory  of  the  foregoing  statements.  The 
sensitive  tentacles  of  the  former  and  leaf -blades  of  the  lat- 
ter were  rendered  insensible  to  the  peculiar  stimulus  of  con- 
tact with  soluble  nitrogenous  bodies  when  subjected  to  most 
of  the  above-mentioned  conditions. 

**<  Insectivoroofl  Plants."    London,  1875.    Chap.  IV.,  DC,  and  Xm. 


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MOVEMENTS  OF  PLANTS.  199 

These  facts  indicate  the  correctness  of  the  ylew  that  the 
movements  are  the  results  of  the  motility  of  the  protoplasm. 
261.— Movements  of  Nutation.  In  the  organs  of  many 
plants  an  inequality  of  growth  is  often  noticeable,  one  side 
growing  for  a  time  more  rapidly  than  the  other.  If  this  is 
followed  by  a  more  rapid  growth  upon  the  other  side,  and  this 
again  by  a  more  rapid  growth  upon  the  first  side,  and  so  on, 
alternating  from  side  to  side,  simple  movements  of  nutation 
will  take  place,  the  apex  of  the  organ  swaying  or  oscillating 
from  side  to  side  in  one  plane.  If  the  tracts  of  unequal 
growth  pass  slowly  and  regularly  around  the  organ,  its  apex 
will  describe  a  circle  in  its  nutation. 

Of  simple  nutation  in  one  plane  many  leaves  afford  good 
examples  ;  thus  in  the  bud  the  growth  is  greatest  upon  the 
outer  or  under  side  of  each  leaf,  which,  as  a  consequence,  is 
bent  upward,  but  in  the  opening  of  the  bud  the  greater  growth 
takes  place  upon  the  upper  side.  The  greater  growth  of  the 
upper  side  of  an  organ  has  been  termed  epinasty  ;  that  of  the 
lower  side,  hyponasty.  Many  floral  leaves  exhibit  first 
hyponasty  and  afterward  epinasty,  the  first  in  the  bud  and 
the  second  in  anthesis  (i.e.,  the  opening  of  the  flower). 
Many  stamens  and  styles  exhibit  nutations  of  this  nature ; 
thus  in  Claytonia  both  sets  of  organs  are  at  first  erect,  but 
afterward  they  become  divergent  by  epinasty. 

In  many  cases,  particularly  in  leaves  and  the  parts  of 
flowers,  these  movements  of  nutation  are  controlled  by  vari- 
ous external  agents,  among  which  light  and  heat  are  the 
most  important.  To  these  are  to  be  referred  the  successive 
opening  and  closing  of  many  flowers,  and  the  diurnal  and 
nocturnal  positions  of  the  leaves  of  many  plants. 

262. — Of  the  second  class  of  nutations,  the  leaves  of  the 
onion,  and  the  ends  of  the  stems  and  the  tendrils  of  climb- 
ing plants,  furnish  good  examples.  These  rotate  through 
circles  or  spirals,  in  the  case  of  the  hop  and  honeysuckle  to 
the  left,  and  in  the  bean  and  morning-glory  to  the  right.* 

*  To  the  right,  or  from  left  to  right,  is  opposite  to  the  direction  of 
the  hands  of  a  watch ;  to  tlie  left,  or  from  right  to  left,  is  in  the  direc- 
tion of  the  hands  of  a  watch. 


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200  BOTANY. 

When  such  rotating  stems  come  in  contact  with  an  up- 
right object  they  continue  their  rotation,  and  in  this  way 
come  to  twine  around  it.  The  plants  mentioned  above  af- 
ford common  examples  of  twining.  In  the  case  of  tendrils 
nutations  also  occur  ;  but  after  coming  in  contact  with  any 
object  there  is  a  very  unequal  growth  of  the  two  sides,  that 
in  contact  with  the  object  growing  very  slowly,  as  compared 
with  the  rapidity  of  growth  of  the  outer  side.  Thus  Do 
Vries  found  that  in  the  tendrils  of  the  pumpkin  twined 
around  an  object  1.2  mm.  in  diameter  the  ratio  of  the 
growth  of  the  inner  side  to  that  of  the  outer  was  as  1  to  14. 
This  inequality  of  growth  is  due  to  a  retardation  of  growth, 
upon  the  inner  side  and  an  acceleration  upon  the  outer.  In 
some  cases  there  appears  to  be  an  actual  contraction  of  the 
inner  side. 

268.— Movements  of  Torsion.  In  many  cases  in  the 
higher  plants  the  stems  or  other  organs  become  twisted  upon 
their  axes.  Even  in  the  lower  plants  this  is  not  uncommon — 
e.g.y  in  NitelUiy  the  pedicels  of  mosses,  etc.  This  twisting 
appeal's  in  many  cases  to  be  due  to  a  peculiar  inequality  in 
the  growth  of  the  tissues.  Thus  if  the  outer  layers  of  cells 
grow  in  length  more  rapidly  than  the  inner  ones,  the  stem 
will  become  twisted  upon  its  axis,  and  the  greater  the  ine- 
quality in  growth  of  the  inner  and  outer  layers,  the  greater 
the  torsion.  In  some  cases  torsion  arises  in  a  much  simpler 
way,  by  the  twisting  due  to  the  unequal  distribution  of  the 
weight  of  certain  organs,  as  in  some  prostrate  plants,  where 
the  weight  of  the  leaves  and  the  advancing  and  obliquely 
ascending  growing  extremity  of  the  stem  produce  torsions 
which  become  permanent  by  the  hardening  of  the  tissues. 
Likewise  torsions  may  arise  on  account  of  the  heliotropism  or 
geotropism  of  an  organ  itself,  or  of  organs  connected  with  it. 

It  may  be  in  place  here  to  direct  attention  to  tlie  fact  that  ineqoali- 
ties  in  the  growth  of  the  tisBues  of  plants  are  of  common  occurrence. 
They  are,  however,  for  the  most  part  of  such  a  nature  as  to  prevent 
torsions  of  the  stem,  giving  it,  on  the  contrary,  a  rigidity  which  en- 
ables it  to  stand  erect.  If  the  pith  of  a  growing  stem  of  a  Dicotyledon 
be  isolated  from  the  surrounding  tissues,  the  former  elongates,  while 
the  latter  contracts,  showing  that  the  pith  has  grown  more  rapidly  in 


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MOVEMENTS  OF  PLANTS,  201 

length  tliaa  tbe  other  tiseuea  Thus  in  a  young  intemode  of  the  Moan- 
tain  Asb,  60  mm.  long,  tlie  pith,  when  isolated,  elongated  8  mm.,  while 
the  soiToanding  parts  shortened  1  mm.  Close  examination  of  the  tissues 
«arroandin((  the  pith  shows  that  thej  also  have  developed  unequal- 
ly. Sachs  expresses  this  inequality  by  the  formula,  E  <  C  <  X  <  P, 
which  indicates  that  the  epidermis  is  shorter  than  the  cortex,  the 
cortex  shorter  tban  the  xylem,  and  the  xylem  shorter  than  the  pith.  It 
is  at  once  evident  that  in  such  a  condition  of  things  the  epidermis  is 
elongated  by  t)ie  other  tissues ;  the  cortex  is  shortened,  on  the  one 
hand,  by  the  epidermis,  and  elongated  on  the  otber  by  the  xylem  and 
X^th  ;  the  xylem  is  shortened  by  the  cortex  and  epidermis,  and  elon- 
gated by  the  pith  ;  while  the  pith  is  shortened  by  the  three  surround, 
inif  tissues.  There  is  thus  a  considerable  tension  in  the  several  tissues, 
and  upon  this  condition  it  may  be  remarked  : 

Ist.  That  it  produces  a  rigidity  of  the  stems  or  other  organs  in  which 
it  occurs. 

2d.  That  it  tends  to  prevent  ordinary  torsion ;  for  the  twisting  of 
such  a  stem  must  elongate  still  more  tlie  already  elon^ted  tissues, 
while  contracting  the  shortened  ones ;  on  the  other  hand,  there  is  some 
tendency  to  an  internal  torsion. 

8d.  That  tbe  exact  len^h  of  a  stem  is  dependent  upon  a  balancing 
of  the  tensions  of  its  tissues. 

There  are  in  many  cases  tensions  whose  directions  lie  at  right  angles 
to  the  foregoing.  Thus  in  the  trees  of  the  colder  climates  the  growth 
of  new  tissues  from  the  cambium  layer  produces  an  outward  pressure 
npon  the  bark,  and  an  equal  inward  pressure  upon  the  wood.  Even  in 
herbaceous  plants  similar  tensions  are  often  to  l)e  observed,  the  epider- 
mis being  laterally  distended  by  the  enclosed  tissues.  Tensions  in  this 
direction  have  been  denominated  transverse  tensions,  to  distinguish 
them  from  the  others,  which  may  be  called  longitudinal  tensions.* 

*  For  a  full  discussion  of  tensions  the  student  is  referred  to  larger 
works,  such  as  Sachs'  "Lehrbuch,"  and  his  "  Experimental-Physi- 
ologie." 

The  whole  subject  of  the  movements  of  plants,  including  heliotro- 
pism  and  geotropism,  is  fully  treated  by  Mr.  Darwin  in  his  recent 
work  •*  The  Power  of  Movement  in  Plants,"  New  York,  1881. 


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PART  II. 

SPECUL  ANATOMY  AND   PHYSIOLOGY  OF   PLANTS, 
AND  OUTUNES  OF  THEIR  CUSSIFICATION. 


CHAPTER    XIII. 
CLASSIFICATION. 

264. — ^In  order  to  obtain  a  definite  knowledge  of  the  com- 
parative structure  of  plants,  it  is  necessary  here  to  take  up 
in  order  the  different  groups,  and  to  study  with  some  care 
the  more  important  modifications  and  differences  noticeable 
in  the  plant-body.  This  study,  so  taken  up,  is  intimately 
connected  with  the  classification  of  plants ;  the  differences 
and  modifications  of  structure  which  we  study  in  order  to 
gain  a  better  knowledge  of  plants  as  a  whole,  are  the  very 
ones  which  serve  to  separate  the  vegetable  kingdom  into 
larger  or  smaller  groups.  This  part  (Part  II.)  of  this  trea- 
tise will,  therefore,  include  the  outlines  of  the  Classification 
of  Plants,  as  well  as  a  discussion  of  Special  Morphology. 

266. — (1.)  In  the  classification  of  living  objects  they  "are 
arranged  according  to  the  totality  of  their  morphological  re- 
semblances, and  the  features  which  are  taken  as  the  marks 
of  groups  are  those  which  have  been  ascertained  by  observa- 
tion to  be  the  indications  of  many  likenesses  or  unlikenesses.  "* 
Such  an  arrangement  is  "  a  statement  of  the  marks  of  sim- 
ilarity of  organization,  and  of  the  kinds  of  structure  which, 
as  a  matter  of  experience,  are  universally  found  associated 
together." 

♦  T.  H.  Huxley  In  the  article  "Biology."  in  "  Encyclopsedia  Britan. 
nica/'  ninth  edition,  Vol.  III.,  p.  688. 


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OLASaiFIOATIOK  203 

266. — (2.)  Every  natural  classification  takes  into  consider- 
ation not  only  the  adult  characters^  but  also  those  of  the 
embryonic  life  of  its  objects.  It  is  not  enough  to  know  the 
differences  and  resemblances  between  two  plants  in  their 
adult  state  ;  we  must  also  know  whether  they  differed  or  not 
in  their  modes  of  reaching  that  state.  In  other  words^  in 
order  to  determine  the  degree  of  relationship  existing  be- 
tween two  or  more  plants^  all  the  characters  of  each  plant, 
as  presented  in  its  whole  life,  must  be  taken  into  the  ac- 
count. By  ignoring  this  important  law  great  confusion  has 
arisen,  especially  in  the  lower  groups  of  plants. 

267. — (3.)  There  is  still  another  factor  which  should 
enter  into  classification.  Every  classification  should  show 
real  relationship,  not  similarity  alone ;  it  should  bring  to- 
gether not  those  which  simply  show  present  coincidences, 
but  those  in  which  similarity  of  form  indicates  similarity 
of  origin  ;  in  addition  to  structural  relationship,  it  should 
show  genetic  relationship.  This  can  be  accomplished  only 
by  a  study  of  the  genealogy  of  plants,  a  subject  surrounded 
by  many  difficulties.  In  but  few  cases  can  we  trace  an 
ancestral  line,  and  yet  it  is  desirable  that  we  should  use  the 
facts  we  have,  as  by  so  doing  we  shall  be  the  more  likely  to 
discover  others. 

(a)  It  is  a  mistaken  notion  tliat  living  tbin^  can  be  g^ronped  natu- 
rally by  taking  into  consideration  only  one,  or  even  two  or  three  cbar- 
acters.  Botany  and  zoology  are  fall  of  the  debris  of  attempts  at  classi- 
fications upon  single  characters,  and  in  every  case  such  classifications 
have  proved  a  bindrauce  to  knowledge.  Tbe  division  of  tbe  vegetable 
kingdom  into  Flowering  and  Flowerless  Plants,  by  Ray,*  in  1708,  is  an 
iUastration  of  one  based  upon  a  single  character.  The  influence  of 
this  classification,  wbicb  is  even  yet  much  followed,  has  been  injurious. 
It  has  kept  alive  the  notion  that  the  so-called  Flowerless  plants  are 
qoite  different  as  to  their  reproductive  organs  from  tbe  Flowering  ones ; 
it  fixed  an  imaginary  gulf  between  groups  of  plants,  some  at  least  of 
wbicb  are  in  nature  placed  side  by  side.  Endlicber'sf  two  great 
g^ups,  Cormopbyta  and  Thallopbyta,  are  likewise  based  upon  a  single 
character,  and  are,  as  a  consequence,  misleading.     Tbe  Thallopbytes  are 

*  John  Ray  :  "  Metbodus  Plantarum  emendata  et  aucta." 
f  Stephen  Endlicber :  "  Genera  Plantarum  secundum  Ordines  Natu> 
rales  disposiU.''    182^6-40. 


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204  BOTANY. 

not  all  tluJlas  plants,  nor  are  all  the  thaUos  plants  foond  in  the  Thai- 
lophyta ;  on  the  other  hand,  the  Gormophytee  are  not  all  plants  with 
trunks  or  stems. 

if)  We  often,  however,  retain  in  oar  present  classification  some  of 
the  groups  founded  originally  in  tliis  erroneous  way,  and  even  some- 
times retain  their  old  names.  For  example,  the  group  Phanerogamia 
includes  now  the  same  plants  It  did  when  its  exceedingly  inapplicable 
name  (Phanerogamia,  from  ^vep^S,  open  to  sight,  and  }^/m>S,  marriage) 
was  applied  to  it ;  but  it  now  rests  upon  a  more  scientific  basis.  The 
name  is  now  unmeaning,  and  refers  to  no  character  or  set  of  characters 
now  used  to  designate  the  group  ;  and,  more  tliau  this,  its  etymological 
signification  is  actually  directly  opposite  to  the  facts  as  now  known. 
The  term  Cryptogamia  (icpvn-rdc,  hidden,  and  yafio^^  marriage)  no  longer 
exists  in  a  scientific  sense,  as  it  is  no  longer  the  name  of  a  group  of 
plants ;  not  only  has  the  term  now  no  meaning  (for  the  plants  it  refers 
to  have  a  fertilization  which  is  far  less  '*  hidden  "  than  in  the  so-called 
Phanerogams),  but  the  plants  it  formerly  designated  by  a  negative 
character  are  now  known  by  positive  characters  to  belong  to  several 
groups.  We  may  still  use  the  word  Cryptogam  in  speaking  of  the 
members  of  certain  groups  of  plants,  just  as  in  zoology  we  frequently 
make  use  of  the  word  Invertebrate  ;  but  in  neither  case  are  the  terms 
the  names  of  natural  groups,  or  of  natural  assemblages  of  groups.  It 
is  convenient  to  retain  them  as  popular  names  of  certain  artificial  as  • 
semblages  of  groups. 

(e)  The  term  Thallophyta  is  to  be  placed  in  the  same  category.  It  is 
still  used  to  designate  a  great  assemblage  of  the  lower  plants,  but  the 
original  meaning  of  the  term  is  lost,  and  the  limits  of  the  group  to 
which  it  was  applied  have  been  somewhat  changed,  while  the  plants 
composing  it  have  undergone  an  entirely  new  distribution  into  new 
groups.  Nevertheless,  it  is  convenient  to  retain  the  term,  although  in 
this,  as  in  the  previous  cases,  care  must  be  taken  not  to  suppose  that 
when  used  it  designates  more  than  an  artificial  assemblage  of  natural 
groups  of  plants. 

(if)  The  importance  of  the  study  of  the  individual  development  of 
plants  can  hardly  be  overestimated.  What  Embryology  has  done  for 
zoological.  It  doubtless  can  do  for  botanical  classification.  It  is  already 
bearing  fruit ;  the  recent  advances  in  the  classification  of  the  algsB  and 
fungi  are  due  to  a  study  of  the  whole  life  of  the  individual.  In  the 
fungi  the  long  list  of  spurious  families  and  genera,  and  tli^yet  longer 
one  of  spurious  species,  bear  witness  against  the  system  of  classification 
under  which  they  came  into  existence. 

(e)  There  is  another  reason  for  studying  closely  the  life-history  of  the 
individual,  which  is  that  it  throws  some  light  upon  the  difficult  ques- 
tions relating  to  the  ancestry  of  plants.  The  life-history  of  the  indi- 
vidual appears  to  bear  much  resemblance  to  the  life-history  of  the 
species ;  and  while  no  doubt  it  would  be  unsafe  in  any  particular  case 


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CLASSIFICATION. 


205 


to  aasume  that  the  specific  development  had.  followed  lines  parallel  to 
those  of  the  individual,  jet  the  latter  may  always  serve  to  point  out  the 
probable  coarse  of  the  former. 

268. — Applying  the  preceding  principles,  so  far  as  possi- 
ble, we  find  that  the  vegetable  kingdom  may  be  quite  readily 
separated  into  six  principal  Divisions,  which,  although  by  no 
means  distinct,  are  capable  of  being  quite  clearly  character- 
ized. To  these  must  be  added  a  seventh,  composed  mainly 
of  unclassified  and  poorly  understood  forms.  These  seven 
Divisions,  beginning  with  the  lowest,  are,  (1)  Protophyta, 
(2)  Zygophyta,  (3)  Oophyta,  (4)  Carpophyta,  (5)  Bryophy- 
ta,  (6)  Pteridophyta,  (7)  Phanerogamia,  or  Anthophyta. 

Their  relation  to  the  old  groups  Cryptogamia,  Thallophy- 
ta,  etc.,  may  be  seen  from  the  following  tabular  comparison  : 


Bay,  1706;  Limueus,  1785. 

Plowerless  (Ray), 

Cryptogamia     (Lin-  - 

neus). 

Flowering  (Ray), 
Phanerogamia(Ijinn.) 


II. 

De  CandoUe, 
1818. 


III. 

Endlicher, 
1886-40. 


IV. 

1.  Protophyta. 

2.  Zygophyta. 


Thallopbyt..^--^4-i;P"^^; 

i4.  Carpophyta. 
5.  Bryophyta. 
«.  Pteridophyta. 
7.  Phanerogamia. 


The  arrangement  in  the  fourth  column,  which  will  be  fol- 
lowed in  this  book,  is  essentially  that  of  Sachs,  with  some 
modifications,  which  will  be  pointed  out  hereafter. 

It  is  only  necessary  in  this  place  to  say  that  the  classification  here 
given  does  not  recognize  the  old  groups  Algce  and  Fungi,  The  terms 
are,  however,  quite  useful,  if  properly  used  and  understood,  and  con- 
sequently they  will  he  retained  when  general  reference  is  made  to  the 
chlorophyll-bearing  and  the  chlorophyll-free  Thallophytes.  By  the 
term  aJga  must  be  understood  a  Thallophyte  wldch  contains  chloro- 
phyll ;  and  by  fungus  one  which  is  saprophytic  or  parasitic  in  habit, 
and  which  ^,  as  a  consequence,  destitute  of  chlorophyll.  The  terms 
have  thus,  as  here  used,  a  physiological  meaning  only,  and  not  a  class- 
ificatory  one. 


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CHAPTER  XIV. 

THE    PROTOPHYTA. 

269. — ^The  Protophytes  are  the  lowest  and  simplest  plants. 
In  many  cases  they  are  exceedingly  minute,  requiring  the 
highest  powers  of  the  microscope  for  their  study.  For  the 
most  part  the  cells  are  poorly  developed ;  the  protoplasm 
is  frequently  destitute  of  granular  contents ;  the  nucleus  is 
wanting  in  many  cases,  and  not  infrequently  there  is  either 
no  cell-wall,  or  only  a  poorly  developed  one.  The  cells  in 
all  cases  have  little  or  no  coherence,  and  even  when  they  are 
united  into  loose  masses,  each  cell  retains  nearly  as  much 
independence  as  in  the  unicellular  forms.  The  diflferentia- 
tion  of  cell-form  is  very  slight,  even  in  those  cases  where 
there  is  the  greatest  coherence  of  cells,  and  yet  in  some  or- 
ders certain  cells  of  the  filaments  are  uniformly  larger  than 
the  others,  as  the  ^^heterocysts''  of  Nostoc,  and  the  "  basal 
cells'^  of  the  filaments  of  Rivularia. 

270. — No  sexual  organs  are  known,  and  whether  the  sex- 
ual act  occurs  or  not  is  somewhat  doubtful.  As,  however, 
we  must  not  expect  to  find  well-developed  organs  or  as 
distinct  a  sexual  act  in  these  simple  organisms  as  in  more 
complex  ones,  it  is  possible  that  both  exist  in  the  group, 
but  have  hitherto  been  overlooked  or  misunderstood. 

Their  most  common  mode  of  reproduction  is  by  fission, 
and  in  only  a  few  cases  by  internal  cell-division. 

271. — The  lowest  Protophytes  are  destitute  of  chlorophyll, 
or  any  other  coloring-matter,  and  in  those  orders  in  which 
chlorophyll  occurs  it  is  usually  associated  with  a  blue  or  red 
pigment. 

Many  Protophytes  exist  in  masses  of  a  considerable  size, 
composed  of  large  numbers  of  individuals  imbedded  in  a 


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MTXOMTCETEB.  207 

gelatinous  matter,  which  appears  to  be  formed  by  a  partial 
degradation  of  the  walls  of  the  cells.  They  are  mostly 
aquatic  ;  and  the  species  which  are  terrestrial  live  in  damp 
and  generally  shaded  places. 

§  L  Class  Myxomyoetes.    The  Slime  Moulds. 

272. — In  this  class  is  included  a  large  group  of  remark- 
able organisms,  which  differ  in  many  respects  from  all  other 
vegetable  structures.  In  many  of  their  characters,  as  in 
haying  no  cell- wall  during  the  period  of  their  active  growth, 
in  being  destitute  of  a  nucleus,  in  their  mode  of  nutrition, 
and  in  the  motility  of  their  naked  protoplasm,  they  resemble 
certain  Monera  among  the  Protozoa ;  ♦  while,  on  the  other 
hand,  they  have  a  close  external  resemblance  to  certain 
higher  fungi  (puff-balls  and  their  allies). 

278. — It  is  difficult  to  give  the  Myxomycetes  a  satisfac- 
tory place  in  a  system  of  classification.  They  have  no  struc- 
tural affinities  with  plants  higher  than  they  are,  nor  with 
any  lower  ;  they  stand  alone,  and  appear  to  belong  to  a  dif- 
ferent genetic  line.  So,  although  taken  up  here,  they  must 
not  be  regarded  as  on  that  account  the  lowest  or  the  first  of 
the  Protophytes. 

274. — All  members  of  this  class  agree  in  being  composed 
during  the  vegetative  portion  of  their  existence  of  naked 
masses  of  protoplasm  (Fig.  140),  which  are  yellow,  brown, 
purple,  etc.,  but  never  green.  Th^^Q plasmodia,  as  they  are 
called,  are,  during  the  period  of  their  active  growth,  endowed 

*  There  are  fewer  reasoDs  now  than  formerly  against  regarding  these 
as  near  relatives  of  the  Monera.  We  no  longer  imagine  an  absolute 
line  of  separation  between  the  lower  portions  of  the  great  domain  of 
life,  and  hence  may  now  admit  relationships  which  formerly  were  in- 
admissible. It  is  by  no  means  an  improbable  hypothesis  that  in  the 
Myxomycetes  we  have  the  terrestrial  phase  and  in  the  Monera  the 
aquatic  phaee  of  a  common  group  of  organisms.  The  Myxomycetes  are 
not  Monera,  but  they  are  Moneran  in  their  structure,  and  probably  also 
in  their  affinities.  All  the  differences  between  the  Myxomycetes  and  a 
Moner  like  Protomj/xa,  for  example,  are  probably  referable  to  the 
terrestrial  habit  of  the  former  as  contrasted  with  the  aquatic  habit  of 
the  latter. 


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208  BOTANT. 

with  a  remarkable  motility,  enabling  them  not  only  to 
change  their  form,  but  their  place  also.  When  the  proto- 
plasm passes  into  a  condition  of  rest,  it  forms  itself  into 
small  rounded  masses,  each  of  which  secretes  a  covering  of 
cellulose  about  itself.  This  resting  condition  may  be  brought 
about  in  two  ways :  first,  through  unfavorable  conditions, 
as  the  absence  of  the  requisite  amount  of  moisture ;  in  such 


Fig.  140.— Flaamodium  of  Fhysarttm  Uuooput  (Didymium  leuooput  of  Link),    st^ 
the  more  gmmlttr  central  part  of  the  threads,    x  860.— After  Sachs. 

case  the  masses  formed  are  larger,  and  irregular  in  size,  and 
*  bute  the  so-called  scleroHum  stage ;  upon  the  return  of 
oper  conditions  the  sclerotia  return  to  the  soft  and 
condition  of  the  original  plasmodium  ;  the  second 
of  formation  of  the  resting  stage  takes  place  only 
the  Plasmodium  has  apparently  concluded  its  period 
station  ;  the  protoplasm  becomes  heaped  up  in  a  com- 
►r  even  elevated  mass,  which  then  separates  internally 


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MTX0MTCETB8. 


209 


into  a  large  number  of  minute  rounded  bodies,  the  spores, 
each  of  which  is  provided  with  a  cell- wall.     This  latter  is 
called  the  spore-bearing  stage,  or  simply  the  fructification  of 
the  organisms. 
276. — When  placed  under  proper  conditions  of  moisture 


Fig.  lAX.^FtUigo  varioM  (.^thaUvm  MeptHeum  of  Fr.).  a  spore;  d,  e,  spore-case 
roptaring  and  permitting  the  protoplasmic  contents  to  escape;  cf.ronnded  mass  of 
naked  protoplasm  escaped  from  the  spore-case;  «,  /,  ciliated  swarm-spore  or 
soospore  stage;  g^  A,  i,  ib,  /,  amoeba  stage;  m,  young  plasmodiom.— After  Prantl. 

and  temperature,  the  spores  burst  their  walls,  and  the  im- 
prisoned protoplasm  in  each  escapes  and  soon  becomes  a 
motile,  nucleated  mass,  provided  with 
a  cilium,  or  having  an  amoeboid  form  ; 
in  this  stage  (called  the  swarm-spore) 
it  repeatedly  divides  by  simple  fission 
(Fig.  142).  After  a  day  or  two,  the 
Bwarm-spores,  now  destitute  of  cilia, 
begin  the  reverse  process  of  coales- 
cing, two  or  more  of  them  fusing  into 
a  common  mass ;  the  process  may 
continue  until  a  new  plasmodium  is 
formed,  differing  from  the  first  one  mentioned  only  in  size 
(Fig.  141,  a  to  w,  and  Fig.  143).    (See  Note  on  page  49.) 

276. — ^The  classification  of  the  Myxomycetes  is  mainly 
based  upon  the  fructification,  which  usually  consists  of  a 


Fig.  142.— Swarm-spores  of 
Ctumdriodtrma  difforme 
(Didvmium  lAberHanum  of 
De  Bary)  nndergniag  fission. 
X  890.— After  De  Ba^r. 


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210 


BOTANY. 


sporangium,  which  may  be  distinct  (Fig.  144,  B),  or  it  may 
be  a  flattisb,  cake-like  mass,  the  so-called  cethalium,  directly 
derived  from  the  Plasmodium.  In  most  cases  the  spore* 
bearing  masses  contain  internally,  besides  the  spores,  a 
structure  called  the  CapiUiiiu7n,  consist- 
ing of  thin-walled,  spirally  thickened,  or 
otherwise  marked  tubes  variously  disposed 
(Fig.  144,  Cy  cp).  In  some  cases,  where 
there  is  a  distinct  sporangium,  the  pedi- 
cel of  the  latter  is  continued  into  it  as  a 
central  column  ;  this  is  known  as  the  Col- 
umella;  it  may  send  out  branches  which 
BpSfiof  ^IrtX:  support  the  walls  of  the  sporangium. 

ma     difbrme     (Didy- 

mUim  Uderiianum  of       (a)  The  following  classification  of  the  Myxomy- 

SfnjiStiii^.'^^x*^.-   cetes  is  by  Rostafinski.*    He  distinguishes  seven 
After  CienkowBki.  ordei*s : 

Order  L  Protodermeeo.  Sporangia  simple,  of  regular  shape,  not 
possessed  of  a  capUlitium,  with  violet  spores. 

Order  H.  Calcarefle.    Sporangia  simple  or  compound,  often  pro- 
vided with  a  columella,  spores  violet  or  violet  brown  ;  whole  fructifica- 
tion, with  more  or  less  de- 
posits of  carbonate  of  lime. 

This  includes  many  com- 
mon species,  under  the 
genera  Physarum,  FSdigo, 
IHdymiitm,  Spumaria,  etc 

Order  lYT.  Amauro- 
chstesB.  Single  sporan- 
gium or  eethalium,  with- 
out lime;  spores,  capilli- 
tium,  and  columella  almost 
always  uniformly  black,  or 
brownish-violet  colored. 

In  this  order  the  genus 
Stenumitis  furnishes  the 
most  common  species. 

Ord^r  IV.  AnemesB. 
Sporangium  or  setbalium 
without  capillitium  or  lime;  columella  not  evident,  waU  of  sporan- 

♦  "  Sluzowce  Monografia"  by  Joseph  Rostafinski,  1875.  Zopf  (•*  Die 
Pilzthiere,"  1884)  extended  the  class  so  as  to  include  many  genera,  e.g., 
Vampyrella,  Protomonas,  Protomyxa,  Plasmodiophora,  etc.,  which 


Fig.  144.— Practiflcatlon  of  Areyria  ineamata 
{A.  adnata  of  Rtfki.).  B,  young  gporangium;  0, 
nutture  pporaDgium  raptured ;  00,  capUlitium  ; 
p,  wall  of  sporangiam.   X  80.— After  Sachs. 


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8CHIZ0MTCETE8.  211 

giom  witbont  net-like  thickenings,  now  and  then  STmmetrically  per. 
foiated. 

Ueea  and  TubuUna  are  genera  of  this  order  of  which  we  have 
species. 

Order  V.  Heterodermeeo.  Sporangia  without  capillitium,  colu- 
mella, or  lime  ;  wall  of  sporangium  delicate,  when  mature  at  least  partly 
cracked,  exposing  the  net-like  flat  thickenings  of  the  inner  side  of  wall ; 
spores  and  thickenings  of  the  inner  wall  in  one  and  the  same  sporan- 
gium usually  of  uniform  color. 

Dietgdium  and  Onbraria  are  our  common  genera. 

Order  VL  Ck>lumellifer8B.  Spores,  capillitium,  and  columella 
uniformly  bright-colored,  without  lime  ;  capillitium  of  very  thin-sided 
tubes,  without  thickenings,  combined  into  a  thickly  intricate  but  loose- 
hanging  net. 

Represented  by  the  genus  Beticularia, 

Order  Vn.  CalonemesB.  Walls  ofsporangia,  spores,  and  capillitium 
usually  uniformly  colored  in  the  same  sporangium.  Color  variable 
from  yellow  to  brownish  or  chestnut ;  more  rarely  olive  green  or  gray- 
ish white ;  capillitium  usually  strongly  developed  ;  threads  simple,  or 
combined  into  a  net,  either  entirely  free  or  grown  to  certain  places  of 
the  wall  of  the  sporangium  ;  walls  of  the  threads  very  rarely  smooth, 
usually  provided  externally  with  protruding  thickenings,  either  spiral- 
shaped  or  under  the  form  of  numerous  spines,  warts,  or  transverse 
rings;  without  fixed  columella;  exceptionally  containing  lime,  exclu- 
sively on  the  walls  of  the  sporangia ;  now  and  then  aethalia  covered 
with  a  stout  double  cortex  of  colored  cells. 

Areyria  and  Triehia  are  our  common  genera. 

(&)  Specimens  of  the  Slime  Moulds  may  be  obtained  for  study  by  ex- 
amining  the  surfaces  of  decayed  lo^,  and  the  bark-covered  ground  in 
tan-yards.  They  may  frequently  be  found  on  decaying  leaves,  and 
occasionally  on  the  grass  and  mosses  near  decaying  vegetable  matter. 

§  II.  Class  Schizomycetes. 

277. — These  are  minute  unicellular  Protophytes,  whicli 
reproduce  mainly  by  transverse  fission.  The  cells  are  gener- 
ally somewhat  elongated,  often  much  so,  although  in  one 
family  they  are  spherical ;  they  are  sometimes  provided  with 
cilia,  by  means  of  which  they  move  rapidly  through  the 


are  commonly  placed  in  the  Animal  Kingdom.  Zopf 's  system  is  fol- 
lowed by  Berlese  in  Saccardo's  "  Sylloge  Fungorum."  vol.  vii.,  1888, 
in  which  all  the  known  species  in  the  world  (about  460)  are  described 


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1 


212  BOTANY. 

water.  Tbey  occur  in  solutions  of  organic  matter  in  im- 
mense numbers,  and  are  said  even  to  appear  in  solutions  of 
inorganic  salts  under  proper  conditions.* 

278.— Order  Bacteriaoesd.  This  includes  the  organisms 
known  as  Bacteria,  and  which  are  present  in  fermenting  and 
putrefying  matter ;  they  also  occur  in  the  blood  and  the  air- 
passages  of  diseased  animals,  and  the  tissues  of  some  dis- 
eased plants,  where  they  have  been  shown  to  be  the  cause  of 
many  kinds  of  disease.  Cohn  f  defined  Bacteria  as  *'  chlor- 
ophyll-less cells  of  spherical,  oblong,  or  cylindrical  form, 
sometimes  twisted  or  bent,  which  multiply  themselves  ex- 
clusively by  transverse  division,  and  occur  either  isolated  or 
in  cell-families."  Many  forms  have  since  been  shown  to 
produce  spores,  and  these  are  most  important  agents  in  their 
multiplication  and  reproduction.  In  the  unicellular  Bac- 
teria the  cells  resulting  from  division  separate  at  once,  while 
in  the  filamentous  forms  they  remain  in  connection,  forming 
elongated  strings  or  threads.  Bacteria  sometimes  form  a 
jelly-like  mass  by  the  swelling  up  of  their  cell  membranes; 
this  is  the  Zooglcba  stage.  When  they  have  exhausted  the 
nutriment  from  the  liquid,  they  form  a  pulverulent  precipi- 
tate, which  may  be  regarded  as  a  resting  state.  "  Most 
Bacteria  present  a  motile  and  a  motionless  condition;  the 
former  is  connected  with  the  presence  of  oxygen.'* 

It  is  now  known  that  many  Bacteria  pass  through  various 
stages,  e.g..  Coccus,  Bacillus,  Vibrio,  etc.,  which  were  for  a 
time  supposed  to  be  generic  forms,  under  which  species  were 
described,  as  was  done  by  Cohn.  The  real  limits  of  genera 
and  species  cannot  in  the  present  state  of  our  knowledge  of 
thefie  organisms  be  determined.  We  may,  for  the  present, 
make  use  of  Cohn's  system,  remembering  that  it  is  merely 
a  classification  of  observed  forms. 

♦  See  Bastian's  **  Beginning  of  Life,"  Vol.  II.,  Appendix. 

f  "  Reeearches  on  Bacteria  "  (Untereuch.  ilber  Bacterien)  in  "  Beitrftge 
zur  Blologie  der  Pflanzen,"  Breslaa,  1872.  See  a  resam^  of  tliis  paper 
in  (Quarterly  J>»umnl  of  }fiero9oapieal  Science,  1873,  p.  156.  See  also 
English  acooQDts  of  farther  researches  bj  Cohn,  1875,  1876;  in  the 
journal  just  cited,  1876,  p.  259.  and  1877.  p.  81.  Consult  '*  The  Bac- 
teria," by  Dr.  A.  Magnin  ;  translated  by  Dr.  Sternberg.    Boston,  1880. 


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BCHIZOMTCETES. 


213 


(a)  Cohn  separated  Bacteria  into  four  tribes,  as  follows  : 

(1)  Spharobaeteria,  with  spherical  cells.  The  only  genus  is  IdierocoO' 
mo.  The  species  M,  erepumUum,  if.  candidus,  and  if.  urea  produce 
eertain  kinds  of  fermentation  ;  the  color-producing  species  are  JH,  pro' 
diffiows  (a.  Fig.  145),  which  causes  the  blood-like  patches  on  bread, 
flour,  parte,  etc.,  M,  luieus,  M.  aurantiaeus,  M.  ehhrinw,  M,  eyaneus, 
Kad  Jf.  viokieeus  ;  those  producing  or  accompanying  diseases  are  If, 
vaeeina,  M,  diphth&ricus,  M.  septieus,  and  M,  bombycU.  This  latter 
group  is  of  great  importance,  but  it  is  one  the  investigation  of  which 
presents  unusual  difficulties.    0th-         a  I 

er  spedea  than  those  named  are      {     *• 
supposed  to  exist. 

(2)  Microbacteria,  with  very 
small  cylindrical  cells.  The  only 
genus  is  Bacterium.  The  species 
are,  B.  Termo  (6,  Fig.  145),  the 
common  agent  of  putrefaction; 
B.  Hneola  (c.  Fig.  145),  a  larger 
species  found  in  brooks  and 
ponds  ;  B.  xanthinum  and  B,  ^yn- 
eyanum,  which  are  color-produc- 
ing; and  B.  arugino^um,  which 
is  found  in  blue-green  pus. 

(8)  Btnnobaeteria,  with  filiform 
ceUa  There  are  two  genera.  Bet- 
eillui,  with  the  filameut  straight, 
and  Vibrio,  with  the  filament  curv- 
ed or  undulated.  Of  the  first  there 
are  three  species,  viz.:  B.  mbtUis, 
which  is  the  butyric  ferment ;  B, 
ulna  (d,  Fig.  145),  much  like  the 
preceding,  but  larger ;  and  B, 
anthradi,  which  is  the  cause  or 
accompaniment  of  .  the  diseases 
known  as  anthrax  and  "ma- 
lignant pustule."  Vibrio  has  two 
species,  viz. :  F.  Rugula  {e.  Fig.  145),  whose  cells  are  thick  and  rather 
short ;  and  F.  serpena,  whose  cells  are  of  smaller  diameter,  but  of 
greater  length  than  the  preceding. 

(4)  Spirobacteriaf  with  spirally  twisted  cells.  There  are  two  genera, 
SpwrochcBte,  with  a  much  twisted  spiral ;  and  SpiriUum,  with  a  less 
twisted  spiral.  Of  the  first  the  single  species  is  J^,  pHeaUlii  (/,  Fit;. 
145),  and  of  the  second,  8p.  tenue,  Sp.  andula  and  8p.  tduians  (g. 
Fig  145),  the  latter  a  gigantic  species,  with  a  flagellum  at  each  end 
of  the  spiral. 

{b)  Bacteria  may  be  readily  procured  for  study  by  infusing  a  pincb 


c:^ 


Fig.  146.  a,  Mierocoeous  prodigioeut^ 
(Mona9  prodiiniogtts  of  Ehrcnberg) ;  6, 
Bacterium  Termo,  zoogloea  etage ;  c,  Bae- 
terium  lineola  :  d,  BaciUue  tuna ;  «,  Fi- 
brio  Buffula  :  /,  Spiroehate  plicaUUe  ;  ff, 
Spirillum  votutane.    X  650.— After  Cohn. 


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214  BOTANY. 

of  cat  bay  or  any  other  similar  vegetable  sabstance  in  warm  water  for 
an  boar,  and  then  filtering ;  the  filtrate  will,  if  kept  at  tbe  ordinaiy 
temperatare  of  a  room  (20''  C),  and  allowed  free  access  of  air,  become 
tarbid  witb  Bacteria  in  tbe  coarse  of  one  or  two  days. 

{c)  By  adding:  a  drop  of  the  bay  infasion  to  Pastear'ssolation.^made 
witboat  stigar,  tbe  previoasly  clear  liqaid  is  soon  made  tarbid  by  tbe 
rapid  increase  of  Bacteria.f 

279. — Allied  to  the  Schizomycetes  are  the  species  of  Seuh 
charomyces  which  produce  fermentation  in  sugar  solutions. 
The  type  of  the  genus  is  Saccharomyces  cerevisics,  the  yeast 
plant  (Fig.  146).  It  presents  two  conditions  :  in  the  first  it 
is  in  the  form  of  transparent  round  or  oval  cells,  averaging 
.008  mm.  (.0003  inch)  in  diameter ;  these  reproduce  by  bud- 
ding (a  modification  of  fission),  a  small  daughter-cell  being 

formed    by    the    side    of    the 

mother-cell,  and  sooner  or  later 

separating  from  it  (Fig.  146,  a, 

»  ^  -^_  J).    The  other  form  consists  of 

jS      ^A    Cf^         larger  cells,  which,  by  a  division 

W^      ^W  O         of  their  protoplasm,  form  four 

new  cells  within  the  parent-cell 
Pig.  i46.-The  Yea8t  Plant,  ^kjcfto-   (Fiff.  146,  c,  d).  This  is  probably 

romycM  cerevigia.     a,  ronnded  cells    ^     o  , ,         xi  j  • 

from  ••  bottom  yeast,*'  60  hours  after  no  more  than  the  ordmary  pro- 

Su?Som^i^'7«a»t;"0  bottom  cess  of    internal   cell-division, 

LlSwti%±fba?intttuJ  although  it  has  been  thought 

SJSgSteJSfeir^a^indSx^^^^  to  be  of  greater  importance.! 

x?&).-AfterRees8.  Tj^jg  formation  of  new  cells  by 

internal  cell-division  appears  to  occur  only  when  the  supply 
of  nourishment  is  less  abundant,  as  when  the  yeast  is  grown 
on  cut  slices  of  potato  or  carrot. 

♦  Made  aa  followa  :  Potassium  phosphate,  20  parts  ;  calcium  phoe- 
phate,  2  parts  ;  magnesium  sulphate,  2  parts ;  ammonium  tartrate, 
100  parts ;  cane  sugar,  1500  parts ;  water,  8876  parts.  The  sugar  is 
to  be  omitted  in  some  cases. 

t  The  student  may  profitably  refer  to  Huxley  and  Martin's  "Ele- 
mentary Biology,"  Chap.  IV..  for  directions  in  making  his  observations. 

t  Reees,  in  bis  "Botanische  Untersucbungen  ilber  die  Alcobolgftb- 
rungspilze,"  1870,  calls  this  process  the  formation  of  asoospores,  tbe 
mother-cell  be  calls  an  ascus,  and  tbe  daughter-cells  true  ascospores. 
Accordingly  be  considers  these  plants  to  be  very  simple  Ascomycetee  I 


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CYANOPHTCEjE.  5ei5 

280. — Ifc  was  formerly  held  that  the  yeast  plant  was  only 
the  immature  condition  of  a  mould;*  but  Brefeld's  re- 
fiearchesjf  which  were  undertaken  to  determine  whether 
true  yeast  ever  deyelops  into  a  filamentous  form,  appear  to  be 
decisive  against  that  view.  He  found  that  under  different 
conditions,  as  with  free  access  of  air,  or  growth  in  a  thin 
stratum  of  a  neutral  solution,  the  results  were  always  nega- 
tive, and  no  filamentous  forms  appeared. 

(a)  ExamiDations  of  the  yeast  plant  are  easily  made  by  placing  a 
very  small  drop  of  active  yeast  upon  a  glass  slide,  and,  after  covering 
it  in  the  usual  way»  keeping  it  in  a  warm  and  moist  chamber  for  some 
hours,  at  the  end  of  which  time  the  "budding"  will  have  become 
quite  well  marked.  A  slide  so  prepared  may  be  examined  immedi- 
ately, but  with  less  satisfactory  results. 

(&)  Teast  may  be  grown  in  abundance  by  placing  a  few  drops  in  a 
quantity  of  Pasteur's  solution,  in  which  it  grows  with  great  rapidity 
in  a  temperature  of  80''  to  85°  C.  (about  90"  Fahr.). 

(c)  The  state  in  wh^ch  daughter-cells  aro  formed  may  be  developed 
by  growing  the  yeast-cells  (those  called  bottom  yeast  are  the  most  sat- 
isfactory) upon  fresh-cut  slices  of  potato,  kohl-rabi,  carrot,  or,  better 
still,  upon  small  slabs  of  plaster  of  Paris.  The  preparations  must  be 
kept  moist  by  covering  with  a  bell-jar  ;  with  proper  care  the  formation 
of  daughter-cells  will  be  seen  in  a  week  or  ten  days  from  the  begin- 
ning of  the  experiment. 

((Q  In  order  that  the  study  of  these  organisms  may  be  at  all  satisfac- 
tory the  student  should  be  provided  witli  high  powers  of  the  micro 
80ope,  say  from  600  to  800  diameters.  ^ 

§  III.   Class  Cyakophyce^. 

281. — These  are  blue-green,  verdigris-green,  brownish 
green,  or  rarely  purple  or  red  Protophytes,  which,  in  addi- 
tion to  chlorophyll,  contain    a    soluble  coloring-matter — 


*  "  Yeast  is,  in  fact,  nothing  more  than  a  peculiar  condition  of  a 
species  of  PenicUUvm,  which  is  capable  of  almost  endless  propagation 
without  ever  bearing  perfect  fruit."  Berkeley's  *•  Introduction  to  Cry p- 
togamic  BoUny,"  1857,  p.  299. 

t  In  Flora,  1873. 

X  The  student  is  again  referred  to  Huxley  and  Martin's  '*  Elemen- 
tary Biology ;"  in  Chap.  I.  will  be  found  a  valuable  account  of  the 
yeast  plant,  with  directions  for  making  examinations. 


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216 


BOTANY. 


phycocyanine — and  a  less  soluble  ono—phycoxanthine.'^ 
Structurally  the  members  of  this  class  differ  but  little  from 
the  Schizomycetes,  although  they  are  of  a  much  larger  size. 
The  cells  generally  show  a  little  more  coherence  than  in  the 
last  class. 

They  live  in  fresh  or  stagnant  water,  or  upon  damp 
ground,  rocks,  or  decaying  wood.  Unlike  the  Schizomycetes, 
they  do  not  normally  inhabit  putrid  solutions. 

282.— Order  Chrooooooaoeee.  This  is  made  up  of  uni- 
cellular plants.  The  cells,  which  are  spherical,  oblong,  cylin- 
drical, or  angular,  are  either  single,  or  more  commonly  united 
by  a  conmion  jelly  into  families.  Cell-division  (in  reality 
internal  cell-division)  takes  place  in 
either  one,  two,  or  three  planes  (Fig. 
147). 

Thirteen  genera  are  known  in  tbe  United 
States :  (1)  Chroocoecus,  with  globose,  oval, 
or  angular  (from  pressure)  cells,  which  are 
solitary  or  in  free  families;  our  four  species 
grow  on  wet  rocks  or  in  springs;  (2) 
Glosoeapsa  (Fig.  147),  with  spherical  cells, 
which  are  solitary  or  in  enclosed  families ; 
our  eleven  species  form  a  firm  grumous  or 
grelatinous  coating  of  a  light  brown  color 
on  wet  rocks ;  (8)  ClcBospharium,  with  very 
small  cells,  forming  a  thallus-like  mass ;  we 
have  oi\e  species,  forming  a  light-colored 
scum  on  stagnant  water ;  (4)  Merismopedia, 
with  globose,  oval,  or  oblong  cells,  which  occur  in  tabular  families  of 
four,  eight,  sixteen,  etc. ;  our  two  species  inhabit  streams  and  fresh 
ponds.     ClalhroeystiSt  AnacyaUs,  etc.,  are  common. 

288.— Order  Nostooacesd.     The  plants  of  this  order  are 

♦  Phycocyanine,  the  blue  coloring-matter,  is  extracted  from  the 
crushed  plants  by  cold  water  ;  the  solution  is  blue  by  transmitted  and 
blood-red  by  reflected  light.  After  the  extraction  of  phycocyanine, 
treatment  of  the  crushed  plants  with  stronsr  alcohol  produces  a  green 
solution  which  contains  chlorophyll,  and  a. yellow  coloring-matter, 
phycoxanthine ;  the  latter  may  be  separated  by  shaking  up  with  the 
green  solution  a  large  quantity  of  benzine,  which  takes  up  the  chloro- 
phyll, and  when  at  rest  rises  and  forms  a  green  upper  layer  containing 
chlorophyll,  below  which  Is  the  yellow  alcoholic  solution  of  phycoxan- 
thine. 


Fig.  \€t.—Gflaoeap9a  in  dif- 
ferent  etaget  of  growth,  show- 
ing mode  of  cell-mnltiplica- 
tion.  The  daughter- cells  are 
snrroQDded  by  the  gelatinoas 
walls  of  the  mother-cells.  A^ 
youngest;  E^  oldest  stage. 
X  800.— After  Sachs. 


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CTANOPUTCEJS,  217 

composed  of  rounded  cells  loosely  united  into  a  filament  and 
generally  imbedded  in  jelly  (Fig.  148,  A) ;  they  frequently 
form  large  masses,  united  by  the  glutinous  jelly.  At  inter- 
vals in  the  filaments  there  are  larger  clear  cells — ^the  hetero- 
cysts — which  appear  from  analogy  to  be  reproductive  bodies, 
although  nothing  is  positively  known  as  to  their  function. 
The  usual  mode  of  reproduction  is  by  the  simple  fission  of 
the  cells.  New  masses  or  colonies  are  formed  by  the  break- 
ing up  of  the  old  filaments  into  pieces  composed  of  a  few 
cells,  which  then  become  endowed  with  a  power  of  motion 
which  consists  of  a  slow  bending  from  side  to  side  with  a 
forward  movement  at  the  same  time.  Each  moving  fila- 
ment, when  it  comes  to  rest,  may  become  the  centre  of  a 
new  colony,  which  arises  from  it  by  fission. 

Six  genera  and  thirty    or  more  species  are  known  in  the  United 
States.    The  principal  genus 
is  Nottoe  (Pig.  148.   ^);   its  ^ 

species  form  jelly-like  masses  ^^-  - 

from  the  size  of  a  pin-head  to 
4wveral  inches  in  diameter  in 
ponds  and  streams,  adhering 
to  sticks  and  twigs,  and  on  wet  pig.  \4R,—a,  a  lUament  of  a  Noetoc,  with  a 
wcks  or  wet  ground;  they  l^^u,rocy^;_B.  .nd^m.m.nt  of  «,- 
-even   grow    inside    of    other 

plants— «.^.,  ArUhoceros  lasvis — and,  according  to  the  present  view,  con- 
stitute the  80^»lled  gonidia  of  certain  lichens. 

284.~Order  OsoillatoriaoeeB.  The  filaments  in  this  or- 
der are  composed  of  more  cldsely  cohering  cells  than  in  the 
previous  one ;  the  cells  unite  by  broad  surfaces  to  form  a 
rigid,  cylindrical,  straight  or  slightly  curved  filament  (Fig. 
148,  B),  They  form  dark-green,  loose,  or  felted  masses  in 
water  or  on  wet  earth,  and  are  remarkable  for  the  peculiar  ^ 
oscillating  movements  of  their  filaments.  No  other  method 
of  reproduction  than  by  fission  is  known. 

The  principal  genus  is  OacUlaria,  of  which  we  have  about  thirty 
species. 

286.~Order  BiytOariaoeeB.  The  filaments  in  this  order 
present  a  greater  differentiation  than  in  any  of  the  preced- 
ing ;  they  are  usually  arranged  in  a  radiating  manner,  and 
imbedded  in  a  common  jelly,  so  as  to  form  small  rounded 


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^18  BOTANY. 

ma88es.  Each  filament  has  a  basal  cell  (which  is  spherical 
and  thick  walled),  and  sometimes  interstitial  ones ;  the  prin-r 
cipal  cells  of  the  filaments  are  usually  cylindrical  and  often 
much  elongated  ;  at  the  outer  end  they  become  attenuated 
into  long  slender  hyaline  hairs.  Special  reproductive  bod- 
ies, called  resting  sporet,  are  formed  before  the  close  of  the 
growing  season  ;  these  appear  just  above  the  basal  cells,  one 
on  each  filament,  and  are  much  larger  and  thicker  walled 
than  the  remaining  cells.  Upon  the  death  of  the  mass  of 
filaments  the  resting  spores  remain,  and  from  these  upon  the 
advent  of  favorable  conditions  new  filaments  are  developed. 

Five  genera  are  known  in  the  United  States,  the  principal  ones 
being  Rivularia,  Calothrix,  and  M(uUgonema  ;  their  species  are  found 
in  water  or  wet  places  ever3rwhere ;  they  also  constitute  the  so-called 
gonidla  of  lichens. 

286.— Order  ScytonemaoesB.  In  this  order  the  differen- 
tiation becomes  so  great  that  the  filaments  may  be  said  to 
attain  a  distinct  individuality  ;  they  branch  here  and  there, 
and  are  furnished  with  thick-walled  heterocysts,  which  ai-e 
basal  or  interstitial.  In  this  order  there  is  also  a  well-de- 
veloped sheath  surrounding  each  filament,  which  may  be 
compared  with  the  poorly  defined  one  of  the  preceding 
orders.  The  filaments  form  little  masses  or  mats,  growing 
in  the  water  or  on  wet  ground,  or  even  on  the  moist  bark  of 
trees. 

We  have  five  genera,  the  principal  one  of  which  is  BcyUmema, 
which  contains  nineteen  species.  Some  of  these  are  the  "  gonidia"" 
of  lichens. 

287. — Closely  related  to  the  foregoing  orders,  but  not 
falling  within  the  class  Cyanophyceae,  is  the  doubtful  order 
PalmellacecB.  The  cells  are  single  or  in  colonies,  and  im- 
bedded in  a  gelatinous  matter,  much  as  in  the  ChroococcacesB  ; 
but  the  cells  are  destitute  of  phycocyanine  or  phycoxanthine, 
containing  only  chlorophyll.  This,  however,  is  hardly  a 
sufficient  character  for  separating  them.  It  is,  moreover, 
not  certainly  known  whether  the  forms  included  in  this 
order  are  autonomous  species  ;  it  seems  probable  that  at 
least  a  portion  of  them  are  only  early  stages  of  other  plants. 


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CYANOPHTCEJE, 


219 


288. — The  genera  Protococcus,  Chlorococcumy  and  one  or 
two  others,  are  probably  to  be  placed  near  the  Palmellaceaa, 
although  their  autonomy  is  doubtful  also.  They  are  all 
unicellular  in  the  strictest  sense  of  the  term,  and  reproduce 
mainly  by  fission.  In  their  resting  stage  they  are  spheroidal ; 
in  their  motile  stage  they  are  provided  with  two  cilia.  The 
latter  form  is  said  to  arise  from  the  former  by  internal  cell- 
division,  which  results  in  the  production  of  "gonidia'*of 
two  sizes,  the  larger  being  termed  macrogonidia,  and  the 
smaller  microgonidia. 

These  organisms  are  common  in  shallow  pools,  in  the  gut- 
ters of  roofs,  and  on  the  wet  earth. 

(a)  For  an  account  of  the  structure  of  Protococcus,  with  directions 
as  to  methods  of  study,  see  Arthur,  Barnes  and  Coulter's  "Hand- 
book of  Plant  Dissection,"  p.  22. 

{b)  In  the  study  of  the  CyanophyceaB,  and  of  other  **  fresh-water 
algie,"  the  student  will  find  Rev.  Francis  Wolle's  "Fresh-water 
Algae  of  the  United  States"  (1887)  of  great  value. 

(c)  On  account  of  their  ready  perishability,  Protophytes  are  scarcely 
found  in  a  fossil  state.  Schimper  records  a  species  of  Nostoc  from  the 
Tertiary. 

(eO  The  relationship  of  the  classes  of  the  Pi^tophytes  may  be  indi- 
cated by  the  following  diagram : 


Abbanoemsnt  of  the  Classes  of  Protophtta. 

Cyanophyce» 


Myxomycetes. 


Schizomyoetes. 


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CHAPTER  XV. 
ZYGOPHYTA. 

289. — This  is  an  assemblage  of  quite  simple  plants,  none 
of  its  members  attaining  any  great  degree  of  complexity. 
For  the  most  part  the  plant-body  consists  of  an  elongated 
filament  composed  of  united  cells ;  sometimes,  however, 
they  form  surfaces,  and  in  other  cases  the  plants  are  unicell- 
ular, or  aggregated  into  communities.  In  these  plants  we 
find  the  first  examples  of  undoubted  sexuality,  and  through- 
out the  group,  the  organs  and  methods  of  fertilization  are 
nearly  enough  uniform  to  enable  us  to  use  them  as  distin- 
guishing characters.  The  sexual  organs  all  have  this  in  com- 
mon, that  between  the  male  and  the  female  there  is  no  ap- 
preciable difference  as  to  form,  size  (with  a  few  exceptions), 
color,  origin,  etc.  In  the  sexual  processes,  likewise,  there  is 
this  in  common,  that  the  result  of  the  union  of  the  two 
sexual  cells  is  the  production  of  a  new  cell,  the  zygospore, 
possessing  very  different  characteristics  from  either.  While 
the  sexual  cells  have  only  ordinary  walls,  or  none  at  all,  the 
zygospores  are  covered  with  thick,  firm  walls. 

290. — The  zygospore  is  frequently  called  the  *^  resting 
spore,"  because  under  certain  circumstances  it  remains  quies- 
cent, while  retaining  its  vitality,  often  for  long  periods  of 
time.  Thus  at  the  close  of  the  growing  season,  as  upon 
the  advent  of  the  summer  drought,  or  of  winter,  the  zygo- 
spores fall  to  the  bottom  of  the  pools  (in  the  aquatic  forms), 
and  in  the  dried  or  frozen  mud  remain  uninjured  until  the 
return  of  favorable  conditions,  when  they  germinate  and  give 
rise  to  a  new  generation  of  plants. 

291. — Nearly  all  the  plants  of  this  group  contain  chloro- 
phyll, only  one  order  being  destitute  of  it.  The  green  forms 
are  all  aquatic,  and  inhabit  either  fresh  or  salt  water.     They 


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ZOOaPOBEJS.  221 

include  the  greater  part  of  the  green  alg»  of  our  ponds 
and  streams.  Those  which  haTC  no  chlorophyll  are  sapro- 
phytes, and  liye  upon  dead  organic  matter.  They  are  doubt- 
less to  be  regarded  as  modified  forms  of  some  of  the  types 
of  the  chlorophyll-bearing  portion  of  the  group. 

§  I.   Class  Zoospores. 

292. — This  class  is  a  somewhat  doubtful  one ;  it  is  com- 
posed of  plants  which,  while  differing  in  many  other  re- 
spects, agree  in  having  locomotive  sexual  cells  {zoospores). 
In  tliis  they  agree,  however,  with  the  VolvocinecB,  and  bear 
a  close  resemblance  to  Frotococcus  and  its  allies.  It  is  prob- 
able that  a  fuller  knowledge  of  some  of  the  plants  of  this 
class  will  result  in  their  being  distributed  elsewhere. 

The  general  structure  of  the  plants  referred  to  this  class 
may  be  understood  from  the  examples  which  follow.  No  at- 
tempt will  be  made  here  to  indicate  the  orders  to  which 
they  belong. 

298. — Pandorina  is  a  unicellular  alga,  which  is  united  into 
colonies  (called  coBnobia),  which  swim  about  freely  in  the 
water  {A,  Fig.  149).  Each  colony  consists  of  sixteen  rounded 
or  pointed  cells  (called  zoogonidia),  each  provided  with  two 
cilia,  and  united  into  a  spherical  mass  by  a  gelatinous  enve- 
lope, through  which  the  cilia  project.  Each  zoogonidium 
breaks  itself  up  into  sixteen  new  zoogonidia,  forming  sixteen 
small  and  new  colonies  {B,  Fig.  149),  which  are  soon  set  free 
by  the  absorption  of  the  common  envelope  of  the  colonies. 
The  process  of  colony-formation  just  described  is  repeated 
again  and  again,  thus  giving  rise,  asexually,  to  a  large  num- 
ber of  colonies. 

294. — The  sexual  process  begins  in  the  same  way  ;  but  the 
zoogonidia  of  the  new  colony  separate  by  the  softening  of 
the  colony-envelope  ((7  and  2>,  Fig.  149),  becoming  zoospores, 
which  are  naked  protoplasm-masses,  which  swim  about  by 
means  of  their  cilia.  After  a  time  two  zoospores  meet,  their 
points  coming  in  contact,  and  their  bodies  soon  fusing  into 
bne  common  body  {E,  F,  G,  Fig.  149).  The  result  of  this 
nnion^  which  is  regarded  as  a  very  simple  kind  of  sexual 


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223  BOTANY. 

act,  is  that  within  a  short  time  a  thick  coat  of  cellulose  is 
formed  over  the  new  cell,  thns  producing  a  zygospore  {ff. 
Fig.  149).     After  a  long  period  of  rest^  these  zygospores 


ft):H^ 


F 

Fig.  U9.—Pnndorina  Morum.  A,  non-sexnal  colony  (orcflenoblnm)  of  16  soogoni- 
dia ;  a,  red  spot ;  d,  transparent  anterior  end  of  soogonldium,  to  which  the  two 
cUia  are  attached. 

B,  sixteen  young  texnal  colonies  about  to  leave  the  gelatinous  wall. 

(7  and  D,  colonies  of  sexual  zoospores  escaping. 

£,  F,  O,  conjugating  zoospores 

2r,  zvgospore  in  renting  stage  (red). 

J,  Jl,  germinating  zygospore,  the  contents  escaping  as  a  large  red  ciliated  awarm- 
q>ore. 

L.  new  colony  formed  by  the  divii>ion  of  JT,  very  young  stage. 

M,  the  aame  colony  as  X,  in  a  farther  atage  of  development.— After  (Erated. 

germinate  hy  the  hursting  of  the  coat  (exospore),  when  the 
protoplasmic  contents  escape  as  a  ciliated  swarm-spore  {X, 
Fig.  149).    After  swimming  about  for  some  time,  the  swarm- 


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ZOOSPOREjS,  223 

spores  absorb  their  cilia,  and  surround  themselves  with  a 
gelatinous  envelope,  when  each  breaks  up  into  sixteen  cells 
(zoogonidia)  and  gives  rise  to  a  new  colony  {L  and  if,  Fig. 
149). 

Pandorina  is  nearly  related  to  Volvox  (see  p.  243),  from 
which  it  seems  a  violence  to  separate  it.  It  occurs  in  pools 
of  fresh  water  (in  Europe)  as  minute  green  spherical  ccenobia, 
3  mm.  (.012  inch)  in  diameter. 

296. — Hydrodictyo7i,  the  Water  Net,  is  a  common  plant 
in  ponds  and  sluggish  streams.  It  is,  when  full  grown,  a 
tubular  net,  composed  of  a  multitude  of  elongated  cells, 
which  are  attached  only  at  their  ends  ;  the  net  sometimes 
attains  a  length  of  25  to  30  centimetres  (10  to  12  inches), 
and  the  cells  which  compose  the  meshes  are  in  such  speci- 
mens 7  to  8  mm.  (^  inch)  long.  The 
reproduction  is  as  follows  :  The  pro- 
toplasmic contents  of  certain  cells 
break  up  into  a  large  number  of 
daughter  -  cells  (macrozoogonidia), 
there  being  often  a^  many  as  7000  to  p^  i50.-Part  of  a  ceii  of 
20,000 ;    these    soon  arrange  them-  XT^'ttVaSiSj^'adil 

selves    within    the    mother-cell    so    as  are  beginning  to  amiD^  them. 

.    .  .  Helves  80  as  to  form  aminia- 

to   form   a  miniature    net   (Fig.    150),  tnre  net  wUMn   tJie  mother- 

,  .   ,      .      ,        1    ,      j^i         y         \'  i  cell.— After  CErsted. 

which  IS  freed  by  the  absorption  of 

the  walls  of  the  mother-cell.  Under  favorable  conditions 
the  young  net  attains  full  size  within  a  month.  A  second 
mode  of  reproduction  is  known,  or  partly  known.  In  cer- 
tain cells,  in  the  division  of  their  protoplasmic  contents,  in- 
stead of  giving  rise  to  the  comparatively  large  macrozoogo- 
nidia, they  produce  an  extremely  large  number  (30,000  to 
100,000)  of  very  small  ciliated  swarm-spores  (zoospores,  or 
the  chronizoospores  of  Pringsheim),  which,  after  swimming 
about  for  a  time,  acquire  thick  walls,  and  fall  to  the  bottom 
of  the  water,  where  they  remain  in  a  resting  state.  Upon 
their  germination  they  pass  through  a  number  of  curious 
stages,  and  finally  give  rise  to  small  nets.  Suppanetz  is  said 
to  have  witnessed  the  conjugation  of  the  swarm-spores  within 
the  mother-cell,  or  immediately  after  their  emission.* 

♦  (^r.  Jour,  Me.  Science,  1875,  p.  399. 


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224 


BOTANY. 


290. — Closely  related  to  Hydrodidyon  is  Pediastrum  (Fig. 
151), which  consists  of  a  number  of  cells  arranged  into  a 
flat^  thallus-like  mtuss.  The  cells  at  a  certain  stage  produce,  by 


FIs[.  VS\.—A^  a  colODT  of  cells  const itatliijc  a  so-called  Indlvldiial  of  Pediastrum 
grantUatum ;  <,  cells  with  their  contents  remaining ;  the  white  cells  are  empty,  their 
contents  having  escaped  by  the  slits  sp:  a,  contents  of  a  cell  (macrozoogonidia) 
escaping.  B,  macrozoogonidia  g^  in  the  motile  state,  enclosed  in  the  membrane  h.  V, 
the  macrosooffonidia  arranging  themselves  in  a  colony,  still  enclosed  by  the  mem- 
brane b.    X  400.— After  Brann. 

internal  cell-division,  a  large  number  of  daughter-cells,  which 

are  of  two  sizes.     The  function  of  the  smaller  ones  is  un- 

0  known ;    the  larger  ones 

(macrozoogonidia)    escape 

by  a  slit  in  the  wall  of  the 

mother-cell,  surrounded  by 

a  thin  membrane,  in  which 

they  swim  freely  for  a  time 

(Fig.  151  B).       After    a 

while  they  lose  their  pow- 

er  of  motion  and  arrange 

themselves  symmetrically, 

as  in  C,  Fig.  151.    They 

soon  grow  together,  and 

thus  form  a  colony  like 

the  parent  one. 

297.  —  In    Cladophora 

(one  of  the  common  Confervaceae)  the  cells  of  the  branching 

filaments  break  up  into  ciliated  zoospores  which  directly 


Fig.  152.~Portion  of  the  thallns  of  Viva,  a, 
cells  filled  with  zoospores  (zoogonidia) ;  5, 
opening  in  cell-wall,  by  which  the  zoospores 
escape  from  the  cells;  c,  zoospores  (zoogo- 
nidia)—After  (Ersted. 


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DE8MIDIACEJE,  225 

reproduce  new  filaments.    Smaller  bodies — swarm-spores — 
are  also  produced,  and  these  are  said  to  conjugate.* 

298. — In  Ulva  the  plant-body  is  flat,  and  composed  of  a 
single  layer  of  polyhedral  cells,  in  which  are  found  zoospores, 
which  are  asexatJ  (Fig.  152,  c),  and  smaller  swarm-spores, 
which  are  said  to  conjugate.!    [See  foot-note  on  p.  242.] 


§  IL   Class  Conjugate. 

299* — In  this  class  .the  sexual  process  is  a  distinct  conju- 
gation, and  it  always  takes  place  in  the  mature  plant. 
Swarm-spores  are  wanting.  The  orders  of  this  class  are  well 
marked. 

SOO.—Order  Desmidiaoese.  The  Desmids  are  minute  uni- 
cellular algae ;  the  cells  are  of  very  various  forms,  mostly 
more  or  less  constricted  in  the  middle,  and  divided  into  two 
symmetrical  half-cells ;  they  are  free,  or  united  into  loose 
families,  sometimes  involved  in  a  jelly.  The  cell-wall  is 
more  or  less  firm,  but  not  silicious. 

801. — ^The  reproduction  of  Desmids  takes  place  asexually 
and  sexually.  In  the  first  the  neck  uniting  the  two  halves 
of  the  cell  elongates  and  becomes  divided  by  a  transverse 
partition,  so  that  instead  of  the  original  symmetrical  cell 
there  are  now  two  exceedingly  unsymmetrical  ones;  these 
grow  by  the  rapid  enlargement  of  the  new  and  small  halves ; 
eventually  the  two  cells  become  symmetrical,  by  which  time 
they  have  separated.  This  process,  which  is  essentially  fis- 
sion, may  be  repeated  again  and  again. 

The  sexual  process  takes  place  in  this  way :  each  of 
two  cells  which  are  near  one  another  sends  out  from  its 
centre  a  conjugating  tube,  which  meets  the  corresponding 
one  from  the  other  (d,  Fig.  153).  At  the  point  of  meeting 
the  two  tubes  swell  up  hemispherically,  and  finally,  by  the 
disappearance  of  the  separating  wall,  the  contents  unite  and 
form  a  rounded  zygospore  (e,  Fig.  153),  which  soon  becomes 

♦  and  f.  Areschoag,  in  •'  ObservationeB  PhycologlcflB/*  1874,  records 
having  seen  the  conjugation  in  Cladophora  and  XJlva, 


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.BOTANY. 

coated  with  a  thick  wall  (/^  Fig.  153).  This  zygospore  is  a 
resting  spore^  and  may  retain  its  vitality  for  an  indefinite 
period. 

802. — In  the  germination  of  the  zygospore  the  first  notice- 
able change  is  the  partial  separation  of  the  contents  into  two 
portions^  and  the  escape  of  the  whole^  surrounded  by  a  deli- 
cate wall,  through  a  rent  in  the  exospore  (^,  A,  Fig.  153) ; 
the  separation  of  the  protoplasm  now  becomes  complete 
{iy  Fig.  153),  and  each  portion  becomes  again  partly  divided 
by  lateral  constrictions,  which,  however,  do  not  quite  reach 
the  centre ;  in  this  way,  within  the  mass  which  escaped  from 
the  zygospore  there  are  formed  two  constricted  cells,  which 


_  ^.  168.— Conjneitioii  of  Ornnarium  MenenghinU.  a,  front ;  5,  end  ;  «,  side 
Tiew  of  the  sdnlt  plants ;  (i,  two  cells  copjngating ;  «,  young  zygospore  formed ;  /, 
ripe  zygospore,  with  spiny  wall— the  foar  halves  of  the  parent  cells  are  empty  ;  g^ 
the  zy^pore  germinating  after  a  period  of  rest ;  A,  the  yoong  cell  escapcSd  IWnn 
zygospore ;  i,  young  cell  dividing,  showing  two  new  plants  similar  to  a,  placed 
crosswise  in  the  interior  of  the  cell,    x  475.— After  (Ersted. 

are,  in  fact,  new  individuals  resembling  the  original  ones 
which  conjugated  (a,  J,  c,  Fig.  153). 

The  descriptions  above  given  are  of  the  processes  as  they 
take  place  in  the  bilobed  Desmids  ;  in  those  which  are  not 
lobed  it  takes  place  in  essentially  the  same  way,  with  differ- 
ences only  in  the  minor  details. 

808. — Desmids  have  the  power  of  slow  locomotion,  and 
they  may  often  be  seen  moving  across  the  field  of  the  micro- 
scope, or  in  a  jar  or  bottle  they  may  frequently  be  seen  to 
congregate  in  particular  places.  The  mechanism  of  the 
movement  is  unknown,  but  it  appears  to  be  certain  that  it  is 
not  ciliary. 

Desmids  are  exclusively  inhabitants  of  fresh  water  (not 
salt),  and  in  almost  all  cases  they  appear  to  prefer  pure  and 


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DIATOMACEJE,  227 

dear  water  to  that  which  is  stagnant,  although  they  are  to  be 
found  in  the  latter  also. 

The  principal  genera  are  Cotmarium  (Fig.  153),  EuatiTMm  and 
ifioftM^ariM,  whicli  are  constricted  in  tbe  middle  ;  and  Clostmium,  in 
which  the  individnals  are  cylindrical  or  fasiform.* 

804.— Order  Diatomaoese.f  The  Diatoms  are  micro- 
scopic unicellular  algae,  resembling  in  many  particulars  the 
Desmids,  but  differing  from  them  in  having  walls  which  are 
silicified,  and  in  the  chlorophyll  being  hidden  by  the  pres- 
ence of  phycoxanthine.  The  endochrome,  as  the  colored 
contents  are  called,  is  always  symmetrically  arranged.  Each 
cell  (technically  called  a  frustule)  is  usually  composed  of  two 
similar  and  approximately  parallel  portions,  called  the  valves. 
Each  valve  may  be  described  as  a  disc  whose  edge  is  turned 
down  all  around,  so  aa  to  stand  at  right  angles  to  the  remainder 
of  the  surface,  making  the  valve  have  the  general  plan  of  a  pill- 
box cover.  The  two  valves  are  generally  slightly  different 
in  size,  so  that  one  slips  within  the  other  {A,  Fig.  154),  thus 
forming  a  box  with  double  sides.  In  other  cases — ^as,  for  ex- 
ample, in  Diatoma  and  Fragilaria — ^the  valves  are  simply 
opposed,  and  do  not  overlap.  In  figures  and  descriptions  of 
Diatoms,  the  parts  corresponding  to  the  top  and  bottom  of  a 
box  are  referred  to  as  the  valves,  or  as  the  side  view  {C,  Fig. 
154),  and  that  which  in  the  box  would  be  called  the  side,  is 
in  the  Diatom  called  the  front. 

806. — The  individuals  may  exist  singly,  or  in  loose  fami- 
lies ;  they  are  free,  or  attached  to  other  objects  by  little 
stipes,  and  they  are  frequently  imbedded  in  a  mucous  secre- 
tion. The  free  forms  are  locomotive,  and  may  be  seen  in 
constant  motion  under  the  microscope.  As  in  the  Desmids, 
the  mechanism  of  this  movement  is  not  certainly  known ; 

*  The  student  Is  referred  to  Rev.  Francis  WoUe's  "  Desmids  of 
the  United  States,"  1884,  for  an  account  of  our  species. 

f  Most  of  our  species  are  figured  and  described  in  Henri  Yan 
Heurck's  *'  Synopsis  des  Diatom€es  de  Belgique,"  1880-5. 


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2^S  BOTANY. 

the  most  probable  explanation  is  that  it  is  due  to  protmsionB 
of  the  protoplasm  through  orifices  in  the  rigid  wall. 

806. — Diatoms  bear  a  close  resemblance  to  the  Desmids 
in  their  modes  of  reproduction  ;  the  differences  that  exist 
are  easily  referable  to  the  differences  in  the  wall.  The 
asexual  reproduction  is  a  true  fission,  although  at  first  sight 
it  might  not  be  recognized  as  such.  The  protoplasmic  con- 
tents of  the  cells  divide  in  a  plane  parallel  to  the  valves ; 
3  each    portion    then    forms    a 

new  valve  in  the  plane  of  the 
division.     As  during  this  pro- 
cess the  two  original  valves  are 
pushed  apart,  the  new  valves 
are  fitted,   the    one  into  the 
larger  and  the  other  into  the 
I  smaller  one  (By  Fig.  154).     By 
I  a  slight    subsequent    increase 
of    their    contents,    the    two 
daughter-cells  are  pushed  out 
so  as  to  be    free    from    each 
other  ;  in  many  cases  they  sep- 
arate, while  in  others  they  re- 
main   in    contact,     although 
^^         really  free.      This  process  re- 
viSi^'of'l-Tf^lSSff^i?^  quires  from  three  to  four  days 

in'Sltre^lS^n^fe  for    its  completion.      It    will 

called  the  raphe,  the  central  and  termi-  readilv  be  Seen  that  the  COU- 
nal  nodulee,  and  the  surface  markingi.    *^**^    J   ^^   ^'^^^    *'"*•*'    *'"^  ^^" 

—After  (Ei-Bted.  tmucd  formation  of  individu- 

als in  this  way  must  result,  in  all  species  whose  valves  are  of 
a  slightly  unequal  size,  in  producing  smaller  and  smaller 
cells.  This  reduction  of  size  does  not,  however,  take  place 
in  those  species  whose  valves  are  simply  opposed,  as  in  Dia- 
toma.  The  reduction  of  size  is  corrected  by  the  formation 
of  what  are  termed  auxospores  ;  *  these  are  large  individu- 
als, which  form  either  by  an  asexual  or  a  sexual  process. 
The  asexual  formation  of  auxospores   takes  place  by  the 

*  From  the  Greek  ai^dvUf  to  increase. 


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DIATOMACE^,  229 

protoplasm  of  one  of  the  small  Diatoms  leaving  its  silieious 
shell  (the  latter  falling  apart),  and  then  increasing  by  growth 
until  it  reaches  the  normal  size,  when  it  forms  a  new  coat 
about  itself.  This  is  not  unlike  what  has  been  called  the 
Bejuvenescence  of  the  cell.     (See  p.  42.) 

307. — The  second  mode  of  the  formation  of  auxospores  is 
a  sexual  one,  and  is,  in  fact,  the  sexual  mode  of  reproduc- 
tion above  referred  to.*  Two  individuals  come  near  ea^h 
other ;  their  valves  separate,  and  the  two  protoplasm-masses 
unite  with  each  other  into  one  mass,  or  in  many  cases  two 
masses  {Ay  Fig.  155).  These  new  masses  develop  directly 
into  auxospores,  the  whole  process  ^ 

requiring  from  ten    to    fourteen 
days  {B,  Fig.  155). 

308. — Diatoms  are  exceedingly 
abundant ;  they  occur  in  both  -^ 
salt  and  fresh  water,  usually 
forming  a  yellowish  layer  at  the 
bottom  of  the  water,  or  they  are 
attached  to  the  submerged  parts  of 
other  plants,  and  to  sticks,  stones, 
and  other  objects  ;  they  have  been 
dredged  from  the  ocean  at  great 

depths,  and  appear  to  exist  there  ^^  ,55.-i««<«*.  «««mi.«. 
m  enormous  quantities.     They  are  e^owing  coi^jagation  and  forma- 

,       -  ,         *  1     ii  tion  of  auxospores.    ^,  coniusra- 

also  found  among  mosses  and  other  tion  of  two  fmstuies ;  b,  two  auz. 

^1      .  •   .  J  ,     ospores,  with  the  four  valves  of 

plants     on     moist     ground  ;     great    the   two  parent  fhi8tuIee.-After 

numbers  occur  as  fossils,  forming  ^''•'®^ 
in  many  instances  vast  beds  composed  of  their  empty 
fmstuies.  The  varied  and  frequently  very  beautiful  mark- 
ings of  their  valves  have  long  made  Diatoms  objects  of 
much  interest  to  the  microscopist.  The  great  regularity 
and  the  extreme  fineness  of  the  lines  and  points  upon  some, 
have  caused  them  to  be  used  as  microscopic  tests.     The 

*  Tliifl  process  takes  place  at  certain  seasons  of  the  year  for  each 
apedes ;  according  to  Professor  H.  L.  Smith,  in  Oomphonema  oHvaceum 
it  occurs  in  February  and  March. 


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230  BOTANY. 

fineness  of  some  of  these  markings  is  astonishing,  as  will 
be  seen  from  the  following  list : 

*Pleur<mgina  Balticum 0006  mm.  (.000026  inch). 

Pl&uroHgma angukUum .0005    "     (.000019    " 

NawviarhomboideB 0004   "     (.000015    " 

Amphipleurapellueida 0002   "     (.000008   " 

(a)  Tbe  classification  of  Diatoms  is  as  yet  largely  artificial.  That 
proposed  by  Professor  H.  L.  Smith  f  is  one  of  the  most  satisfactory  ;  it 
is  baaed  upon  tbe  stractore  of  tbe  frastule.  He  divides  tbe  order  into 
tbree  tribes,  each  containing  several  families,  as  follows : 

TkIBB  I.    RAFHIDIEiB. 

Frustules  mostly  bacillar  (i.^.,  longer  than  broad) ;  always  with  a  dis- 
tinct raphe  or  median  line  on  one  or  both  valves,  and  with  central  and 
terminal  nodules ;  withoat  teeth,  spines,  awns,  or  processes. 

Family  1.  CymbellesB.  Raphe  mostly  carved ;  valves  alike,  more 
or  less  arcaate,  cymbiform  (».«.,  lunate). 

Illustrative  genera,  Amphora,  CymbeUa, 

Pamily  2.  KaviculesB.  Valves  symmetrically  divided  by  the 
raphe  ;  frustules  not  cuoeate  or  cymbiform. 

Namcula  (Figs.  154  and  155),  StauroneU,  Pkurotigma,  Amphi- 
pleura. 

Family  8.  GtompbonemesB.  Valves  cuneate  ;  central  nodule  un- 
equally distant  from  the  ends. 

Oamphonema,  Bhaicosphenia. 

Family  4.  AchnanthesB.  Frustules  genuflexed ;  nodule  or  staU' 
ros  on  one  valve  ;  mostly  stipitate. 

Aehnan(he8,  Aehnanthidium. 

Family  6.  Cocconidess.  Frustules  (generally  parasitic)  with  valves 
unlike  ;  valves  broadly  oval 

Cooeaneia,  AnoriheU. 

TbIBB  II.    PSKUDO-RAPHIDIBiB. 

Frustules  generally  bacillar  (t.«..  longer  than  broad) ;  valves  with- 

♦  These  measurements  are  those  given  in  Carpenter's  work  on  "  The 
Microscope,"  fifth  edition,  p.  212.  Those  jjiven  by  Professor  Morley,  m 
Am,  Naturalist,  1875,  p.  429,  are  a  trifle  less  in  each  case. 

"     "   ispectus  of  the  Families  and  Genera  of  the  Diatomaoeas/'  by 
mith,  published  in  The  Lem,  1872-8,  and  republished  in  Le 
pe,  sa  construction,  etc.,  by  Henri  Van  Heurck,  1878. 
rief  sketch  of  this  system  of  classification  here  given  is  fur- 
Y  Professor  Smith. 


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DIATOMAOEJB.  231 

oat  a  true  raphe;  without  central  and  marginal  nodules;  without 
teeth,  processes,  or  spines. 

Ftunily  6.  Fragilarieas.  Frnstules  adherent,  forming  a  ribbon- 
like, fan-like,  or  zigzag  filament,  or  attached  by  a  gelatinous  cushion 
or  stipe  ;  sometimes  arcuate  in  front,  or  side  view. 

EpUKemia,  Eunotia,  FragHaria,  Synedra,  Diatoma, 

Family  7.  Tabellarieas.  Frustules  with  internal  plates,  or  imper- 
fect septa,  often  forming  a  filament. 

CUmaeosphenia,  Orammatophora,  Bhabdonema,  TaSbeUaria^  8tria- 
telia. 

Family  8.  Surirellen.  Frustules  alate,  or  carinate;  frequently 
cuneate  in  front  view  and  side  view. 

Nituchia,  Surirelia,  Cymatopleura, 

TBIBE  III.    CBTFTO-RAFHIDIBiB. 

Frustules  cylindrical  or  angular  ;  frequently  with  processes,  spines, 
teeth,  or  awns  ;  and  often  coherent,  forming  a  filament. 

Family  9.  ChastoceresB.  Frustules  mostly  hyaline  and  armed 
with  bristles  or  awns,  and  generally  coherent. 

Bhkosolenia,  OhcUoceroi, 

Family  10.  MelosiresB.  Frustules  cylindrical,  adhering  and  form- 
ing a  stout  filament ;  valves  cylindrical,  sometimes  armed  with  spines. 

Ifelonra,  Stephanopyxis, 

FUnily  11.  Biddulphiess.  Frustules  adherent,  forming  generally 
a  zigzag  filament,  attached  by  one  or  two  processes. 

Isthmia,  Terpsinoe,  BiddtUphia,  HenUaulus. 

Family  12.  Eupodiiceas.  Frustules  not  forming  a  filament ; 
▼alves  cylindrical,  with  ocelli ;  often  with  radial  ribs  or  furrows. 

AtUi9eu8,  Aulacodi$eu8,  EupodUeus, 

Family  13.  Heliopeltess.  Valves  divided  into  compartments  al- 
ternately light  and  dark,  often  with  marginal  spines  or  teeth. 

Aetinoptyehtt$,  HeUopeU'i,  Halionyx. 

Family  14.  Asterolamprees.  Valves  circular  (rarely  angular)  and 
mostly  hyaline,  with  linear,  often  bifurcating,  rays. 

Actinodi9cu$,  Mcutogonia,  Aateroiampra, 

Family  16.  OoscinodiscesB.  Valves  circular,  generally  with  radi- 
ating cellules,  granules,  or  punctae  ;  sometimes  with  marginal  or  intra- 
marginal  spines  or  distinct  ribs  ;  without  distinct  processes. 

CffdottUa,  Aetinoeyelun,  SUphanodUofus^  Arachn&idiaetu,  Coseino- 
dUcui, 

{b)  Diatoms  are  very  easily  obtained  for  study ;  it  is  only  necessary 
to  scrape  off  a  little  of  the  slippery  covering  of  submerged  stones  or 
sticks  to  procure  numerous  specimens.  They  may  be  obtained  also 
from  ordinary  drinking  water,  allowing  it  to  flow  from  a  hydrant 
through  a  filter  of  "  Canton  fiannel "  for  an  hour  or  so.     Often  appar- 


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232  BOTANY. 

ently  pare  water  placed  for  a  few  weeks  in  a  clean  bottle  and  expoBed 
to  the  light  will  yield  an  abundant  crop,  generally  of  one  species. 

309.~Order  Zygnemacese.  The  plants  of  this  order  are 
elongated  unbranched  filaments,  composed  of  cylindrical 
cells  arranged  in  single  rows.  The  cells  ai*e  all  alike,  and 
each  one  appears  to  be  independent,  or  nearly  so,  of  its  asso- 
ciates. The  filament  is  thus,  in  one  sense,  rather  a  com- 
posite body  than  an  individual.  Each  cell  has  usually  a 
centrally  placed  nucleus,  with  radiating  extensions  of  the 
protoplasm  passing  from  it  to  the  layer  lining  the  inner  sur- 
face of  the  wall.  The  chlorophyll  is  generally  arranged  in 
bands  or  plates,  but  under  certain  conditions  it  exists  in 
shapeless  masses. 

810. — The  vegetative  increase  of  the  number  of  cells  takes 
place  by  the  fission  of  the  previously  formed  cells.  The 
protoplasm  in  a  cell  divides,  and  a  plate  of  cellulose  forms  in 
the  plane  of  division.  This  is  repeated  again  and  again,  and 
by  it  the  filament  becomes  greatly  elongated.  It  is  interest- 
ing to  note  that  this  increase  of  cells,  which  here  constitutes 
the  growth  of  the  plant-body,  is  that  which  in  simpler  plants 
is  called  the  asexual  mode  of  reproduction.  In  the  plants 
under  consideration  there  is  barely  enough  coherence  of  the 
cells  to  enable  them  to  constitute  a  plant-body,  and  one  can 
readily  see  that  the  same  fission  of  the  cells  which  now  takes 
place,  and  which  here  increases  the  size  of  the  plant,  would, 
if  the  cells  cohered  less,  simply  increase  the  number  of  indi- 
viduals. 

As  might  be  expected,  the  filaments  occasionally  separate 
spontaneously  into  several  parts  of  a  considerable  length, 
and  the  parts  floating  away  give  rise  to  new  filaments.  The 
separation  takes  place  by  the  cells  first  rounding  off  slightly 
at  the  ends,  so  that  their  union  is  weakened  at  their  cor- 
ners ;  finally  only  the  centres  of  the  rounded  ends  are  left 
in  slight  contact,  which  soon  breaks. 

311. — The  sexual  reproduction  is  well  illustrated  in  Spi- 
rogyra,  one  of  the  principal  genera.  At  the  close  of  their 
growth  in  the  spring,  the  cells  push  out  little  processes  from 
their  sides,  which  extend  until  they  come  in  contact  with 


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ZYQNEMACEJE. 


233 


similar  processes  from  parallel  filaments  (a,  (,  Fig.  156). 
Upon  meeting,  the  ends  of  the  processes  flatten  upon  each 
other,  the  walls  fuse  together,  and  soon  afterward  become 
absorbed,  thus  making  a  channel  leading  from  one  cell 
to  the  other  (Fig.  157).     Through  this  channel  the  proto- 


Fie.l5r. 


Fio.  156. 

Fig.  156.— Beginning  of  the  process  of  coojagation  jn  Spirogyra  longakL.  a, 
beginning  of  the  fonnation  of  lateral  tubes ;  6,  c,  the  tabes  in  contact,  x  650. 
—After  ^bs. 

Fig.  157.— Ooi^Jagatioa  of  Spirogyra  longatn.  A,  the  protoplasm  parsing  from 
one  cell  to  the  oiher  at  a ;  6,  the  mass  of  protoplasm  formed  by  the  union  of  the 
protoplasmic  contents  of  the  two  cells. 

B^  two  young  zrgospores  (c),  each  with  a  cell-wall.  They  contain  numerous  oil 
4rops,  and  are  still  enclosed  by  the  walls  of  the  parent  cell,    x  560.— After  Sachs. 

plasm  of  one  cell  passes  into  the  other,  and  the  two  fuse  into 
one  mass,  which  becomes  rounded,  and  in  a  short  time  secretes 
a  wall  of  cellulose  around  itself  (Fig.  157,  A  and  B),  The 
zygospore  thus  formed  is  set  free  by  the  decay  of  the  dead 


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234  BOTANY. 

cell-walls  of  the  old  filament  surrounding  it ;  it  then  falls  to 
the  bottom  of  the  water  and  there  remains  until  the  proper 
conditions  for  its  growth  appear. 

812. — The  conjugation  described  is  the  one  best  known  ; 
it  prevails  in  a  large  part  of  the  genus  mentioned.  There 
are  some  curious  modifications  of  the  process.  In  what  is 
called  genuflexous  conjugation  the  opposing  cells  of  parallel 
filaments  become  strongly  bent  back  so  as  to  form  an  angle 
at  their  central  points ;  then  the  angles  approach  each  other 
and  fuse^  allowing  the  cell-contents  to  pass  Over^  as  in  the 
other  case. 

Lateral  conjugation  takes  place  between  the  cells  of  the 
same  filament.  At  the  contiguous  ends  of  two  cells  tubular 
processes  are  pushed  out,  which,  meeting,  form  a  curved 
channel  from  one  cell  to  the  other.  Occasionally  there  ap- 
pears to  be  only  a  slight  enlargement  of  the  contiguous  enda 
of  the  cells,  and  this  is  followed  by  the  breaking  away  of  a 
portion  of  the  separating  wall.  These  cases  of  lateral  con- 
jugation show  that  the  cells  are,  to  a  great  extent,  to  be  re- 
garded as  independent  organisms,  and  that  the  conjugation 
is  primarily  the  union  of  two  cells,  instead  of  two  filaments. 

818. — The  germination  of  the  zygospore  is  a  simple  pro- 
cess. The  inner  mass  enlarges  and  bursts  the  outer  hard 
coat;  it  then  extends  into  a  columnar  or  club-shaped  mass, 
gradually  enlarging  upward  from  its  point  of  beginning; 
after  a  while  a  transverse  partition  forms  in  it,  and  this 
is  followed  by  another  and  another,  until  an  extended  fila- 
ment is  formed. 

(a)  The  principal  genera  are  Spirogyra,  in  which  the  chlorophyll 
bands  are  spirally  arranged  in  the  cells,  and  Zygnema,  in  whidi  th& 
chlorophyll  is  usually  arranged  in  a  stellate  manner.  Thirty-nine 
species  of  Spvrogyra  are  recorded  as  occurring  within  the  United 
States,  and  of  these  8p.  longata  and  8p.  quinina  are  the  most  common. 
Of  Zygn&ma  six  species  are  recorded  in  the  United  States,  several  of 
which  are  common. 

(6)  These  plants  may  be  found  at  any  time  in  ditches  and  streams, 
where  they  often  form  extensive  masses  of  green  felt ;  but  it  is  only 
from  the  middle  to  near  the  end  of  spring  that  they  can  be  found  ia 
conjugation.  For  the  Northern  States  the  lime  varies  from  April  to 
the  first  of  June  ;  in  the  South  it  is  of  course  much  earlier,  being  ixk 


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MUCOBINL  235 

Florida  as  early  as  February.  In  searcbing  for  coDjugating  Bpecimens 
only  tbe  yellow  and  brown  masses  of  filaments  need  be  examined,  as 
the  process  never  takes  place  in  the  bright  green  ones. 

814. — ^In  the  genera  Mesocarpus  and  Phurocarpus  the 
conjugation  is  slightly  different  from  that  described  above. 
The  conjugating  tube,  which  is  much  longer,  becomes  di- 
lated midway  between  the  two  filaments,  and  in  this  the 
contents  of  the  two  cells  unite  and  form  a  zygospore.  This 
difference  has  been  considered  by  some  botanists  to  be  of 
sufficient  importance  to  set  off  these  genera  in  a  group  allied 
to,  but  distinct  from,  the  Zygnemaceae.  When  they  are  so 
set  off  they  constitute  the  MesocarpecB  ;  but  it  is  altogether 
probable  that  they  are  to  be  considered  rather  as  a  subdivi- 
sion of  the  ZygnemacesB  than  as  a  distinct  order. 

Mesacarpui  sctUarii  is  our  most  common  species.  In  general  appear- 
ance it  resembles  tbe  previously  mentioned  species,  but  its  cblorophyU 
is  not  so  regularly  arranged. 

816.— Order  Muoorini.  ^he  Moulds  are  saprophytic  and 
sometimes  parasitic  plants;  they  are  composed  of  long 
branching  filaments  {hyphce),  which  always  form  a  more  or 
less  felted  mass,  the  mycelium  ;  when  first  formed  the  hyphae 
are  continuous,  but  afterward  septa  are  formed  in  them  at 
irregular  intervals.  The  protoplasmic  contents  of  the  hy- 
phsB  are  more  or  less  granular,  but  they  never  develop  chlo- 
rophyll. The  cell-walls  are  colorless,  except  in  the  fruiting 
hyphae,  which  are  usually  dark  colored  or  smoky  (fuliginous). 
The  mycelium  sometimes  develops  exclusively  in  the  inte- 
rior of  the  nutrient  medium  ;  in  other  cases  it  develops 
partly  in  the  medium  and  partly  in  the  air.  In  some  species 
the  mycelium  may  occasionally  attach  itself  to  the  hyphae 
of  other  plants  of  the  same  order,  and  even  to  nearly  related 
species,  and  derive  nourishment  parasitically  from  them.  It 
is  doubtful,  however,  whether  any  Moulds  are  entirely  para- 
sitic, and  so  far  as  parasitism  occurs  it  appears  to  be  con- 
fined to  narrow  limits  ;  none,  so  far  as  known,  are  parasitic 
upon  higher  plants. 

816. — The  reproduction  of  Moulds  is  asexual  and  sexual. 
In  the  asexual  reproduction  the  mycelium  sends  up  erect 


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236 


BOTANY. 


hyphae,  which  produce  few  or  many  separable  reproductive 
cells — the  spores  (Fig.  158).  The  method  of  formation  of 
the  spores  in  Mucor  Mucedo  is  as  follows  :  the  vertical  hy- 
phae, which  are  filled  with  protoplasm,  become  enlarged  at 

the  top,  and  in  each 
a  transverse  partition 
forms  {A,  a.  Fig.  159), 
the  portion  above  the 
partition  (J,  Fig.  159) 
becomes  larger,  and, 
at  the  same  time,  the 
transverse  partition 
arches  up  {B^  a,  Fig. 
159),  finally  appearing 
like  an  extension  of 
the  hypha,  then  c^led 
the  Columella  (C,  a, 
Fig.  159).  The  pro- 
toplasm   in    the    en- 

rged  terminal   cell   {h)   divides   into  a  large  number  of 

inute  masses,  each  of  which  surrounds  itself  with  a  cell- 
ill  ;  these  little  cells  are  the  spores,  and  the  large  mother- 

11  is  now  a  sporangium. 

In  the  other  Moulds  the  process  is  essentially  like  that 
Mucor    Mucedo.      In 

any  cases  there  aresev- 

al   sporangia  formed  at 

e   top    of    the    vertical 

rphae ;  in  such  cases  the 

tter  are  branched  before 

e  formation  of  sporan- 

a.      Another    variation 

om   the  method   as  de- 

ribed  above   is   that  in 

me  species  but  one  spore    nres  repreMents  the  partition  wall  between  the 
•  ■,    .  y  last  cell  of  the  filament  and  t 


Fig.  166.~Diagram  showing  the  mode  of  growth 
'  Mucor  Mucedo.     m.  the  mycelinm:  #,  single 

iranginm,  borne  on  an  aerial  erect  hyph%— After 

mU. 


A 

B 

c 

^  \ 

^€ 

;':•' 

•::- 

% 

Fig.  159.— Diagrams  showing  modp  of 
growth  of  the  sporangium  of  Mucor  Mucedo. 
A,  very  younjj  ntajje ;  B.  somewhat  later ;  ('. 
sporangium  with  ripe  spores,    a  in  all  the  fl?- 


l  the  sporangium  t 

bear  naked  spores. 


formed  in  each  sporan- 
um ;  the  hyphae  then  appear  to 
317. — The  spores  are  set  free  in  different  ways ;  in  some 
tses  the  wall  of  the  sporangium  is  entirely  absorbed  by  the 
tne  the  spores  are  mature  ;  in  other  cases  only  portions  of 


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MUCORINL 


237 


the  sporangium-wall  are  absorbed,  producing  fissures  of  va- 
rious kinds— c.^r.,  at  the  base  in  Piloholus  ;  about  the  middle 
in  Circinella ;  irregular  in  Mucor,  etc.  The  spores  germi- 
nate readily  when  on  or  in  a  substance  capable  of  nourishing 
them  (but  not  in  pure  water) ;  they  send  out  one  or  two  hy- 
phsB  (sometimes  one  from  each  end),  which  soon  branch  and 
give  rise  to  a  mycelium.  Spores  may,  if  kept  dry,  retain 
their  vitality  for  months. 

318. — A  second  kind  of  asexual  formation  of  spores  takes 
place  in  some,  if  not  all,  the  genera  of  the  Mucorini.     The 


160.— Conjnffatlon  of  Muoor  tMotAfer.  a,  two  hyphse  near  each  other,  and 
eending  oat  short  lateral  processes  or  branches,  whicn  come  in  contact ;  6,  the 
branches  ftrown  larger ;  c^  the  formation  of  a  partition  near  the  end  of  ««ach  branch  ; 
dy  absorption  of  the  wall  between  the  two  branches,  and  the  consequent  anion  of 
the  protoplasm  of  the  end  cells;  «,  zygospore  folly  formed.  «  x  90;  the  others 
nearly  the  some.—Af ter  De  Bary. 

protoplasm  in  certain  parts  of  the  hyphae  condenses  and  be- 
comes transformed  into  single  reproductive  bodies,  known  as 
chlamydospores.  Occasionally  they  form  at  the  ends  of 
hyphae,  and  are  then  apt  to  be  mistaken  for  the  "fruiting** 
of  other  fungi. 

819. — Sexual  reproduction  takes  place  after  the  produc- 
tion of  asexual  spores ;  the  mycelium  produces  at  particular 
points,  in  the  air  or  within  the  nutritive  medium,  two  simi- 
lar branches,  which  come  in  contact  with  each  other,  and  by 
fusing  their  contents  give  rise  to  a  zygospore  (Fig.  160). 


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238 


BOTANY, 


The  steps  in  the  process  in  Jfucor  stolonifer  are  briefly  as 
follows :  two  hyphfe  come  near  each  other^  and  send  ont 
small  branches,  which  come  in  contact  with  each  other  (a. 
Fig.  160) ;  these  elongate  and  become  club-shaped,  and  at 
the  same  time  they  become  more  closely  united  to  each  other 
at  their  larger  extremities  {b,  Fig.  160);  a  little  later  a  trans- 
Terse  partition  forms  in  each  at  a  little  distance  from  their 
place  of  union  {c,  Fig.  160) ;  the  wall  separating  the  new 
terminal  cells  is  now  absorbed,  and  their  protoplasmic  con- 
tents unite  into  one  common  mass  (d.  Fig.  160) ;  the  last 
stage  of  the  process  is  the  secretion  of  a  thick  wall  around 
the  new  mass,  thus  forming  a  zygospore  (e,  Fig.  160,  and  z. 
Fig.  161). 

It  is  interesting  and  instructive  to  note  here  the  close  simi- 
larity between  the  zygospore  of  Mucor  stolonifer  and  that  of 
Mesocarpus,  briefly  described  above  (par.  314).     In  both  the 

zygospore  is  formed  in  the  lateral 
branches  of  the  ordinary  filaments. 
820. — ^In  Piptocephalis  the  for- 
mation of  the  zygospore  is  essen- 
tially like  that  in  MucoVy  with 
some  minor  differences.  The 
uniting  hypha-branches  are  large 
and  curved,  and  are  smaller  at 
their  points  of  union ;  the  zygo- 
spore is  formed  at  first  in  the 
small  neck  formed  by  the  union  of 
the  tips  of  the  branches,  but  it  soon  grows  so  much  as  to 
appear  to  be  external  (Z,  Fig.  162).  In  this,  as  in  all  other 
cases,  however,  the  zygospore  is  strictly  an  endogenous  for- 
mation. 

"  The  zygospore  does  not  germinate  until  it  has  under- 
gone desiccation,  and  has  experienced  a  certain  period  of 
rest,"  *  when,  if  placed  in  a  moist  atmosphere,  it  sends  out 
hyphsB  which  bear  sporangia.     The  zygospores  appear  never 

♦  "  Reseaiclies  on  the  Mucorini/*  by  Ph.  Van  Tiegbem  and  G.  Le 
Monnier  (translated  in  Quarterly  Journal  of  Microscopical  Scienee, 
1874,  p.  49),  upon  wbloh  moet  of  what  is  bere  said  about  the  Moulds  is 
based. 


Fig.  161.— ZTgospore,  «,  of 
w;  m,  myceliam.— After  Pn 


JTm- 

PraoU. 


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MUCOEINL  239 

to  form  a  mycelium;  that  is  always  the  result  of  the 
growth  of  spores  from  the  sporangia. 

(a)  In  the  ttadj  of  the  Moolde  it  is  almoet  always  necessary  to  make 
vm  of  alcohol  for  freeing  the  specimens  of  air ;  afterward  tlie/  usoall/ 


Mueedo. 

faU  spore    .  ,  . 

macpiifled.— After  Brefeld. 

reqoire  to  be  treated  witli  a  dilute  alkali,  as  a  weak  solution  of  am- 
monia or  potassic  hydrate,  whicli  causes  the  hyphae  to  swell  up  to  their 
original  proportions  before  drying ;  care  must  be  taken  that  the  hyphas 
and  spores  are  not  unduly  swollen,  or  serious  mistakes  may  be  made. 

(&)  In  the  careful  study  of  the  Moulds  it  is  necessary  to  resort  to  arti- 
ficial cultures  of  the  different  species,  in  order  to  be  able  to  follow  them 


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240  BOTANY. 

through  all  their  ehanges.  The  spore  of  a  particular  epedefl  most  bft 
•own,  and  the  development  of  hyplue,  mycelium,  eporangia,  etc,  care* 
iuUy  followed  ;  and  the  greatest  care  must  be  taken  to  guard  against 
error  from  the  accidental  presence  of  other  species. 

(c)  "  Pan  culture,"  which  consists  in  sowing  the  spores  upon  or  in  the 
nutritive  medium  in  pans  or  deep  plates  covered  by  bell-jars,  must  always 
be  resorted  to,  even  if  more  accurate  cultures  are  also  made.  By  placing 
a  quantity  of  horse<iung  in  a  pan  under  a  bell-jar,  there  will  soon  be 
obtained  a  good  supply  of  vigorous  Moulds ;  sometimes  several  species 
may  be  obtained  from  a  single  pan.  By  care  a  few  sporangia  of  each 
species  may  be  obtained  from  this  firet  culture,  with  little  probabilit/ 
of  contamination  wiih  other  species.  These  are  to  be  used  for  more 
careful  cultures. 

(d)  If  now  moistened  pieces  of  fresh  bread  are  placed  under  a  bell- 
Jar,  and  a  few  of  the  spores  of  a  particular  species  are  sown  on  them, 
the  growth  and  successive  stages  of  development  may  be  easily  fol- 
lowed. Instead  of  bread,  other  materials  may  be  used,  as  stewed 
prunes  and  other  fruits,  pieces  of  oranges  or  lemons,  etc.,  and  for  oer* 
tain  species  the  half-cleaned  bones  of  beef  from  the  kitchen. 

(e)  Where  still  greater  care  is  desirable,  the  nutritive  media  may  be 
prepared  by  boiling  and  filtering,  after  wliich  they  are  placed  in  Uior- 
oughly  cleaned  pans  or  plates,  and  covered  by  clean  bell.jars  ;  in  these 
are  placed  pieces  of  hardened  plaster  of  Paris  or  earthenware  (porous), 
which  have  previously  been  heated  so  as  to  destroy  all  spores,  and  upon 
them  are  sown  the  selected  spores.  The  sources  of  error  are  in  this 
way  very  much  reduced,  but  it  must  be  borne  in  mind  that  they  are  by 
no  means  all  eliminated  ;  hence  the  student  must  be  constantly  on  the 
lookout  for  other  species  than  the  one  under  culture. 

(/)  The  media  recommended  by  Van  Tieghem  and  Le  Monnier  are. 
(1st}  boiled  and  filtered  orange  Juice,  which,  being  acid  and  saccharine, 
is  not  so  liable  to  be  invaded  by  other  common  Moulds  ;  (2d)  a  decoc- 
tion of  horse-dung,  boiled  and  filtered  ;  this  is  neutral  and  alkaline,  and 
serves  as  a  medium  for  maoy  species ;  but  it  is  open  to  the  objection 
that  it  is  liable  to  the  invasion  of  intruding  species ;  (3d)  a  saline  sola* 
Uon  of  the  following  composition  : 

Calcium  nitrate 4  parts. 

Potassium  phosphate 1    *' 

Magnesium  sulphate 1     '* 

otassi  urn  nitrate 1    ** 

istilled  water 700    " 

Sugar 7parts.j 

cases  the  sugar  may  be  omitted. 

le  most  accurate  and  satisfactory,  but  at  the  same  time  most 
cultures,  are  cell-cultures.  These  are  made  as  follows:  glass, 
Qdia-rubber  rings  four  to  five  millimetres  high  are  fastened  to 


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MUCOBINL  241 

ordinary  glass  slides  ;  a  verj  little  water  is  placed  in  the  bottom  of  the 
cell  so  formed,  to  keep  the  air  in  it  always  moist ;  a  small  drop  of  the 
nntrient  liquid,  free  from  spores  of  any  kind,  is  placed  in  the  middle  of 
a  cover-glass  of  the  proper  dimensions,  and  in  this  a  single  spore  of 
0ome  particalar  Mould  is  placed  ;  the  cover-glass  is  now  inverted  over 
the  cell,  and  held  in  place  by  a  minute  quantity  of  oil  on  the  edge  of 
tbe  cell.  The  preparatiou  must  be  placed  in  a  warm  and  saturated 
atmosphere.  An  ordinary  boll-jar  set  over  a  plate  of  water,  or  l)etter 
still,  of  wet  sand,  u  ill  furnish  a  very  good  moist  chamber.  The  appa- 
ratus used  by  Vhu  Tughem  and  Le  Monnier  is,  however,  in  many  re- 
spects the  best  that  has  yet  been  devised  (Fig.  163). 

By  means  of  such  cultures  as  this,  the  student  may  follow  all  the  de- 
tails of  the  germination,  and  after-development  of  any  particular 
spore,  as  all  that  is  necessary  to  do  is  to  remove  the  slide  from  tlie 
growing  box,  and,  without  disturbing  the  cell,  to  place  it  under  the 
microscope  ;  the  same  specimen  may  thus  be  examined  any  number 
of  times,  with  the  least  possible  liability  of  error. 

(Ji)  The  most  common  Moulds  are  species  of  tbe  genus  Mucor,    M, 


ll^e^ii  o      ■  H^jxyijo 


Fie.  168.— Section  of  apparatus  for  cell  cultures.  The  shaded  portion  represents  a 
section  of  a  tin  or  zinc  box :  a,  a,  tbe  supporting  ledges ;  6,  b,  the  glass  slips  ;  e.  e, 
glass  or  meUil  rings  fastened  to  the  glass  slips,  seen  in  section,  and  covered  wltn  a 
niece  of  thin  glass  :  g,  plate  of  glass,  covering  the  box.  The  dotted  line  shows  the 
neighi  of  the  moist  sand  with  which  the  bottom  of  the  box  is  covered. 

Mueedo  and  M.  stolonifer  (if  distinct)  are  common  on  many  decaying 
substances.  M,  Syzygites  occurs  on  decaying  Agarics  and  Polypori, 
PilcMus  eryst^iUinus,  Piptocephaliu  Freseniina,  and  CliCBtodadium 
Jontaii  occur  on  animal  excrement.  Phycomyces  nitens  grows  on  oily  or 
greasy  substances,  as  old  bones,  oil  casks,  etc. 

(i)  The  Moulds  are  evidently  related  to  the  Mesocarpe®  in  their 
sexual  reproduction,  which  is  the  most  important,  as  it  is  the  most  con- 
stant.  The  conidia  of  Moulds  are  clearly  homologous  with  the  zoospores, 
of  tbe  Zoos{>orese.  bein$;  nothing  more  than  aerial  modifications  of  them. 
The  non-septated  condition  of  the  filaments  of  the  Moulds  does  not  con- 
stitute so  jsrreat  a  difierence  between  them  and  the  filaments  of  the  green 
Conjugatee  as  might  at  first  be  imagined ;  in  the  germination  of  the 
zygospore  of  Spirogyra  it  will  be  remembered  that  the  filament  elon- 
gates quite  a  g^ood  deal  before  a  septum  forms  in  it ;  between  this  and 
the  very  late  formation  of  septa,  as  in  the  Moulds,  the  difference  is 
only  one  of  degree.  The  Moulds  may  then  be  looked  upon  as  Meso- 
carpous  Conjugatce  which  have  lost  their  chlorophyll  through  their 
saprophytic  habits,  and  which  have  otherwise  undergone  slight  modifi- 
cations mainly  correlated  with  their  aerial  hahits. 


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242 


BOTANT. 


The  PHiBospoRRfi,  containing  the  kelp  and  its  allies,  are  marine 
plants  of  an  olive-brown  color,  varying  greatly  in  size  and  structure, 
from  minute  filamentous  forms  to  the  gigantic  kelp  with  stems  and 
leaves,  often  a  hundred  metres  or  more  in  length.  In  previous 
editions  they  were  regarded  as  more  nearly  related  to  the  FucacesB 
[p.  264],  but  their  reproduction  by  the  conjugation  of  similar  zoo- 
spores indicates  their  relationship  to  the  zygophytic  zoospores.  They 
include  the  highest  plants  of  the  class. 

Twelve  families,  viz.,  Scytosiphonece,  Punctariece,  Desmarestieae, 
Dictyosiphoneas,  Ectocarpes,  Sphacelariea.  Leathesiese,  Chordarieee, 
Asperococcese,  Ralfsiese,  Sporochnese,  Laminariese,  are  represented 
on  the  New  England  coast  by  twenty-six  genera  and  forty-eight 
species,  while  many  more  occur  on  the  Pacific  coast,  where  the 
great  bladder  ke\p  {M<ioroeifsti$  pyrffera)  eometimes  attains  a  length 
of  two  hundred  metres  or  even  more. 

Fossil  Zygophytes.— In  the  Silurian  period  species  of  Lamin- 
ariies,  JIarlania,  etc.,  probably  represented  the  Phseosporeae,  which 
order  was  also  abundantly  represented  in  the  Devonian.  Cottfertfiteg 
occurs  in  the  Jurassic,  and  in  the  Tertiary.  Fossil  diatoms  of  many 
species  have  been  found  in  the  Tertiary ;  at  Richmond,  Ya.,  they 
form  a  vast  bed  nearly  ten  metres  thick,  and  one  at  Monterey  is 
sixteen  metres  in  thickness. 

Abbanoement  of  the  Classes  and  Ordebs  of  Zyoophtta. 


o 

i 


I 


CONJUGATiB. 


ZOOSPORKS. 


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CHAPTER   XVI. 

OOPHYTA. 

821. — The  distinguishing  feature  of  the  plants  belonging 
to  this  division  is  that  they  develop  a  large  cell  (the  oogo- 
nium),  differing  from  those  about  it  in  size  and  general  ap- 
pearance, which  contains  one  or  more  rounded  masses  of 
protoplasm  (the  oospheres),  which  are  subsequently  fertilized 
by  the  contents  of  a  second  kind  of  special  cell  of  much 
smaller  size  (the  antheridium).  The  oogonium  is  the  fe- 
male reproductive  organ,  and  the  antheridium  the  male. 
The  protoplasm  of  the  latter  is  in  some  cases  transferred  by 
direct  contact  to  the  oosphere ;  in  other  cases  it  is  first  broken 
up  into  motile  bodies,  the  spermatozoids,  which  then  come 
to  and  become  fused  with  the  oosphere.  Tha  oosphere  itself 
is  never  motile,  and  in  most  cases  it  remains  within  the 
parent  plant  until  long  after  it  is  fertilized.  The  result  of 
fertilization  is  the  production  of  an  oospore,  which  differs 
from  the  oosphere  structurally  in  having  a  hard  and  gener- 
ally colored  coating,  and  physiologically  in  having  the  power 
of  germination  and  growth  after  a  period  of  rest  of  greater 
or  less  duration. 

822. — The  plants  of  this  division  vary  greatly  as  to  the 
development  of  the  plant-body.  In  some  cases  it  is  a  feebly 
united  colony  (Volvox  and  its  allies),  while  in  its  highest 
forms  it  is  a  well-developed  thallus,  with  even  the  beginning 
of  a  differentiation    into  Gaulome^   Phyllome,  and    Boot 

§  I.    VOLVOX  AKD  ITS  ALLIES. 

828. — In  the  classification  of  the  plants  of  this  division 
the  lowest  place  must  be  assigned  to  Volvox  and  Etidorina, 
which,  as  previously  stated,  are,  with  doubtful  propriety, 


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244  BOTANY, 

separated  from  Pandorina,  If  the  two  genera  are  to  be 
separated  from  Pandorina  there  can  be  but  little  doubt  that 
their  position  must  be  in  the  very  lowest  part  of  the  Oophy- 
ta.  Such  a  position  would  indicate  what  is  probable  on 
other  grounds  also,  that  the  diyisions  Zygophyta  and  Oophy- 
ta  lie  side  by  side  as  t\vo  diyergent  systems,  and  that  in 
their  lowest  members  they  almost,  if  not  entirely,  coalesce.* 
824. —  Volvox  globator  is  a  hollow  spherical  colony  of  uni- 
cellular alg89,  having  a  diameter  of  .5  to  .8  mm  (.02  to  .03 
inch).  Each  individual  of  the  colony  is  a  flask-shaped  cell 
of  green-colored  protoplasm,  bearing  two  cilia  upon  its 
pointed  extremity,  and  surrounded  by  a  hyaline  gelatinous 
envelope.  These  individuals  are  arranged  so  as  to  form  a 
spherical  surface,  their  hyaline  envelopes  being  in  contact 
with  one  another,  and  so  placed  as  to  bring  the  pointed  ends 

of  the  green  masses,  with  their 
cilia,  to  the  surface.  The 
sphere  is  thus  made  up  of 
h  closely  approximated  individ- 
uals, which  dot  its  surface, 
and  whose  cilia  give  to  the 
whole  colony  a  hairy  appear- 
ance.    The  movements  of  the 

Pie.  164.—  VoUmm  globator.   a,  pperma-   cilia  givC  to  the   Sphere  a  TO- 
tozoid,  X  800.     6,  oogoniam,  with  sper-    .  . .  i  •   i.    •  n 

matozoids  BurrouDding  the  oosphere,  X    tary  mOtlOn,  WlllCll  15  USUaxly 

400.-Af ter  cohn.  ^^^  ^j  progression  also. 

826. — The  sexual  reproduction  of  Volvox  takes  place  in 
this  way  :  some  of  the  cells  in  a  colony  undergo  conversion 
into  spermatozoids,  which  are  elongated  club-shaped,  and 
provided  with  two  cilia  {a,  Fig.  164) ;  other  cells  of  the  same 
colony,  or  of  different  colonies,  become  greatly  enlarged  into 
oogonia,  consisting  of  an  outer  hyaline  coat  enclosing  an 
inner  rounded  mass  of  dense  and  granular  protoplasm  (J,  Fig. 
164).  Upon  the  escape  of  the  spermatozoids  they  penetrate 
the  cavity  of  the  colony  (into  which  the  oogonia  have  now 
pushed),  and  there  coming  in  contact  with  the  oogonia,  they 

*  It  will  not  do  violence  to  anj  laws  of  classification,  based  npon 
the  general  tlieorj  of  evolution,  to  propose  that  Volvox,  JSudarina, 


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VOLVOX  AND  ITS  ALLIES.  245 

bury  themselves  in  the  hyaline  envelope,  and  finally  pene- 
trate and  become  fused  into  the  oosphere  (b,  Fig.  164).      A 
thick  wall  now  forms  upon  the  fertilized  oosphere,  and  it 
becomes  transformed  into  an  oospore.      Thus  we  have  in 
these  plants  the  transformation  of  an 
individual  of  the  colony  into  an  oogo- 
nium and  oosphere,  and  the  subse- 
quent fertilization  of  the  latter  by 
spermatozoids,  which  are  themselves 
fractional  parts  of  other  members  of 
the  colony. 

326. — The  relationship  of  the  low- 
er Oophytes  with  the  lower  Zygo-  * 
phytes,  as  indicated  by  Volvox  and 
Pandorina,  is  further  shown  by  the 
position  of  SphcBroplea,  an  undoubted 
relative  of  the  ConfervacecB  {Clachh 
phora,  etc.).     Sphmroplea  is  a  free, 
unbranched,   filamentous  alga,  com- 
posed of  long  cells  joined  end  to  end  i6B.-AjA«f«ptei  ann^ 
(Ay  Fig.  165).    It  produces  oospheres  itna. '  a, IwSSMy'ftJmJ^t^ 
in  some  of  its  filaments,  each  cell  roent^^coSsfstirST^  oogoniit 
producing   several    (B,   Fig.    165).  JSSpZrro'To^„£W"o? 
While  these  are  forming  in  one  set  of  t^i^t^^^^'X^ZgOxi 
filaments,  in  another  the  protophvsm  2r!S:l"„i,Sti:?j*Vt«'o^ 
becomes  broken  up  into  a  multitude  «.  fertiuaed  oosphfres,  now 

-    ,  ^    -1    1  •     •!•   i.  i.        'J      encloeed  in  ft  thin  cell-wall.   C, 

of  elongated,  bl-Clliate  spermatozoids   Ulument  consisting  of  unthdr- 

(Cand  0,  Fig.  165);  these  escape  SitJzJid^i^^uin^Qgh'fh; 
through  lateral  openings  in  the  cells,  SSff'?,?  .^hfck  LuoTl^.Z''. 
which  are  formed  by  the  absorption  ^^^-  f;,«>?«po5?  (veg^ti^uye 

•'  *   .  zoogonidlam).    ^,  oosphere  iu 

of  a  part  of  the  wall,  and  then  swim-   the  act  of  being  fertlllred  by  a 

.^.,  ,.1.  ,t  «t    spermatozoid,  k.    G.  Hpt-miato 

ming  through  the  water  they  find  aoids— After (Ersied. 

their  way  to  corresponding  openings  in  the  walls  of  the 

and  their  allies  in  the  Oophyta,  and  Pandorina  and  its  allies  in  the 
Zygophyta,  be  placed  iu  a  common  class  2k>08pore8B.  This  class 
would  thus  have  t^o  branches,  one  in  the  division  Zygoph3rta,  and 
the  other  in  the  Oophyta.  Such  an  arrangement  would  indicate  the 
evident  relationship  of  the  plants  under  consideration  better  than  any 
yet  proposed. 


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246  BOTANY, 

cells,  which  contain  the  oospheres ;  upon  coming  in  contact 
with  an  ooephere  they  bury  themselves  in  its  substance,  after 
which  the  oosphere  secretes  a  thick  wall,  and  thus  becomes 
an  oospore  (Z>,  Fig.  165).  In  germination  (which  takes  place 
after  a  period  of  rest)  the  protoplasmic  contents  of  the 
oospore  become  broken  up  into  a  large  number  of  bi-ciliated 
zoospores  having  nearly  the  shape  and  general  appearance 
of  the  spermatozoids  ;  these,  after  swimming  about  for  a 
time,  become  gradually  elongated  into  narrowly  fusiform 
filaments,  which  are  the  young  Sphcsroplea  individuals ;  by 
growth  these  take  on  the  form  and  size  of  the  adult  indi- 
viduals. 

§  II.  Class  (Edooonie^. 

827. — The  plants  constituting  this  well-marked  class  are 
composed  of  articulated,  simple,  or  branched  filaments, 
which  are  attached  to  sticks,  stones,  earth,  or  other  objects 
by  root-like  projections  of  the  basal  cells.  The  chlorophyll 
in  the  cells  is  always  dense  and  uniform.  They  inhabit 
ponds  and  slow  streams,  and  form  green  masses,  which  fringe 
the  sticks  and  other  objects  in  the  water. 

328. — The  QSdogoniesB  are  interesting  for  the  well-marked 
examples  they  afford  of  the  intercalary  growth  of  cells.  It 
is  commonly  the  case  that  in  any  filament  at  one  or  two 
points  there  may  be  seen  near  one  end  of  a  cell  a  number 
of  transverse  parallel  lines,  which  in  profile  have  the  appear- 
ance of  as  many  caps  slipped  into  one  another  (Ci  Fig.  10, 
page  22) ;  these  are  the  results  of  several  extensions  of  the 
filaments  by  intercalary  growth.  The  process  is  as  follows  : 
in  a  cell,  a  little  below  its  upper  wall,  a  growtn  mward  from 
the  surface  of  the  wail  takes  place  in  such  a  way  as  to  lorm 
a  cylindrical  ring  {A,f,  Fig.  10);  after  a  time  the  eeU-wall 
splits  circularly  from  the  outside  to  the  centre  of  the  circu- 
lar cylinder  (/),  and  the  two  parts  of  the  cell  then  retreat 
from  each  other,  united  only  by  the  straightened  out  cylb- 
der  {B,  z,  Fig.  10);  this  new  part  elongates  and  the  procesp 
is  repeated,  finally  giving  rise  to  the  series  of  caps  first  men- 
tioned (C>  Cy  Fig.  10),  and,  in  conjunction  with  cell-division, 
resulting  in  a  considerable  elongation  of  the  filaments. 


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(EDOQONIEJB. 


247 


829. — The  asexual  reproduction  of  (Edogoniese  is  as  curi- 
ous  as  the  growth  of  its  cells,  just  described.  During  the 
early  and    active   growth  of    the  ^ 

plants  the  protoplasmic  contents  of 
certain  cells  in  a  filament  become 
detached  from  their  walls,  and  upon 
the  splitting  of  the  latter  the  now 
rounded  protoplasm  escapes  as  a 
large  zoospore  (Fig.  166,  A  and 
B) ;  it  is  oval  in  shape,  and  provid- 
ed with  a  crown  of  cilia  about  its 
smaller  hyaline  end,  by  means  of 
which  it  swims  rapidly  hither  and 
thither  in  the  water  (Fig.  166,  (7). 
After  a  time  it  comes  to  rest, 
clothes  itself  with  a  cell-wall,  and 
sends  out  from  its  smaller  end  root- 
like prolongations  (Fig.  166,  2)), 
which  attach  it  to  some  object ;  it 
now  elongates,  and  at  length  forms 
partitions,  taking  on  eventually  the 
form  of  the  adult  filament.  It 
sometimes  happens  that  before  the 
new  plant  resulting  from  the 
growth  of  a  zoospore  has  formed  its 
first  partition,  the  protoplasm  sep- 
arates from  its  wall  and  again  aban- 
dons it^  to  be  for  a  time  a  zoospore 
(Fig.  166,  E).  This  method  of 
formation  of  zoospores  is  what 
Braun  called  Rejuvenescence.  (See 
p.  42.) 

830. — The  sexual  reproduction 
of  the  plants  of  this  class  is  in 
many  respects  closely  allied  to  that 


Mas^ 


Fig.  106.  —  Aeexoal  reprodae* 
tion  of  (Edogonium.  A^  mtcture 
of  a  filament  and  vscape  of  the 
protoplasm  of  the  broken  ceU : 
the  protoplasm  in  the  whole  eel] 
below  Is  seen  to  be  somewhat 
withdrawn  fh>m  the  cell>wall, 
preparatory  to  escaping.  B^  es- 
cape  of  protoplasm  and  f  ormatiob 
of  a  zoospore;  the  hyaline  por* 
tion  of  the  latter  is  seen  to  be  lat- 
eral. O^  a  ciliated  and  swimming 
zoospore,  the  hyaline  portion  now 
terminal.  2>,  zoospore  at  rest, 
and  sendine  out  root  like  pro* 
longations  from  the  hyaline  end. 
S^  a  yoang  plant  composed  of 


of  Sphmoplea.  The  female  organs  ^,  ^  youn^  p,.,,^  composed  of 
are  in  all  cases  developed  in  essen-  S^p^^.^^'S^llRS^?}^ 
tially  the  same  way,  but  the  male  *^**™- 
organs  present  a  considerable  diversity.     The  female  organ 


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248 


BOTANY. 


consists  of  a  rounded  oosphere  situated  within  a  cavity— the 
oogonium ;  it  is  developed  from  one  of  the  cells  (sometimeB 

two)  of  the  filament 
by  a  condensing 
and  rounding  off 
of  the  protoplas- 
mic contents;  when 
the  oosphere  is  ful- 
ly formed,  an  open- 
ing is  formed  in 
the  oogonium-wall 
for  the  ingress  of 
the  spermatozoids 
(A  and  B,  Fig. 
167).  One  or  more 
spermatozoids  aie 
produced  in  each  of 
certain  small  cells 
which  are  formed 
from  the  large  ones 
by  a  process  of 
simple  fission;  in 
shape  they  resem- 
ble the  zoospores 
mentioned  above — 
that  is,  they  are 
oval  and  provided 
with    a   crown  of 

Fig.  107  —^,  middle  part  of  a  sexnal  filament  of  iBdo-  vibratilc     cilia     On 

gonivm  oUiatutn  {Androgvnia  of  Wood),  with  male  cella  . ,     .                ,. 

above  at  m;  og,  oogonia  (fertilized);   m,  dwarf  male  tneiT     Smaller     ex- 

plants  attached  to  the  side  of  the  oogonia,  the  fperma-  .          'l      tn 

toroidi  already  dlecharged.     x  250.    B,  oogonium,  og,  trcmity    (//,     Z,    Z, 

at  the  moment  of  fertilization  ;  o,  the  oosphere  ;  «.  the  -ci*         i  cty\        TTtinn 

spermatozold  forcing  ita  way  into  the  oocphere ;  m.  the  -^  'g*     •■■"  •  r        ^  r"" 

dwarf  male  plant.     6',  ripe  oospore.    Z>,  (Siogonium  aanamnit     lYifn    fhp 


one  with  an  oospore  escaping,  the  lower  empty, 
zoospores  result  ing  from  an  oospore  of  T 


F,  four  ,  -    -  *    .1 

r .       hcBte.  o,  a  splitting  of  the 

cocjpore  come  to  rest  and  germinating.-Alter  Prlngs-    ^  J^^  ^j^^  ^^^^^_ 

cell,  they  swim  about  vigorously,  and  eventually  make  their 
way  through  the  opening  in  the  oogonium,  and  then  bury 


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(EDOGONIE^.  249 

themselves  in  the  substance  of  the  oosphere  (B,  z,  Fig.  167). 
After  fertilization  the  oosphere  becomes  covered  with  a  thick 
and  colored  (brown  or  red)  coat,  and  it  then  becomes  an 
oospore  ((7,  Fig.  167). 

831. — In  certain  cases  the  cells  which  produce  the  sper* 
matozoids  occur  on  the  same  filaments  which  produce 
oogonia  also ;  this  is  the  tnonoBcious  type.  In  other  cases  one 
of  the  ordinary  cells  of  the  filament  which  bears  oogonia  be- 
oomes  divided  by  simple  fission  into  two  or  more  cells  ;  the 
protoplasm  in  each  of  these  new  cells  condenses  into  an 
ovate  mass,  which  by  a  rupture  of  the  cell-wall  is  set  free  as 
a  motile  body  resembling  a  small  zoospore,  and,  like  it,  pro- 
Tided  with  a  crown  of  vibrating  cilia;  this  is  the  androspore. 
After  swimmmg  about  for  some  time,  it  comes  to  rest  upon, 
or  near  to,  an  oogonium,  and  attaches  itself  by  root-like  pro- 
jections, exactly  as  in  the  case  of  the  growth  of  true  zoo- 
spores ;  the  result  of  the  growth  of  tlie  androspore  is  the  pro- 
duction of  a  miniature  plant  composed  of  three  or  four  cells 
{Ay  f»,  wi,  and  B,  m,  Fig.  167).  The  upper  cells  of  these 
little  plants  develop  spermatozoids,  and  hence  the  plants  are 
called  dwarf  males.  This  is  the  so-called  gynandrous  type 
{A  and  By  Fig.  167).  In  a  third  class  of  cases,  the  ordinary 
plant  filaments  are  of  two  kinds,  the  one  producing  sperma- 
tozoids only,  and  the  other  only  oogonia ;  this  is  the  dioecious 
type  (A  Fig.  167). 

382. — After  a  period  of  rest  the  oospore  germinates  by 
rupturing  its  thick  coat,  and  permitting  the  escape  of  the 
contents,  enclosed  in  a  thin  envelope  ;  by  this  time  the  pro- 
toplasm has  divided  into  four  portions,  which  take  on  an 
oval  form,  and  develop  a  crown  of  cilia  {Fy  Fig.  167).  They 
fioon  escape  from  the  investing  membrane,  and  after  a  brief 
period  of  activity  grow  into  an  ordinary  filament  in  exactly 
the  same  manner  as  the  zoospores. 

(a)  It  wiU  be  UDDecessary  in  this  place  to  fully  discues  the  arrang^e- 
ment  of  the  genera  belonging;  to  this  class  ;  they  probably  may  be  all 
brooght  within  the  limits  of  one  order  coextensive  with  the  class. 
Wood  has  separated*  two  sub-families  (=  sub-orders),  which  differ  in 

*  "  A  Contribution  to  the  History  of  the  Fresh-water  Algae  of  the 
United  States."  by  H.  C.  Wood,  1873. 


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260  BOTANY. 

the  filaments  in  tlie  one  case  {Butboehate)  being  branched  and  tennlnaled 
with  setsB,  while  in  the  other  case  ((Eiogonium  and  its  allies)  the  fila- 
ments are  not  branched,  and  are  destitute  of  true  setae. 

{f>)  The  old  genus  (Biogonium  is  divided  bj  Wood  into  three  new 
genera,  as  follows : 

MoDGBcious :  antheridia  and  oogonia  upon  the  same  individual — 

(EkUfgonium, 
Dicecious :  antheridia  and  oogonia  arising  upon  distinct  individuals 

— Pringsheimia, 
Gjnandrous :  antheridia  upon  dwarf  plants,  growing  attached  to 
the  female  plant — AndrogffrUa, 
Wolle  records  thirteen  species  of  the  first,  thirteen  of  the  second* 
and  twenty-six  of  the  third  of  the  foregoing  divisions  in  the  United 
States.    He  does  not,  however,  consider  these  divisions  as  having 
generic  rank.    (**  Fresh-water  AlgSB  of  the  United  States,"  Vol.  1. 
p.  66.) 

{e)  The  genus  Bulboehais  includes  gynandrous  species,  of  which 
there  are  sixteen  in  the  United  States. 


§  III.   Class  Cceloblaste^. 

888.—  In  the  plants  of  this  class  the  protoplasm  is  con- 
tinuous throughout  the  vegetative  organs  of  the  plant,  and 
is  not  divided  into  cells.  Only  the  reproductive  organs  are 
separated  by  partitions.  They  may  hence  be  spoken  of  ag 
unicellular,  although  they  often  attain  a  considerable  length 
and  are  frequently  much  branched. 

The  other  characters  of  the  group  will  be  best  understood 
from  a  study  of  some  of  the  plants  included  in  it.  Many  of 
them  are  chlorophyll-bearing  plants,  living  in  brooks  and 
streams,  while  others  are  destitute  of  chlorophyll,  and  are 
saprophytes,  living  upon  decaying  animal  or  vegetable  matter, 
or  are  parasites,  living  upon  the  living  tissues  of  the  higher 
plants. 

884. — The  genus  Vaucheria  may  be  taken  as  a  represen- 
tative of  the  chlorophyll-bearing  members  of  this  class.  It 
is  a  filamentous  alga  growing  in  water  or  on  damp  earth,  and 
forming  dark  green  tufts.  Each  plant  consists  of  long, 
branching,  thick-walled  tubes,  which  have  a  rather  large 
diameter ;  they  are  attached  to  the  earth,  or  to  sticks  or 


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C(EL0BLA8TEjE.  251 

other  objects,  by  root-like  processes  {w,  Fig.  168).  The 
protoplasmic  contents  of  the  tubes,  which  are  destitute  of  a 
nucleus,  consist  of  a  thick  green  layer  upon  the  inner  sur- 
face of  the  wall,  leaving  the  centre  of  the  tubes  open  for  the 
more  watery  portions. 

386.— The  asexual  reproduction  of  Vaucheria  presents 
some  considerable  variations;  it  consists  essentially  of  a 
spontaneous  separation  of  a  portion  of  the  protoplasm  of  the 
parent  plant    In  some  species  this  takes  place  by  the  sepa- 


Fig.  168.—  Vaueh^ria  tetHHt.  A,  end  of  a  branch,  with  escape  of  a  sooepore,  fp.  B, 
sooapore  In  lu  rectinf?  stage,  after  the  dlaappearance  of  its  cilia.  C,  the  same,  germl- 
sating.  A  the  name,  farther  advanced.  Js,  much  later  stage  of  germination  ;  sp,  the 
Eootpore:  w  the  root-Ilk**  proceraes  (rhlzoidn).  ^,  fertile  plant;  og^  og,  oogonik  fer- 
tflized ;  A,  an  old  antheridlam.    x  30.— After  Sachs. 

ration  of  swollen  lateral  branches,  which  then  send  out  fila- 
ments ;  in  other  species  the  protoplasm  in  the  swollen  lateral 
branch  becomes  separated  from  that  in  the  general  cavity  of 
the  plant  by  a  septum,  and  it  afterward  condenses  into  a 
rounded  mass  and  acquires  a  wall  of  its  own  ;  it  is  set  free 
by  the  decomposition  of  the  old  surrounding  wall,  and  it 
germinates  by  sending  out  one  or  two  tubes,  which  grow 


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262  BOTANY, 

directly  into  new  plants.  In  still  other  species  the  spore 
forms  as  in  the  last  case,  but  there  is  a  dehiscence  of  the  sur- 
rounding wall  which  permits  the  spore  to  slip  out ;  it  begins 
to  germinate  soon.  In  some  species,  instead  of  forming  a 
spore,  the  naked  protoplasm  in  the  swollen  branches,  after 
condensing  somewhat,  escapes  into  the  water  through  a 
fissure  in  the  cell-wall,  and  becomes  a  zoospore  (Ay  Fig. 
168) ;  it  is  covered  throughout  its  whole  surface  with  delicate 
vibratile  cilia,  by  means  of  which  it  moves  through  the 
water  (Fig.  169).  After  a  short  period  of  activity  the  zoo- 
spores come  to  i-est,  their  cilia  disappear,  and  a  wall  of  cellu- 
lose is  formed  (J9,  Fig.  168) ;  in  this  condi- 
tion (the  zoogonidinm)  they  remain  for  some 
hours,  when  they  begin  to  germinate  by 
sending  out  one  or  two  tubes  ((7,  Z>,  Fig. 
,  ^pp  168) ;  the  root-like  organs  grow  either  direct- 
;^tj>^n  ly  from  the  zoogonidinm  {Fy  Fig.  168),  or 
^^^0  from  one  of  the  tubes  {E,  Fig.  168). 

336. — Sexual  reproduction  takes  place  in 
lateral  branches  also.  Both  antheridia  and 
oogonia  develop  as  lateral  protuberances  upon 
at^'f'ii^s^^tS  the  main  stem  (pg,  og^  A,  Fig.  168).  They 
Spore 'oTroJkjS*^  originate  as  diverticula  of  the  principal  cavity 

J&!rb^ng**t£^  (^'  ^9>  ^'  ^'S-  ^^^)  >  ^^^^  develop  on  the  one 
cuu:ft,endopia«ni.  hand  iuto  male  orirans,  and  on  the  other 

X  e00.-O8mfc  add    .    ,      ^         ,  mu  i  •     i 

preparation,    after  mto  female  Organs.     The  male  organ  is  long 
***^^*  and  rather  narrow,  and  soon  much  curved 

{By  a.  Fig.  170) ;  its  upper  portion  becomes  cut  off  by  a 
partition,  and  in  it  very  small  bi-ciliate  sperpiatozoids  (i>. 
Fig.  170)  are  developed  in  great  numbers.  The  female  or- 
gan is  short  and  ovoid  in  outline,  and  usually  stands  near 
the  male  organs.  In  it  a  partition  forms  near  its  point  of 
union  with  the  main  stem  ;  the  upper  portion  becomes  an 
oogonium,  and  its  protoplasm  condenses  into  a  rounded 
body,  the  oosphere  (Cand  Ey  Fig.  170) ;  at  this  time  the 
wall  of  the  oogonium  opens,  and  permits  the  entrance  of  the 
spernmtozoids  which  were  set  free  by  the  rupture  of  the 
antheridium-wall.  Upon  coming  into  contact  with  the 
oosphere  the  spermatozoids  mingle  with  it  and  disappear ;  the 


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CtELOBLABTEM,  253 

oosphere  immediately  begins  to  secrete  a  wall  of  cellulose 
about  itself,  and  it  thus  becomes  an  oospore  {F^  Fig.  170). 
According  to  Pringsheim,  the  oospore  remains  for  three 
months  in  a  resting  state  before  germinating ;  in  the  latter 
process  the  outer  coat  of  the  spore  splits,  and  through  the 
opening  a  tube  grows  out  which  eventually  assumes  the  form 
and  dimensions  of  the  full-grown  plant. 


Fig.  170.— Sexnal  or^ns  of  Vaucheria  se^HlU.  A,  besdnnlng  of  the  formation  of 
the  ooi^nium  (og)  and  antheridinm  (h)  upon  the  branch  b.  B.  later  stage  of  the 
same,  the  antheridiam  (a)  now  fieparated  from  the  main  branch  (6)  by  a  transverse  par- 
tition. O.  an  open  oo«^ninm  expelling  a  drop  of  roncilage.  d.  Z>,  spermatozoids.  K^ 
spermatozoids  collected  at  the  mouth  of  the  oogoninm.  F,  the  antheridiam.  a,  col- 
lapsed after  the  escape  of  the  ppprmntozoids  ;  oip,  the  oospore,  x  about  100,  except 
/>,  which  ismnch  more.— C,  2>,  after  Pringsheim,  the  others  after  Sachs. 

(a)  The  formation  of  zoospores  begins  in  the  night,  they  escape  In 
the  morninsT,  and  the  night  following  they  germinate. 

(5)  The  formation  of  sexual  organs  begins  in  the  evening,  and  is 
completed  the  next  morning  ;  fertilization  takes  place  during  the  daj 
(from  10  A.M.  to  4  P.M.). 

(c)  Good  specimens  of  Vaucheria  may  be  found  clothing  the  boggy 
gronnd  about  many  springs.  The  bright  green  mats  may  be  trans- 
ferred  to  the  aquarium  for  the  study  of  zoospores ;  but  for  the  sexual 
organs  the  dingy  and  dirty  looking  specimens  must  be  collected. 


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254  BOTANY. 

(d)  The  genua  Vaueheria  may  be  taken  as  the  type  of  a  groap,  the 
Vaucheriaeea,  bat  whether  it  is  entitled  to  rank  as  an  order  instead 
of  a  family  cannot  be  decided  in  this  place.  Allied  to  Vaueheria  toe 
(Ja/^Uerpa,  HaUmeda,  etc ,  but  their  exact  position  is  as  yet  problematicaL 

(e)  Thirteen  species  ot  Vaueheria  occur  in  the  fresh  waters  of  the 
United  States,  one  of  the  most  common  being  F.  semUii,  which 
occurs  everjrwhere  in  brooks  and  springs. 

(/)  CaulerpUes  eaetoide$  is  the  oldest  known  fossil  species  of  this 
class.  It  occurs  in  the  Silurian  :  other  species  have  been  detected  in 
the  Devonian  and  Tertiary.  CatUerpa  exteuds  from  the  Tertiary  to 
the  present. 

387.— Order  Saprolegniaoesd.  The  plants  of  this  order 
are  saprophytes  or  parasites,  more  frequently  the  latter ;  they 
are  colorless,  and  generally  are  to  be  found  in  the  water  or  in 
connection  with  moist  tissues.  The  plant-body  is  greatly 
elongated  and  branched,  and  all  its  vegetative  portion  is 
continuous — i.e.,  unicellular ;  the  reproductive  portions  only 
are  separated  from  the  rest  of  the  plant-body  by  partitions. 

388. — Tho  reproduction  is  very  much  the  same  as  in 
Vaueheria^  and,  as  in  that  genus,  is  of  two  kinds — ^asexual 
and  sexual.  The  asexual  reproduction  may  be  briefly  de- 
scribed as  follows^:  the  protoplasm  in  the  end  of  a  branch 
becomes  somewhat  condensed,  a  septum  forms,  cutting  off 
this  portion  from  the  remainder  of  the  filament,  and  the 
whole  of  its  contents  becomes  converted  by  internal  cell- 
division  into  zoospores  provided  with  one  or  two  cilia 
(Fig.  171,  1).  These  soon  escape  from  a  fissure  in  the  wall 
and  are  active  for  a  few  minutes  (3-4),  after  which  they 
come  to  rest  and  their  cilia  disappear  (2  and  3,  Fig.  171). 
In  one  or  two  hours  they  germinate  by  sending  out  a  filament 
(4,  Fig.  171),  from  which  a  new  plant  is  quickly  produced.* 

339. — The  sexual  organs  bear  a  close  resemblance  to  those 
of  Vaueheria.  The  oogonia  are  spherical,  or  nearly  so  (in 
most  of  the  species),  and  contain  from  two  to  many  oospheres, 
which  are  fertilized  by  means  of  antheridia,  which  usually 
develop  as  lateral  branches  just  below  the  oogonia.     In 

♦The  student  is  referred  to  an  article,  •'Observations  on  Several 
Forms  of  Saprolegnieae,"  by  F.  B.  Hine,in  American  Quarterly  Miero- 
•copieal  Journal,  1878,  p.  18.  from  which  some  of  the  above  facts  are 
taken,  and  the  accompanying  figures  adapted. 


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SAPOLEGNIACE^. 


255 


some  species  the  antheridia  and  oogonia  are  upon  the  same 
plants,  and  in  such  cases  the  fertilization  takes  place  by  the 


Fig.  171.— 1,  end  of  filament  of  SaproUgtiia.  with  zoospores  (swarm-spores)  eecap* 
ing;  8,  zoospores  of  the  same  at  rest ;  8,  the  same  more  enlarged ;  4,  the  same, 
serminating :  6,  a  portion  of  a  filament  of  Aehlya,  bearing  eexoal  organs,  x  190 ;  6, 
first  stage  in  the  development  of  sexual  organs  of  Achlya ;  7. 8,  9,  tacceeding  stages ; 
10,  sexual  organs  of  6,  more  enlarged,  showing  the  antheridia,  and  the  nearly  ripe 
oogoaiimif  with  ita  contained  oospores.— Adapted  from  Hlne. 

direct  contact  of  the  antheridium  and  the  passage  of  its 
contents  into  the  oogonium  by  means  of  a  tubular  process 


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256 


BOTANY. 


from  the  former  ;  in  other  species  the  plants  are  dicBcious, 
and  in  them  the  antheridia  produce  motile  spermatozoids^  b} 
means  of  which  the  fertilization  is  effected.  After  fertilization 
each  oosphere  becomes  covered  with  a  wall  of  cellolose  and 
is  thus  transformed  into  an  oospore. 

840. — The  development  of  the  sexual  organs  of  Achlya, 
one  of  the  genera  of  this  order,  is  shown  in  Fig.  171,  6  to 
10  ;  at  first  there  is  a  small  pullulation  upon  the  side  of  a 
filament,  as  at  6  ;  this  soon  extends  into  a  bag-like  projec- 
tion (7),  which  is  readily  seen  to  be  a  young  oogonium ; 
it  continues  to  enlarge,  while  its  protoplasm  becomes  more 

dense,  and  at  its  narrower 
part  a  second  pullulation 
forms  (frequently  two),  as 
shown  at  8 ;  when  the  larger 
part  has  enlarged  somewhat 
more  and  become  rounded,  a 
partition  separates  it  from 
the  remainder  of  the  filament, 
and  from  the  young  anther- 
idium,  as  shown  at  9 ;  the 
''^**'''*^^^'  I  protoplasm  in  the  oogonium 

jr'.^j^    ^  _^^  forms  several  round  masses — 

the  oospheres — and  by  this 
time  the  terminal  portion  of 
M^Sed!^  the  antheridium  is  cut  off  by 
a  partition.  In  the  monoe- 
cious species  a  tube  is  formed  by  the  closely  applied  anther- 
idium, which  penetrates  into  the  oogonium  through  open- 
ings in  it  formed  by  the  absorption  of  portions  of  its  wall 
and  comes  in  contact  with  one  of  the  oospheres  (Fig.  172). 
341. — In  some  cases,  instead  of  the  oogonia  developing 
way  described  above,  they  are  formed  in  the  terminal 
a  filament  by  one  or  more  partitions  arising  in  it ; 
gonia  are  cylindrical  or  barrel-shaped,  and  sometimes 
of  them  etand  upon  one  another.  The  antheridia  in 
icies  which  have  such  oogonia  are  developed  from 
he  partition  which  cuts  off  the  oogonium,  and  when 
re  several  superimposed  oogonia  it  actually  happens 


:fiKA£LS3fLr> 


Fig.  172.— Fertilization  of  the  oospheres 
in  Achlya  racemosa.    Each 
contains  two  ooepheras. 
After  Coma. 


+Vifl 


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BAPROLEQNIACEJE,  25? 

that  the  antheridia  which  fertilize  one  oogonium  grow  out 

of  the  oogonium  lying  immediately  beneath.*    In. this  case 

it  appears  that  the  terminal  oogonium  is  formed  first,  and 

that  the  antheridia,  in  each  case,  grow  out  from  what  is  yet 

a  part  of  the  whole  filament,  and  that  it  is  only  subsequently 

to  the  formation  of  antheridia  that  an  oogonium  is  formed 

out  of  that  part  of  the  filament  out  of  which  they  grew.     In 

the  accompanying  diagram  (Pig.  173)  the 

oogonium   a  is  fertilized  by  antheridia 

which  grew  out  of  that  portion  of  the  ^ 

filament  which  subsequently  became  cut 

off  as  oogonium  J,  which  in  turn  is  fer-  . 

tilized  by  antheridia  from  below  it,  and  so  ^ 

on   to  dy  which   receives    its    antheridia 

from  what  still  remains  as  part  of  the  fil-  ^ 

ament.     Each   oogonium   is   seen  to  be 

younger  than  the  one  above  it — in  other 

words,   the  oogonia  are  developed  from  d 

the  top  of  the  filament  downward. 

The  oospores  of  SaprolegniaceaB  possess, 
when  mature,  a  thick  integument,  which 
is  double — that    is,  formed  of  an  outer     Pig.  i78.-Di«gram  ii- 

■  v  .  ,  J.  /      •  \        J  •  xi_'         Instrating  the  formation 

thicker  coat  (epispore)  and  an  inner  thin-  of  the  eexnai  organs 
ner  one  (endospore).  After  a  considerable  ^^n^^^lnl 
period  of  repose  the  oospores  germinate  which  is^feituS^^^^ 


which  is  fertilized  by 

by  sending  out  a  tube.  \  JH^  beto'llJ'thl  nS 

The  Saprolegniace»  have  been  but  little  rtud-  "J.I.'^^rXfewia; 

led  io  this  country,  although  thej  maj  be  read-  the  oospheres  not  yet 

ily  obUined.      Thej  grow  quicklj   upon  dead  S"^o?J?nl2^  f tSri^^^^ 

fishes,  crayfishes,  flies,  etc.,  when  placed  in  tanks  ter  will  be  fertilized  by 

-        .  J  **        u  *A     I    J  the    antheridia    which 

of  water,  and  may  often  be  seen  attached  para-  grow  out  from  the  upper 

sitically  to  younp:  livin^r  fishes  in  aquaria.     They    ^^  of  'he  filament  bo- 
are  often  so  abundant  in  the  breedin^^-houses  of 
fishes  as  to  cause  great  losses.    In  some  of  tlie  rivers  in  England  dur- 

*  The  student  should  consult  an  article  on  "  Two  New  Species  of 
SapiolejHiieflB,"  etc.,  in  Qr.  Jour,  Mie.  Science,  1867,  p  121,  in  which 
figures  and  a  description  of  such  a  form  as  that  above  referred  to  are 
given. 

t  See  De  Bary's  "  Morphologie  und  Physiologie  der  Pilze,"  etc ,  1866, 
p.  155,  for  an  account  of  the  sexual  reproduction  of  Saprolegniace», 


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258 


BOTANY. 


ing  the  year  1878»  and  for  a  year  or  two  previous  to  that  date,  larg^ 
numbers  of  salmon  and  other  kinds  of  fish  were  destroyed  by  one  of  the 
common  species,  SaproUgnia  ferax* 

342.— Order  Feronospores.  The  plants  of  this  order 
live  paraaitically  in  the  interior  of  higher  plants.  They  are 
composed  of  long  branching  tubes,  whose  cavities  are  con- 
tinuous throughout.  They  grow  between  the  cells  of  their 
hosts,  and  draw  nourishment  from  them  by  means  of  pecu- 


Pio.  174. 

Pig.  174.— A  TeeetatiTe  bypha.  m,  m,  of  Penmospora  ealotheca  from  the  tle^ne  of 
Aeperula  ecUiwt.  The  two  cells  between  «  «  are  flfled  with  the  loDg  branching  haas- 
tona  fh)m  the  hypha  m,  m.   x  890.— After  De  Bary. 

Fig.  175.— Conidia-bearing  hyphie  Of  Peronoapora  infestan*.  a,  fonnation  of  the 
firat  conidia  apon  the  ends  of  slender  pedicels ;  6,  the  formation  of  the  second  and 
third  conidia ;  the  pedicel  is  proliferous  from  the  base  of  each  conidinm  after  it  la 
formed,  and  thns  the  conidia,  which  are  actually  terminal,  come  to  appear  lateraL 
X  aOO.— After  De  Baiy. 

liarly  formed  lateral  branches  {haustoria)^  which  thrust 
themselves  through  their  walls  (Fig.  174,  and  Fig.  176,  A,  h). 
The  vegetative  growth  is  entirely  within  the  host,  and  also 

and  a  translation  in  *•  Qrevillea,"  Vol.  I.,  p.  117.  See  also  Prings- 
helm's  "  Jahrbucher  fttr  Wissenschaftliche  Botanik,"  Vol.  IX.,  p.  289, 
and  Max  Ck>rnu,  in  **  Annales  des  Sciences  Natarelles,"  5e  ser.,  torn. 
XV. 

*  See  a  description  by  W.  G.  Smith  in  '*  Grevillea."  Vol.  VI.,  1878, 
p.  152. 


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PERONOaPORJE. 


259 


the  sexual  organs ;  the  asexnal  reproductive  organs,  (m  the 
contrary,  are  on  the  surface  of  the  host. 

848. — ^The  asexual  reproduction  takes  place  in  the  genus 


B 


^i^rri 


Fig.  ITfi.'^CHfStopw  eandidw.  A,  branch  of  mycellnm,/,  growing  at  the  apex,  t^ 
and  giying  off  hanstoria,  A,  into  ttie  celU  of  the  pith  of  Lepidium  sativum.  B,  co- 
nidifkoeanng  portions  of  the  mycelinm,  with  conidia  in  rows.  C,  a  conidinm  with 
its  protoplasm  divided.  Z>,  contents  of  conidia  escaping  as  swarm-spores  (zoospores). 
E,  swann-spores  (zoospores),  with  cilia.  Fy  germinating  swarm-spores.  O^  two  swarm- 
spores,  »p^  germinating  on  a  stoma  and  penetrating  it.  //.  a  swarm-^pore,  ip,  of  the 
potato  disease  (Peranogpora  infetUms)  penetrating  the  epidermis  of  the  potato  stem ; 
«,  i,  epidermis  cells.    X  400.— After  De  Bary. 

Peronospora  by  the  mycelium  inside  the  host  producing 
branches,  which  protrude  through  the  stomata  into  the  air  ; 
here  their  tips  become  enlarged,  and  finally  separated  by  par- 
titions from  the  remaining  parts  of  the  hyphae,  thus  forming 


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260  BOTANY. 

the  conidia  (Fig.  175).  In  the  different  species  there  are 
considerable  variations  in  the  size  and  shape  of  the  conidia, 
and  the  mode  of  branching  of  the  conidial  hyphse,  and  upon 
these  many  specific  characters  are  based. 

344. — In  the  genus  Cystopus  the  formation  of  conidia  is 
slightly  different.  The  conidial  hyphae  multiply  greatly  at 
certain  points  beneath  the  epidermis  of  the  host,  and  there 
produce  conidia  by  successive  constrictions  {B,  Fig.  176). 
The  conidia  remain  in  loose  connection,  and  form  moniliform 
rows,  in  which  the  uppermost  conidium  is  the  oldest ;  some- 
times six  or  more  conidia  may  be  seen  attached  to  each  other 
in  this  way,  but  generally  the  upper  ones  soon  fall  away. 
When  the  epidermis  of  the  host  ruptures,  the  conidia  appear 
^  as    a    powdery    mass, 

which  may  be  blown 
away  by  the  feeblest 
movement  of  the  air. 

846. — The  germina- 
tion of  conidia  presents 
two  modes :  in  some 
species    of    the   genus 

snora  in/^tans.  a,  conidium  af rer  Ivlng  for  tome  JrerOUOSpora  the  COU- 
thne  in  water,  the  contents  divided  ;  *,  tne  rapture  x^„i.„  ^^  xt,^  «rv«;^:«,« 
of  the  conidium  and  the  escape  of  the  parts  as  tCntS  01  the  COniOlUm, 
8warm-mx>re»  (zoospores);  c,  swarm-spores,  with  «,v,p„  nlopp/l  ri nHpr  iha 
cilia  ;  <ir*warm.8pore8  after  coming  to  rest,  in  va-  wnen  piaCCQ  Unacr  XnC 
riousstagesofgermination.  x890.-^fterDeBar7.  proper      Conditions      of 

moisture  and  temperature,  become  transformed  into  many 
bi-ciliate  swarm-spores  (a,  b,  and  c,  Fig.  177).  These  are 
active  for  a  time,  after  which  they  come  to  rest,  their  cilia 
disappear,  and  a  germinating  tube  is  sent  out  from  each 
{dy  Fig.  177),  which,  if  properly  situated,  enters  a  stoma, 
and  in  the  interior  of  its  host  gives  rise  to  a  system  of  vege- 
tating hyphae  ;  in  other  cases  it  perforates  the  epidermis  cell- 
walls  and  thus  passes  into  the  interior  of  its  host  {H,  Fig. 
176).  In  other  species  of  Peronospora  the  conidium  does  not 
break  up  into  swarm-spores,  but  gives  rise  directly  to  a  ger- 
minating filament.  In  all  the  species  of  the  genus  Cystopus, 
the  conidia  first  give  rise  to  swarm-spores  (C,  A  ^>  -^>  Gf> 
Fig.  176),  in  the  manner  described  above  for  Peronospora. 


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PER0N08P0BEjE,  ^61 

346. — In  the  sexual  reproduction,*  which,  as  above  stated, 
always  takes  place  in  the  intercellular  spaces  of  the  host, 
lateral  branches  of  two  kinds  arise  upon  the  hyphae ;  those 
of  the  one  kind,  the  young  oogonia,  become  greatly  thickened 


Fig.  178.— The  sexual  organs  and  fertillzatloa  of  Perono»pora  AlHnearum.  a. 
Toangest  stage  ;  o.yoang  oogoniam  ;  n,  yoang  antheridinm  ;  &,  the  Mme  somewhat 
later :  the  antheridiam  is  beginning  to  throst  Ita  beak-like  process  (fertilizing  tube) 
into  the  oogoniam  ;  c,  the  same  at  a  stiU  later  stage— the  fertilising  tabe  has  reached 
the  ooephete.    x  850.— After  De  Bary. 

in  diameter,   and  finally  assume  a  globular  shape ;  their 
highly  granular  protoplasm  becomes  condensed,  and  finally 
separated  from  that  of  the  remainder  of  the  filament  by  a 
transverse  septum  at  the  base  of  each  oogonium  {a,  Fig.  178). 
The  other  branches,  the  young  anthe- 
ridia,  which  arise  upon  the  same  fila- 
ments as  the  oogonia  and  near  to 
them,  or  upon  other  filaments  which 
are  in  proximity  to  the  oogonia-bear- 
ing  ones,  become  elongated  and  club- 
shaped  ;  their  protoplasm  (also  gran- 
ular) becomes  condensed  in  their  up-   „,r4i^"i'}tW8^n2an^ 
per  portions,  which  are  80on  separated   2SCerid1i,m%WchTas*5en^ 
from  the  rest  of  the  filament  by  a  ^i^%,')t,  ,3^^  ^SSS 
transverse  partition  in  each  case  (a,   ^^^  contact  with  the  oo- 

TT        ^  ^r.x  A  ,     ,  1  .         .  .1  pphere.     Much  magnified.— 

rig.    178).         At    this    stage    the   an-    After DeBary. 

theridia  become  applied  to  the  oogonia,  and  in  each  of 
the  latter  the  protoplasm  has  still  further  condensed  and 

*  Consult  De  Bary's  "  Morpholoffle  und  Physiolojne  der  Pilze,"  etc.. 
pp.  158-159,  a  translation  of  which  appeared  in  *'  Qrevillea/'  1878,  p 
150. 


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262  BOTANY. 

rounded  into  an  oogphere.  Each  antheridium  now  devel- 
ops a  tubular  beak-like  process,  which  penetrates  the  oogo- 
nium (J,  Fig.  178),  and  finally  reaches  the  oospore  {c,  Fig. 
178,  and  Fig.  179).     It  appears  that  the  contents  of  the  an- 


Wff  lan  —Ojf9fopu9  eandidus.  A,  mycelitun,  with  yoant;  oogonlt,  Off,  B^  oogonl- 
I,  oneport* ;  tin^  antheridimn.  (7,  mature  oogonium,  og^  with  ooepcre,  o»j 
is  the  remnant  of  the  antheridium.  2>,  mature  ooepore  seen  in  aection.  JB^ 
of  germination  of  oospore,  the  endof>pore  i  with  its  contents  escaping 
rent  in  the  epispore  (or  exospore).  F^  the  endospore  i  filled  with  swarm- 
>ppore8)  rfHting  on  the  empty  epispore.  &,  swarm-spores  (zoospores),  each 
iJk.    x400.-AfterDeBary. 

im  pass  into  the  oosphere,  as  in  a  short  time  the 
is  found  to  be  empty,  while  the  latter  becomes  envel- 
L  a  cell-wall,  and  thus  becomes  an  oospore.  In  the 
of  fertilization  there  are  no  spermatozoids,  and  the 


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PERONOSPOBEjE.  263 

process  is  comparable  to  that  which  takes  place  among  the 
monoecious  SaprolegniacesB.  The  wall  of  the  oospore  be- 
comes differentiated  into  two  or  more  layers  (as,  in  fact,  is 
usual  in  resting  spores),  the  outer  of  which  (the  epispore)  is 
thick,  hard,  rough,  and  dark  colored,  while  the  inner  (the 
e^idospore)  is  thin  and  transparent  (C,  D,  E,  F,  Fig.  180). 

347. — In  their  sexual  reproduction  the  species  of  the  genus 
Cystopus  agree  with  those  of  Peronospora  above  described. 
The  various  stages  are  shown  in  Fig.  180. 

348. — The  germination  of  the  oospores  takes  place  in  some 
species  of  the  genus  Peronospora  by  the  formation  of  a  ger- 
minating tube,  which  soon  gives  rise  to  a  mycelium.  In 
Cystopus,  however,  the  oospore  swells,  and  by  the  bursting 
of  the  epispore  the  endospore  escapes  as  a  loose  bladder  sur- 
rounding the  protoplasm,  which  has  by  this  time  become  di- 
vided into  a  large  number  of  naked  masses  of  protoplasm 
(E,  Fy  Fig.  180) ;  by  the  bursting  of  the  surrounding  mem- 
brane, these  bodies  are  set  free  as  bi-ciliate  swarm-spores  (ff, 
Fig.  180),  which,  after  a  short  period  of  activity,  come  to 
rest,  and  germinate  in  exactly  the  same  way  as  those  derived 
from  the  conidia.  In  some  species  of  Peronospora  it  appears 
that  swarm-spores  are  developed  as  in  Cystopus,  and  it  ap- 
pears from  the  observations  of  W.  G.  Smith,  that  in  the  potato 
fungus  {Peronospora  infestans)  some  of  the  oospores  pro- 
duce swarm-spores,  while  others  send  out  a  germinating 
tube.* 

349. — But  little  is  known  regarding  the  time,  as  well  as 
the  mode  of  germination  of  the  oospores,  but  from  those  ob- 
served it  is  probable  that  it  takes  place  after  a  period  of  rest 
extending  from  autumn  to  spring.  This  is  known  to  be  the 
case  in  some  species  of  Cystopus,  in  which  the  oospores  pass 
the  winter  in  the  rotting  tissues  of  its  hosts. 


**  See  a  paper  •*  On  the  Germination  of  the  Resting  Spores  of  Perono- 
spora  Infestans."  by  Wonhington  G.  Smith,  in  Oardeners*  Chronicle, 
July,  1876.  and  reprinted  in  "  Grevillea/'  1876,  p.  18.  He  found  that  the 
oospores  which  germinated  first  produced  swarm-spores  like  those  of 
Cyttopui,  while  tlie  later  ones  "  protruded  a  thick  and  generally  jointed 
thread."    In  his  account  figures  of  both  modes  are  given. 


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264  BOTANY. 

(a)  The  plants  of  this  order  are  easily  obtained,  and  so  far  as  th^r 
Btracture  is  concerned,  are  easily  studied.  Their  development  is,  how- 
evei,  much  more  difficult  to  follow,  and  in  some  species  it  has  thus  far 
baffled  the  most  skilled  botanists.  The  two  genera  Peronospora  and 
CyHopuB  are  distinguished  by  their  conidia,  which  in  the  first  are  ter- 
minal and  single  upon  branches  of  the  aerial  hyplise  (Fig.  175),  while 
in  the  second  they  are  in  moniliform  rows  upon  hyphie  which  burst 
through  the  epidermis  of  the  host  (B,  Fi^.  176). 

(6)  Several  species  of  Peronogpora  are  very  easily  obtained.  P.  tfUi- 
eda,  the  American  grape  mildew,  is  common  on  the  leaves  and  young^ 
shoots  of  the  grape  ;  from  it  may  be  obtained  in  midsummer  an  abun- 
dance of  conidia  and  conidial  hyplue,  and  in  autumn  (October)  the 
oospores  may  be  found  in  abundance  in  tbe  dried  and  shrivelled  parts  of 
the  affected  leaves.*  P.  parasitica  i«  common  in  spring  and  early  sum- 
mer, on  CruciferiB,  especially  on  Ltpidium,  Capsilla,  Draba,  etc.,  fre- 
quently clothing  the  leaves  with  a  white,  frost-like  down.  P.  infesCana^ 
the  potato  fungus,  is  common  in  many  parts  of  the  country  on  the 
leaves  and  stems  of  the  potato,  sometimes  causing  great  injury  by  de- 
stroying the  leaves,  stems,  and  even  the  tubers.  Other  species  occur 
on  Eupatoriam,  Bidem,  Ambrosia,  Impatiem,  PotentUla,  Anemone^ 
etc. 

(e)  The  species  of  Cydopus  which  are  most  common  are  C,  eandidut^ 
which  may  be  found  in  the  spring  and  summer  as  white,  blister-like 
blotches  on  the  leaves  of  Capsella  and  other  CrucifersB  ;  and  C,  Bliti  com- 
mon on  PorttUaea  oleraeea  and  species  of  Amarantus  in  summer  and 
autumn  ;  the  latter  is  an  excellent  species  to  study,  as  its  oospores  are 
very  easily  found,  especially  in  the  stems  of  Portulaea. 

{d)  In  preparing  specimens  for  the  study  of  the  sexual  organs,  small 
portions  of  tlie  tissues  containing;  them  should  be  boiled  for  a  minute 
or  so  in  a  solution  of  potash,  and  then,  while  the  preparation  is  hot,  a 
considerable  quantity  of  acetic  acid  should  be  added  ;  the  effervescence 
which  follows  separates  the  softened  tissues  so  that  hut  little  difficulty 
is  experienced  in  isolating  large  portions  of  the  mycelium  with  oogonia 
and  antheridia.  It  frequently  happens  that  the  parts  are  rendered 
more  distinct  by  the  addition  of  iodine  to  the  s^iecimen  after  mounting 

§  IV.   Class  FucACEiE. 

360. — The  plants  of  this  class,  composed  of  marine  spe- 
cies, present,  in  most  cases,  a  development  of  the  plant-body 
J  unusually  perfect  for  the  Thallophytes.     In  many 

^e  best  account  of  this  fungus  see  a  paper  "  On  the  American 
le  Mildew,"  by  Professor  W.  G.  Farlow,  in  BuUetin  of  the 
iititution,Yo\.  I.,  p.  415.   Several  other  species  are  also  briefly 


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FUCACEJS.  265 

cases  there  is  a  differentiation  of  the  thallus  into  parts  which 
have  a  considerable  resemblance  to  roots^  sterns^  and  leaves  ; 
and  in  size  they  approach^  and,  in  some  cases,  eqnal  or  exceed 
the  larger  Phanerogams.  Their  tissues,  too,  show  a  much 
higher  degree  of  differentiation  than  is  common  in  Thallo- 
phvtes ;  the  cells  are  arranged  in  cell-masses,  and  these  are 
differentiated  into  several  varieties  of  parenchyma,  approach- 
ing, in  some  instances,  to  the  condition  which  prevails  in 
the  Bryophytes  ;  the  outer  tissues  are  composed  of  small  and 
closely  crowded  cells,  which  form  a  dense,  and,  in  some  cases, 
a  hard  mass  ;  the  interior  tissues  are  generally  looser,  and 
are  for  the  most  part  composed  of  elongated  cells  so  joined 
as  to  leave  large  intercellular  spaces. 

361. — With  the  foregoing  there  is  found  in  the  higher 
genera  a  marked  differentiation  of  portions  of  the  plant- 
body  into  general  reproductive  organs,  analogous  to  the 
floral  branches  of  higher  plants.  The  sexual  organs  are 
found  upon  modified  branches,  which  differ  more  or  less  in 
ahape  and  appearance  from  the  ordinary  ones.  This  differ- 
entiation into  vegetative  and  reproductive  parts  is  an  impor- 
tant and  significant  feature  in  the  plant-body,  indicating  a 
decided  advance  over  all  the  previous  groups  of  Thallo- 
phytes. 

In  their  greater  duration  many  of  the  FucacesB  ai*e  in 
tnarked  contrast  to  other  Thallophytes,  which  are  generally 
«hort-lived.  They  are,  for  the  most  part,  of  considerable 
«ze,  rivalling,  in  some  cases,  even  the  larger  Phanerogams. 
They  grow  principally  between  and  a  little  beyond  the  tide- 
marks,  and  furnish  the  great  bulk  of  the  shore  vegetation. 

852. — The  reproduction  of  the  higher  FucaceaB  is  sexual 
only ;  but  in  some  algae  which  appear  to  be  nearly  allied 
<Phjeosporeae)  asexual  zoospores  are  known.  In  Fucus 
the  sexual  organs  are  found  in  the  thickened  ends  of  the 
lateral  branches  of  the  thallus  {Ay  Fig.  181).  They  occur 
on  the  walls  of  hollows  termed  conceptacles,  which  are 
spherical,  with  a  small  opening  at  the  top  {B,  Fig.  181). 
The  conceptacles  are  at  first  portions  of  the  general  surface, 
which  afterward  become  depressions  which  are  walled  in 
and  overgrown  by  the  surrounding  tissues ;  they  are  thus  to 


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266  BOTANY. 

be  still  regarded  as  portions  of  the  general  surface,  and  the 
cells  which  form  the  inner  surface  of  the  conceptaclee  con- 
stitute a  continuation  of  the  epidermal  tissue  of  the  thallus. 
353. — The  walls  of  the  conceptacles  are  clothed  with 
pointed  hairs,  which  in  some  species  project  through  the 


Pig.  \^\.—Fuou9ptatyoarnu%,  A,  end  of  a  portion  of  thallue  ;  /,/.  conceptaclee  in 
fertile  branchlets.  i?,  vertical  section  through  a  conceptade ;  a,  hain*  projecting^ 
from  the  month :  6,  cavity  of  conceotacle  nearly  filled  with  hairs  ;  c,  oogonia  ;  e,  an- 
theridia;  cf,  epiaermal  tissue  of  thallas.— Af  ler  Thuret. 


.,u:^ 


opening,  and  among  these  are  found  the  sexual  organs, 
"h  are  themselves,  as  Sachs  has  pointed  out,  modified 
.  Some  of  the  species  are  monoecious,  while  others  are 
ious.  In  the  monoecious  species  the  antheridia  and 
aia  occupy  the  same  conceptacle  {B,  Fig.  181) ;  the 
3ridia  are  produced  as  lateral  branches  of  modified  hairs 


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FUCACEjE,  267 

(^,  Fig.  182) ;  each  antheridium  is  a  thin-walled  cell,  whose 
protoplasm  breaks  up  into  a  large  number  of  bi-ciliate  sper- 
matozoidsy  which  escape  by  the  rupture  of  the  surrounding  wall 
(By  Fig.  182).  Before  rupturing,  however,  the  antheridia 
detach  themselves  and  float  in  the  water  with  their  contained 
spermatozoids. 

364. — The  oogonia  are  globular  or  ovoid  short-stalked 
bodies,  which  develop  from  papillae  on  the  wall  of  the  con- 
ceptacle.     As  each  papilla  elongates,  it  becomes  divided  into 


Tig.  \^^Fueu9  veticulosus.  A,  bnnched  hair  bearlog  antheridia,  a.  B.  sperma- 
toaoids.  i.,  o^,  oogonium,  with  contenta  divided  into  eight  parts ;  p,  paraphyee^,  or 
aarroandin^  hain*.  //.,  commencement  of  the  escape  uf  the  oospheres— the  outer 
wall,  a,  of  the  oogonium  has  burst,  the  inner,  i,  is  ready  to  open.  III.,  oosphere  es- 
caped, and  8nrronnded  by  spermatozoids  ;  J  V.,  F.,  germinaaoD  of  the  oospoie.  B 
X  880,  all  the  rest  160.— After  Thuret. 

a  basal  and  an  apical  portion  by  a  transverse  partition ;  the 
apical  part  enlarges,  and  (in  the  genus  under  consideration) 
its  protoplasm  divides  into  eight  portions  (/,  Fig.  182), 
which  eventually  become  spherical ;  it  is  thus  an  oogonium 
containing  eight  oospheres.  The  oospheres  escape  from  the 
oogonium  surrounded  by  an  inventing  membrane,  which  floats 
out  through  the  opening  of  the  conceptacle,  where  it  finally 
ruptures  and  sets  the  oospheres  free  (//,  Fig.  182).  The 
spermatozoids  and  oospheres  are  liberated  at  about  the  same 


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268  BOTANY, 

time,  and  the  former  gather  around  the  inactive  ooepheres 
in  great  numbers,  and  by  the  vigor  of  their  movements 
sometimes  actually  give  them  a  rotatory  motion  (///,  Fig. 
182).  The  result  of  the  coming  together  of  the  spermato- 
zoids  and  the  oospheres  is  the  fertilization  of  the  latter,  and 
their  transformation  into  oospores  by  the  secretion  of  a  wall 
of  cellulose  on  each  one.  There  is  thus  seen  to  be  a  close 
similarity  between  the  fertilization  of  Fhicus  and  of  other 
Oosporeae  ;  particularly  does  it  call  to  mind  the  sexual  pro- 
cess in  Volvox  and  its  allies.  When,  however,  the  sexual 
organs  proper,  and  their  accessory  organs,  the  conceptacles, 
are  taken  into  the  account,  the  relationship  of  Fticus  to  Volvox 
is  seen  to  be  much  less  than  it  appears  to  be  at  first  sight. 

355. — The  development  of  the  oospore  takes  place  at 
once ;  it  lengthens  and  undergoes  division  into  numerous 
cells,  and  at  the  same  time  it  elongates  below  into  root-like 
processes,  which  serve  to  hold  fast  the  new  plant  (F,  /F, 
Fig.  18:2).  There  is  a  gap  in  our  knowledge  of  the  life- 
history  of  these  plants,  extending  from  the  young  thallus  to 
the  fertile  plant ;  probably  when  that  is  filled  some  plants 
now  supposed  to  be  distinct  will  be  found  to  be  forms  or 
stages  of  these. 

{a)  The  pnncipal  genera  of  Fueacem  are  Fueus  and  Sargasaum.  Of 
the  first,  F,  7U>do9U8f  F.  fureatuSt  and  F.  vesieuUmu  are  the  most 
common  species  on  our  Eastern  coast,  the  latter  also  occurs  on  the 
Pacific  coast;  both  are  known  as  Rock- weeds.  Sargassum  viUgare  is 
common  on  the  Atlantic  coast ;  8.  baccfferUm,  the  Gulf- weed,  is 
found  in  the  warmer  parts  of  the  several  oceans,  and  in  mid- Atlantic 
covers  an  immense  tract  known  as  the  Sargasso  Sea. 

(6)  The  species  of  Ftteica  and  Sargaasum  are  washed  ashore  in  great 
quantities  during  violent  storms,  constituting  the  bulk  of  the 
'  wrack  "  of  the  coasts.  They  furnish  valuable  manure  for  enrich- 
ing the  soil,  and  are  largely  used  for  this  purpose.  From  their  ashes 
alkalies  and  iodine  are  obtained. 

(c)  In  the  Silurian  period  Fucoides  antiquum  represented  the  order 
Fucaceae.  In  the  Devonian  period  the  order  was  abundantly  repre- 
ed.  Fueus,  Sargasaum,  and  other  genera  were  already  in  exist- 
B  during  Tertiary  times. 


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FUCACEJE.  26! 

Abaanoemeitt  of  the  Classes  and  Orders  of  the  OoPHTTi 


I 


0 

n 


s 

I 


•s  -e 

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1  > 


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► 
200SFOREA?        (EdOOONIB^.    V     CkELOBLASTEiE.        FuCACEiR 


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CHAPTER  XVII. 

CARPOPHYTA. 

366. — ^The  distinguishing  characteristic  of  the  plants 
which  constitute  this  vast  division  is  the  formation  of  a 
sporocarp,  as  a  result  of  the  fertilization  of  the  female  organ. 
The  sporocarp  consists,  except  in  the  simplest  cases,  of  two 
parts  essentially  different  from  each  other,  viz.,  (1)  a  fer- 
tile part,  which  either  directly  or  indirectly  produces  spores, 
sometimes  a  few,  or  even  one,  or,  on  the  other  hand,  a  very 
great  number ;  (2)  a  sterile  part,  consisting  of  cells  or  tis- 
sues developed  from  the  cells  adjacent  to  the  fertile  part, 
and  so  formed  as  to  envelop  it.  This  group  includes  plants 
with  chlorophyll,  and  a  large  number  of  species  which  are 
parasitic  or  saprophytic,  and  which,  as  a  consequence,  are 
destitute  of  chlorophyll.  In  the  former,  the  sporocarp  is 
small  in  proportion  to  the  size  of  the  vegetative  parts  of  the 
plant ;  but  in  the  latter,  where  the  vegetative  parts  are  great- 
ly reduced,  the  sporocarp  is  proportionately  large.  In  this 
the  parasites  and  saprophytes  of  the  Carpophyta  are  like 
those  of  the  Phanerogams,  in  which  the  vegetative  or  assimi- 
lative organs  are  smaller  than  in  those  which  contain  chlo- 
rophyll ;  thus  the  very  large  sporocarp  of  many  of  the  Asco- 
mycetes  and  the  Baeidiomycetes,  and  their  relatively  small 
mycelium,  may  be  compared  to  the  large  reproductive  organs 
and  the  reduced  stems  and  leaves  of  the  BafflesiacecB.* 

*  This  comparison  must  not  be  misunderstood.  It  does  not  imply 
homolo^ry  of  the  parts  compared,  but  it  is  intended  to  compare  the 
Tegetative  and  reproductive  organs  of  the  one  group  of  plants,  func- 
tionally considered,  with  those  of  the  other.  There  can  be  no  doubt 
that  functionally  the  jriant  flower  of  Bafflena  is  the  equivalent  of  the 
sporocarp  of  a  Pezizat  while  structurally  they  are  not  equivalent ;  in 
other  words,  they  are  analogues,  but  not  hcmologues. 


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COLEOCHJBJTE.  271 

367. — The  female  organ  is  in  this  division  called  a  car- 
pogonium,  which  consists  of  a  single  cell  {e.g.,  Coleochmte, 
some  Asconiycetes,  and  the  Characem),  or  of  several  cells  {e.g., 
Floridem  and  most  Ascomycetes).  In  some  cases  a  projec- 
tion, called  the  trichogyne,  is  attached  to  the  carpogoniam  ; 
its  function  appears  to  be  the  conveyance  to  the  carpogonium 
of  the  fertilizing  influence  received  from  the  antheridium. 

368. — The  antheridium  is  here,  as  elsewhere  throughout 
the  Cryptogams,  much  more  variable  in  structure  than  the 
female  organ.  In  some  cases  it  is  applied  to  the  carpogo- 
nium in  fertilization,  while  in  others  it  produces  spermato- 
zoids  ;  in  either  case  contact  with  the  carpogonium  is  either 
direct  {Fodosphmra,  CharacecB),  or  indirect,  through  a  tri- 
chogyne  (e.g.,  ColeochcBiey  Floridece,  Feziza). 

369. — The  plant-body  shows  in  general  a  more  perfect 
development  in  the  Carpophyta  than  in  the  preceding  di- 
visions. While  it  is  but  little  developed  in  the  parasitic  and 
saprophytic  species,  it  is  well  developed  in  many  of  the  Flo- 
ridem  and  the  Characem.  In  these  classes  there  is  often  a 
considerable  amount  of  differentiation  of  the  plant-body 
into  caulome  and  phyllome. 

§   I.    COLEOCH^TE. 

860. — The  genus  Coleochmte  maybe  taken  to  represent  the 
simplest  form  of  sexual  reproduction  in  this  division.  The 
species  are  all  small  green  fresh-water  plants,  composed  of 
dichotomously  branching  filaments,  which  are  arranged  ra- 
dially upon  a  central  disc  (or  sometimes  arranged  upon  irreg- 
ularly branched  threads)  ;  the  diameter  of  each  cushion- 
like mass  is  from  1  to  2  mm.  (.04  to  .08  in.). 

801. — Reproduction  takes  place  both  sexually  and  asexu- 
ally.  The  latter  is  by  means  of  zoospores  which  arise  in  the 
vegetative  cells,  by  the  protoplasmic  contents  becoming,  in 
each  case,  converted  into  a  single  spherical  bi-ciliated  zoo- 
spore, which  escapes  through  a  round  hole  in  the  cell-wall 
(Z),  Fig.  183). 

802. — The  sexual  organs  and  process  bear  some  resem- 
blance to  those  of  CEdogoniacese.      The  female  organ,  the 


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272  BOTANY. 

carpogonium,  is  a  single  cell,  wide  below,  and  tapering  above 
into  a  long  slender  canal,  the  tricbogyne,  which  is  open  at 
its  apex  {A,  og,  Fig.  183).  The  carpogonium  is  the  terminal 
cell  of  a  branch,  which  in  its  development  swells  up,  while 
at  the  same  time  elongating  into  a  tube.  In  the  swollen  basal 
portion  there  is  a  considerable  mass  of  protoplasm,  which  is 
the  essential  part  to  be  fertilized. 

The  male  organs,  the  antheridia,  are  formed  as  flask-shaped 
protuberances  which  grow  out  of  adjoining  cells  ;  they  be- 


Fig.  tS^—OoieoehcUe  pulvinata.  A,  portion  of  fertile  plant ;  on,  antheridia ;  09, 
oarpogonia— each  with  a  irichng^'ne ;  t,  2,  ppermarosoida ;  fu,  balm,  with  »heathin? 
bases,  /f,  fertilized  carpogoDinm  enrroanded  by  coverinff,  r  ("  pericarp*'),  the  whole 
conatitntins  the  eporocarp.  (7,  sporocarpe  burst  open,  Bnowing  the  interior  tionie, 
8ch ;  r.  cortical  cover  (*'  pericarp^O*  ^t  soospores  (ewarm-aporee)  ttom  C.  X  850.— 
After  Pringaheim. 

come  cut  off  from  the  cells  from  which  they  grow,  by  trans- 
verse partitions.  In  each  antheridium  a  single  oval  bi- 
permatozoid  is  formed  {A,  2,  2,  Fig.  183). 
-Fertilization  is  doubtless  effected  by  these  sperma- 
3oming  in  contact  with  the  protoplasm  of  the  carpo- 
,  but  the  actual  entrance  of  the  former  has  not  yet 
n.  After  fertilization  the  protoplasmic  mass  in  the 
nium  increases  considerably  in  size,  and  becomes 
ied  by  a  cellulose  coat  of  its  own.     The  cells  which 


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FLORIDEJE.  273 

support  the  carpogoniam  send  out  lateral  branches^  which 
grow  up  and  closely  invest  it,  and  by  their  growth  finally 
cover  it  entirely  (excepting  the  trichogyne)  with  a  cellular 
"pericarp'*  (By  r,  Fig.  183).  The  whole  mass,  including 
the  fertilized  carpogonium  and  its  investing  "pericarp,'* 
constitutes  the  simplest  form  of  sporocarp, 

864. — The  germination  of  the  sporocarp  takes  place  (the 
next  spring)  by  the  swelling  of  the  protoplasmic  contents, 
and  the  consequent  rupture  of  the  "  pericarp  ;"  the  inner 
portion  becomes  changed  into  a  many-celled  mass  (C,  Fig. 
183),  which  gives  rise  to  bi-ciliate  zoospores  closely  resembling 
those  developed  from  the  vegetative  cells.  From  each  zoo- 
spore a  new  plant  eventually  arises. 

(a)  These  little  plants  occur  in  fresh-water  pools  as  little  green 
masses  adhering  to  leaves,  sticks,  etc.  According  to  Wolle,  we  have 
five  species. 

(&)  The  sexual  process  and  the  development  of  the  sexual  organs  oc- 
cur in  May,  June,  and  July. 

(c)  Notliing  can  be  attempted  in  this  place  to  determine  the  grouping 
of  CoUoeluBU  with  other  Carpophyta.  Its  evident  relutionship  to  the 
Perisporiaceie  in  the  Ascomycetes  suggests  that  possibly  the  latter 
class  may  have  to  be  broken  up,  and  the  first  two  orders  united  with 
CoUoehaU  to  form  a  new  class.  Certainly  the  relationsliip  between 
CoUoehate,  Perisporiaceee,  and  Tuberaces  is  much  closer  tlian  between 
the  two  last  named  and  the  other  orders  of  Ascomycetes.  There 
can  be  but  little  doubt  that  the  Ascomycetes  are  held  together  by  char- 
acters which  are  now  of  but  secondary  value,  drawn  as  they  are  from 
the  asexual  fruiting,  while  characters  which  are  of  fur  greater  value, 
derived  from  the  sexual  organs,  are  disregarded. 

§  II.   Class  Florideje. 

366. — In  the  Florideae  the  reproduction  is  generally 
asexual  as  well  as  sexual.  The  former  is  by  means  of  cells 
which  originate  from  a  division  of  a  mother-cell  into  four 
parts ;  on  account  of  their  number  they  have  received  the 
name  of  tetraspores  {A,  B,  t,  t,  Fig.  184).  These  appear 
to  replace  the  swarm-spores  of  other  algae,  and  may  also  be 
compared  to  the  conidia  of  certain  fungi ;  they  are  destitute 
of  cilia,  and  are,  as  a  consequence,  not  locomotive.  They 
develop  from  the  terminal  cells  of  lateral  branches,  or  from 
the  cells  of  ordinary  thick  tissues,  sometimes  deeply  imbedded. 


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274 


BOTANY. 


866. — The  sexaal  organs  consist,  as  in  Coleochaie,  ot 
carpogonia  and  antheridia.  The  latter  are  composed  of  one 
or  more  mother-cells,  situated  singly  or  in  groups  on  the 
ends  of  branches  {A  and  B,  a,  o,  Fig.  185).  The  sperma- 
tozoids  are  small,  round  bodies,  which  are  destitute  of  cilia, 
and,  as  a  consequence^  incapable  of  independent  movement 
{A,  Xy  Fig.  185)  ;  they  are  carried  about  by  currents  of 
^  water,  and  in  this  way  brought  to 

the  carpogonia. 

367. — The  carpogonia  are  some- 
what variable  as  to  their  complex- 
ity, being  much  more  simple  in 
the  lower  orders  than  in  the  high- 
er. In  the  genus  Nemalion  the  car- 
pogonium  consists  of  a  single  cell 
{B,  by  Fig.  185),  resembling  Coleo- 
chate  closely  in  this  respect.  It 
is  thickened  below,  and  elongated 
above  into  the  trichogyne,  which 
differs  from  that  in  Coleochmte  in 
not  beinff  open  at  the  top.  When 
<,tetm8pore8^ After  Sachs  ^,of  the  spcrmatozoids  are  set  free  from 
In  a  cup-8baped  extremity  of  a  the  anthcridia  tiiev  attach  them- 

branch.— After  Berkeley.  ,  .      xv      x  •   i  i. 

selves  to  the  tnchogjme,  as  shown 
in  Fig.  185  ;  the  result  of  this  contact  of  the  spermatozoids 
with  the  trichogyne  is  the  fertilization  of  the  carpogonium, 
which  immediately  enlarges,  and  at  the  same  time  undergoes 
division  into  many  cells,  which  grow  into  short,  crowded 
branches,  bearing  a  spore  at  the  end  of  each  (Z>  and  Ey 
Fig.  185).  To  this  growth,  which  includes  the  spores  and 
the  short  branches  which  bear  them,  and  which  resulted  from 
the  fertilization  of  the  carpogonium,  the  name  of  sporocarp  is 
applied.  In  the  genus  under  consideration  the  sporocarp  is 
a  comparatively  simple  growth,  as  compared  with  the  degree 
of  complexity  it  reaches  in  some  other  orders  of  this  class. 

368. — In  the  genus  LejoUsia,  the  carpogonium,  before 
fertilization,  consists  of  several  cells  {A,  b.  Fig.  185) ;  the 
trichogyne  is  in  connection  vnth  certain  of  the  exterior  cells 
of  the  carpogonium,  but  not  directly  with  its  central  cell. 


Fig.  184.— Tetraeporea  of  Florid- 
^,  of  L^iHa  rMdUerranta ; 


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FLORIBEM.  275 

TTpon  fertilization  taking  place,  which  is  as  in  Nemalion^ 
the  peripheral  cells  of  the  carpogonium  (excepting  those  con- 
stituting the  trichophore — i,e,y  the  trichogyne-bearer)  undergo 
division,  and  become  deyeloped  into  articulated  branches, 
which  lie  side  by  side,  and  form  a  more  or  less  spherical 


Fig.  18S.— ^,  L^itia  mediUrranea.  r,  root-like  processes  (rhizoids) ;  a,  antherid- 
inm  ;  a;,  spermatozoids  ;  b,  carpogoniam,  with  trichogyne,  to  the  apex  of  which  two 
Bjpermatdzoid^  are  attached ;  $^  section  of  ripe  sporocarp ;  t^  ripe  spore  escaping.  B^ 
SemaUon  muUifidum.  a,  branch  with  anttiendia  ana  spermatozoids  ;  6,  carpogo- 
nium, with  tricboffyne,  the  latter  with  spermatozoids  attached  to  its  apex.  D  and  Ey 
development  of  the  sporocarp  of  yemaliort.    x  150.— After  Bornet. 

organ,  the  so-called  "pericarp."  In  the  meantime  the  cen- 
tral cell  of  the  carpogonium  develops  processes  or  outgrowths 
which  eventually  become  spores,  occupying  the  cavity  of  the 
"pericarp"  {A,  s,  Fig.  185).  An  interesting  fact  in  this 
connection  is  that  neither  the  trichogyne  nor  trichophore 
take  part  in  the  development  subsequent  to  fertilization  ;  in 
other  words,  the  cells  which  directly  receive  the  influence  of 
the  spermatozoids  do  not  themselves  undergo  a  subsequent 
development,  but  adjoining  ones  do  develop,  on  the  one 
hand,  into  the  spores,  and  on  the  other  into  the  filaments 
of  the  pericarp.  The  sporocarp  in  this  genus  is  thus  seen 
to  be  somewhat  more  complex  than  in  Nemalion,  including 


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276 


BOTANY. 


the  pericarp,  in  addition  to  the  parts  found  in  the  latter 
genus. 

369. — In  the  genus  Dudresnaya  there  is  a  curious  and 
complicated  sexual  process.     After  the  fertilization  of  the 
trichogyne,  a  long  "  connecting  tube"  (cty  Fig.  18G)  grows  out  , 
from  beneath  the  trichophore,  and  comes  in  contact  with  the 

fertile  branches  (/,  /, 
Fig.  186),  to  the  ter- 
minal cells  of  which  it 
becomes  closely  applied. 
These  fertile  branches, 
which  grow  as  lateral 
branches  on  the  same 
plant  as  the  trichogyne, 
are  the  true  female  or- 
gans, and  fertilization 
is  consummated  only 
when  the  connecting 
tube  comes  in  contact 
and  coalesces  with 
them.  The  result  of 
this  curious  process  is 
the  production  of  a  spo- 
rocai-p  on  each  fertile 
filament. 

(a)  This  class  is  a  large 
and  interesting  one,  but  un- 
fortunately it  cannot  be 
studied  readily  except  near  the  seaside,  and  even  then,  from  the 
fact  that  the  species  mostly  inhabit  the  deeper  waters,  it  presents  many 
difficulties.  The  plants  are  mostly  red  or  violet  in  color,  although  this 
is  not  due  to  the  absence  of  chlorophyll.  The  red  color  is  due  to  the 
presence  of  a  pijnnent  (phycoerythrine),  which  is  soluble  in  cold  fresh 
water  ;  its  solution  is  carmine-red  in  transmitted  light  and  reddish  yel- 
low in  reflected  light.  Upon  extraction  of  the  phyco€rythrine  the 
plants  are  found  to  be  green  from  the  presence  of  the  chlorophyll 
— *-'ch  had  been  masked  by  the  brighter  pigment. 

))  There  are  many  orders  in  this  class,  the  following  of  which  are 
esented  in  the  United  States.* 

The  sequence  of  the  orders  is  that  given  by  Dr.  Farlow  in  hi* 
St  of  the  Marine  Algse  of  the  United  States,"  1876,  published  in  the 


Fig.  ie6,—I>udremaya  purpftiifera.  tr,  tricho- 
gyne, with  Bpermatozoide  attached;  ct,  connecting- 
tube  which  grows  out  from  below  the  base  of  the 
trichogyne,  and  comes  in  contact  with  the  fertile 
branches,/,/;  cf,  young  connecting-lube.— After 
Thuret  and  fiomet. 


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FLORIDEjS.  277 

Order  BhodomeUa,  of  wliich  Dasya  and  Pdpsiphonia  are  common 
^Dera. 

Order  ChylodaiUa,  represented  by  only  two  Californian  species. 

Order  Sphcgrococeoidea,  represented  abundantly  by  species  Delesseria. 

Order  CoraUiiuod,  containing  plants  which  are  remarkable  for  the 
large  amount  of  calcium  carbonate  they  contain.  CoraUina  is  abundant. 

Order  QelidietB,  represented  by  Gelidium, 

Order  Bypnea,  including  only  a  few  species  of  one  genus  ffypnea. 

Order  Bhodymenieat  of  which  Bhodymenia  and  Lomentaria  are  com- 
mon genera.  Bhodymenia  palmcUa,  the  "  Dulse  "  of  our  coasts,  is  used 
as  human  food. 

Order  Spongiocarpim,  with  one  species  of  Polyidea, 

Order  Squamariem,  with  one  species  of  Peyssonnelia, 

Order  Batraehoapemua,  to  which  Nemalion  (Fig.  185,  B)  belongs. 

Order  WrangeliecB,  with  two  species  of  Wrangelia, 

Order  GigartinecB^  of  which  ChondruB  crispu9f  the  Irish  moss  so 
largely  used  for  food,  for  making  blanc  mange,  etc,  is  the  best-known 
of  the  many  species  on  our  coasts. 

Order  CrypUmemua,  represented  mainly  on  our  Southern  and  Pacific 
coasts.  SeMzynemia  edulis,  of  Europe  and  our  Western  coasts,  is 
used  as  human  food. 

Order  Dumon'iecB,  to  which  HaloMccion  of  our  Eastern  coast  belongs. 

Order  Spyridiea,  represented  by  Spyridia  of  our  Eastern  coast. 

Order  Ceramiea.  This  order  contains  algae  "  which  are  eitiier  strictly 
monosiphonous  {i.e.,  composed  of  a  single  tube)  and  filiform,  or  which 
are  more  simple  in  their  structure  than  others,  approaching  in  this  re- 
spect the  ConfervaceflB.  It  abounds  in  species  which  display  the  most 
exquisite  combination  of  ramification  aud  coloring."  A  large  portion 
of  our  mariue  flora  is  composed  of  individuals  of  this  order,  as  "  they 
abound  on  our  coasts  in  every  little  rocky  pool,  onevery  piece  of  wood- 
work exposed  to  the  waves,  on  rocks  and  stones,  and,  above  all,  on  the 
stems  of  the  larger  or  firmer  a]g»,  or  even  on  marine  Plianerogams, 
which  they  fringe  in  the  most  exquisite  way  with  every  shade  of  red, 
from  a  bright  rose  to  purple."! 

LefoHHa  {A,  Fig.  185)  and  Dudresnaya  (Fig.  186)  are  genera  of  this 
order.    CaUithamnian  is  represented  by  many  species  on  both  our  At- 

Beportofthe  U.  8.  Fish  Commissioner  for  1875.  It  is  modified  from 
Thuret's  arrangement.  The  arrangement  of  tlie  orders  and  the  group- 
ing of  genera  into  orders  are  not  based  upon  sexual  characters,  and  c-^m- 
sequently  must  t)e  regarded  as  to  a  considerable  extent  artificial.  The 
first-named  orders  in  the  list  are  higher  than  those  that  follow. 

t  "  Introduction  to  Cryptogamic  BoUny,"  by  M.  J.  Berkeley,  1857,  p. 
178.  The  student  is  also  referred  to  Harvey's  "  Nereis  Boreali-Ameri- 
cana."  a  '*  Contribution  to  a  History  of  the  Marine  Algae  of  North 
America,"  published  by  the  Smithsonian  Institution,  1852  to  1838. 


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278  BOTANY. 

lantic  aad  Pacific  coasts.    Cetamium  nihrum  is  a  verj  common  spe- 
cies. 

(e)  Tbe  order  CoraHioeae  was  represented  in  the  Silarian  by  a  sp»> 
cies  of  GaralUna.  Others  occur  in  the  Secondary  (Jurassic)  and  Ter- 
tiary. ChondriteM  represented  the  order  Qigartinete  from  the  Permian 
to  the  Tertiary  (Miocene).  The  order  Sph»rococooideffi  was  represented 
in  the  Secondary  by  Jurassic  species  of  Spharococeiies,  and  in  the  Ter- 
tiary by  Deieweria,  In  the  order  Rhodomelete  a  species  of  Polyn- 
pkonides  occurs  as  a  fossil  in  the  Tertiary. 

§  III.  Class  Ascomycetes. 

370.  —  This  large  class  includes  chlorophylUess  plants 
which  differ  much  in  size  and  appearance^  but  which  agree 
with  one  another,  and  differ  from  all  other  Carposporeae  in 
producing  their  spores  {ascospores)  in  sacs  (asct).  The  sex- 
ual reproductive  organs,  consisting  of  carpogoniaand  anthe- 
ridia,  are  produced  upon  the  mycelium,  and,  after  fertiliza- 
tion, a  sporocarp,  which  includes  the  asci  and  ascospores,  is 
developed.  The  asci  are,  at  first,  single  cells  at  the  ends  of 
branches  which  result  from  fertilization  of  the  carpogonium  ; 
in  these,  ascospores  arise  by  internal  cell-formation.  The 
most  common  number  of  ascospores  is  eight  in  each  ascus, 
but  it  sometimes  exceeds,  and  frequently  falls  short,  of  this 
number,  there  being  often  no  more  than  one  or  two.  The 
asci  are  in  many  cases  arranged  side  by  side  in  a  compact 
mass,  forming  a  spore-bearing  surface,  the  hymenium.  In 
addition  to  the  ascospores  thei*e  are  generally  one  or  several 
other  kinds  of  spores,  which  are  developed  on  the  same  my- 
celium as  the  sexual  organs,  or  on  another,  the  latter  case 
being  one  of  an  alternation  of  generations. 

371. — The  Ascomycetes  are  readily  separated  into  a  num- 
ber of  well-marked  groups,  which  may  not  all  turn  out  to  be 
co5rdinates.     For  the  present  they  may  be  treated  as  orders. 

372.— Order  Perisporiaoesd  (or  ErysiphaoesB).  In  this 
order  the  plants,  which  are  mainly  parasitic,  are  composed 
of  branching  articulated  filaments,  which  form  a  white  web- 
like film  upon  the  surface  of  the  leaves  and  stems  of  their 
hosts.  There  are  both  sexual  and  asexual  spores,  and  of 
the  latter  there  are  in  most  cases  two  or  three  different  kinds, 
which  are  produced  earlier  than  those  that  result  from  a  fer- 


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PERISPORIACEjE.  279 

tilization.  The  sexual  organs  and  the  sporocarp  resulting 
from  the  act  of  fertilization  bear  a  striking  resemblance  to 
those  of  ColeochcBte,  the  difference  being  such  as  may  be  ac- 
counted for  by  considering  the  aquatic  habits  of  the  one,  and 
the  aerial  and  parasitic  or  saprophytic  habits  of  the  other. 

378. — In  the  parasitic  PeriaporiacecB  the  jointed  filaments 
of  the  mycelium  closely  invest  and  cover  the  leaves  and 
other  tender  parts  of  their  hosts,  and  draw  nourishment 
from  them  by  means  of  haustoria,  which  project  as  irregular 
pnllulations    from    the    side   of  ^ 

the  hyphae  next  to   the  epider-  m 

mis  (Fig.  187) ;  these  haustoria 
apply  themselves  closely  to  the  ^ 

epidermis  cells,  and,  in  some 
cases  at  least,  appear  to  penetrate 
them.*  The  crossing  and  rami- 
fying hyphae  soon  send  up  many 
vertical  branches,  in  which  parti-  » 
tions  form  at  regular  intervals ; 
the  cells  thus  formed  are  at  first 
oblong  and  cylindrical,  with  flat- 
tened ends ;  but  the  topmost  one 
soon  becomes  rounded  at  its  ex- 
tremities, and  the  others  follow       ^^    ^fft,  ^  wryHpfu   (OUiium) 

in  quick  succession,  thus  giving  TuckeH.    a,  a  piece  of  a  vegi'tatlve 

.    *  ....  '  ^°         ^  hypba,  m,  m,  apoQ  a  fragment  of  the 

nse  to  a  mon inform  row  of  loose-  epidermis  of  the  leaf  of  the  vine,  and 

1       ii     1      "I      IT    o^-      1  J    J  to  which  it  la  fastened  by  the  hau»- 

ly  attached  elliptical  or  rounded  toria.  h,-  6,  an  isolated  piece  of  a 

cells,  the  conidia  (/;  Fig.  188).  rin^rriS.enttdrl\'ew!^\'ln5!- 
Thesefall  off  and  germinate  at  ^^"-vonMohi. 
once  by  pushing  out  a  germinating  tube,   which  gives  rise 
to  a  new  mycelium. 
374. — The  sexual  process,  which  in  most  species  takes 

♦De  Bary  (**  Morpbologie  und  Phyaiologie  der  Pilze,"  etc..  1865,  p. 
19)  says  tbat  the  haustoria  of  the  investigated  species  do  not  penetrate 
into  the  epidermis  cells  ;  while  Sachs  (**  Lehrbuch,  4te  Auflage/'  1874, 
p.  812)  Bays  that  haustoria  are  sent  into  the  epidermis  cells.  A  myce- 
limn  on  Poa  protends  (probably  of  ErympTu  communis)  examined  in 
1877  appeared  to  have  sent  its  haustoria  through  the  outer  walln  of 
the  epidermis  cella 


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280  BOTANY. 

place  late  in  the  season,  is  as  follows  :  where  two  filaments 
cross  each  other  or  come  into  close  contact  they  swell 
slightly  and  send  out  from  each  a  short  branch ;  one  of  these 
thickens  and  assumes  an  oval  form,  becoming  at  the  same 
time  separated  from  the  filament  by  a  partition  ;  this  is  the 
carpogonium  (///,  c,  Fig.  188,  and  c.  Fig.  189).  From  the 
swollen  part  of  the  other  filament  a  corresponding  branch  is 
given  off,  which  grows  up  in  contact  with  the  carpogonium ; 
near  its  extremity  it  forms  a  partition,  which  thus  cuts 


Pig.  188.— /.»  conldia-bearlng  bypha  of  Sphoerotheoa  pannow.  IT.,  the  ripe  pporo- 
carp  of  the  Bame  ;  a,  the  ningle  ascna  ef«ap1ng  from  the  perithecinm.  A;  only  a  few 
of  the  hypha-like  appendages  of  the  perithecinm  are  shown.  III.,  sexnal  oigansof  the 
Bame:  e,  carpogonium  :  p,  antheridfum.  /F.,  the  formation  of  the  peritneciam  by 
the  growth  of  the  enveloping  cells,  h ;  c,  carpogonium  ;  p,  antheridiam.  F.,  section 
of  the  vonng  sporocarp  of  SpfuBrolheoa  Ctutagnei ;  e,  carppgoniam  :  a,  the  yonng 
asGQs ;  A,  hy  cells  of  the  perithecinm.  /.  and  U.  after  Tolaene ;  ///.-  V.  after  De 
Bary. 

off  a  small  rounded  terminal  cell,  the  antheridium  (///.,  p, 
Fig.  188,  and  *,  Fig.  189).  Immediately  after  the  forma- 
tion of  the  antheridium  the  effect  of  fertilization  shows  itself 
in  the  growth  from  below  the  base  of  the  carpogonium  of  eight 
or  ten  branches,  which  join  themselves  to  its  sides  and  to  one 
another,  finally  completely  investing  it  (/F.,  Fig.  188,  andrf, 
Fig.  189).  Each  of  these  joined  enveloping  branches  be- 
comes transversely  divided  several  times,  thus  giving  to  the 
covering  layer  a  distinctly  cellular  structure.     The  enclosed 


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PERISPOmACEJBi  281 

carpogonium  becomes  diyided  in  such  a  way  that  from  one 
portion  of  it  an  inner  layer  of  cells  is  formed  in  contact  with 
the  outer  envelope  described  aboye.  From  the  remaining 
central  part  of  the  carpogonium  one  ascus  (in  Sphcsrotheca 
and  Podosphwra),  and  in  the  other  genera  two  or  more,  are 
developed.  In  each 
ascus    from    two    to  d 

eight  ascospores  arise  ' 
by  internal  cell-for- 
mation (//,  a.  Fig. 
188).  The  sporocarp 
(technically  called 
the  peritkecium)  be-     y,^  ,,,  ..^,  ^^^,  ^^^  ,„  ^j^^^^c,*^ 

comes  dark  and  hard,    aeearum.    a,  threads  or  myceliam;  &,aotheridiam; 
J     .  -  ,        c.  carpogoniom ;  d,  yoang  eporocarp  ;  e.  older  sporo- 

and    from     its    outer   carp.    Highly  magnified.— After  (Ersted. 

cells  there  grow  out  long  filaments  (technically  known  as 
appendages),  which  are  usually  septate,  and  of  a  particular 
shape  in  each  genus  ;  thus  in  Podosphcera  and  Microsphcera 
they  are  dichotomously  branched  ;  in  Phylladmia  they  are 
straight  and  needle-shaped;   in  Uncinula  they  are  curved 
regularly  at  their  tips  (Fig.  190),  while  in  the  other  genera 
they  are  tortuous,  and  simple  or  irregu- 
larly branched.      The  perithecia  remain 
during  the  winter  upon  the  fallen  and 
decaying  leaves,  and  finally,  by  rupturing, 
permit  their  asci,  with  their  contained 
ascospores,  to  escape. 

376. — There  are  usually  present  some 
cJpVrA^^  !^S!^  other  organs,  which  bear  small  spore-like 
«;  the  appendages  of  bodics,  but  whose  functiou  is  not  certain 

the     peritbectum     »re    ,       ,  rni  i  •  i 

curved  in  a  circinate  ly  kuown.       These    orgaus,   which    are 

nuuioer  at  their  free  ex-    ,•'  .      - 1-  i        x  i 

tremWes.— After  Cooke,  kuown  as  pycmdia,  are  clavate,  ovate,  or 
nearly  spherical  in  shape ;  the  bodies  they  contain  (the  so- 
called  pycnidio-spores)  in  their  cavities  are  usually  oblong 
or  elliptical. 

876. — In  the  genus  Eurotium  (composed  of  saprophytes) 
the  conidia  are  produced  in  a  slightly  different  way.  The 
mycelium,  which  is  common  on  articles  of  food,  as  bread, 
pastry,  preserved  fruit,  etc.,  and  on  poorly  dried  specimens  in 


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282 


BOTANY. 


fche  herbarium^  sends  up  yertical  hjrphae^  which  swell  up  at 
the  top,  and  bear  a  large  number  of  small  protuberances  or 
branches,  the  sterigmata  {A^  c,  st,  Fig.  191).  Each  sterigma 
produces  gradually  a  long  chain  of  conidia,  so  that  each 


Pig.  l^i.^Eurotium  repsns.  A,  a  portion  of  the  mycelium,  with  erect  hvpha,  c, 
beanng  at  ita  top  a  radiating  cluster  of  eterigmata,  at,  from  which  the  aonidia  have 
fallen  ;  a#,  yonng  carpogoniam— helow  it  a  yonnger  branch  is  beginning  to  coil  epi* 
rally  to  form  another  carpogoniam.  B,  the  carpogoninm,  as,  and  the  antherldium,  p. 
O,  the  same  banning  to  be  aurronnded  by  the  enveloping  branchea  which  grow  oat 
from  its  base.  A  sporocarp.  K  F,  sections  of  nnripe  sporocarps ;  «7,  outer  wall ; 
/.  inner  cells  of  stenle  tissue  ;  a«,  developing  cnrpogonlum,  giving  rise  to  branches 
from  which  asci  are  produced.  O,  an  aDCus  containing  eight  aacoapores.  J7,  ripe  as- 
cospore.    Highly  magnified.— After  De  Bary. 

vertical  hypha  is  terminated  by  a  round  mass,  made  up  of 
these  radiating  strings  of  conidia.  The  sexual  organs  appear 
a  little  later  than  the  conidia.  The  end  of  a  branch  of  the 
mycelium  becomes  coiled  into  a  hollow  spiral  {A,  as.  Fig. 


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PERISPORIACE^.  283 

191),  which  constitutes  the  carpogonium,  and  which  is  soon 
divided  by  cross-partitions  into  several  cells.  P'rom  below 
the  spiral  there  pushes  out  a  branch  (the  autheridium),  which 
^grows  upward,  and  brings  its  apex  in  contact  with  the  upper 
cells  of  the  carpogonium  {B,  Fig.  191).  After  this  pro- 
•cess,  which  constitutes  fertilization,  other  branches  grow  up 
around  the  carpogonium,  and  finally  completely  enclose  it. 
as  in  the  parasitic  genera  described  above  (C,  2>,  E,  and  Fy 
Fig.  191).  By  the  subsequent  growth  and  division  of  the 
enveloping  branches,  the  carpogonium  becomes  imbedded  in 
a  thick  parenchymatous  mass.  In  the  meantime,  from  the 
cells  of  the  carpogonium  branches  bud  out  and  penetrate  the 
surrounding  parenchyma  {Fy  Fig.  191),  and  finally  produce 
cight-spored  asci  on  their  extremities  {0,  Fig.  191) ;  after  a 
time  the  asci  are  dissolved,  and  the  sporocarp,  now  of  a  sul- 
phur-yellow color,  contains  only  loose  ascospores,  intermingled 
with  the  debris  of  the  broken-up  asci  and  parenchyma.* 

The  plants  of  this  order  are  abandant  and  easily  studied.  The 
followini^  partial  list  will  enable  the  stadent  to  intelligently  begin  his 
investigations : 

Parasitic  Plants. 

A.  Perithecium  containing  a  single  ascos. 

Appendages  fioccose Genus,  SphcBrotheea, 

Appendages  dichotomous "       PodoBpJiara, 

B.  Peritheciam  containing  many  asci. 

Appendayres  needlf^haped,  rigid Genus,  Phj/llaetinin. 

Appendages  hooked "       Undnvia, 

Appendages  dichotomous "      Microiphara, 

Appendages  fioccose '*      Brysiphe, 

Sphmrotheea  pannosa  occurs  on  wild  goo8ei>erries,  on  whose  stems, 
leaTes,  and  fruits  it  forms  brown  felted  masses.  In  its  conidial  stage 
it  is  frequently  so  abundant  on  the  leaves  of  roses  as  to  entirely  destroy 
ihem. 

8.  Oastagnei  sometimes  occurs  upon  the  hop  in  such  abundance  as  to 
-destroy  the  crop. 

*  The  student  is  referred  to  De  Bary's  "  Morphologie  und  Physiolo. 
^6  der  Pilxe/'  etc.,  1865,  p.  162.  A  translation  of  the  part  relating  to 
4he  Erydphei  appc^ired  in  "  Grevillea,"  Vol.  I.,  p.  153. 


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284  BOTANY, 

Podoiphara  Kuntei  may  be  found  on  tbe  leaves  of  tbe  cberry  and 
apple,  wbicb  it  injures  greatly  in  some  cases ;  tbe  conidia  may  be  ob- 
served in  midsummer,  and  the  sexnal  process  and  formation  of  peritbecia. 
in  autumn. 

PhyUactinia  guttata  may  be  obtained  in  great  abundance  in  autumn 
upon  tbe  leaves  of  tbe  hazel  and  ironwood. 

Uneinula  adunca  is  frequently  abundant  on  willow  leaves  in  tbe 
autumn  (Fig.  190). 

U.  »pirali$  is  tbe  species  to  whose  conidial  stage  tbe  name  Oidium 
Tuekeri  has  hitherto  been  applied  in  this  country.  It  occurs  on  tbe 
grape,  and  does  great  injury.  According  to  Dr.  Farlow,  it  18  not  cer- 
tain that  the  so-called  Oidium  Tuekeri  of  this  country  is  identical  with 
wbat  is  so  named  in  Europe,  and  which  is  even  more  injurious  to* 
grapes  in  that  country  than  in  tbis. 

U,  eireinata  occurs  on  the  leaves  of  the  red  and  silver  maples  in  tb» 
autumn. 

Mvcroiphcera  Friesii  is  one  of  tbe  most  common  species.  It  may  be 
found  in  the  conidial  stage  at  any  time  during  tbe  summer  on  tbe 
leaves  of  the  lilac,  and  late  in  summer  or  in  autumn  tbe  perithecia  are 
usually  abundant. 

If.  externa  is  a  nearly  related  species,  often  very  common  on  oak 
leaves. 

Erynphe  {amprc?carpa,  which  may  be  found  on  Compositae  (especially 
on  HeliarUhus),  and  also  on  wild  verbenas,  is  readily  distinguished  by 
its  two-spored  asci.  Tbe  commonness  of  tbis  species  makes  it  a  valua- 
ble one  for  study. 

E.  tortUii  may  be  frequently  obtained  on  the  leaves  of  the  VirginV 
Bower. 

E.  Martii  occurs  in  great  abundance  upon  cultivated  peas,  greatly 
to  their  injury.  In  summer  it  covers  tbe  leaves  and  fruits  with  a. 
white  mould-like  growth,  which  is  the  conidial  stage  of  the  parasite  ; 
as  autumn  approaches  tbe  mycelium  becomes  darker,  and  finally  large 
numbers  of  perithecia  may  be  found. 

E.  eammunis  appears  in  early  cummer  on  g^ss  leaves,  where  tbe 
vegetation  is  rank.  In  autunm  tbe  perithecia  may  be  found  in  abun- 
dance  on  Ranunculaceee  (especially  on  Anemone)  growing  in  grass. 


Saprophytic  Plants. 

?ierbariarum  may  be  readily  obtained  for  study  by  placing 
specimens  of  Phanerogams  in  an  ordinary  plant-press  and 
,bem  to  remain  until  they  become  mouldy.  The  conidial 
first  appears,  is  what  has  long  been  described  as  a  distinct 
sr  tbe  name  of  A»pergiUu%  glaueus ;  somewhat  later  th^ 
V  perithecia  will  be  found  in  abundance. 


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TUBERACEjE. 


285 


377. — Order  Tuberaoe®.  In  this  order  the  sporocarp  is 
a  rounded  underground  mass,  composed  of  pseudo-paren- 
chjrma  and  the  asci  with  their  contained 
ascospores.  In  the  Truflfle  {Tuber)  the 
sporocarp  is  large,  and  dark  colored  and 
warty  on  the  exterior.  Internally  it  con- 
tains narrow  tortuous  chambers,  on  whose 
walls  are  the  asci,  containing  two  to  eight 
usually  areolate  or  echinulate  ascospores  ^ 

(Fig.  192,  A  and  B).  The  sexual  organs, 
•as  well  as  the  early  stages  of  the  Truflfles, 
are  unknown. 

378. — The  common  hlue  mould,  found 
on  all  soHs  of  decaying  bodies,  and  known 
as  PenicilUum  glaucurri  (or  P.    crusta- 
ceum)f  has  recently  been  found  by  Brefeld 
to  be  a  member  of  this  order.    Its  life-his- 
tory is  now  pretty  well  known,  and  it  in- 
dicates what  the  early 
stage    of   the   Truffle 
must  in  all  probability 
turn  out  to    be.     In 
PenicilUum    the   my- 
celium sends  up  a  large 
number     of     vertical 
hyphae,  which  branch 
at  the  top,  and  produce  chains  of  conidia 
(Fig.    193).     It  appears,  from  Brefeld's 
researches,   that  this  stage  is  the  only 
one  which    the    plant    passes    through 
under  ordinary  circumstances  ;  by  care- 
ful culture,  however,  he  succeeded  in 
S&b^rV^7pi?;Tt  making  it  pass  into  its  sexual   stage. 
l.^'ed*'cVai^  orrSSiiit   He  found  the  sexual  organs  to  be  in  all 
Magnifled.-After Cooke,   esscutials  similar  to  those  of  Eurotiu7n 
(Fig.  191) ;  like  it,  the  carpogonium  is  a  spirally  twisted  end 
of  a  hypha,  and  the  antheridium  a  branch  growing  out  from 
below  it.      The  subsequent  development  is  also  much  as  in 
Europium;  a  thick  covering  forms  over  the  fertilized  carp- 


Plfir.  \9Z.— Tuber  ms- 
lana$porum»  A,  a  por- 
tion of  a  transverM  eec- 
tion,  Bhowins  the  asci, 
with  contained  asco- 
Bpores ;  B^  an  aecus 
with  ripe  ascospores. 
Both  marh  magnified.— 
After  Tnlasne. 


Fig.  193.  -  PtnMUium 


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286  B0TAN7, 

ogonium  by  the  growth  of  many  basal  enveloping  branches, 
and  inside  of  this  the  carpogonium  increases  in  size,  and 
sends  out  branches,  which  finally  produce  eight-spored  a«ci. 
The  little  tuber-like  mass  thus  formed  is  yellowish,  and  of 
the  size  and  appearance  of  a  coarse  sand  grain. 

(a)  Aside  from  PenidlUum,  we  have  in  this  country  very  few  repre- 
sentatives of  this  order.     Two  or  three  species  of  Tuber  have  been 

recorded,  and  two  of  Etaphomy^ 
ees* 

(6)  In  Europe,  where  they  grow 
abundantly,  Tuber  (Bstivum,  T, 
melanoipomtn^  and  T.  magualum. 
are  gathered  for  food.  They  are 
found  by  the  aid  of  dogs  and  pigs, 
which  are  trained  to  search  for 
them. 

379. — Order  Helvellaoea 
(or  Disoomycetes).  These 
are  for  the  most  part  disc-like 
or  cup  -  like  saprophytes, 
which  frequently  attain  large 
dimensions.  The  hymenium 
is  spread  over  the  upper  and 
generally  exposed  surface  of 
the  full-grown  plant,  which 
is  in  reality  the  sporocarp. 

In  Peziza,  one  of  the  prin- 
Wg.i94.-Se™iorg«iiis  of  TVaiw  CO.-  cipal  genera,  the  sexual  or- 

fuefis,  hiifhly  magnified.    A,  at  time  of  orans  OCCUr  OU   the   mVCelium 

fertilization;  a,  carpogonium ;  /,  tricho-  o  .  •' 

gyoe ;  <,  anthi-ridinm.  3,  after  fertilisa-  on  Or  in  the  fiTOUnd  I  the 
lion ;  A,  A,  the  hyplie  from  which  the  re-  _        .  .    •      i        i  n 

ctptade  is  developed.— After  Tnlasne.  endS  01  Certain  nypnse  SWell 

up  into  ovoid  vesicles,  the  carpogonia  (Figs.  194  and  195), 
each  of  which  is  provided  with  a  more  or  less  bent  and 
curved  appendage,  the  irichogyne  (Fig.  195,  and/,/.  Fig. 
194).  From  below  the  carpogonium  a  branch  grows  out, 
and,  curving  around,  becomes  closely  applied  by  its  tip  to 
the  extremity  of  the  trichogyne  (Figs.  194  and  195).    The 

♦  See  Bulletin,  of  the  Torrey  Botanical  Club,  November.  1878,  for  the 
species  of  Tuber  discovered  in  North  America. 


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HELVELLACEJE.  287 

immediate  result  of  this  process  of  fertilization  is  the  bud- 
ding out  and  upward  growth  of  a  large  number  of  hyphsB  from 
beneath  the  earpogonium  a  h 

{By  Fig.  194) ;  these  form 
a  dense  felted  mass^  from 
which,  eventually,  there 
rise  vertical,  closely 
crowded  hyphse,  which 
form  tho  hymenium  {A, 
A,  Fig.  19C).  In  the  ter- 
minal portions  of  certain 
of  the  vertical  hyphas 
the  protoplasm  condenses 
around  certain  points,  and 
thus  gives  rise  to  asco- 
fijiores  (jB,  a  to  /,  Fig. 
196).  In  this  genus  (P^ 
ziza)y  as  well  as  most 
others  of  this  order,  the 
ascospores  are  always  eight 
in  each  ascus.    At  matur- 


Pio.  195.  Fio.  196. 

Fig.  196.— Sexual  orgmoff  of  Pewkaa  ompkalodea.  The  two  spherical  carpogonia  have 
each  a  crooked  trichonme,  and  to  each  tiichogyne  i«  applied  the  swollen  end  of  the 
cnrred  antheridiam.    Mnch  magnified— A  frer  Tolarae. 

Fig.  l96.~Pesi«a  conveanda.  A,  vertical  section  of  the  whole  plant ;  A,  hymen- 
fam  ;  «,  sterile  tissue  forming  a  margin,  a,  and  giving  off  below  fine  hyphn  which 
pass  mto  the  soil,  x  90.  B^  vertical  section  of  a  portion  of  the  hvraeninm  ;  a  to  /, 
asci,  with  ascospores  in  various  stages  of  development,  intermixed  with  slender 
paraphyses ;  a^,  sob-hymenial  hjrphie.    x  660.— After  Sachs. 

ity  the  ascospores  escape  by  the  rupture  of  the  walls  of  the 
asci,  this  generally  taking  place  at  the  upper  or  free  end. 


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288  BOTANY. 

880. — In  Ascobolus  the  carpogoninm  consists  of  a  row  of 
cells  ;  it  develops  from  the  end  of  a  branch  of  the  mycelium, 
which  becomes  curved  and  divided  by  several  partitions  (c, 
Fig.  197).  On  account  of  its  peculiar  shape  it  is  frequently 
spoken  of  as  the  "  vermiform  body,"  or  scolecite.  From 
another  portion  of  the  mycelium  an  elongated  and  branched 
antheridium  rises,  and  comes  in  contact  with  the  free  end  of 
the  carpogoninm  (Z,  Fig.  ^ 

197) ;  after  this  pro- 
cess numerous  filaments 
branch  from  the  mid- 
dle cell  of  the  carpogo-  ^ 
nium  and  pass  upward, 
eventually  producing 
asci  {s  and  a.  Fig.  197). 
At  the  same  time  an 
abundant  growth  of  hy- 
phaB  takes  place  from  the  < 
mycelium  below  the  car- 
pogoninm, and  from  this 
the  greater  part  of  the 
mass    of    the    fruiting 

plant     is     produced  ;     it        FI^.  m.-Diflgramraatic  verdcal  iection  of 
also  invests    the     nyme-      myceliam- c,  carpogoninm ;  /,  antheridium ;  ». 

nium,  forming  the  so-    ^rJSc^yi'SiMir^"': 'r.^'SSS'^ 
called    pericarp    which    ??,?ir,^'rtSS5!Vrh'7a'X'±i'„TeiS'oS 

encloses  it  (r,  Fig.  197).      thohymeniam,A.-AfterJancMW8k7. 

Vertical  branches  of  the  sterile  tissue   also  pass  into  the 
hymenial  layer  and  constitute  the  paraphyses. 

381. — The  asexual  reproductive  bodies  are  but  little 
known,  but  enough  is  known  to  indicate  that  there  is  at 
least  a  conidia-bearing  stage  for  these  Ascomycetes,  as  for  all 
others.  De  Bary  has  shown  that  the  early  stage  of  the  little 
plant  known  as  Peziza  Fuckeliana  is  mould-like  in  appear- 
ance, in  fact  having  been  described  as  a  mould  under  the 
name  of  Polyactis  cinerea.  In  this  stage  it  grows  upon  dead 
grape  leaves,  sending  its  mycelium  through  the  dead  tissues. 
Its  vertical  hyphae  produce  clusters  of  oval  conidia,  which 
are  much  like  those  produced  in  the  corresponding  stage  of 


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PTBENOMYCETES.  289 

£uroHum  and  Penicillium.  In  another  species,  Peziza 
fusarioides,  the  conidial  stage  has  been  pretty  certainly  de- 
termined to  be  the  growth  which  was  formerly  supposed  to 
be  a  species  of  Dacrymyces ;  it  consists  of  little  tubercles 
which  contain  slender  linear  bodies  on  branched  threads. 
Bulgaria  sarcoides  is  known  to  bear  conidia  in  an  earlier 
stage,  which  was  formerly  referred  to  the  genus  IVemella 
(Hyinenomycetes) .  * 

(a)  The  principal  genus  of  this  order  is  Penaa,  which  contains  many 
species  ;  they  are  common  on  the  ground  in  forests.  Ascobolus  furftt^ 
raeeus  is  common  on  cow  dung.  M&rcJieUa  esculenta,  the  Morel,  grows 
on  the  ground  in  forests.  It  attains  a  height  of  from  10  to  15  centim- 
etres (4  to  6  inches),  and  bears  its  hymenium  in  sliallow  depressions 
of  its  convex  surface. 

(b)  The  Morel  is  edible,  and  is  mucli  used  for  food  in  some  places. 
According  to  Dr.  M.  A.  Curtis,  some  species  of  Helvetia,  also,  are  edible. 

(c)  Penza  gyhatica,  P.  Candida,  and  Cenangium  Piri  occur  as  fossils 
in  the  Tertiary. 

d82.~Order  Fyrenomycetes.  The  plants  of  this  order 
are  parasitic  or  saprophytic  in  habit ;  their  tissues  are  usually 
hard  and  somewhat  coriaceous,  differing  in  this  respect  from 
the  HelvellacecBy  which  are  generally  fleshy  ;  they  differ  also 
from  the  plants  of  the  last-named  order  in  having  the  hyme- 
nium  imbedded  in  deep  cavities  (perithecia)  with  narrow 
openings.  In  other  respects  the  Fyrenomycetes  present  a 
close  similarity  to  the  HelvellacecBy  to  which  they  are  doubt- 
less closely  related. 

383. — Their  general  structure  may  be  illustrated  by  a 
couple  of  examples.  In  Claviceps  purpureuy  the  fungus 
which  produces  ergot  on  rye  and  other  grasses,  the  first 
stage  consists  of  a  profuse  growth  of  the  mycelium  in  the 
tissues  and  upon  the  surface  of  the  young  ovary  {s.  A,  and 
By  Fig.  198).  In  this  stage,  which  is  called  the  Sphacelia 
stage^  it  produces  a  multitude  of  conidia  on  the  ends  of 
hyphjB  which  grow  out  at  right  angles  to  the  surface  of  the 
mycelial  mass  (C7,  Fig.  198,  b  and  p) ;  these  conidia  fall  off 
very  easily,  and  quickly  germinate  (jD,  Fig.  198),  gi^^ng 
rise  under  favorable  circumstances  to  new  sphacelia,  which 
in  turn  may  produce  conidia,  and  these,  new  sphacelia,  and 

♦  See  further,  De  Bary,  op.  cit.,  p.  200. 


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290  BOTANY. 

BO  on.  The  contact  of  an  infected  head  of  rye  with  an  unin- 
fected one  is  sufficient  to  communicate  the  fungus  to  the 
latter^  and  doubtless  the  conidia  are  also  f  i*eel7  carried  by  the 
winds^  and^  to  a  certain  extent,  by  insects.     It  appears  that, 

in  some  cases  at  least, 
the  germinating  co- 
nidia produce,  first, 
short  hyphae,  which 
bear  a  few  small 
spores  {sporidia,  Z>, 
Fig.  198,  ar),  which 
themselves  germi- 
nate, and  then  pro- 
duce the  sphacelia ;  it 
is  doubtful,  however, 
whether  this  always 
takes  place. 

384. —  After  the 
conidial  stage,  the 
mycelium  at  the  base 
of  the  ovary  becomes 
greatly  increased,  and 
assumes  a  hard  and 
compact  form ;  it 
grows  with  a  consider- 
able rapidity,  and  car- 
ries up  on  its  summit 
the  old  sphacelia  and 

Big.  196.— Oavieept  purpurea.    A,  young  eclero-  the    remains     of     the 

Hum,  0,  with  old  sphacelia,  *  ;  »,  the  apex  of  the  dead  „^-„  Arxoi-^^rTo^A      ^TrA»«r 

ovary  of  rye.  B,  upper  part  if  A,  in  lolngitudlnal  8ec-  noW-destroyed     O  Vary 

tion,   showing  sphacelia,  t.     C,  transverse  section  i  J  or\i\    7?    l?icr    1  Qfi\ 

through  the  pphacella  more  highly  magnified  ;  m,  the  V^  *"^  -^9  ^*6-  ^^^h 

myceunm,  surrounded  with  the  hyphw  6,  bearingco-  TIip    pomnii/^f      Vinm. 

nidia  ;  p,  conidia  fallm  oflf ;  «;,  the  wall  of  the  ovary.  ^  "^^    compact,     iiom- 

^,  geiTOinating  conidia,  forming  sporidia^x.  il  and  shaped,  and  dark-COl- 
B  moderately,  C  and   2>  highly  magnified.— After  ,    ,      ,         ,  .  , 

Sachs.  ored  body  which  re- 

sults is  called  the  sclerotium  ;  that  which  is  produced  upon 
rye  is  from  one  to  three  centimetres  long  (.4  to  1.2  in.)  and 
from  two  to  six  millimetres  in  diameter  (.08  to  .25  in.)  ;  on 
other  grasses  it  is  usually  of  less  size.  The  sclerotium  occu- 
pies the  position  of  the  displaced  ovary,  and  in  the  autumn 


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PTRBN0M7CETE8.  291 

falls  to  the  ground,  where  it  usually  remains  till  the  follow- 
ing spring,  when  its  hyphse  begin  a  new  growth.  As  a  re- 
sult of  this  new  growth  several  little  branches  shoot  up,  and 
each  forms  a  globular  head  (the  receptacle)  at  its  summit 
{Ay  Fig.  199).  Large  numbers  of  flask-shaped  perithecia 
form  in  the  cortical  region  of  the  receptacles  {B,  Fig.  199,  cp)\ 
each  contains  many  elongated  asci,  which  rise  from  the  bot- 


Fig.  199.— ClavUens purpurea.  A,  a  sclerotiam  (ergot),  e,  forming  the  roceptacles 
(eporocarps  t),  d.  B,  longitudinal  section  of  a  receptacle,  Bhowin<;  the  pf'ritliecia,  cp. 
CC  a  perithecinm.  with  the  surrounding  tissue  ;  cp.  its  orifice ;  hy^  hyphee  of  the  re- 
ceptacle ;  «A,  outer  layer  of  the  receptacle.  D^  a  single  ascus,  ruptured,  permitting 
the  elongated  narrow  ascospores,  itp,  to  escape.  A  and  B  moderately,  V  and  D  high- 
ly mi^piifled.— After  Tnlasne. 

tom  of  the  cavity  (C,  Fig.  199),  and  themselves  contain 
several  greatly  attenuated  ascospores  {D,  Fig.  199,  sp). 
The  ascospores  germinate  under  proper  conditions,  and  pro- 
duce sphacelia,  thus  completing  the  round  of  life. 

386. — Thus  far  no  sexual  organs  have  been  found,  but 
from  the  general  similarity  of  these  fungi  to  the  FezizcB  and 
other  Helvellaceae,  it  may  be  surmised  that  sexual  organs  and 


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292  BOTANY. 

a  sexual  process  precede  the  formation  of  each  receptacle 
which  springs  from  the  sclerotium.  It  may  be,  however, 
that  each  perithecium  is  the  result  of  a  sexual  act ;  in  the 
latter  case  the  single  perithecium  would  be  the  homologue  of 
the  Peziza  cup,  while  in  the  former  the  whole  receptacle  of 
Claviceps  would  be  homologous  to  the  receptacle  of  Peziza. 

386. — As  a  second  illustration  of  the  plants  of  this  order, 
the  Black  Knot  {SphcBria  morbosa)  which  attacks  the  plum 
and  cherry  may  be  taken.*  In  the  spring  the  hyphaB,  which 
the  previous  year  penetrated  the  young  bark,  multiply 
greatly,  and  finally  break  through  the  bark,  and  "form  a 
dense  pseudo-parenchymatous  tissue."  The  knot-like  mass 
grows  rapidly,  and  when  full  sized  is  usually  from  two  or 
three  to  ten  or  fifteen  centimetres  long  (8  or  1.2  to  4.  or  6. 
in.),  and  from  one  to  three  centimetres  in  thickness  (.4  to 
1.2  in.)  ;  it  is  solid  and  but  slightly  yielding,  and  is  composed 
of  hyphae  intermingled  with  an  abnormal  development  of  the 
phloem  parenchyma  of  the  host  plant ;  bast  fibres  and  modi- 
fied vessels  of  the  wood  also  occur.  Externally  the  knot  is 
at  this  stage  of  a  "  very  dark  brownish-green  color,"  and  has 
a  velvety  appearance,  which  is  due  to  the  fact  that  its  surface 
is  covered  with  myriads  of  short,  jointed,  vertical  hyphae, 
each  of  which  bears  one,  two,  or  more  ovate  pointed  conidia 
(Fig.  200, 1).  The  conidia  fall  off  readily,  and  doubtless  are 
important  agents  in  multiplying  the  number  of  these  para- 
sitic growths ;  they  are  produced  until  the  latter  part  of 
summer,  when  the  hypha  branches  which  bear  them  shrivel 
up  and  disappear. 

387. — During  the  latter  part  of  summer  x)erithecia  are 
produced  ;  but  the  asci  require  the  greater  part  of  winter  to 
come  to  perfection.  In  February  the  ascospores  are  fully 
ripe.  The  perithecia  at  this  time  are  nearly  globular  in 
shape,  and  are  situated  in  minute  papillae  (3,  Fig.  200) ;  the 
asci  loosely  cover  the  walls  of  the  perithecial  cavity,  and  are 
intermingled  with  slender  paraphyses  (4,  Fig.  200).     Each 

♦  What  foUowB  is  condensed  from  a  paper  on  **  The  Black  Knot,"  by 
Professor  W.  G.  Farlow,  in  the  BuUetin  of  the  Bmaey  Institution,  Vol. 
I.,  p.  440  (1876).    Three  excellent  plates  accompany  the  paper. 


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PTREN0MTCETE8.  293 

ascus  contains  eight  ovate  ascospores,  which  are  two-parted, 
as  is  the  case  in  many  other  members  of  this  order  (5, 
Fig.  200).  The  ascospores  escape  through  a  pore  in  the  top 
of  the  ascus,  and  in  from  three  to  five  days  begin  to  ger- 
minate by  sending  out  a  tube  or  small  hypha ;  sometimes 
two  or  more  hyphae  start  out  from  a  single  ascospore  (6, 
Fig.  200). 

388. — Besides  the  perithecia,  there  are  other  cavities 
found  which  much  resemble  them,  but  which  contain  other 
supposed  reproductive  bodies.  In  one  kind  are  found  the 
stylospores,  which  are  quadrilocular  oval  bodies,  borne  on 
long  stalks  (2,  Fig.  200) ;  they  occur  generally  in  definite 


Fig.  200.— Repmdnctlve  oifrans  of  SphcBria  mnrbota.  1.  conidia-bcaring  hyphie 
from  a  nection  of  the  knot  on  the  cherry,  made  in  May  ;  3,  8tylo«ipor»  s  ;  8,  outline  of 
a  vertical  section  of  a  perithecium,  made  in  winter;  4, two  asci.  with  the  contained 
aacoeporet,  enlarged  from  8 :  j»,  paraphyses ;  5,  a  ripe  ascospore  ;  6,  two  ascospores 
in  process  of  germination.    All  much  magnified.— After  Farlow. 

patches  on  the  walls  of  the  globular  cavities  above  men- 
tioned. Their  function  is  unknown  ;  but  in  all  probability 
they  are  asexual  reproductive  bodies.  In  other  perithecium- 
like  cavities  slender  filaments  are  produced  ;  these  are  thesper- 
matia,  and  the  cavities  in  which  they  occur  are  the  sperma- 
gonia.  Still  other  cavities,  much  like  the  preceding,  "  are 
lined  with  short  delicate  filaments,  which  end  in  a  minute 
oval  hyaline  body ; "  these  small  bodies  are  produced  in 
immense  numbers ;  when  they  are  discharged  from  the  cavi- 
ties in  which  they  grow,  they  ooze  out  in  long  jelly-like 
masses.     The  cavities  are  called  pycnidia,  and  the  small 


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294  BOTANY. 

bodies  pycnidio-spores.  Neither  the  spermatia  nor  the 
pyenidio-spores  have  been  known  to  germinate ;  but  from 
the  resemblance  of  the  former  to  those  of  Cucurbiiaria, 
Valsa,  and  other  genera  of  this  order,  which  have  been  seen 
to  germinate,*  it  is  quite  certain  that  they,  at  least,  are 
reproductive,  and  that  "  they  are  the  agents  for  the  dissem- 
ination of  the  species  to  a  great  distance, "for  which  they  are 
fitted  by  their  extreme  minuteness.  In  all  probability  the 
pycnidio-spores  have  also  a  similar  function. 

389. — No  'Sexual  organs  have  as  yet  been  observed. 
Doubtless  they  exist  in  the  dense  tissues  of  the  knot,  and 
fertilization  probably  occurs  in  the  spring  or  early  summer, 
while  the  conidia  are  being  produced  on  the  surface  of  the 
young  knot.  ^ 

390. — The  hyphas  of  each  year's  knot  generally  penetrate 
downward  some  centimetres  into  the  uninjured  bark,  and 
remain  dormant  there  until  the  following  spring,  when  they 
begin  the  growth  which  results  in  the  production  of  a  knot, 
as  described  in  paragniph  386. 

(a)  The  Pyrenomycetes  include  a  large  Dumber  of  exceedingly  In- 
jnriouR  fungi ;  they  often  attack  and  destroy  not  only  plants,  but  aJao 
insects,  upon  which  their  ravages  are  in  many  cases  very  great. 

(6)  The  classification  is  as  yet  in  great  confusion.f  The  principal 
prenus  is  Sphwia^  which  contains  many  species.  Valsa,  Diatfypeftind. 
Hypoxylon  are  other  important  genera. 

(c)  Good  specimens  of  Claviceps  purpurea  may  be  obtained  from 
almost  any  rye-field,  and  more  certainly  from  the  isolated  bunches  of 
rye  growing  here  and  there  in  many  fields.  By  making  repeated  ex- 
aminations soon  after  the  flowering  of  the  rye  the  conidia  may  be 
obtained ;  and  by  gathering  the  sclerotia  and  burying  them  in  moist 
sand  under  a  bell-jar,  the  receptacles  may  be  grown. 

{d)  Specimens  of  Spharia  moi'bosa  for  study  should  be  gathered  at 
different  times  in  the  season — from  early  spring  to  the  latter  part  of 
the  winter  following.     The  first  gathered  will  be  necessary  to  the 

*  Dr.  Max  Comu,  in  **  Annales  des  Sciences  Naturelles."  Sixth  Series, 
Vol.  III.,  gives  the  details  of  his  experiments  upon  germinating  the 
spermatia  of  many  Pyrenomycetes.  A  translation  appeared  in  "  Gre- 
villea,"  1877  and  1878.  Nos.  86  to  89. 

t  The  student  may  profitably  consult,  in  studying  this  difilcult  order, 
the  finely  prepared  sets  of  "  North  American  Fungi,"  by  J.  B.  Ellis, 
begun  in  1878,  and  still  continuing. 


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LICHENES, 


295 


stodj  of  the  jouD^  and  fonning  knot,  while  the  eacceeding  ones  will 
show  first  the  conidia,  and  then  the  forming  perithecia  and  developing 
aaci  and  ascoBpores.  The  last  gathered  specimens  in  Febrnarj  will 
show  the  fully  formed  ascospores* 

(e)  Brgot,  which  occurs  on  rye  and  manj  of  the  forage  grasses,  is 
poisonous,  producing  gangrenous  sores  when  eaten  in  considerable 
quantities.     It  is  used  somewhat  in  medicine. 

(/)  Xylomitea  in  the  Jurassic,  and  SpTiceria,  Phcuddium,  Bhytiama 
and  other  genera,  in  the 
Eocene  and  Miocene,  are 
the  fossil  representatives    ^ 
of  this  order. 

391.— Order  Lioh- 
enes.  Lichens  agree, 
in  all  the  essentials  of 
their  structure,  with 
the  two  preceding  or- 
ders, HeluellacecB  SLiid 
PyrejiomyceteSy  and 
there  can  no  longer 
be  shown  any  good 
reasons  for  not  class- 
ing them  with  the 
latter,  under  the  As- 
comycetes. 

392. — ^The  tissues 
of  lichens  consist  of 
various  aggregations 
of  colorless,  jointed 
hyphae ;    in    general 

the  hyphae  in  the  cor-    distinct  hyplue.  maiiyof  which  are  cat  transversely; 
tlCal    portion    of    the    funded  by  a  gllatinoas  envefope 


201.— Transverse  section  of  the  thallos  ot 
fuliginosa.  o,  cortical  layer  of  the  upper  snr- 
face ;  «,  cortical  layer  of  lower  surface ;  r,  rhizoid^ 
or  attaching  fibres ;  m,  medullary  layer,  composed  of 


>nidia  groupie  ptir- 
X55(f-i 


-After 


thallus  are  compact- 
ed and  developed  into  a  pseudo-parenchyma  {o  and  w,  Fig.  201, 
and  cc,  B,  Fig.  202),  while  in  the  medullary  portion  they  are 
distinct  (m,  Fig.  201,  and  cm,  B,  Fig.  202).  In  all  lichens 
there  occur  numerous  green,  blue-green,  or  brown-green  cells, 
the  gonidia,  which  are  either  scattered  through  the  interior 
(homo6merotis)y  or  disposed  in  one  or  more  distinct  layers 
(heteromerous)  ;  of  the  former,  Collema  and  Leptogium  are 


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296  BOTANY. 

examples,  while  of  the  latter  UsneUy  Pannelia  (Fig.  204 
and  Sticta  (Fig.  201)  may  be  taken  as  illustrations. 
B 


0 

J 


Wg.  902.— Porme/ia  iOpolia.  A,  a  portion  of  a  thallua  with  two  apothecia,  ap, 
and  several  spermad^onia.  «, «.  B^  transverse  section  of  thallns  through  an  apothe- 
clum  ;  «,  cortical  layer  of  peeado-parenchvma ;  g^  j/,  gonidial  layers ;  cm,  medul- 
lary layer;  A.A,  hypothecfum;  <. «,  i,  <,  the  hymenium  ;  th,  asci  (ihecee),  with 
ascospores.  (7,  section  throogh  three  spermagonia,  «, «,  $ ;  rh,  rh,  rhizolds.  A 
sterigmata  flrom  the  interior  of  a  spermagonium,  bearing  spennatia,  t^,  t'.— After 
Tulaane. 


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LICHENE8.  297 

898. — In  their  modes  of  reproduction,  also,  lichens  agree 
with  the  before-mentioned  orders  of  the  Ascomycetes.  Like 
them,  they  produce  asci,  containing  ascospores,  spermago* 
nia,  with  their  contained  spermatia,  and  one  or  more  othef 
organs  whose  functions  are  supposed  to  be  reproductive. 

394. — The  asci  ai-e  always  developed  from  the  hyphae,  and 
have  no  connection  whatever  with  the  gonidia.  They  arise 
in  most  (but  not  all)  cases  from  the  hyphse  of  the  interior  of 
the  lichen.  It  appears  that  the  particular  hyphse  which 
produce  asci  differ  from  those  which  are  found  elsewhere  in 
the  lichen  in  being  of  greater  diameter  and  richer  in  proto- 


FSff.  908.— Vertical  section  through  the  yoang  apotheclam  of  Lecanora  subfiuca 
(partly  diagrammatic) ;  /»,  h,  hymeniura,  composed  of  (1)  paraphyt<e8,  which  de- 
veloped from  the  ordinary  hyphse,  and  (2)  the  yoang  a^cl  in  vanons  stages  of  de- 
Telopment ;  sh^  ascophorous  hvphse,  from  which  the  asci  develop;  e,  excipulam— i.^., 
the  layer  of  hyphae  upon  wliich,  or  above  which  the  ascophorous  hyphae  are  borne ; 
f,  r,  cortical  layer  of  thallns ;  m,  medoUary  portion  of  thallas  ;  g^  the  gonidia.  x  190. 
—After  De  Bary. 

plasm.  The  asci  are  developed  from  vertical,  club-shaped 
branches,  which  penetrate  between  narrow,  vertical  branches 
(paraphyses)  of  the  ordinary  hyphsa  (Fig.  203).  In  many 
cases  they  are  collected  in  a  disc-like  surface,  forming  an  ex- 
posed hymenium  (gymnocarpous  lichens),  while  in  other  cases 
they  are  in  the  interior  of  cavities  (perithecia),  whose  walls 
they  line  (angiocarpous  lichens).  The  ascigerous  fructifica- 
tion is  in  either  case  technically  called  an  apothecium, 

896. — The  spores  arise  in  the  asci  exactly  as  in  the  case  of 
Peziza  and  other  Ascomycetes  previously  described  ;  that  is, 
they  are  formed  simultaneously  by  the  condensation  of  the 
protoplasm  about  certain  points  in  the  interior  of  the  young 


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298 


BOTANY. 


d, 


%¥ 


ascus  (the  so-called  free  cell  formation).  Usually  there  is  a 
considerable  quantity  of  the  unused  protoplasm  left  oyer 
after  the  ascospores  are  fully  formed  (Fig.  204,  a,  J,  c).  The 
usual  number  of  ascospores  is  eight  (Figs.  202,  203,  204), 
although  in  exceptional  genera  they  range  from  one  or  two 
( Urnbilicaria)  to  a  hundred  or  more  (Bactrospora,  and  other 
genera).  They  are  frequently  septate,  sometimes  being  di- 
vided into  two  portions — e.g.,  Parmelia  (Fig.  202)— or 
many,  as  in  Gollema  Urceolariay  etc.  In  the  gymnocarpons 
hchens  the  ascospores  escape  directly  into  the  air.  and  this 
they  generally  accomplish  with  such  force  as  to  be  projected 

some  millimetres  ;  in  the  angio- 
carpous  genera  they  first  escape 
into  the  cavity  of  the  perithe- 
cium,  from  which  they  pass  out 
through  an  opening  in  its  apex. 

396. — In  germination  the  as- 
cospore  commonly  sends  out  a 
germinating  tube,  which  is  a 
growth  from  the  endospore;  it 
develops  directly  into  a  hypha, 
and  becomes  branched  and  sep- 
tate.    Bi-  or  multilocular  asco- 

Pig.  204. — ^Asd  and  BSCoeporeB  of  n  j  i.  • 

Spharophorui  globiferM.     a,  young  SporCS  USUally  Send   OUt  a  germi- 

S?ai?nriSSSe"^'|Sik^!^!a'^'«:i'  mating  tubc  from  each  cell.  In 
IV^rSr^f^.i^Z^'^-M^r  the  genera  With  very  large  asco- 
'^^^^n-  spores — e.g.,   Megalospora,   Per- 

tusaria,  etc. — the  germination  takes  place  in  a  way  somewhat 
different  from  that  just  described.  In  the  endospore  a 
great  number  of  cavities  or  canals  form  {g,  Fig.  205),  from 
each  of  which  there  grows  out  a  germinating  tube  (d.  Fig. 
205) ;  these  many  tubes  elongate  into  hyphae,  and  become 
septate  and  branched  (/,  Fig.  205). 

897. — In  addition  to  the  apothecia,  with  their  contained 
ascospores,  there  are  other  organs  which  contain  bodies 
which  are  probably  reproductive  in  their  nature.  The 
best  known  of  these  are  the  spermagonia  (Fig.  202,  A,  s, 
and  Fig.  206),  which  are  small  cavities,  usually  found  upon 
the  same  thallus  as  the  apothecia ;  they  contain  branched 


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LICHENES.  299 

threads  {sierigmata),  which  line  the  inside  of  the  wall  (Fig. 
202,  D) ;  upon  the  sterigmata  are  borne  large  numbers  of 
Tninute  cells  (the  spermatia),  which  fall  off  and  are  per- 
mitted to  escape  through  the  small  opening  at  the  apex  of 
the  spermagonium.  It  is  unknown  whether  these  germinate 
or  not ;  some  botanists  have  supposed  them  to  be  sexual  in 
their  nature— hence  their  name,  spermatia ;  the  recent  in- 
Testigations  of  Stahl,  to  be  referred  to  below,  seem  to  indi- 


Pijp.  906.— Germination  of  the  spores  of  lichens,  a,  ripe  ascoepore  of  Megal' 
otporaq^nia;  6 and  e,  sticcescive  stages  of  germination,  seen  in  optical  section; 
d.  still  later  stai^  of  {Termination,  seen  in  perspective.  «,  beginning^  of  germination 
of  at*cospore  of  Ochrot^tchia  paUesetns ;  /,  the  same  at  a  mnch  later  stage,  show- 
ing the  manv  young  hyphae,  much  less  magnified.  ^,  half  of  an  ascospore  of  Per- 
tu§aria  eeuthocarpar  seen  in  optical  section,  showing  the  pores  in  the  endof^re 
throngh  which  the  hyphie  puss  oat.  The  exospore  »  sbaaed  in  the  figure,  /x 
190^  the  others  x  SBO.— After  De  Bary. 

cate  the  truth  of  the  theory  that  they  are  the  male  sexual 
elements ;  on  the  other  hand,  their  analogies  to  the  similar 
organs  of  Helvellacem  and  Pyrenomycetes  point  rather  to 
their  conidial  nature. 

Still  other  cavities  (pycnidia)  occur,  in  which  spore-like 
bodies  are  found,  differing  in  size  and  other  characters  from 
the  spermatia. 


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300  BOTANY. 

398. — Until  Stahl's  researches*  showed  the  existence  of 
sexual  organs  in  Collmna,  they  were  entirely  unknown  among 

lichens.      He  discovered,  deeply 
imbedded    in  the    tissue  of   the 
plant,  an  organ  composed  of    a 
spiially  coiled  hypha- branch,  and 
a  vertical  septate  portion,  which 
^  rises  to,  and  projects  above,  the 
surface;   the  spirally  coiled  por- 
tion he  called   the  ascogonium, 
and  the  vertical  portion  the  tri- 
chogyne.    The  whole  he  regarded 
Fiff.  206.--verficai  wction  of  a  as  a  specics  of  carpogonium  (Fig. 
2r  "^SX^JiiX  'iAI  ^0  207,  A,  c,  and  d).      He  observed 
rh^:t'hlN^TcS!X'gon^^  adhenng   to  the  pro- 

epennagonium,  ftom  which  sperma-  jec ting     portion    of     the     tricho- 
tia  are  escaping.    Magnified.— After  •'  ox-  .      ^     , 

Tuiaane.  gyne  ;  some  of  these  united  them- 

selves to  the  trichogyne  by  means  of  a  tube  (C,  Fig.  207). 
The  result  of  this  coalescence  was  the  withering  and  disap- 
pearance of  the 
cells  of  the  tricho- 
g}'ne,  and  the 
growth  and  devel-  A 
opment  of  the  as- 
cogonium. The 
latter  process  takes 
place  as  follows : 
'*  The  cells  of  the 
ascogonium  first  of 
all  increase  in  size. 
Mi  undergo 

°         Pig.  207.— Scxnal  organs  of  Coilema  mlcrophylltfm.  A, 

;    as   a   re-  fectlon  of  thallns;  a,  a,  hyphse;    b.b,  the  Noftoc-like 

I r  •        ii       gonidia  ;  c,  aBcogoniuni ;  d,  toe  exserted  trichogyne.    J3, 

tniS,     tne  the  epermatia,  d,  eurronnding  the  exserted  trichozyne,  a. 

„-_  „__„-^i    C,  coaleeicenco  of  a  spermatium,  b,  with  trichogyne,  a, 

rangeraeni  ah  the  figures  magnified,  B  and  (7  much  more  than  A.— 

cells    be-^^'^^"- 
jss  and  less  conspicuous,  for  the  cells  gradually  sepa- 

ber  die  Geschlechtliche  Fortpflanzung  der  Collemaceen,"  1877 
exual  Organs  of  the  Collemacea?).  A  brief  synopsis  of  Stahl's 
>peared  in  the  Qr.  Jour,  of  Mic.  Science,  October,  1878. 


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LI0HENE8,  301 

Tate  from  one  another.  Whilst  these  changes  have  been 
taking  place  in  the  ascogonium,  it  has  become  invested  by  a 
dense  felt-work  of  hyphae,  formed  by  the  active  growth  of 
the  hyphflB  of  the  thallus.  From  this  investing  layer  hyphaB 
grow  inward  between  the  separating  coils  of  the  ascogo- 
niam,  and  bear  paraphyses,  which  form  the  rudimentary 
hymenium.  At  the  same  time  outgrowths  have  been 
formed  from  the  cells  of  the  ascogonium,  which  either  are 
asci,  or  grow  into  hyphal  filaments,  which  bear  asci  as 
lateral  branches.  The  asci,  whether  derived  directly  or  in- 
directly from  the  cells  of  the  ascogonium,  come  to  lie  in  the 
hymenium  among  the  paraphyses."  Thus  the  apothecium 
is  partly  developed  from  the  carpogonium,  and  partly  from 
the  hyphae  of  the  thallus,  agreeing  in  this  with  what  is  now 
known  to  be  the  mode  of  formation  of  the  corresponding 
parts  of  some,  at  least,  of  the  Helvellacem, 

Whether  there  are  similar  sexual  organs  in  other  lichens, 
is  at  present  unknown ;  probably,  when  discovered,  they  will 
be  found  to  bear  some  resemblance  to  those  of  CoUema,  just 
described  ;  but  it  is  altogether  likely  that,  instead  of  fertili- 
zation taking  place  by  means  of  free  male  elements  (sper- 
matia),  it  will  bo  shown  to  be  more  nearly  like  that  now 
known  in  Peziza  or  Ascotolus. 

399.— The  Qonidia.  The  gonidia  of  lichens  are  of  so 
much  importance  that  they  demand  a  somewhat  extended 
notice.  As  above  stated  (paragraph  392),  they  are  green  or 
greenish  cells,  or  rows  of  cells,  which  occur  either  distributed 
irregularly  through  the  tissue  of  the  lichen-thallus  (the  ho- 
moOmerous  lichens),  or  in  different  layers  or  regions  (the 
heteromerous  lichens).  These  green  bodies  are  of  different 
forms  in  different  groups  of  lichens,  while  in  nearly  related 
species  they  are  often  exactly  alike.  They  may  consist  of 
isolated  cells,  or  groups  of  cells,  as  in  most  fruticose  or  folia- 
ceous  lichens  {e,g.,  Parmelia,  Fig.  202,  Stida,  Fig.  201, 
Sphcerophorus  and  Usnea,  Fig.  208),  while,  on  the  other 
hand,  they  may  be  made  up  of  rows  or  chains  of  cells 
(e.g.y  Lecanactis  and  Gr aphis,  Fig.  209,  MaUotiuniy  Fig. 
210,  and  Collemay  Figs.  206  and  207).  They  are  known  to 
reproduce  by  the  division   (fission)  of  their  cells,  and,  in 


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BOTANY, 


some  cases  at  least,  when  free  from  the  lichen-thaUus,  by 
the  production  of  zoospores. 

Their  connection  with  the  hyphai  is  sometimes  by  the 
prolongation  of  a  short  branch  from  the  latter,  which  passes 
to  each  gonidial  cell  (Pig.  208) ;  in  other  cases  the  connec- 
tion is  with  one  cell  of  a  row,  as  in  Pleciosporay*  where  the 
connection  may  be  with  the  terminal  cell  of  the  row,  or  with 
any  of  the  intermediate  ones ;  in  either  case,  the  cell  to 
which  the  hypha-branch  is  attached  is  considerably  larger 
than  the  others  in  the  row.     Schwendener  describesf  a  con- 


Fio.  906. 


Fio.  209. 


Fig.  906.— Oonidia  of  different  lichens,  a  to  «,  of  Parmelia  tiUacm,  Bhowlng  a,  bj 
and  e,  the  attached  hyphae,  x  390 ;  /,  of  Ufnea  barbata,  with  attached  hvpna,  x 
701) ;  g,  of  SpharophoruB  gMi\feru$,  with  attached  hypha,  x  890.~Af ter  De  Bary  and 


Schwendener. 

Fig.  909.— Oonidia. 
After  De  Bary. 


a,  tf,  of  Leoanaetit  iUecebroia;  b,  6,  of  Graphis  teripteu-' 


nection  which  he  has  seen  in  certain  gelatinous  lichens,  in 
which  two  and  three  short  branches  pass  off  from  the  same 
hypha,  and  unite  with  the  cells  of  one  gonidial  chain. 
TreubJ  confirms  Schwendener's  statement,  saying  that  he 

*  See  De  Bary's  **  Morpbologie  und  Physiologie  der  Pilze,  Flecbten," 
etc,  p.  204. 

t  "  Die  Flechten  als  Parasiten  der  Algen,"  1873. 

t  Dr.  Melcbior  Treub,  "  Onderzoekingen  over  de  Nataur  der  Licbe- 
nen."  1878. 


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LICHENE8.  303 

fc«i8  *'  succeeded  many  times"  in  finding  gonidia  so  connected 
to  the  hyphflB  by  more  than  one  bmnch. 

400. — With  regard  to  the  origin  of  gonidia,  Fries  asserts 
that  the  hypha-bmnches  swell  up  at  their  ends,  become  glob- 
ular, and,  after  a  while,  filled  with  green  contents.*  He, 
however,  does  not  speak  of  any  observations  of  his  own  upon 
wbich  he  bases  his  statement.  Berkeleyf  likewise  regards 
them  as  developed  from  the  mycelium,  but  made  no  observa- 
tions which  can  be  considered  conclusive.  Speerschneider's 
observations,!  in  1853  to  1857,  along  with  those  of  Bayr- 


rUf.  2W.-'Mallofium  (or  L^pfogium)  HUdenbrandii.  a,  yertical  section  through  the 
thallaf*,  1/,  the  under  Bide,  x  190 ;  d,  porfion  of  a  very  thin  section  near  the  under 
aide,  ehowint;  three  gonidia  chains,  two  hvpbee,  a  portion  of  the  lower  limitary  tissue, 
and  two  large  and  several  small  hairs,  whica  are  organs  of  attachment,  x  890.— After 
DeBary. 

hoffer,§  some  years  earlier,  appear  to  be,  in  reality,  the  ones 
upon  which  the  view  that  gonidia  develop  from  the  hyphae 
depends  ;  their  statements  appear  to  have  been  accepted  and 
repeated  by  lichenologists  without  sufficient  inquiry.  The 
other  errors  of  observation  and  interpretation  made  by  these 
observers  render  their  testimony  upon  the  question  of  the 
origin  of  the  gonidia  of  doubtful  value.     Schwendener,  in 

♦  "  Lichenograpllia  Scandlnavica/'  1871. 

t  "  Introd action  to  Cryptogamic  Botany/'  1857. 

X  In  Botanische  Zeitung,  1853,  1854,  1855,  1857. 

g  '*  Einiges  tiber  die  Lichenen  und  deren  Befrucbtan^,"  1851. 


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304 


BOTANY. 


reviewing  the  subject,  afltans  that  the  actual  development  of 
a  gonidium  from  the  end  cell  of  a  hypha  has  not  been  ob- 
served. Nylander  even  goes  so  far  as  to  declare  that  in  no 
case  do  the  filaments  themselves  give  birth  to  gonidia,  but 
that  they  "have  their  origin  in  the  parenchymatous  cortical 
cells  which  are  observed  on  the  prothallian  filaments  of  ger- 
mination."* 

401. — The  recent  observations  of  Dr.  Minks, f  if  con- 
firmed, will  put  to  rest  the  question  as  to  the  origin  of  go- 
nidia.  He  studied  the  small  green  cells  sometimes  called  mi- 
crogonidia,  and  makes  the  announcement  that  they  originate 
in  the  interior  of  the  cells  of  every  portion  of  the  llchen- 
thallus,  viz.,  the  cortical  and  medullary  cells,  the  paraphy- 

ses  and  young  asci,  and 
even  the  spores  and 
spermatia.  The  proto- 
plasm in  the  cells  forms 
an  axial  column,  which 
becomes  broken  up  into 
rounded  bodies  of  a  pale 
greenish  color ;  these 
finally  become  covered 
by  cell-walls,  and  after- 
ward escape  from  the 
mother-cell  as  free  mi- 
crogonidia.  He  asserts 
that  intermediate  forms  of  all  degrees  are  to  be  met  with  be- 
tween microgonidia  and  gonidia.  Dr.  Muller,in  making  simi- 
lar observations,  arrived  at  the  same  conclusion!  as  to  the 
origin  of  the  microgonidia. 

The  third  view  as  to  the  origin  of  gonidia  is  so  intimately 
connected  with  the  question  of  the  real  nature  of  the  gonid- 
mm  and  its  functional  relation  to  the  hyphse,  that  it  can 
only  be  explained  by  taking  these  into  consideration. 

*  In  Illora^  1877,  p.  256,  as  quoted  in  Bevue  Mycologique,  p.  4, 1879, 
and  in  "Grevillea."  1879,  p.  91. 

t  For  accounts  of  these  observations  see  Flora,  1878,  Bevue  MyeoUh 
ffique,  1879,  and  American  Journal  of  Science  and  Arts,  1879,  p.  254 

X  FUra.  1878. 


Fig.  211.- 


A,  sore- 


„ -     _-«cc»  vurr/u^u.     .a.%  w^iw- 

dium,  consisting  of  one  gunidiam  covered  with 


Soredia  of  Umea  barbata. 

"  ^     '  goi    "  

'hyphae ;  B,  of  many  gonidia  formed  by  division  ; 
C,  the  gonidia  separated  by  hyphae ;  D  and  E,  the 
soredia  developing  into  new  lichen  plants,  x 
600.— After  Schwendeuer. 


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LICHENES.  805 

402. — The  gonidia  sometimes  escape  from  the  thallus  of 
the  lichen  surrounded  with  a  few  hyphae  (Fig.  211) ;  these 
are  called  soredia.  Under  favorable  circumstances  they  may 
give  rise  to  new  lichens,  and  hence  have  been  looked  upon 
by  some  as  asexual  organs  of  reproduction.  Soredia  are, 
however,  rather  of  the  nature  of  buds  or  gemmae,  which, 
under  certain  circumstances,  become  detached.  Their  pro- 
duction is,  to  a  certain  extent,  accidental. 

(a)  1.  The  Kature  of  Gonidia.  Until  recently,  tlie  gonidia  of 
lichens  have  been  f^enerallj  regarded  as  accessory  reproductive  bodies. 
De  Bary/  however,  iu  studying  the  Collemacese,  and  noting  the  remark, 
able  resemblance  between  their  gonidia  and  certain  alg®,  came  to  the 
following  conclusion : ' '  Either  the  lichens  in  question  are  the  perfectly 
developed  states  of  plants  whose  imperfectly  developed  forms  have 
hitherto  stood  among  the  alg^  as  the  Nostocacese  and  Ciiroococcaccse ; 
or  the  NostocaceflB  and  ChrooooccaceaB  are  typical  al jrae  which  assume  the 
form  of  CoUema,  EpTiebe,  etc,  through  certain  parasitic  Ascomycetes 
penetrating  into  them,  spreading  their  mycelium  into  the  continuously 
growing  thallus,  and  becoming  attached  to  their  phycochrome-contain- 
Ing  cells."  Schwendener,f  Ree884  and  Bometg  have  taken  up  the 
second  theory  in  the  above  alternative,  and  extended  it  to  all  lichens. 
8chwendener,  who  first  made  the  definite  statement  of  the  theory,  holds 
that  every  lichen  is  a  colony  composed  of  a  parasitic  fungus  on  the  one 
hand,  and  a  number  of  low  a1g»  on  the  other  ;  the  former,  which  pro- 
duces  the  asd,  spermatia,  and  other  reproductive  bodies,  is  nourished 
by  the  latter,  which  constitute  the  gonidia  of  the  lichen. 

A  lichen,  according  to  this  view,  is  not  an  individual  plant,  but  rather 
a  community  made  up  of  two  kinds  of  individuals  ;  and  the  gonidia  are 
only  the  tMmporurily  imprisoned  algse,  which  furnish  nutriment  to  the 
parasitic  fungus.  The  fungus  parasite  does  not  differ  in  any  essential 
character  from  those  of  the  two  higher  orders  of  the  Ascomycetes. 
Leville,  in  speaking  of  lichens  and  the  ascomycetous  fungi,  said,| 
"  I  find  the  distinctions  to  be  so  trifling,  that  I  have  always  regretted 
that  these  vegetables  should  not  be  placed  under  one  head.  The  para- 
physes,  thecse  (asci),  aod  spores  are  identical." 

♦  "  Morphologic  und  Physiologic  der  Pilze,  Flechten,  und  Myxomy. 
C6ten,"1865,  p.  291. 

t  Dr.  8.  Schwendener  :  **  Untersuchungen  fiber  den  Flechten  thallus," 
1868,  and  "  Die  Algentypen  der  Flechtengonidien,"  1869. 

X  Professor  Max  Reess  :  **  Ueber  die  Entstehung  der  Flechte  Collema 
glaaoescens."  etc .  1871. 

g  Dr.  E.  Bornet :  '*  Recherches  sur  les  Gk>nidies  des  Lichens,"  1878. 

I  A  letter  to  Decaisne,  as  given  in  Le  Maout  and  Decaisne*s  "  Traits 
O^n^rale  de  Botanique,"  1868. 


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306  BOTANY. 

2.  Schwendener  has  shown*  that  the  gonidia  may  be  referred  to  well* 
known  groups  of  alga),  some  of  which  belong  to  the  ZygophTta,  while 
others  belong  to  the  Protoplijta.  Thns  the  gonidia  of  CoUema,  LeptO' 
gium  (including  MaUotium),  PeUigera  and  some  other  genera,  are  iden- 
tical with  NostocacesB ;  those  of  Omphalatia  and  others,  with  Chroo. 
ooccaceiB ;  those  of  Oraphis,  Vefrucaria,  etc..  with  Chroolepide»  (re- 
lated to  Confei'va  and  CladopJiora) ;  thos^  ot  Usnea,  Cladonia,  Physeia, 
Pannelia,  and  most  higher  lichens  with  Palmellacese.  The  gonidia  of 
some  other  lichen  gepera  are  referred  to  btill  other  alga  groups. 

3.  When  gonidia  are  dissected  out  from  the  lichen-thai  1  us  they  are 
capable  of  independent  existence  ;  and  there  can  be  no  doubt  that  (as 
De  Bary  intimated)  many  of  the  forms  regarded  as  alg»  are  identical 
with  gonidia.f  With  these  facts  before  us,  it  c»n  scarcely  be  doubted 
that  the  mode  of  origin  described  by  Speerschneider  aod  Bayrhoffer  is 
incorrect.  There  cannot  now  be  shown  any  good  evidence  that  the  go. 
nidia  develop  from  the  hyphse  with  which  they  are  seen  to  be  in  contact. 
The  connecticn  between  hyphse  and  gonidia  is  doubtless  one  which  takes 
place  after  the  origin  of  the  latter.  The  two  remaining  views — i.«., 
Schwendener's  and  Minks' — agree  upon  this  point,  and  in  both  the  idea 
of  a  genetic  connection  between  gonidium  and  the  hypha-filament  in 
contact  with  it  is  rejected.  These  two  theories,  however,  differ  radi- 
cally in  this,  that  while  on  the  one  hand  the  gonidia  are  regarded  as 
true  lichen-cells,  on  the  other  they  are  held  to  be  algsB  belonging  to  en- 
tirely different  thallophytic  groups. 

4.  It  must  at  once  be  evident  to  any  one  that  the  actual  relation  of 
the  hyphal  portion  of  the  lichen  to  the  gonidia  is  the  same  whether  the 
origin  of  the  latter  be,  as  asserted  by  Minks,  within  the  hyph»,  or  en- 
tirely independent  of  them,  as  maintained  by  Schwendener.  Any  con. 
nection  which  subsists  between  these  two  can  be.  under  the  circum- 
stances,  of  only  one  kind,  namely,  that  of  a  greater  or  less  degree  of 
parasitism.  It  makes  no  difference  to  show  that  the  gonidia  are  derived 
from  the  hyphie  themselves,  for  they  are  (it  is  said)  set  free  after  their 
formation  in  the  mother-cell  ;  now  any  subsequent  connection  of  these 
green  cells  with  the  hyphsB  cannot  possibly  have  any  other  meaning 
than  that  the  latter  derive  nourishment  from  them.  The  only  differ- 
ence between  the  two  theories  may  be  expressed  in  this  way  :  according 
to  the  one,  the  imprisoned  slaves  which  furnish  nourishment  for  the 
hyphal  master  are  members  of  entirely  different  groups  of  the  vegetable 
kingdom  ;  while  according  to  the  other,  the  slaves  are  the  offspring  of 
the  hyphal  master  which  imprisons  them.     In  the  first  the  gonidia  are 

♦  **  Die  Algentypen  der  Flechtengonidien,"  1869. 

t  This  was  long  since  shown  by  Itzijrsohn — BotanUche Zeitung.lSSi, 
by  Hicks — Qr,  Jour,  of  Mic.  Science,  1861 ,  and  by  Famintzin  and  Baranet- 
sky — Botanische  Zeitung,  1867  ;  Nylander  also  arrived  at  the  same  con- 
clusion with  regard  to  the  gonidia  of  CoUema — F%ora,  1868. 


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LICHENE8.  307 

slaves  not  at  all  related  to  the  hypbae  ;  in  the  other  thej  are  produced 
by  them,  and  alter  a  brief  period  of  freedom  are  fastened  upon,  and 
compelled  to  do  service  for  the  hyph»  which  produced  them. 

It  is  impossible  to  decide  between  these  two  tbeones  until  further  in- 
T^estigations  shall  determine  the  truth  or  falsity  of  Dr.  Minks'  state- 
ment  as  to  the  origin  of  microgonidia.  It  must,  however,  be  said,  that 
the  view  which  appears  to  be  most  in  accord  with  what  we  now  know 
of  plants,  is  that  taken  by  Schwendener. 

(&)  1.  Cultures  of  lichens  have  been  made  by  many  observers, 
especially  by  Bornet,  Reess,  and  Treub.  The  latter  made  an  extended 
series,  from  which  the  following  details  of  methods  are  condensed. 
Spores  may  be  secured  for  p^ermination  by  placing  freshly  gathered 
lichens  upon  plates  covered  with  well-moistened  glass  slips,  and  keep, 
ing  them  under  a  bell-jar  for  from  twelve  to  tweuty-four  hours,  at  the 
end  of  which  time  a  number  of  spores  will  be  found  on  the  slides. 

2.  The  spores  may  be  left  upon  the  slides  and  allowed  to  remain  in  a 
moist  atmosphere,  as  in  a  bell -jar.  Others  may  be  placed  upon  very 
thin  pieces  of  the  bark  upon  which  the  lichens  naturally  grow.  Still 
otherd  may  be  made  to  grow  in  the  presence  of  a  small  quantity  of  the 
ash  of  the  same  species  of  lichen. 

8.  A  too  copious  supply  of  moisture  is  unfavorable  to  the  successful 
lirermination  of  the  spores.  If  the  conditions  are  favorable  germination 
"will  begin  in  from  two  to  eight  days.  In  about  a  month  after  sow- 
ing, the  protoplasm  of  the  spore  becomes  in  great  part  used  up  in  the 
formation  and  elongation  of  the  germinating  filaments.  It  always  hap- 
jiens  that  the  growth  of  the  hyphsB  from  the  spores  ceases  soon  after  the 
exhaustion  of  the  protoplasm,  unless  the  hyphsB  come  in  contact  with 
algsB  of  the  proper  kind,  or  with  gonidia. 

4.  An  interesting  culture  may  be  made  by  repeating  Bomet's  exper- 
iment,  as  follows:  He  placed  on  fragments  of  bark,  previously  boiled 
to  kill  all  other  germs,  and  also  on  pieces  of  limestone  freshly  broken, 
a  layer  of  Prctococciis  viridia  scraped  off  of  a  damp  wall,  and  to  this 
added  the  spores  of  TheloscJiis'ea  paneUnv8.  In  about  a  fortnight  the 
hyph»  were  seen  to  be  large  and  ramified  ;  wherever  they  came  in 

,  contact  with  cells  of  the  Protococcus  they  adhered  either  directly  or  by 
means  of  latenil  branches.  Bornet  made  at  the  same  time  parallel  cul- 
tures, without,  however,  bringing  the  germinating  spores  into  proximity 
to  Protoeoccu8 ;  the  growth  was  much  less,  and  in  no  case  did  he  get 
any  evidence  that  the  hyph®  themselves  formed  gonidia. 

5.  Treub  modified  Bomet's  culture  by  using,  in  some  of  his  experi- 
ments, the  artificially  isolated  gonidia  of  one  species  of  lichen — for  ex- 
ample, of  some  species  of  Ramalina — and  the  spores  of  a  different  one,  as 
Tkdoschistea  pcmetintis.  He  also  used  glass  slides  for  his  cultures, 
whether  with  gonidia  or  free  algse,  taking  the  precaution,  however,  to 
allow  the  drop  of  water  in  which  the  spores  and  gonidia  were  placed 


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308  BOTANY. 

to  completelj  evaporate  before  placing  in  the  moist  chamber.  By  tak« 
infr  precautions  to  keep  out  moulds,  bj  supplying  the  moist  chamber  with 
air  passed  through  one  or  two  pluj]:s  of  cotton-wool,  he  succeeded  in 
continuing  the  growth  of  the  hypha?  for  three  months,  at  the  end  of 
which  time  the  alg®  were  surrounded  by  a  good  number  of  branches 


Fio.  212.  Fis.  818. 

Fig.  9li%.—'n8nfabarbata,  nat.  size,    a,  a,  apothecia ;  /,  disk  by  which  it  is  attached 
to  the  bark  of  a  tree.— After  Sachs. 
Fig.  ftl^.—Stieta  pulmanaeea^  nat  sice,    a,  a,  apothecia.— After  Sachs. 

of  the  hyplue,  many  of  which  had  firmly  attached  themselves  to  the 
cells  of  the  algse. 

(c)  The  classification  of  lichens  is  by  no  means  settled. 

The  arrangement  which  is  followed  in  this  country  is  that  of  Profes- 
sor Tuckerman.*     He  divides  the  order  into  five  tribes,  as  follows: 

Tribe  I.  Parmbliacbi. 

Apothecia  rounded,  open,  scutelliform,  contained  in  a  thalline  exciple. 

Family  1.  XTsneeL  RocceUa,  Ramalina,  Dactylina,  Cetraria,  Bver- 
nia,  Usnea  (Fig.  212),  Alectoria.  BocceUa  linctaria  and  other  species  of 
the  genus  furnish  the  dye  known  as  orchil,  and  chemical  test  **  litmus." 
Cetraria  ulandica,  the  Iceland  moss,  is  used  both  as  a  food  and  a  medi^ 

♦  Edw.  Tuckerman  :  "  Genera  Lichenum ;  An  Arrangement  of  North 
American  Lichens."  1872,  and  "  Synopsis  of  N.  A.  Lichens,"  1882. 


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LICHENE8.  309 

dne.     Species  of  Evernia  are  eometimes  used  for  famishiDg^  yellow 
dyes. 

Family  2.  ParmelieL  Speei  sehneidera,  Thelo8c?iUtes,  Partnelia 
{Fig.  202),  Phy9cia,  Pyxine.  From  Parmelia  parietina  fine  dyes  have 
besD  obtained. 

Family  3.  Umbilicariei.     UmbilieO' 
Ha. 

Family  4.    Peltig^erei.     Stieta  (Fig.   d 
213),  Nephroma,  Peltigera,  Solorina.   SHc-   " 
ta  pulmonaeea  was  formerly  used  in  medi- 
cine, but  it  has  fallen  into  disuse,  except-      ' 
ing  with  quacks. 

Family  5.  Pamwiriei  Heppia,  Pan-  p,g.  2l4.-CWfema  puipofum, 
naria.  sllghtlj  magnified,  showing  Che 

-»_     -I      A4^ii         •       rt-rr      r'x     apothecia.— AftcT  Sachs. 

Family  6.    CoUemei.    Bphebe,  L%ch-    *^ 

ina^   SynaUsM,   OmphaUvria,  CoUema  (Fig.  214),  Leptogium,  IIydr<h- 

thyria. 
Family  7.  Lecanorei.    Placodium,  Lecanora,  Einodina,  Pertusa- 

ria  (Fig.  215,  (7),  Ckmotrema,  ZHiina^  Gyalecta,  Urceolaria,  Thdotrema, 

Oyrogtomum.  Lecanora  tarta- 
rea  furnishes  a  dye,  and  L. 
esculenta,  of  Asia  Minor,  sup. 
plies  a  valuable  food ;  it  is 
sometimes  **  carried  up  by 
whirlwinds  and  deposited  aftei 
traversing  the  air  for  many 
miles,  giving  rise  to  stories  of 
the  miraculous  descent  of  food. 
A  few  years  since,  in  a  time  of 
great  scarcity  at  Erzeroum,  a 
sliower  of  these  lichens  fell 
most  opportunely,  to  the  great 
relief  of  the  inhabitants."^ 

Tribe  II.  Lecidbacei. 

Apothecia  rounded,  open,  pa- 
telliform,  contained  in  a  proper 
exciple. 
-  Family  1.  Cladoniei    Ste- 

nified  ;  C,  PtrUimria  Wulfeni,  sliehtly  mag-  Gladonia     rangiferina    is     the 
nllled,  on  a  piece  of  old  wood—After  Sachs.     ..  Reindeer  moss  "  of  the  Arctic 

regions ;  it  furnishes  a  valuable  food  to  the  reindeer. 

♦  Berkeley :  "  Introduction  to  Cryptogamic  Botany,"  p.  888. 


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310  BOTANY. 

Family  2.  CoenogonieL    Ccmogonium. 

Family  3.  LecideeL  Baomyces,  Biatora,  HeUrathecium,  Leeidea, 
BueUia, 

Trebb  III.  Grafhidacsi. 

Apothecia  of  various  forms,  frequently  lirelliform,  in  a  proper  ex« 
dple.    ThaUns  crastaceous. 

Family  1.  Lecanactidei    Leeanaetis,  PlatygrapTui,  MeUupUea, 

Family  2.  OpegrapheL  Opegrapha,  Xylographa,  Oraphis  (Fig. 
215,  A), 

Family  8.  Glyphidei    ChiodeeUm,  Olyphis, 

Family  4.  Arthoniei    Arihonia,  Mycoporum, 


Tribb  IV.  Caliciacbi. 

Apothecia  turbinate-lentiform  or  globose,  frequently  stipitate,  mar- 
gined by  a  proper  exciple,  the  disk  breaking  up  into  naked  spores, 
which  form  a  compact  mass. 
Family  1,  SpluerophoreL    SpharopJiorus,  Acroscyphus, 
Family  2.  Caliciei    AcoUum,  Calicium,  Coniocyhe. 

Tribe  V.  Verrucariacei. 

Apothecia  globose,  in  a  proper  exciple,  becoming  pertuse  with  a  pore. 

Family  1.  Endocarpei.    Endocarpon,  Normandina. 

Family  2.  VemicarieL  Segeairia,  Staurothele,  Trypethelium,  So- 
gedia,  Verruearia,  Pyrenula,  Pyrenastrum,  Strigula. 

(d)  Fossil  lichens  are  extremely  rare,  only  a  few  Tertiary  spedes  of 
modem  genera  being  recorded. 

403.— Order  UredineeB. — The  UredineaB  are  related  to  the 
foregoing  orders  of  the  Ascomycetes,  and  probably  should  be 
grouped  with  them.  They  are  all  parasitic  in  habit,  and  the 
vegetative  portions  of  the  plant-body  are  greatly  reduced, 
leaving  but  little  more  than  the  organs  of  reproduction. 
Their  life-history  is  but  imperfectly  known,  and  nothing  is 
yet  known  as  to  their  sexual  organs.  They  are  generally 
polymorphic — that  is,  they  assume,  in  their  production  of 
various  kinds  of  spores,  such  apparently  distinct  forms,  that 
these  have  frequently  been  mistaken  for  distinct  plants. 

404. — So  far  as  made  out,  the  life-history  of  the  UredineaB 
appears  to  be  about  as  follows  :  In  the  spring  there  appear  in 
the  tissues  of  the  leaves  of  various  plants  dense  masses  of 


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UREDINE^.  311 

hyphsB,  which  penetrate  between  the  cells,  causing  the  leaves 
to  become  usually  much  thickened  and  distorted  in  those 
parts  which  are  infested  with  the  parasitic  growths.     Oc« 


Fig.  216.— Several  etases  of  Puceinia  fframlnU.  A,  part  of  a  yertlcal  eection  of  a 
leaf  of  the  Barberry  (Berberis  vulgarit)^  with  a  young  unopened  fficidium  fruit ;  u. 
epidermis.  /.,  section  of  a  Barberry  leaf,  natural  IhickneBs  at  X,  greatly  thickened 
from  A  toward  y ;  u,  epidermis  of  the  under  surface ;  o,  of  the  upper  surface ;  o, 
unopened  lecldium  fVuit ;  a,  a,  a,  opened  tecidium  fruits  ;  fp,  «p,  spermagunla.  7/.. 
a  mass  of  teleutospores  on  a  leaf  of  Couch-grass  ( TriHcum  repens) ;  e,  the  ruptured 
epidermis  ;  b,  sub-epidermal  fibres  or  the  grass  leaf.  ///.,  tnree  uredospores,  ur. 
with  one  teleutospore,  tj  sh,  sub-bymenial  bypbie.  All  highly  magnified.— .^  and  I, 
after  Sachf ;  //.  and  ///.  after  De  Bary. 

casionally  these  hyphas  are  found  in  other  parenchymatous 
parts  besides  the  leaves,  as  the  petiolesi  young  stems,  and 
even  the  flowers  and  iruits.    After  a  short  time  there  form 


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812  BOTANY. 

globular  masses,  which  lie  in  the  parenchyma  just  beneath 
the  epidermis  ;  these  are  composed  at  the  bottom  of  an  hyme- 
nium-like  layer  of  sterigmata  (shown  in  Fig.  216,  A  and  7,  as 
a  layer  of  elongated  cells).  Each  sterigma  produces  a  chain 
of  cells,  which  are  at  first  many-sided  from  mutual  pressure, 
but  afterward  spherical.  By  their  growth  these  globular 
masses  finally  burst  through  the  epidermis  (Fig.  216,  /.,  p), 
and  soon  afterward,  by  tlie  rupture  of  the  thin  investing 
layer  of  cells  (peridium),  they  become  opened  and  cup- 
shaped  (Fig.  216,  /.,  «,  a,  a).  The  now  rounded  cells  are  set 
free  as  large  yellow  conidia  (or  aecidiospores).  At  one  time 
this  stage  was  supposed  to  constitute  a  distinct  plant,  and  it 
received  the  generic  name  of  ^cidium,  hence  it  is  still 
known  as  the  aecidium  stage. 

In  many  (if  not  all)  cases  there  is  a  second  kind  of  repro- 
ductive organ  present,  resembling  in  some  respects  the  aecid- 
ium  fruits  just  described.  These  are  smaller  flask-shaped 
cavities,  which  are  filled  with  slender  hair-like  filaments  (Fig. 
216,  /.,  sp,  sp) ;  these  are  the  spermagonia,  and  they  pro- 
duce, by  the  breaking  up  of  the  filaments,  numerous  ex- 
ceedingly small  oblong  bodies,  the  spermatia.  The  function 
of  these  is  not  known  ;  at  one  time  it  was  supposed  that  they 
were  the  male  reproductive  bodies,  but  it  is  very  doubtful 
whether  they  are  of  this  nature. 

406, — The  conidia  (aecidiospores),  when  they  fall  upon  the 
leaves  of  the  proper  host  plant,  germinate,  and  penetrate 
thestomata,  thus  reaching  the  leaf  parenchyma,  where  a  dense 
mycelium  is  formed.  Upon  this  are  formed,  within  a  short 
time,  stalked  spores  (uredospores.  Fig.  216,  ///.,  ur) ;  these 
finally  burst  through  the  epidermis,  and  form  orange-colored 
spots  upon  the  leaves.  The  uredospores  fall  off  very  easily, 
and  germinate  quickly,  giving  rise  immediately  to  another 
mycelium  (Fig.  217,  D),  which  produces  uredospores,  which 
may,  in  turn,  give  rise  to  new  mycelium,  and  so  on  indefi- 
nitely. The  function  of  the  uredospores  is  clearly  the  quick 
reproduction  of  the  fungus. 

406. — After  the  production  of  uredospores  has  continued 
for  some  time,  the  same  mycelium  gives  lise  to  stalked,  thick- 


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UBEDINEJE.  313 

walled  bodies  (ieleuiospores,*  or  pseudo-spores),  which  are 
one,  two,  three,  or  many-celled  (Fig.  216,  ///.,  t).  Like 
the  uredospores,  the  teleutospores  are  produced  beneath  the 


F!g.  2l7.-'PueeMa  fframifUs.  A^  germinaUng  teleutospore,  t.  with  promyceliam 
TornOng  the  eporidia.  ttp.  B,  similar  proinyceliuaa,  with  eporidia.  6',  a  Hporidlum, 
^  germinating  on  a  piece  of  the  under  side  of  a  leaf  of  the  Barberry,  the  mycelium, 
1.  penetrating  the  epidermis.  Z),  a  terminating  nredospore,  u,  fourteen  hoars  after 
beiDff  placed  on  the  leaf  of  a  grass,  forming  a  branched  mycelium.  Highly  magnified. 
-After  Be  Bary. 

epidermis  of  their  hosts,  which  in  their  growth  they  burst 
through,  and  appear  as  small  rounded  clusters  (sori),  or  more 

*  From  tbe  Greek  Tekevrrj^  end ;  so  named  becaaae  it  is  generally  the 
last  reprodactlve  body  of  these  fungi  produced  in  the  season. 


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314 


BOTANY. 


or  less  elongated  lines.  In  color  they  are  almost  invariably 
brown  or  nearly  blacky  in  marked  contrast  to  the  reddish  yellow 
(orange)  uredospores.  In  some  cases  they  are  produced  early 
in  the  season,  but  in  the  greater  number  of  cases  they  appear 
in  the  autumn,  and  then  remain  through  the  winter  upon 
the  dead  stems  of  their  host  plants.  The  following  spring 
the  teleutospores  germinate  by-sending  out  a  jointed  filament 
{the promyceluim)  from  each  cell ;  this  grows  to  several  times 
j  the  length  of  the  teleutospore,  and  then  sends  out  a  few  lateral 
branches,  each  of  which  bears  a  small  terminal  cell,  a  sporid- 
ium  (Fig.   217,  A  and  B,  and  Fig.  218).     The  sporidia  are 

extremely  minute,  and,  as  a 
consequence,  are  carried  about 
from  place  to  place  in  the  wind 
with  great  ease.  When  they 
fall  upon  the  proper  plant,  each 
sporidium  sends  out  a  minute 
filament,  which  perforates  the 
epidermis-cells,  and  from  these 
passes  into  the  leaf  parenchy- 
ma, where  it  develops  into  a 
mycelium  (Fig.  217,  C),  From 
this  last  mycelium  the  aecidium 
fruits  first  described  develop. 

(a)  The  life-cycle,  as  above  given, 
is  apparently  abridged  in  some  of 
the  Uredineae.  The  »cidium  and  uredo  stages  are  merged  into  one,  or 
either  the  first  or  second  is  entirely  wanting.  This  appears  to  t)e  the 
ca9e  in  Phragmidium,  Gymnosparangium,  Melampsora,  etc. 

(b)  With  most  of  the  species  it  happens  that  the  secidiospores  (conidia) 
develop  upon  one  host,  and  the  aredo8|K>res  and  teleutospores  upon  an- 
other. This  alternation,  which  is  termed  by  De  Bary  heteraseism,  has 
added  very  much  to  the  difficulty  of  the  study  of  these  fungi,  and  pes- 
sibly  the  apparent  abridgement  of  the  life-cycle  above  mentioned  may 
in  some  instances  be  only  an  obscure  heteroecism. 

(c)  Thus  far  the  sexual  organs  have  not  been  discovered  ;  Sachs* 
argues  that  they  must  precede  the  lecidiospores,  and  that  the  scidinm 
fruit  is  in  all  probability  the  result  of  a  sexual  act.  He  bases  his  argu- 
ment upon  the  law  that  the  reproductive  organs  of  most  complex  struc- 


PIjj.  218.— Germ  ilia  I  in?  teleatoepore 
of  Puccinia  Molinia,  hhowing  proray- 
cellnm  and  sporidia.— After  Toianne. 


♦  '^  Lehrbuch  der  Botanik/'  4te  Auflage,  1874,  p.  881. 


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UREBINEjE. 


315 


tore  follow  or  proceed  from  a  sexual  act ;  and  maintains  that  the  »cid. 
iiim  fruit  is  more  complex  in  structure  than  any  of  the  others.  He 
further  says, "  The  aecidium  fruit  corresponds,  then,  to  the  perithecium  of 
the  Ascomjcetes,  the  secidiospores  to  the  ascospores ;  and  the  uredo- 
spores  and  teleutospores  are  evidently  differ- 
ent forms  of  conidia."  It  is  very  doubtful, 
however,  whether  future  investigations  will 
prove  the  correctness  of  Sacljs'  surmise.  It  is 
much  more  probable  that  the  teleutospores  re- 
suit  from  a  sexual  act,  and  that  they  are  to 
be  compared  to  the  asci  of  the  Ascomycetes. 
The  teleutospores  are  possibly  reduced  asci, 
containing  one  or  more  large  ascospores ;  in 

some  canes— tf.^r.,  in  Puccinia  HelianUii—9in  ^^S-  ^^cr^^^^  tcleut©- 
»..#».:  -     *•  u  u     J'  ^.         .  »       Spores  of  PAro^wiW/wm  mt*- 

ontermvestmg  membrane  can  be  distmguish-  oronaium,  showing  the  an- 
ed  after  treatment  with  potassic  hydrate,  gjjlar  masses  which  eventu- 
-.1.-1    -n       '   •    /TT  -^  A  »,  *"y  develop  Into  the  cells 

while  m  Puccmta  (  Uropyxis)  Amorphm  there   of  the  mature  teleutospote. 
is  "  a  deciduous  outer  coat,"*  which  contains   Highly  magnified, 
the  double  spore,  and  (when  moistened)  a  mass  of  jelly.     In  both  these 
cases  the  membranous  coverio^  closely  resembles  an  ascus  which  fits 
closely  over  its  contained  double  spore.     In  the  genus  Phragmidium 
(Fig.  220),  especially  in  younjr  teleuiospores,  the  resemblance  to  asci 
and  ascospores  is  still  more  striking ;  the  so- 
called  "  cells"  of  the  teleutospore  originate  as  so 
many  separate  masses  iu  the  interior  of  a  large 
ascus-like  membrane  (Fig.  219) ;  in  their  further 
development  ^he  cells  become  large,  and  at  last 
fill  up  the  whole  cavity,  and  then  have  the  ap- 
pearance of  Fig.  220. 

The  resemblance  of  the  teleutospores  to  re- 
duced asci  is  close  enough  to  make  it  probable 
that  sexual  organs  resembling  those  of  Asco- 
mycetes will  be  found  to  precede  them.     This 
is  rendered  the  more  probable  from  the  resem 
blance  of  aecidiospores,  spermatia.  and  uredo- 
spores  to  the  conidia,  spermatia,  and  stylospores 
of  various  Ascomycetous  fungi,  f 
Pig.  220 -Mature  teleu-       ^^  '^^^  principal  genera  in  this  order  are 
^ores or  Phragmidium    Uromyces  And  Jfelampsora  with  one-celled  te- 
ited.-ArterCc»ke^™**^°*"    ^e^tospores,  Puccinia  and  Oymiw^porangium, 
with  two  cells,  and  Phragmidium  (Fig.  220)  with 
many  cells.    Many  species  are  known,  there  being  in  the  genus  Puo 


*  So  described  by  Berkeley :  ••  Introduction  to  Cryptogamic  Botany," 
1857,  p.  825. 
f  Some  of  these  resemblances  were  pointed  out  many  years  ago  by 


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316  BOTANY. 

eirUa  alone  from  forty  to  fifty  species  in  the  United  States.  They  at* 
tack  many  species  of  Plianerogams,  but  are  scarcely  known  as  para- 
sites upon  Cryptogams.  The  first  stage  was  long  known  as  the  genus 
./Eeuiium,  and  under  this  many  supposed  species  were  described,  and 
this  is  still  the  case  in  all  English  systematic  works  ;  in  the  same  way 
the  second  stage  gave  rise  to  the  supposed  genera,  Uredo,  Triehcbam, 
etc.,  and  even  these  are,  to  a  great  extent,  retained  in  the  ordinary 
books,  although  their  autonomy  was  long  since  disproved. 

{e)  One  of  the  best  known  species  of  this  order  is  that  which  appears 
upon  wheat,  oats,  and  souio  other  cultivated  grasses,  producing,  or 
rather  being,  the  disease  known  as  RuBt  {Puccinia  graminU).  It  ap> 
pears  in  the  spring;  upon  the  leaves  of  the  Barberry,  developing  there 
the  eecidiospores  (conidia),  and  constituting  what  for  a  long  time  has 
been  known  as  th«  Barberry  Cluster-Cups,  or  Barberry  Rust  (Fi^.  216, 
A  and  L),  Later  in  the  season,  and  usually  after  the  Cluster-Cups 
have  entirely  disappeared  from  the  Barberry,  the  uredo  stage  begins 
to  make  its  appearance,  first  upon  the  leaves,  and  then  upon  the  stems 
of  the  wheat,  oats,  etc. ;  at  first  it  may  be  detected  by  the  pale  yellow- 
ish or  whitish  spots  on  the  leaves  ;  these  mark  the  places  where  the 
uredospores  are  beginning  to  form  beneath  the  epidermis.  Within  a 
few  days  the  uredosporea  (Fig.  216,  III.,  ur)  break  through  the  epider- 
mis and  expose  lon^  lines  of  the  orange-red  spores.  By  the  quick  ger- 
mination of  the  uredospores,  first  produced,  the  fungus  is  greatly 
iccreased,  so  that  frequently  the  host  plant  is  destroyed  before  reach- 
ing its  maturity.  This  stage  is  known  popularly  as  the  Red  Rust  of 
wheat,  oats,  barley, and  other  similar  grasses.  Still  later  in  the  season, 
and  usually  after  the  ripening  of  the  host  plants,  the  dark-colored 
teleutospores  (Fig.  216, 77.)  appear  in  long  black  lines,  sometimes  upon 
the  leaves,  but  more  frequently  upon  the  stems,  and  in  ordinary 
cases  upon  the  uncut  part  of  the  stem,  viz.,  the  "  stubble."  This  stage 
is  known  as  the  Black  Rust.  The  teleutospores  remain  upon  the  dead 
stems  through  the  winter,  and  in  the  following  spring  germinate  and 
produce  sporidia,  which  jrive  rise  to  a  mycelium  in  the  Barberry 
leaves  (Fiff.  217,  J,  B,  and  C). 

De  Bary,t  by  placing  the  teleutospores  upon  young  leaves  of  the 
Barberry,  succeeded  in  producing  the  cecidium  stage,  thus  proving 
Barberry  rust  to  be  but  a  stajie  of  Puccinia  graminis.  Similarly  it 
has  been  shown  that  the  secldiospores  of  Barberry  rust  will  not  grow 
upon  Barberry  leaves,  but  that  when  placed  on  a  leaf  of  wheat,  oats, 


Frederick  Currey.  In  a  paper  **  On  the  Affinities  of  the  Uredineae,"  pre- 
sented to  the  Iowa  Academy  of  Sciences,  May,  1878, 1  pointed  out  that 
the  structural  similarity  of  Uredineae  and  Ascomycetes  rendered  it 
probable  that  the  sexual  organs  of  the  former  preceded  the  teleuto. 
spores.  1  did  not  then  know  of  Currey's  paper, 
f  Published  in  MonaUber.  d,  BerL  Acad.,  1865. 


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USTILAQINEJE.  317 

iMirlej,  etc.,  tliej  send  out  filaments,  wlicih  pass  throagh  the  stomata, 
and  give  rise  to  a  mjcelium,  which,  in  about  a  week,  produces  uredo- 
spores. 

(f)  Uredine®  are  easily  obtained  for  study  in  either  the  first,  second, 
or  third  stage.  In  most  species  the  scidium  stage  occurs  in  spring  or 
early  summer,  the  second  in  spring  or  summer,  and  the  tliird  in  the 
autumn  ;  in  some  species,  however,  the  teleutospores  are  produced  in 
the  spring,  as  in  Of^nosporangium  and  Pucdnia  AnemoneB. 

{g)  The  sporidia  may  be  obtained  by  placing  pieces  of  grass  stems 
containing  teleutospores  in  a  damp  atmosphere,  after  soaking  for  a  few 
hours  in  water.  The  teleutospores  should  be  freshly  taken  in  most 
cases  from  those  which  have  remained  upon  the  stems  out-of-doors 
daring  the  winter. 

407.— Order  UstilaginesB.  The  plants  which  compose 
this  order  are  all  parasites  living  in  the  tissues  of  Phanero- 
gams. Like  the  UredineeB,  the  Ustilagineae  send  their  my- 
celium through  the  tissues  of  their  hosts,  and  afterward 
produce  spores  in  great  abundance,  which  burst  through  the 
epidermis.  There  is,  however,  in  many  respects  a  greater 
simplicity  of  structure  in  the  plants  of  the  present  order 
than  in  the  UredineaB,  and  this  has  induced  eome  botanists 
to  doubt  their  relationship  to  the  last-named  order ;  how- 
ever, it  appears  that  the  simplicity  is  one  due  rather  to 
degradation  than  to  any  essential  difference  in  structural 
plan. 

408. — The  mycelium  of  the  UstilaginesB  is  well  defined, 
and  consists  of  thick-walled,  jointed,  and  branching  hyphaB, 
which  are  generally  of  very  irregular  shape.*  The  hyphas 
grow  in  the  intercellular  spaces,  as  well  as  within  the  cell 
cavities  of  their  hosts.  They  send  out  suckers  (haustoria), 
which  penetrate  the  adjacent  cells  much  as  in  the  Perono- 
sporeae ;  these  are  more  abundant  in  the  compact  tissue  of 
the  nodes  of  stems  than  in  the  long-celled  tissue  of  the  in- 
ternodes.  The  mycelium  generally  begins  its  growth  when 
the  host  plant  is  quite  young,  and  grows  with  it,  spreading 
into  its  branches  as  they  form,  until  it  reaches  the  place 
of  spore-formation.     In  perennial  plants  the  mycelium  is 

♦  The  following  account  of  the  Ustilaginese  Is  based  upon  an  article  on 
this  order  by  Dr.  A.  Fischer  von  Waldheim,  published  in  Pringsheim's 
*' Jahrbftcher  fur  Wissen.  Bot./'  1869.  A  translation  appeared  in  the 
Tnmioctioni  of  the  If.  Y,  State  Agricultural  Society,  1870. 


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318  BOTANY. 

perennial,  the  fungus  reappearing  year  after  year  upon  the 
same  stems,  or  upon  the  new  stems  grown  from  the  same 
roots ;  in  annuals  it  must  obtain  a  foothold  in  the  young 
plants  as  they  grow  in  the  spring. 

409. — The  mycelium  can  be  traced  in  the  Monocotyle- 
dons often  for  long  distances ;  thus  in  the  smut  of  Indian  com 
( Ustilago  Maydis),  at  the  time  the  spores  are  found  in  the 
distorted  grains  the  hyphae  have  been  detected  at  all  inter- 
mediate points  down  to  the  lower  internodes,  and  in  the 
smut  on  wheat  ( Ustilago  carbo)  they  have  been  observed  in 
every  part  of  the  plant,  from  the  root  through  the  stem  to 
the  inflorescence.  In  neither  case,  however,  ai'e  the  hyphae 
to  be  found  in  parts  through  which  it  is  not  necessary  for 
them  to  pass  in  order  to  reach  the  point  where  the  spores 
are  formed ;  thus  they  are  usually  not  found  in  the  leaves 
unless  spores  are  formed  in  them. 

410. — The  formation  of  spores  appears  to  have  some  re- 
lation to  the  development  of  the  host  plant,  as  they  form 
only  in  certain  parts  of  the  latter,  and  are  not  produced 
until  the  growth  of  these  parts  has  taken  place.  Thus  in 
the  Bunt  of  wheat  {TiUetia  caries)  the  spores  are  formed 
only  in  the  young  ovaries ;  in  the  anther  smut  of  the  Si- 
lenecB  ( Ustilago  antherarum)  the  spores  are  formed  in  the 
young  anthers  ;  in  one  of  the  smuts  of  the  sedges  {Ustilago 
urceolorum)  they  form  on  the  upi)er  surface  of  the  ovary,  and 
in  the  smut  of  wheat,  oats,  etc.,  in  the  young  flowers.  In 
cases  like  these  it  is  evident  that  the  time  of  spore-forma- 
tion is  dependent  upon  the  development  of  the  flowers  of 
their  host ;  and  if  these  are  earlier  or  later  in  their  appear- 
ance, the  spore-formation  will  vary  accordingly.  In  the 
smut  of  Indian  com  ( Ustilago  Magdis),  on  the  other  hand, 
the  spore-formation  may  take  place  in  other  parts  of  the 
plant,  as  well  as  in  the  ovary  ;  thus  it  not  infrequently  makes 
its  appearance  upon  the  stems,  and  even  upon  the  leaves.  In 
Ustilago  hypogcea  the  spores  are  produced  underground 
upon  the  root  of  the  host  plant  {Linaria  spuria)^  and  in 
Ustilago  marinay  in  the  tissues  of  Scirpus  parvulus,  under 
water ;  with  these  two  exceptions,  the  spore-formation  always 
takes  place  in  parts  above  ground. 


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JJ8TILAQINEJE.  319 

411. — Immediately  preceding  the  formation  of  spores 
the  hyphae  give  rise  to  many  branches,  which  differ  mnch  in 
appearance  from  the  ordinary  ones.  This  takes  place  in 
those  parts  of  the  host  plant  where  the  spores  are  afterward 
produced.  These  spore-forming  hyphae  are  thicker  than  the 
vegetative  ones,  and  are  more  gelatinous ;  they  are  more  or 
less  granular,  and  they  sometimes  contain  oil  globules. 

412. — The  spores  are  formed  in  Tilletia  caries  by  little 
lateral  branches  budding  out  upon  the  spore-forming  hyphae, 
and  acquiring  a  pear-shaped  outline ;  they  become  thicker 
and  more  spherical,  and  each  eventually  secretes  a  dark,  thick 
wall  (Fig.  224,  Jc'  and  k).  When  mature,  the  spores  become 
free  by  the  drying  up  of  the  attaching  pedicel.  In  Ustilago 
the  spore-forming  hyphae  break  up  their  contents  into 
spores,  and  in  some  cases — as,  for  example,  in  Ustilago 
Maydis — the  process  much  resembles  the  formation  of  asco- 
spores  in  asci  (Fig.  221).  It  frequently  happens  that  the 
spore-forming  hyphae  fuse  together  on  account  of  the  gelat- 
inous nature  of  their  envelopes  ;  when  this  takes  place,  the 
spores  are  formed  in  very  irregular  masses  (Fig.  222,  b). 

In  Sorisporium  SapoTiaricB  this  fusing  takes  place  to  so 
great  an  extent  that  the  real  nature  of  the  process  is  greatly 
obscured.  The  spore-forming  hyphae,  which  are  very  abun- 
dant, become  curved  at  their  extremities,  and  many  of  these 
twist  themselves  into  a  little  ball,  and  are  fused  into  a  single 
gelatinous  body,  which  eventually  becomes  a  mass  of  spores. 
The  real  nature  of  the  spore-formation  is  probably  indicated 
by  the  "solitary  spores,"  which  appear  singly  upon  those 
spore-forming  hyphae  which  do  not  compact  themselves  into 
balls ;  in  these,  the  resemblance  to  asci  containing  single 
ascospores  is  striking  (Fig.  223). 

413. — The  spores,  when  ripe,  have  a  double  wall.  The 
outer — the  epispore — is  thick,  usually  brown  or  black,  some- 
times smooth,  but  frequently  more  or  loss  rough  by  projec- 
tions, or  marked  by  reticulations  (Fig.  224,  e).  The  inner 
wall — the  endospore — is  a  delicate  colorless  membrane,  which 
protrudes  through  the  ruptured  epispore  in  germination. 

414. — The  germination  of  the  spores  has  been  made  out 


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BOTANY. 


for  a  few  species  only.*  In  all  which  have  been  examined 
the  spore  sends  out  a  promycelium,  which  is  generally  short 
and  jointed,  and  upon  this  several  sporidia  are  produced, 
much  as  in  the  Uredineae.  In  Tilletia  caries  the  promyce- 
lium produces  a  tuft  of  slender  branches  (Fig.  224,  h)y  which 


Fio.  221. 


Fio.  222. 


Fio.  223. 


Fig.  221.— Spore-formation  in  UstUago  Maydh.  a,  the  end  of  a  spore-forminff  hy« 
pba  containing  a  row  of  yonng  apores ;  b,  another  apore-forminff  hypha.  oontauing 
two  young  epores;  o,  a  cppre  nearly  ripe,  still  sarroanded  by  the  gelatinoaa  mem- 
brane of  the  nypha.    x  1800.— After  Fischer  von  Waldheim. 

Fig.  222.— Spore-formation  in  UvMago  antherantm.  a,  an  isola  <'(*>  gelatinous  by- 
pha.with  thecontenta  distinctly  breaking  op— at  the  lower  end  a  portion  not  yet 
oroken  np ;  b,  a  number  of  gelatinous  hyphee  fused  into  an  irregular  mass,  showing 
the  formation  of  miiny  spores  ;  0,  a  spore  nearly  ripe,  still  snrrounded  by  the  gelat- 
inous hypha  membrane,  also  a  young  spore  upon  a  lateral  branch,  a  and  e  x  1800 ; 
b  X  900.— After  Fischer  von  WaJdheim. 

Fig.  223.— Formation  of  **  solitary  spores'*  in  SorUpofium  Saponaria.  a,  hTpba 
with  twoyouns  spores;  6,  a  spore  at  a  later  stage;  c,  hypbie  with  spores  in  aiflisr- 
ent  stages  of  development ;  at  </  a  thin  wall  has  formed  around  the  contained  pro> 
toplasm  as  in  6 ;  at  c''  the  wall  is  much  thicker,  and  at  &"  It  is  still  thicker,  x  900.— 
After  DeBary. 

have  been  seen  to  unite  laterally  by  a  kind  of  conjugation 
(not,  however,  of  a  sexual  nature,  in  all  probability) ;  from 
these  branches  (called  by  some  writers  "  secondary  spores**)! 

*  According  to  Fiscber  von  Waldlieim,  the  germination  of  the  fol- 
lowinpr  species  is  known/ viz.,  TUletia  caries,  T,  Lolu,  UstUago  aU" 
therarum,  JJ,  floseulorum,  U,  earbo,  XT.  destruena,  U.  MaydU,  U,  reeep* 
taeulorum,  U.  longUHma,  U.  VaiUarUii,  UrocystU  pomphdygodes, 
Uroe.  occulta. 

f  De  Bary  calls  these  branches  sporidia,  and  what  are  here  called 
sporidia,  he  calls  secondary  sporidia. 


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USTILAOINE^, 


321 


there  grow  out  small  sporidia,  which  germinate  by  sending 
out  a  slender  hypha ;  when  this  hypha  comes  in  contact 
with  the  proper  host  plant,  it  penetrates  the  walls  of  its 


*A^L~   kTo 


Fig.  i2L—TUletia  caties.  d,  transverse  section  of  an  infected  wbeat-erain ;  «,  ripe 
spore  ;  /,  the  flr«t  Btage  of  germination  ;  g^  the  formation  of  a  branching  promyce- 
Iram,  with  granular  urotoplai>m  in  its  upper  end ;  A,  the  formation  of  slender 
branches  which  unite  by  a  kind  of  conjugation  ;  the  ends  of  these  branches  give  rise 
somewhat  later  to  very  small  sporidia,  and  when  the^e  germinate  very  sieudt  r  hy- 
phie  are  produced,  which  penetrate  the  epidermis  as  at  i ;  kf^  mycelium  from  the 
youDg  ovary  of  the  wheat — two  small  lateral  branches  are  shown,  from  which  spores 
will  develop  ;  *,  spores  more  fully  developed.— d,  after  (Ersted  ;  #-A,  after  Tulasne, 
X  460 ;  ink,  after  Kuhn,  x  800. 

cells,  and  thus  gains  admittance  to  its  interior,  where  it  pro- 
duces a  new  mycelium*  (Fig.  224,  t).     In  Ustilago  carlo  the 

*  This  is  upon  tlie  autliority  of  Kuiin  :  "  Krankheiten  der  Calturge- 
w&chfie/'  1859.  There  are  some  doubts  as  to  the  correctness  of  his 
observations,  and  they  have  not  been  confirmed  bv  any  one. 


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322  BOTANY. 

promycelium  branches  less  frequently,  and  generally  pro 
duces  from  three  to  four  sporidia.  In  no  other  case  than 
TiUetia  caries  is  the  mode  of  entrance  of  the  fungus  into 
the  host  plant  known. 

416. — No  sexual  organs  have  yet  been  discovered.  They 
are  probably  to  be  looked  for  just  preceding  the  formation 
of  the  spore-bearing  hyphae.  The  uniting  of  the  hypha- 
branches  in  the  germination  of  the  spores  of  Tilletia  caries 
(Fig.  224,  h)  has  probably  no  sexual  significance. 

(a)  In  the  study  of  tlie  mjceliom  of  the  Ustilagines,  the  hjpbsD 
may  be  made  more  distinct  in  thin  sections  of  the  host  plant  bj  the 
application  of  a  solution  of  potassic  hydrate.  A  similar  effect  is  pro- 
duced by  treating  the  specimen  for  some  hours  with  thinned  glycerine. 

(6)  In  the  study  of  the  spore  development,  the  specimens  must  be 
examined  in  very  early  stages  of  the  growth  of  ihe  fungus.  This  can 
generally  be  done  in  the  case  of  those  species  which  affect  the  Gram- 
ineae,  by  taking  the  affected  **  suckers  "  or  lateral  branches  of  the  host 
plant,  after  the  spores  are  pretty  well  advanced  on  the  main  stem. 

(c)  Upon  the  application  of  a  solution  of  iodine,  the  contents  of  the 
young  spores  become  yellow,  indicating  their  protoplasmic  nature ; 
treated  with  Schultz's  solution,  the  contents  become  brownish  yellow. 
The  gelatinous  membrane  is  not  colored  by  the  last-named  reagent, 
showing  that  it  is  not  cellulose  ;  but  when  treated  with  a  solution  of 
potassic  hydrate,  it  is  colored  yellow,  and  in  sulphuric  acid  it  is  dis- 
solved. 

id)  The  ripe  spores  frequently  require  to  be  treated  with  reagents  to 
bring  out  their  structure.  The  endospore  may  be  rendered  visible  by 
the  application  of  sulphuric  acid  which  makes  the  epispore  more 
transparent ;  in  concentrated  sulphuric  acid  the  structure  of  the  epi- 
spore is  made  much  plainer;  treatment  with  a  solution  of  potassic 
hydrate  causes  the  spore  to  swell  up. 

{e)  In  the  study  of  the  germination  of  the  spores,  it  is  only  neces- 
sary to  place  freshly  gathered  spores  in  a  drop  of  water,  or  upon 
moistened  earth,  or  in  an  atmosphere  kept  moist,  as  under  a  bell-jar. 
Germination  takes  place  in  the  proper  temperature  (20''  to25''  G.,  or  68° 
to  77*  Fahr.)  in  from  three  hours  (UstUago  longissima)  to  fifty  or  sixty 
(TOletia  caries). 

V/)  All  attempts  thus  far  to  determine  experimentally  the  mode  of 
entrance  of  the  fungus  into  the  tissues  of  tlie  host  plant  have  failed, 
with  the  exception  of  Kuhn's  experiments  upon  JlUetia  caries.  The 
recent  attempts  made  by  Fischer  von  Waldheim  upon  UstUago  earbo 
and  other  species,  although  made  seemingly  under  the  most  favorable 
conditions,  utterly  failed.  He  placed  fresh  spores  upon  the  germinated 
seeds  of  oats  and  barley,  upon  the  entire  surface  of  the  rootlets,  and 


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BA8IDI0M70ETE8.  323 

«l0o  upon  all  parts  of  the  young  stems  and  leaves.  He  even  sprinkled 
ihe  young  plants  with  germinated  spores,  and  in  one  series  of  ezpen- 
inents  brought  tlie  young  rootlets  in  contact  with  the  promycelium 
and  sporidia  of  the  germinating  spores.  In  no  case,  however,  was 
there  any  penetration  of  the  fungus  into  the  host  plant. 

ig)  Tlie  most  important  genus  of  the  order  is  UstUago,  which  con> 
tains  many  species,  the  most  common  of  which  are  U.  cai'bo,  the 
smut  of  wheat,  oats,  barley,  and  many  other  grasses  :  U,  MaydU^  the 
smut  of  Indian  com ;  U.  dentruens,  on  JSetaria  glauca;  U.  tUrictUosa, 
on  species  of  Polygonum ;  U,  ureeolorum,  on  many  species  of  Ca/rex, 
TiUetia  contains  several  species,  but  one  of  which — T.  c€mes — ^has  yet 
heen  detected  in  this  country.  Of  Urocystis  we  have  several  species,  of 
wliich  U,  eeptUcB,  on  onions,  and  U.  pompholygodes^  on  Ranunculaceae, 
are  best  known. 

§  IV.    Class  Basidiomycetes. 

416. — The  plants  of  this  class  are  among  the  largest  and 
finest  of  the  fungi.  They  are  mostly  saprophytes,  provided 
with  an  abundant  mycelium,  which  ramifies  through  the 
nourishing  substratum,  and  from  which  there  arises  after- 
ward a  spore-bearing  growth,  the  sporocarp.  The  spores,  ol 
which  but  one  kind  is  yet  certainly  known,*  are  produced 
upon  slender  outgrowths  from  the  ends  of  enlarged  cells, 
termed  basidia.  The  basidia  are  usually  so  arranged  as  to 
form  an  hymenium,  which  is  at  length  external  in  Hymeno- 
mycetes,  and  internal  in  most  Gasteromycetes. 

417. — The  sexual  organs  probably  precede  the  formation 
of  the  sporocarp,  but  they  have  been  but  little  studied. 
CErsted  discovered!  bodies  in  Agaricus  variabilis  which, 
judging  from  his  description,  bear  a  considerable  resemblance 
to  the  sexual  organs  of  Feziza.  Whether  they  occur  through- 
out the  class  is  at  present  entirely  unknown,  and  as  (Er- 
sted's  discovery  has  not  been  confirmed  by  other  observers, 
the  whole  question  as  to  the  sexual  organs  of  the  Basidiomy- 

*  (Ersted,  in  *'  Eongeliflre  Danske  Videnskabemes  Selskabs  Forhand- 
linger,"  Copenhagen,  1865  (translated  in  Qr,  Jour,  Mic,  Science,  1868,  p. 
18),  describes  certain  little  stalked  bodies  which  he  found  growing  upon 
die  mycelium  of  Agaricus  variabilis,  and  which  he  regards  as  conidial 
in.  their  nature.     Spermatia  also  occur  on  the  Tremellini. 

f  Described  in  his  paper  just  referred  to  above. 


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324  BOTANY. 

cetes  must  be  considered  as  involved  in  much  doubt  Two 
orders  may  be  readily  separated  in  this  class,  the  Gasteromy- 
cetes  and  the  Hymenomycetes. 

418.— Order  Gkusiteromycetes.  The  plants  of  this  order 
are  saprophytes,  producing  sporocarps  which  are  often  of 
large  size,  and  usually  of  a  more  or  less  globular  outline, 
sometimes  long-stalked.  The  spores  are  always  borne  in  the 
intenor  of  more  or  less  regular  cavities,  and  from  these  they 
escape  by  the  drying  and  rupture  of  the  surrounding  tissues. 
419.— The  mycelium  of  the  Gasteromycetes  penetrates  the 
substance  of  decaying  wood,  and  the  soil  filled  with  decaying 
organic  matter.  *  It  is  composed  of  colorless  jointed  hyphae, 
which  usually  aggregate  themselves  into  cylindrical  root- 
like masses.  After  an  extended  vegetative  period,  the  my- 
celium forms  upon  its  root-like  portions  small  rounded 
bodies,  the  young  sporocarps,  which  increase  rapidly  in  size, 
and  assume  the  form  characteristic  of  the  different  genera. 

420. — The  sporocarps  are  composed  of  hyphae  which  are 
much  interlaced  ;  in  the  interior  they  are  more  loosely  ar- 
ranged, while  externally  they  form  a  more  or  less  well-defined 
limitary  tissue,  the  peridium.  In  some  genera  the  peridium 
is  composed  of  two  or  more  layers,  as  in  the  Earth -star  (Oeas* 
ter).  The  spores  are  borne  upon  hymenial  layers  which  line 
cavities  in  the  interior  of  the  sporocarp.  The  basidia  upon 
which  the  spores  are  borne  are  the  rounded  or  elongated  ter- 
minal cells  of  hypha-branches ;  each  basidium  bears  four  or 
more  (frequently  eight)  spores  upon  the  ends  of  as  many 
small  projections  (spicules).  In  Phallus  and  its  allies  the 
hymenial  cavity  lies  beneath  the  double  peridium  and  paral- 
lel to  its  surface ;  when  the  spores  are  formed,  by  the  rapid 
growth  of  the  axial  portion  of  the  sporocarp,  the  hymenium 
is  carried  up  through  a  rent  in  the  apex  of  the  peridium  and 
the  spores  thus  set  free.  In  the  Earth-star  {Geaster),  Puff- 
ball  {Lycoperdon)y  and  their  allies,  the  hymenial  cavities  are 
numerous,  of  irregular  shape,  and  scattered  through  the  tis- 
sue of  the  sporocarp.  The  spores  are  set  free  by  the  rupture 
of  the  peridium,  and  the  drying  of  the  whole  sporocarp, 
thus  reducing  its  interior  hyphae  to  a  fine  powder.     In  the 

Puff-ball  the  single  peridium  ruptures  irregularly,  but  in  the 


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GA8TEB0MTCETE8,  325 

Earth-star  the  outer  peridium,  which  is  dense,  and  when  dry 
quite  hard,  splits  from  the  top  into  partially  separated  seg- 
ments, which  recurve  and  expose  the  inner  more  delicate  perid- 
ium ;  the  latter  ruptures  more  or  less  regularly  at  the  top,  and 
thus  allows  the  escape  of  the  spores  and  dusty  broken-up 
hyphsB. 

421. — In  the  curious  little  Crucibulum  and  its  allies  the 
structure  and  mode  of  development  are  much  more  compli- 
cated. The  mycelium,  which  grows  over  the  surface  of  de- 
caying wood,  forms  first  a  rounded  mass  of  hyphae  in  its 
centre  ;  this  becomes  cylindrical,  and  then  undergoes  several 
remarkable  changes.  In  the  interwoven  hyphae  of  the  inte- 
rior, at  certain  points,  there'  is  a  very  great  increase  in  the 
number  of  hyphae  and  the  density  of  the  tissue  ;  this  takes 
place  with  such  regularity  that  several  round  bodies  are 
formed.  The  interior  of  each  of  these  round  bodies  is  at 
first  composed  of  interwoven  hyphae,  but  these  become  mu. 
cilaginous,  and  finally  entirely  dissolved,  forming  a  central 
cavity  in  each  mass ;  into  these  cavities  hypha-branches  now 
grow,  and  line  them  with  an  hymenial  layer  of  spore-bearing 
basidia.  The  round  bodies  are  thus  sporangia.  While  the 
above-described  changes  are  going  on,  the  tissue  lying  between 
the  sporangia  undergoes  conversion  into  mucilage,  and  be- 
comes entirely  dissolved,  leaving  only  a  surrounding  wall 
(the  peridium),  and  slender  pedicels  composed  of  hyphae, 
which  support  the  sporangia.  When  these  changes-  are  com- 
pleted, the  peridium  ruptures  at  the  top  and  opens  out, 
forming  a  cup-shaped  ♦eoeptacle,  in  which  the  sporangia  lie. 
The  sporocarp  of  Crucibulum  is  thus  a  much  more  highly 
developeu  organism  than  that  of  Lycoperdon,  although  not 
differing  from  it  in  any  essential  point  of  structure. 

422. — No  sexual  organs  have  yet  been  discovered  in  the 
Gasteromycetes,  but  analogy  points  to  their  probable  exist- 
ence upon  the  mycelium  just  previous  to  the  first  appearance 
of  the  spore-bearing  portion  of  the  plant  (sporocarp). 

423. — The  mode  of  germination  of  the  spores  is  as  yet 
almost  entirely  unknown. 

(a)  The  principal  genera  of  tlie  Gasteromycetes  are  PhaUtu,  which  in- 
dadesthe  common  Stink-horn ;  Lycoperdon  including  several  species  of 


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326  BOTANY. 

Puff-balls,  of  whicli  tlie  beet  known  is  L,  giganteum,  the  Giant  Puff- 
ball,  an  edible  speciee,  from  ten  to  thirty  cm.  in  diameter ;  GeatUr, 
the  £arth.8tare,  including  several  species,  and  CrueibtUum,  of  whicli  C. 

vulgare  is  very  common. 

(6)  This  order  presents 

no  unusual  difficulties  to 

the  student,  and  it  is  one 

I  which  should  receive  more 

attention  than  it  has  hith'- 
erto.  For  the  study  of 
the  structure  the  specl- 
mens  should  be  taken  in 
their  earlier  stages,  as  but 
little  can  be  made  oui 
after  the  hyph®  b^in 
breaking  up  or  dissolving. 

424.  —  Order  Hy- 
menomycetes.  These 
plants  ure  doubtless  to 
be  regaided  as  the 
highest  of  the  chlo- 
rophyll -  free  Carpo- 
sporeaa.  They  are  not 
only  of  considerable 
size  (ranging  from  one 
to  twenty  centimetres, 
or  more,  in  height), 
but  they  present  a 
structurcJ  complexity 
which  is  so  much 
greater   than  that  of 

'    Fig.  825.— Development  of  Agaricut  campestrii.  the  other  OrdcrS,  that 
A,  underground  mycelium  .(m),  bearing  nnmerouB     ,  j.  v    i.  i. 

young  sporocarps  of  various  Bt£ee>.   /..vertical  »ec-  they  Caunot  OUt  DC  re- 
tion  of  a  young  sporocarp,  i»howin«;  its  attachment  -i    ^  .  i       i.  •    i_      i. 

to  the  mycelium,  m.    //.  vertical   section   of  an  garaed  aS   tnc  nigbest 
older  sporocarp,  showing  the  annular  opening, /.   ^*    ^u^    •r,-..,^*;  T  il-/v 

///..  the  tame  at  a  sdll  later  stage.  IV..  youug  sporo-  01  t ne  lUUgl.  Lilke 
carp,  with  stalk  (st):  rudhnentary  gills  (0,  and  the  j.Up  aaijfftrnTTivpAtAH 
beginning  of  the  veif  («).  F.,  sporocarp  nearly  ma-  ^^^  UaSieromyceiCS, 
ture  ;  m,  mycelium;  A.  pileus  ;  /,  the  gills  (hyme-  fhpv  Tirodnofi  an  ahun- 
nial  famell«);  r,  the  veil,  not  vet  rupturSd;  i,  a  very  ^"^J^  prouiice  an  ttuuu 
young  sporocarp.  All  natural  sire.— Alter  Sachs.  dant  myCClium  under- 
ground, or  in  the  substance  of  decajring  wood ;  it  fre- 
quently consists  of  multitudes  of  whitish  jointed  hyphae, 
which  are  loosely  interwoven,  but  in  some  cases  they  be- 


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HTMENOMYCETEa,  327 

come  densely  felted  into  tough  masses  five  to  ten  or  more 
millimetres  in  thickness^  and  of  many  centimetres  in 
breadth  and  length ;  it  frequently  also  becomes  compacted 


Fiff.  236.— i4,  cros8-0ection  of  the  gills  or  lamellie  (/),  of  AgaHew  campestHs ;  h, 
portiou  of  pUeuB  ;  J9,  section  of  one  of  the  ffills,  more  highly  magnified  ;  t.  the  cen- 
tral tiasae  of  the  eill  {trama) ;  ihy  the  snh-nymenial  layer  of  short,  rounded  cells ; 
Ay,  hymeninm.  C,  a  small  portion  of  By  more  highly  magnified  (x  660) ;  t.  trama ; 
shy  sub-hymenial  layer ;  q^  young  ba^idia  and  paraphyses  ;  ^.  basfdium  with  fpores 
in  earliest  stage :  (t'\  basidium  with  spores  nearly  ripe  ;  s^"^  basidinm  with  ripe 
spores;  t^'^\  basidium  from  which  the  npe  spores  have  fallen.— After  Sachs. 

into  cylindrical  root-like  forms  (Fig.  225,  A,  m).  Upon  the 
mycelium  there  arise,  after  a  longer  or  shorter  period  of  vege- 
tation, small  rounded  or  oblong  masses,  tlie  young  sporo- 


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328  BOTANY. 

carps.  These  are  composed  of  parallel  vertical  hyphae, 
which  grow  upward,  and  finally  bend  out  laterally,  or  send 
out  lateral  branches  at  the  top,  forming  the  umbrella-shaped 
pileus  common  in  many  of  the  genera  (Fig.  225,  F.,  A). 

425. — In  the  common  Mushroom  {Agaricua  campestris) 
the  young  sporocarp  is  at  first  composed  of  a  mass  of  similar 
hyph»  (Fig.  225,  /.) ;  somewhat  later,  however,  an  annular 
opening  a  little  below  the  apex  is  visible  in  a  longitudinal 
section  (Fig.  225,  //.,  I) ;  this  enlarges,  and  the  overlying 
tissue  becomes  the  pileus  (Fig.  225,  ///.,  IV.,  and  F.,  /*), 
while  that  between  the  opening  and  the  margin  of  the  sporo- 
carp becomes  the  "veil"  (Fig.  225,  IV.  and  F.,  r),  which 
finally,  by  the  rapid  expansion  of  the  pileus,  becomes  rup- 
tured, leaving  an  annular  fragment  (the  ring,  brannulus)  sur- 
rounding the  stalk  of  the  fully  developed  sporocarp.  Upon 
the  under  surface  of  the  pileus  the  hyphae  form  a  great 
number  of  thin  radiating  plates  or  lamellae,  the  so-called 
gills,  and  upon  their  surfaces  there  develops  an  extended 
hymenial  layer.  The  hymenium  consists  of  elongated  cells, 
which  are  slightly  club-shaped,  and  placed  closely  side  by 
side  perpendicular  to  the  gill  surfaces  (Fig  226,  B  and  (7). 
Some  of  these  cells,  the  basidia,  are  somewhat  longer  than 
the  rest,  and  have,  in  this  species,  two,  and  in  most  others, 
four,  slender  projections,  upon  which  spores  (basidiospores) 
are  eventually  produced  (Fig.  226,  C,  s',  s",  «'").  Here  and 
there  upon  the  hymenium  there  may  be  found  larger  bladder- 
shaped  cells,  looking  like  overgrown  sterile  basidia;  their 
significance  is  not  known,  and  they  have  received  the  name 
of  Cystidia  (Fig.  226a).  In  some  other  genera  the  hyme- 
nium, instead  of  extending  over  lamellae,  is  found  lining  the 
walls  of  vertical  pores,  as  in  Polyporus,  or  covering  depen- 
dent spines,  as  in  Hydnum,  or  spread  out  on,  the  smooth 
surface  of  the  sporocarp,  as  in  Stereum. 

426. — The  development  of  the  spores  of  the  Hymeno- 
mycetes  takes  place,  according  to  De  Bary,*  as  follows  :  The 
young  basidia,  which  have  much  the  shape  of  the  young  asci 

*  ••  Morphologic  und  Phjaiologie  der  Pilze,  Flecbten,  und  Myxomy- 
wten,"  1865,  p.  Ill,  et  seq. 


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HTMENOMTCETES,  329 

of  the  Ascomycetes  (Fig.  196,  a,  b,  and  c),  are  filled  with 
granular  protoplasm  ;  when  the  projections  {sterigmata) 
make  their  appearance,  the  protoplasm  in  the  basidium 
passes  into  them,  and  is  slightly  withdrawn  from  its  lower 
end.  Each  sterigma  swells  at  its  extremity  into  a  bladder- 
shaped  body,  the  young  spore,  and  as  it  enlarges  the  proto- 
plasm of  the  basidium  is  passed  into  it.  By  the  time  the 
spores  are  full  grown  the  protoplasm  has  nearly  all  disap- 
peared from  the  basidia.  The  spores,  when  ripe,  separate 
themselves  from  the  sterigmata  by 
a  transverse  partition,  and  soon 
fall  off. 

427. — Witii  regard  to  the  ger- 
mination of  the  spores  but  little  is 
known,  but  in  Coprmus,  according 
to  Van  Tieghem,*  they  give  rise  to 
a  mycelium,  and  this  is  probably 
the  case  with  all. 

428. — The  existence  of  sexual 
organs  in  the  Ilymenomycetes  is 
still  involved  in  much  doubt.  CEr- 
sted  described!  long  ago  certain 
bodies  which  he  discovered  on  the 
mycelium  of  Agaricus  variabilis 
just  before  the  formation  of  the 
sporocarp.     1  n ey  are  descn  bed  as   with  some  of  the  spores  attached ; 

consisting  of    two    kinds  of    cells,     ^.«cyBtidlum.-AfterDeSeyue8. 

viz.,  (1)  single  curved,  and  almost  reniform  cells,  which  grow 
out  from  the  sides  of  the  hyphse  ;  they  are  .02  mm.  long  and 
about  .01  mm.  in  diameter,  and  appear  to  be  separated  from 
the  hypha9  from  which  they  grow  by  a  septum  ;  (2)  very  slen- 
der filiform  cells,  which  grow  out  from  beneath  the  former. 
CErsted  saw  (in  two  instances)  a  union  of  these  two  organs. 
He  came  to  the  conclusion  that  the  sporocarp  was  the  result 
of  a  growth  due  to  several  such  unions — i,e,,  that  the  sporo- 
carp was  the  result  not  of  one,  but  of  several  fertilizations. 


♦  '*  Cotnptes  renduB,"  1875. 

f  In  the  work  already  cited  in  the  foot-note  on  p.  323. 


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330  BOTANY. 

For  some  reason  these  observations  haye  fallen  out  of  notice^ 
and  they  still  are  wanting  confirmation.  The  close  resem- 
blance of  these  organs,  as  described,  to  the  sexual  organs  ot 
Feziza,  renders  it  probable  that  they  are  actually  sexual  in 
their  nature. 

429. — More  recently  Reess  has  published  the  results  of 
his  obseryations  upon  Coprinus  stercoraritis.*  He  found 
that  upon  short  lateral  branches  of  the  young  mycelium 
many  minute  bodies  (spermatia)  are  produced  ;  these,  after 
falling  off,  come  in  contact  with  a  thick  three-celled  body 
(carpogonium  ? ),  which  they  are  supposed  to  fertilize. 
Afterward  from  the  basal  cell  numerous  filaments  grow 
out,  and  eventually  give  rise  to  the  sporocarp.f 

(a)  In  tlie  study  of  the  tissaes  of  the  HymenomjceteB  young  and 
perfectly  fresh  specimens  are  the  best ;  where  this  is  impossible  they 
may  be  preserved  in  alcohol,  and  then  studied  at  leisure.  Thin  trans- 
verse sections  of  the  gilis  will  invariably  show  basidia  and  spores. 

(b)  The  genera  of  this  order  differ  not  only  as  to  the  disposition  of 
the  hymenium,but  also  as  to  the  form  of  the  sporocarp.  With  respect 
to  the  latter,  it  is  symmetrical  and  stalked,  as  in  the  common  Mush- 
room, or  unsymmetrical  and  sessile,  as  in  many  species  of  Polyporus. 
The  texture  of  the  sporocarp  also  varies  from  boft  and  deliquescent  to 
hard  and  durable. 

(c)  The  more  common  genera  are  Agaricus,  with  several  hundred 
spt^ies,  Boletus^  Polpporus,  Hydnum,  Stereum,  and  Clavaria, 

(d)  Nearly  related  to  the  Hymenomycetes,  if  not  indeed  to  be  included 
with  them,  are  the  Tkbmellini,  which  are  gelatinous  fungi,  upon  whose 
uneven  surfaces  is  spread  an  hymenial  layer,  composed  of  basidia  re- 
sembling those  of  Hymenomycetes.  Bachs  regards  these  plants  as  con- 
stitutinjj  a  group  related  to,  but  distinct  from,  Hymenomycetes. 

(e)  Many  species  are  edible  and  nutritious.  Agaricus  campestria,  the 
Mushroom,  is  commonly  cultivated.    Dr.  M.  A.  Curtis  found  in  North 

*Dr.  Max  Reess,"  Zur  Befruchtungsvorgang  l>ei  den  Basidiomyceten," 
1876.  Van  Tieghem,  in  "Comptes  rendus,"  1875,  p.  373,  makes  pub- 
lic the  results  of  his  investigations,  which  art*  essentially  the  same  as 
those  of  ReeBS,  but  a  few  months  later  he  withdraws  his  statements  : 
"  Comptes  rendus,"  1875,  p.  877. 

f  It  is  scarcely  necessary  to  refer  to  the  paper  by  W.  G.  Smith  in 
"  Qrevillea,"  1875,  p.  53,  in  which  he  describes  a  fertilization  of  the 
spores  by  spermatozoids  developed  by  the  cystidia.  The  many  other 
evident  errors  in  the  paper  make  the  value  of  his  observations  upon 
the  supposed  organs  of  fertilization  exceedingly  doubtful 


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CHARACEuE,  331 

<!aroliDa  thirty-eight  edible  species  of  Agarieus,  eleven  of  Boletus,  nine 
of  Polyporus,  seven  of  Hydnum,  and  thirteen  of  Clavaria, 

(J)  Polyporitts  Bovomani  of  tbe  Carboniferous  is  the  oldest  known 
member  of  this  order.  In  the  Tertiary  the  modern  genera  LenziUs, 
J*olyporas,  and  Hydnum  are  represented. 


§  V.  Class  Characejs. 

430. — In  this  small  group  of  chlorophyll-bearing  aquatic 
plants  the  sexual  organs,  while  still  preserving  essentially 
the  structure  common  to  other  Carposporeae,  present  con- 
siderable modifications.  The  female  organ  consists  of  a 
'*  central  cell"  or  carpogonium  (Fig.  227,  c),  which  is  the 
terminal  one  of  a  row  of  cells  (a, 
b,  c,  Fig.  227).  From  the  basal 
cellK  there  grow  out  five  elongat- 
^  cells  (d,  dy  Fig.  227),  which 
take  an  upward  direction  and 
surround  the  carpogonium  ;  they; 
cohere  laterally,  so  as  to  form  a 
-complete  covering.      The  top  of  — 

,,       ^  ,       .  1        i.1      1.  F!sr.    227.— Development  of   tbe 

this  enveloping  sheath  becomes   carpogouinm  of  Muua  jiexiu$, 

modified   into  a  projecting  crown     grammatlcf    a,  very^(Mr?y'^«tage*; 

of  five  (or  by  division  ten)  more  ?h.".V.1?%tl"cl?rnSd"^S 

or  less  divergent  cells  (i,  i,  Fig.  e^l!?:!; ASk VtWraT/^SSl 

227  B;  and   c,   Fig.   228,   A),  ^i.  be'-.lD.^.r^'&ir'I^S: 

jPinally,  the  whole  envelope  be-  cipwd  the  cemraceii,<?/ i.i.  ceiis 

•^        .        _  -  \  which  form  a  cr«»wn  npon  the  en- 

comes  twisted,  so  that  each  en-  veiopin«  ceiis.  x  aoo.— After sachs. 
Teloping  cell  passes  spirally  around  the  carpogonium  {A, 
Fig.  228). 

431. — The  male  organ,  or  antheridium,  consists  of  a 
globular  body  composed  externally  of  eight  spherically  tri- 
angular cells,  Ciilled  the  shields,  which  are  united  by  their 
zigzag  margins  (a.  Fig.  228,  A),  From  the  centre  of  each 
shield  there  projects  into  the  cavity  of  the  antheridium  a 
cyhndrical  cell  {manubrium),  and  upon  each  of  these  there 
are  borne  large  numbers  (twenty  to  twenty-five)  of  long 
coiled  and  bent  many-celled  filaments  {b  and  c.  Fig.  229). 
Each  filament  contains  from  one  to  two   hundred  cells. 


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332  BOTAffT. 

which  are  at  first  filled  with  granular  protoplasm ;  after- 
ward eacli  cell  develops  a  single  spirally  coiled  spermato- 
zoid.  When  the  antheridium  is  mature — i.e.,  when  the 
spermatozoids  are  fully  formed — the  shields  separate  from 
each  other,  and  thus  expose  the  filaments  (Fig.  229).  The 
spermatozoids  escape  by  the  rupture  of  the  walls  of  the  fila- 
ment cells  ;  each  consists  of  a  slender  spiral  thread  of  proto- 
plasm^ thicker  at  one  end  than  the  other,  and  provided  at 

the    more   attenuated  ex- 
tremity with  two  very  del- 
icate and  greatly  elongated 
;  cilia  (Fig.    229,   d).     By 

means  of  these  cilia  the 
spermatozoids  movf 
through  the  water  with  a 
spiral  rotary  motion. 
432.— Fertilization  takes 
fi  place  by  the  entrance  of 

spermatozoids  through  the 
orifice  between  the  diverg- 
ing cells  of  the  croTm  ;  they 
come  in  contact  with  the 

FiR.  228.— Beprodnctlve  organs  of  Chora  r^r^ox  nf  tliA  rarnnironium 

ftagUU.     A.  a  ceniral  portion  of  a  leaf,  6,  »P®^  "^   ^^^®  carpogonium, 

with  an  antheridium.  a,  and  a  carpogonlnm,  <<  where  the  cell- wall  is  aD- 
«,  surrounded  by  th»-  spirally  twisted  envelop-        ^^  ^^^^  *'"^  ^^^^  ^*  **"  ***  *r 

Ing  cells  ;  c,  crown  of  five  cells  at  aj.ex;  ^,  parently  absent  ;"  aS  a  re- 
sterile  lateral  leaflets ;/?',  large  lateral  leaf-        ,,         -      ,,.       „^-   „       ^i_ 

let  near  the  fruit; /J^.bracteoles  spring  ng  SUIC     01     iniS     Union,     ine 

from  the  basal  node  of  the  reproductive  or-  envelopiuff  CcUs  bcCOme 
gans.     A  a  young  antheridium,  a,  and   '^^,.,  nj     i.      j  j 

youni;  oirpogonium.  **;  tr.  nodal  cell  of  tiiicker  walleu,  nard,  and 

l»-af;  »/.  iniei-mediaie  cell  betwfenu»  and  the     , ,      ^  i^^^j       #^«^:««.    „ 

ba..al  node  cell  cf  the  antheridium  ;  /.  cavity  dark  -  COlorCd,  lormmg  a 
of  the  interuode  of  the  It-af  ;  ftr,  cortical  cells    j-^^j,^  ^^a  raoicfino'  of\tki\r\(r 

of  ihe  itaf  A  X  about 88 ;  B  x  a40.-After  dense  ana  resisting  coanng 
8*ch«.  ^Q  tijQ  fully  formed  carpo- 

spore  within.  The  seed-like  sporocarp  thus  formed  soon 
separates  itself  from  the  parent  plant  and  falls  to  the  bot- 
tom of  the  water,  where  it  remains  until  the  advent  of  favor- 
able conditions  for  germination. 

433,— In  germination  the  sporocarp  gives  rise  first  to  a 
simple  structure  consisting  of  a  single  row  of  cells  (the  pro- 
embryo),  and  from  this  the  more  complex  sexual  plant  is 
developed  by  the  growth  of  a  lateral  bud-cell.     The  sexual 


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GHARACEJE.  333 

plant  is  composed  of  a  jointed  stem,  which  bears  whorls  of 
leaves  at  regular  intervals.  The  stem  is  one-celled  in  trans- 
verse section,  as  in  Nitella,  or  it  has  a  large  axial  cell,  which 
is  surrounded  by  many  long  narrow  ones,  which  form  a 
cortical  envelope,  as  in  many  species  of  Chara.  In  some 
species  the  stem  and  leaves  become  incrusted  with  lime,  giv- 
ing to  them  a  good  deal  of  hardness  and  brittleness. 

(a)  The  class  is  readily  divisible  into  two  orders — NitellesB  and 
Chare®.* 

Order  Nitelleo. — In  this  order  the  stem  and  leaves  are  always 
naked — ».«.,  not  cor- 
ticated; the  leaves 
are  in  whorls  of 
five  to  eight,  and 
bear  large  leaflets, 
which  are  often 
many  -  celled.  The 
sporocarps  arise  sin- 
gly or  in  clusters  in 
the  forkings  of  the 
leaves,  and  each  has 
a  crown  consisting 
of  two  saperimposed 
whorls  of  five  cells 
each. 

These  delicate 
plants  occur  in 
ponds  and  streams, 
and  are  rarely  more 
than    a   few    centi- 


^unrpm^ 


metres  in  Ijeight.  Y\K.m.-CharafragUU,  a,  an  Isolated  shield,  m,  seen 
1  wo  genera — HueUa   from  within,  with  manaorinm  bearing  the  filaments,  &,  in 

An<1    TfJtivk0lln. fLra    which  the  spermatozoids  are  developed  ;  c,  a  small  portion 

ana  i  w>ypuka  are  ^,  ^^^  ^ ,  ^g^  filaments,  the  spermatozoids  not  shown ;  rf, 
distinguished  by  the  two  free  spermatozoids.  a  and  6  x  60 ;  o  and  d  x  800.— 
position  of  the  anthe-  ^^'  T»»«'«t. 

ridium,  which  is  terminal  upon  the  single  node  of  the  primary  leaf  in 
the  former,  while  in  the  latter  it  is'  lateral,  and  the  primary  leaf  has 
two  or  three  nodes. 
The  species  of  Nitella  (ten  to  fifteen  of  which  are  American)  are  ar- 

*  What  follows  is  mainly  from  a  synopsis  of  the  CharacesB,  furnished 
for  this  work  by  Dr.  T.  F.  Allen,  the  author  of  *'  Characeao  Americanae," 
now  issuing  in  numbers.  Use  has  also  been  made  of  Dr.  B.  D.  Hal- 
sted's  paper  on  the  *'  Cassification  and  Description  of  the  American 
species  of  Characem,"  published  in  Proc,  Boston  Soc.  Nat,  HxH.,  1879, 


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334  BOTANY. 

ranged  under  three  tribes ;  oar  more  common  species  onlj  are  given 
below. 

Tribe  Am — Mbnarthrodaetyla,  with  the  terminal  segments  of  the 
leaves  one-celled. 

N.flexUis,  N,  translueens,  y,  gekUinoaa. 

Tribe  B.—Diarthrodactyla,  with  the  ultimate  segments  of  the 
leaves  two-celled. 

N,  gracUU,  N,  tehuissima. 

Tribe  C. — Potyarthrodactylm,  with  the  ultimate  segments  of  the 
leaves  three  to  six-celled. 

N,  eapillata,  N.  intricata. 

Tlie  genus  Tolypella  contains  about  a  dozen  known  species,  most  of 
which  are  American. 

Order  OharesB. — In  this  order  the  stem  and  leaves  are  sometimes 
naked,  and  sometimes  corticated ;  the  leaves  are  in  whorls  of  six  to 
twelve,  and  their  bracts  or  leaflets  are  always  one-celled.  The  sporo- 
carps  arise  upon  the  upper  side  of  the  leaves,  and  each  has  a  crown  of 
one  whorl  of  five  cells. 

These  plants  resemble  the  Nitelleae  in  size  and  habit.  The  species 
are  separated  into  two  genera,  Lychnothamnus  and  Chara.  The  former 
has  no  representatives  in  America ;  it  may  be  distinguisiied  by  the  an- 
theridia  being  by  the  side  of  the  carpogonia  instead  of  below  them,  as 
is  the  case  in  Chara, 

The  species  of  Chara  are  arranged  under  three  tribes ;  there  are 
about  a  dozen  representatives  in  America,  the  more  important  of  which 
are  here  given. 

Tribe  A. — Aitephanm,  with  no  circle  of  stipules.  No  American 
representative. 

Tribe  S. — HaplostephancB,  with  a  circle  of  stipules  consisting  of  a 
simple  series  of  cells. 

Ch.  eoronata,  Ch,  Ilydropitys. 

Tribe  C. — DiplostephanoB,  with  the  stipular  ring  double. 

Ch,foUida,Ch,fragilU,Ch.gymnopus. 

(b)  The  genus  Chttra  is  a  very  old  one  ;  some  species  occur  in  the  Sec- 
ondary (Jurassic)  strata,  and  in  the  Tertiary  (of  Europe)  they  are  very 
abundant,  no  less  than  thirty-seven  species  being  recorded  by  Schim- 
per.*  According  to  Lesquereuz  f  no  fossil  species  of  Charace®  have 
yet.  been  discovered  in  America,  which  is  a  remarkable  fact,  for  at 
the  present  time  the  plants  of  this  group  are  as  abundant  here  as  in 
Europe,  and  the  sporocarps  possess  great  durability  and  are  likely  to 
be  preserved  as  fossils. 

*  *'  Traits  de  Pal^ntologie  V^g^tale,"  par  W.  Ph.  Schimper,  Paris, 
1869-1874. 

t " Contributions  to  the  Fossil  Flora  of  the  Western  Territories; 
Part  U..  The  Tertiary  Flora,"  by  Leo  Lesquereux.  Washington.  1878. 


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CLASSIFICATION  OF  THALLOPHTTES. 


335 


ABItANOEMBNT  OF  THB  CLASSES  OF  THE  CaBPOFHYTA. 


.?..?. 


.?..?...„> 


VI.  The  OiiASsmoATiON  op  Thallofhytes. 

(1.)  The  claseification  of  the  Thallophytes,  outlined  in  the  preceding 
pages,  is  essentially  that  given  hj  Sachs  in  the  fourth  edition  of  his 
'*  Lehrhuch."  Sachs,  however,  considered  the  Protophyta,  Zygophyta, 
Oophyta,  and  Carpophyta  to  be  Ciaspes,  whereas  in  this  book  they  are 
raised  to  Divisions,  co-ordinate  with  Brjophyta,  Pteridophyta.  and  Pha- 
nerogamia.  It  is  evident,  even  from  the  hasty  examination  sketched  in 
the  preceding  pages,  that  there  are  three  welj-marked  kinds  of  repro- 
ductive apparatus  in  the  Thallophytes,  which  are,  to  a  considerable 
degree,  distinct.  There  are,  of  course,  here  and  there  cases  in  which 
one  kind  merges  into  another,  but  this  is  no  more  than  is  to  be  observed 
in  everything  else  throughout  both  the  vegetable  and  animal  king, 
doms.  After  making  all  due  allowance  for  the  doubtful  cases,  the  fact 
yet  remains  that  there  are  three  kinds  of  reproductive  apparatus  in  the 
Thallophytes,  which  are  as  readily  distinguishable  2A  are  those  of  the 
Cormophyte  Divisions,  Bryophyta,  Pteridophyta,  and  Phanerogamia. 

(2.)  Of  the  differentiation  of  tissues  we  know  less ;  but  enough  is 
known  to  warrant  the  statement  that,  as  in  the  Divisions  of  theCormo. 
phytes,  there  is  a  progressive  increase  in  complexity  as  we  pass  from 


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1 


336  BOTANY. 

the  lower  to  the  higher  ThallophTtea  Thug  the  Zygophytes,  as  a  rule, 
are  single  cells  {Detmidiacea  and  DicUomaeea),  or  rows  of  cells  (Zygne^ 
macecBf  etc),  of  simple  stmctare ;  the  Oophytes  are  generally  single 
cells  of  a  complex  stracture  (Calablatiea),  rows  of  differentiated  cells 
((Edoganieai),  or  even  tissaes,  forming  stractares  which  have,  in  some 
cases,  a  close  approximation  to  stems  and  leaves  {Fueaeea) ;  the  Car- 
poph3rtes  are  all  multicellolar ;  the  lower  ones  are  made  ap  of  rows  of 
cells,  which  are  generally  anited  into  a  plant-body  (sporocarp  of  Aseo- 
mycetea  and  BaHdiomyeetes),  while  in  the  higher  ones  there  are  tissues 
which  form  stems  and  leaves  (some  Floridea  and  Characea). 

(8.)  It  can  scarcely  l>e  doabted,  then,  that  the  three  Thallophyte  groups 
Zygophyta,  Oophyta,  and  Carpophyta,  are  as  much  entitled  to  rank  as 
Divisions  as  are  those  of  the  Gormophytes.  The  Protophyta  constitute 
a  provisional  group,  but  while  it  is  very  likely  that  many  of  the  forms 
now  iucluded  in  it  may  be  placed  elsewhere  when  they  are  better  un- 
derstood, it  is  extremely  improbable  that  all  will  be  thus  disposed  of  ; 
it  seems  more  probable  that  the  group  may  be  preserved,  very  likely  in 
a  modified  form,  as  a  sort  of  primary  Division. 

(4.)  The  arrangement  followed  in  this  book  may  be  made  plainer  by 
the  subjoined  table.  The  Classes  only  (printed  in  small  capitals) 
are  given,  excepting  where,  for  obvions  reasons,  it  is  necessary  to 
particularize  more  closely  (Orders  and  genera  in  lower  case).  The 
groups  on  the  left  are  composed  of  chlorophyll-bearing  plants,  and 
are  regarded  as  the  proper  representatives  of  the  Divisions.  The 
groups  on  the  right  hand  (printed  in  ita/ies)  are  composed  of  plants 
which  are  parasitic  or  saprophytic,  and  which,  as  a  consequence,  show 
more  or  less  of  degradation  in  their  vegetative  parts  ;  the  absence  of 
chlorophyll  here,  as  in  the  case  of  parasitic  Phanerogams,  is  an  accom- 
paniment of  structural  changes  in  the  vegetative  parts  of  the  plant, 
which  are  always  degradational  in  their  nature. 


PROTOPHYTA. 
•    Myxomtcbtes. 


SCHIZOMTCETBS. 

Saeehartmiyeetei  (?). 


CTAKOPHTCE-fi. 

ZYGOPHYTA. 

Pandorina,  etc 

CONJUOATA Muearini. 


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CLA88IFICATI0N  OF  THALLOPHTTEB.  337 

OOPHYTA. 
Volvox,  etc, 

(EDOGOKIKfi. 

O-B'— ' |^.SJ^- 

FnOACBiB. 

CARPOPHYTA. 
O)leoch8ete. 

FLOBlDKiB. 

AacoMTCBTsa. 

Uredin&B  (?). 
UatOaginecB  (?). 

Babidiomycetss, 

Characra. 

It  will  be  instmctiye  to  compare  the  foregoing  witli  other  attempts 
at  an  arraDg^ement  of  the  Thallophytes. 

(5.)  The  arrangement  which  has  long  been  followed,  and  which  is 
still  in  use  in  most  English  books,  is  that  which  divides  the  Thallo- 
phytes  (considered  a  class)  into  three  orders,*  viz., 

1.  Algm,  aquatic  and  chlorophyll-bearing. 

2.  Fungi,  terrestrial,  and  destitute  of  chlorophyll. 

8.  Liehenes,  terrestrial,  and  containing  green  gonidia. 
Berkeley's  arrangementf  differs  from  this  only  in  the  relative  rank  of 
the  groups. 
Alliance  L  Algales  {Alga), 

AllUnce  U.  MyceUdea    { !;riTeit^^2 W 
Algae  have  usually  been  divided  into  three  groups  (sometimes  called 
sub-orders),  as  follows  : 

1.  CMorospermecB,  inclvLdiug  all  the  chlorophyll -bearing  plants  of  the 
Protophyta  and  Zygophyta,  and  all  the  Oophjrta,  excepting  FueacecB. 

2.  Bhodospermea,  nearly  equivalent  to  the  FUyridea. 

8.  MelanogpemucB,  including  the  Fuecusea,  PhceosporecB,  and  some 
other  plants. 

(6.)  Fungi  are  still  arranged  in  most  English  books  in  six  groups 
(caJled  orders,  sub-orders,  or  even  families),  as  follows  4 

1.  AacomycetM,  nearly  as  in  this  book. 

*  See  Hooker's  "  Synopsis  of  the  Classes,  Sub-classes,  Cohorts,  and 
Orders,'  in  the  Elnglish  edition  of  Le  Maout  and  Decaisne's  "  General 
System  of  Botany,"  1872,  p.  1028. 

t  "  Introduction  to  Cryptogamic  Botany,"  1857,  p.  81. 

X  See  Berkeley's"  Introduction,"  already  cited  ;  Berkeley's  " Outlines 
of  British  Funsrology,"  1860;  Cooke's  "  Hand-book  of  British  Fungi," 
1871 ;  Cooke  and  Berkeley's  "  Funs^i,  their  Nature,  Influence,  and 
Uses,"  1874;  and  Fries'  '•  Systema  Mycologicum,"  1821. 


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338  BOTANY. 

2.  PhyaomyceteB,  iDclading  the  Mucorini  and  8aproUgniaee(B, 
8.  Hyphomyeetet,  inclading  Permosporea,  PenieiUium,  and  manx 
imperfect  forms. 

4.  Coniomycetes,  inclading  Uredinem  and  UstUaginem,  and  in  addi- 
tion a  great  number  of  imperfect  stages  of  Ascomyoetes. 

5.  OcuUromycetes,  as  in  this  book,  with  the  addition  of  Myxomff- 
eetes, 

6.  Eymenomyceles,  as  in  this  book,  and  including  the  Trem^Uni, 

De  Bary*  arranged  Fungi  under  four  groups,  as  follows  : ' 

1.  Phycomyoetes. 

SaproUgniaeea,    Perono»porem,    Mucorini, 

2.  Hypodermiss. 

Uredinea.     Uttilaginea. 

8.  Basidiomycetes. 

TremeUini,    Hymenomyeetes,    Oasteromyeetes. 

4.  Ascomycetes. 

Protomyeetes.     Tub&raeea,     Onygenem,     Pyrenomycetes,    Du- 
eomycetes. 

In  both  the  foregoing  arrangements  of  Fungi  the  Lichens  are  omitted* 
they  being  regarded  as  of  a  different  nature. 

(7.)  In  1872  Ck)hn  publishedf  an  outline  of  a  classification  of  the  Cryp- 
togams  in  which  the  old  distinctious  between  Alg»,  Fungi,  and  Lich- 
ens were  abandoned.  He  considered  the  Thallophytes  as  constituting 
a  single  class,  co-ordinate  with  Bryophyta,  Pteridophyta,  and  Phanero- 
gamia,  and  divided  it  into  seven  orders,  and  each  of  these  into  many 
families  ;  the  latter  are  in  most  cases  equivalent  to  what  are  called 
orders  in  this  book.  The  families  in  Roman  contain  clilorophyll,  those 
in  italics  are  chlorophyll-less. 

Glass  ThaUophyta. 

ORDER  L    SCHIZOSPORE^ 

1.  Schizomycetee.  2.  Chroococcacese.  8.  OscillatoriacesB.  4.  Nos. 
tocacee.    6.  Rivulariacete.    6.  ScytonemaoesB. 

ORDER  n.    ZYGOSPORES. 
1.  Diatomace®.    2.  Desmidiaces.    8.  Zygnemace».    4.  MfieartieecR. 

*  In  Streinz :  "  Nomenclator  Funjrorum,"  1861,  p.  722.  and  also  in 
"  Morphologic  und  Physiologic  der  Pilze,  etc.,"  1865,  preface,  p.  6. 

f  Ferdinand  Cohn,  "  Conspectus  familiarum  cryptogamarum  secun- 
dum methodum  naturalum  dispositarum,"  in  "  Hedwigia,"  February, 
1872. 


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CLASSIFICATION  OF  THALLOPHTTES.  339 

ORDER  III.    BASIDIOSPORE^ 
SBcnoN  1.  Htfodbrmla. 
1.   Uredinaeea,    2.   UsHiaginaeea, 

Section  2.  Basidiomtcbtes. 

8.  Tremettace(B.  4.  Agarieaeea  (Hymenomyceies),  5.  Lycoperdacea 
{GhuteramyeeUs), 

ORDER  rV.   ASOOSPORE^ 

1.  Tuberiieea.  2.  Onygenacea,  8.  BrynphaceiB,  4.  SpharioMCB  {Py- 
renomyceU$),    6.  HelveUaee(B,    6.  Lichenes  {excijiding  CoUemticeed), 

ORDER  V.   TETRASPOREJB  (FLORIDE^.) 

1.  BangiaceflB.  2.  Dictyotace®.  8.  Ceramiaceffi.  4.  Nemaliaceae. 
5.  Lemaniace®.  6.  Sphsrococcaceo  7.  Melobeeiaceaa.  8.  Rhodo- 
melace». 

ORDER  VL  ZOOSPORES. 

1.  PalmellaceflB.  2.  Confervace».  8.  Ectocarpeie.  4.  Sphacelari- 
aoes.    5.  Sporochnaceae.    6.  Laminariace®. 

ORDER  Vn.  OOSPORES 

SeCTIOH  1.  LEUCOSPORBiB. 

1.  OhytritUacea,    2.  Per(mosporacea.    8.  SaprolegniaeecB, 

SbCTFON  2.    CHLOROSPOREiB. 

4.  VolvocacesB.  5.  Sipbonacese.  6.  Spbaeropleace®.  7.  (EdogonU 
ace».    8.  ColeocbsetaceeB. 

Section  8.  Phaosporba 

9.  Tilopterideie.    10.  Fncace®. 

(8.)  In  1878  Fiscber  proposed  an  arrangement*  of  tbe  Thallopbytes 
which  in  many  respects  is  like  that  of  Sachs.  Like  the  latter,  Fischer 
diyidea  the  Thallopbyta  (co-ordinate  witb  Cormopbyta)  into  four 
claases,  composed  in  each  case  of  chloropbyll-bearing  and  chlorophyll, 
free  plants,  the  algsB  and  fungi.  Instead,  however,  of  considering  the 
fongi  as  degraded  forms,  he  regards  them  as  constitutin^jf  with  the 
algie  two  parallel  but  entirely  distinct  genetic  lines.  The  Myxomy- 
oetes  he  places  in  a  third  genetic  line,  nearest  to,  but  still  distinct  from, 
tbe  f  nngi. 

»  Given  in  Sachs'  "  Lehrbuch,"  fourth  edition,  p.  248.  Tbe  groups 
given  under  each  class  are  of  very  unequal  value. 


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340  BOTANY. 

THALLOPHTTA. 
(AliOiB.)  (FUNOI.)  MtZOMTCBTBS. 

Class  I. 

Without  sezoal  reprodaction. 
PhyoocbromaoeaB.  SaceharamyceUa, 

Class  n. 

Sexual  reproduction  hj  copulation. 
Diatomes. 
Conjugate®.  Zygomycetes, 

Class  IIL 

Producing  oospores  after  fertilization. 
PalmellaceaB.  Peronosporea. 

SipbonesB.  Saproiegniaeea, 

Confervffi. 
Fucacese. 
Coleocbffitee. 
CbaraceaB. 

Class  IV. 

Producing  a  oomplex  froit-bodj  [sporocarp]  after  fertilliation 
FlorideflB.  Aaeomycetes, 

BcundkmyeeUi 


LiTBRATURB. 

In  the  study  of  the  f ungf  the  following  works  will  be  found  of 
great  service : 

A.  De  Baiy :  "  Morphology  and  Biology  of  the  Fungi,  Mycetozoa, 

and  Bacteria." 
P.  A.  Saccardo:    "Sylloge   Fungorum  omnium  hicusque   cognf- 

torum.** 

George  Winter:  '*Die  Pilze  Deutschlands,  Oesterreichs,  und  der 
Schweiz." 


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CHAPTER    XVIIL 

BRYOPHYTA. 

484. — This  diyision  includes  plants  of  a  much  greater  de- 
gree of  complexity  than  any  of  the  preceding.  In  all  there 
is  a  well-marked  alternation  of  sexual  and  asexual  genera- 
tions. The  first  generation — that  is,  the  one  proceeding 
from  the  spore — bears  the  sexual  organs,  and  hence  it  is 
called  the  sexual  generation.  After  fertilization,  and  as  a 
result  of  it,  there  grows  a  sporocarp,  which  consists  of  a  case 
or  body,  in  which  spores  arise  asexually  ;  hence  this  is  called 
the  asexual  generation.  From  these  spores  the  sexual  gen- 
eration is  again  produced. 

436. — The  production  of  the  sexual  generation  may  take 
place  either  directly  or  indirectly.  In  the  first  a  thallus-like 
structure  is  produced  directly  from  the  germination  of  the 
spore,  as  in  some  of  the  Liverworts  {Anthoceros,  Frullafiia, 
etc.) ;  in  most  Mosses,  however,  there  is  first  produced  from 
the  spore  a  Conferva-like  mass  of  threads,  the  pro-embryo  or 
protonema,  and  upon  this  buds  arise,  which  grow  into  the 
leafy  sexual  generation. 

436. — The  sexual  organs  of  Bryophytes  consist  of  arche- 
gonia  and  antheridia.  The  former  are  flask-shaped  bodies, 
whose  walls  are  composed  of  a  single  layer  of  cells.  In  the 
bottom  of  the  cavity  of  each  archegonium  is  a  naked  mass  of 
protoplasm,  the  germ-cell,  which  is  the  essential  part  of  the 
female  organ.  The  anthendia  are  of  various  shapes ;  but 
they  are  generally  club-shaped,  or  somewhat  spherical,  stalked 
bodies,  whoso  walls,  like  those  of  the  archegonia,  are  com- 
posed of  a  single  layer  of  cells.  The  antheridia  are  filled 
with,  usually,  a  great  number  of  sperm-cells,  each  of  which 
contains  a  single  spirally  coiled  spermatozoid. 


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342  BOTANY. 

437. — Feitilization  takes  place  by  the  spermatozoids  find- 
ing their  way  down  the  neck  of  the  archegoniam  (open  at 
this  time)  and  uniting  their  substance  with  that  of  the  germ- 
cell.  The  first  result  of  fertilization  is  the  formation  of  a 
wall  upon  the  germ-cell,  which  then  begins  to  divide  into 
a  mass  of  cells  by  the  formation  of  diagonal  partitions. 

488. — The  sexual  organs  are  generally  numerous,  and 
they  are  frequently  produced  in  little  clusters  of  several  to- 
gether, surrounded  by  enveloping  leaves  (the  perichmtium), 
thus  forming  a  sort  of  flower.  In  some  species  the  anther- 
idia  and  archegonia  are  in  the  same  flowers  (hermaphrodite), 
while  in  others  they  are  upon  different  parts  of  the  same  plant 
{monoecious),  or  upon  entirely  different  plants  (dioecious), 

439. — The  second,  or  asexual,  generation  is  always  devel- 
oped from  the  fertilized  germ-cell  belonging  to  the  first ;  but 
while  it  is  nourished  by  the  latter,  there  is  no  organic  con- 
nection between  the  sexual  and  the  asexual  generations. 
The  asexual  generation  consists  of  a  spore-case,  or  sporogo- 
nium,  with  a  gretiter  or  less  developed  stalk,  or  seia,  support- 
ing the  former.  The  gpore-case  varies  much  in  form  and 
degree  of  complexity,  being  in  some  Ctises  but  a  globular 
body. tilled  with  spores,  while  in  others  its  structure  is  quite 
complex,  and  difficult  to  understand.  • 

440. — The  spores  are  produced  from  mother-cells,  each  of 
which  gives  rise  by  internal  cell-division  to  four  daughter- 
cells,  the  spores.  The  mature  spores  are  provided  with  a 
double  wall,  the  outer  (exospore)  being  usually  hard  and 
somewhat  roughened,  while  the  inner  (endospore)  is  thin  and 
elastic.  The  interior  of  the  spore  is  composed  of  colorless 
protoplasm,  chlorophyll  granules,  starch,  and  minute  drops 
of  oil.  In  germination  the  endospore  breaks  through  the 
exospore,  and  becomes  prolonged  as  a  narrow  tube,  which  by 
division  gives  rise  to  the  sexual  stage  of  the  plant. 

441. — In  a  portion  of  the  Division  the  plant-body  is  either 
a  true  thallus,  or  a  structure  which  is  best  described  as 
thalloid  in  form  ;  in  all  of  the  Mosses,  however,  and  some  of 
the  Liverworts,  there  is  a  differentiation  into  stem  and  leaf. 

442. — ^No  true  roots  are  found  in  the  Bryophyta,  but  in 
place  of  them  there  are  root-hairs,  consisting  of  single  cells. 


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HEPATICJE.  343 

or  rows  of  cells ;  these  are  attached  to  the  under  surface  of 
the  thallus,  or  to  the  side  of  the  stem,  and  serve  to  support 
and  fix  the  plant,  as  well  as  to  absorb  nutritious  substances 
for  its  sustenance. 

448. — The  tissues  of  Bryophyta  are  much  more  highly 
deyeloped  than  in  the  preceding  divisions ;  the  epidermis  is 
in  many  cases  quite  well  defined,  and  here  for  the  first  time 
true  stomata  make  their  appearance  (paragraph  119,  page  91). 
The  greater  part  of  the  plant-body  is  in  most  cases  composed 
of  a  well-developed  parenchyma,  composed  of  thin-walled 
cells,  which  are  compacted  into  a  true  tissue.  There  is, 
moreover,  a  slight  indication  of  the  development  of  a  fibro- 
vascular  system  in  the  elongated  bundles  of  cells  which  oc- 
cur in  the  leaf  veins  and  the  axial  portions  of  the  stems  of 
some  of  the  species.  The  cells  immediately  beneath  the  epi- 
dermis are  much  thickened  in  some  cases,  so  as  to  form  a 
strengthening  tissue.  This  may  be  regarded  as  a  simple 
kind  of  sclerenchyma, 

444. — The  Bryophytes  are  usually  divided  into  two  classes, 
the  Liverworts  {HepaticcB)  and  the  Mosses  (Musci). 

§  I.   Class  Hepatic^. 

446. — In  this  class  of  plants,  commonly  called  the  Liver- 
worts, the  plant-body  is  for  the  most  part  either  a  true 
thallus  or  a  thalloid  structure.  Even  when  there  is  a  differ- 
entiation into  stem  and  leaves,  it  still  retains  some  of  the 
peculiarities  of  the  thallus ;  thus  in  most  cases  the  plant- 
body  has  two  distinct  and  well-marked  surfaces,  an  upper  or 
dorsal,  and  an  under  or  ventral  one,  the  latter  bearing,  for 
the  most  part,  the  rhizoids,  by  means  of  which  the  plant  is 
fixed  to  the  ground.     Growth  is  always  from  an  apical  cell. 

446. — The  tissues  of  the  Liverworts  are  quite  simple,  and 
even  in  the  leaf-bearing  kinds  there  is  but  little  differentia- 
tion ;  the  leaves,  when  present,  have  no  midrib  or  other  veins, 
but  consist  of  a  simple  plate  of  cells.  The  mode  of  branch- 
ing is  dichotomous  in  the  lower  species — ue.,  those  with  a 
thallus  or  thalloid  plant-body — while  in  those  which  have 
stem  and  leaves  it  is  lateral  and  monopodial. 


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HEPATIC^. 


345 


and  by  the  repeated  division  of  their  apical  cells  produce 
upon  each  a  little  flattened  mass  of  cells^  the  gemma.     These 


Fig.  01.— Vale  organs  of  Marehantla  pdymwnha.  A,  a  portion  of  the  thallas,  t^ 
with  two  ascending  branches  bearing  the  autheriaial  receptacles,  hu.  B,  vertical  sec- 
tion throagh  yoang  antheridlal  receptacle,  hu  ;  a,  anthendium  enclosed  in  a  cavity 
which  has  a  narrow  opening,  o;  t,  portion  of  thallus ;  h^  root-hairs  ;  b,  leaf-like  bod- 
ies seen  in  section.  C,  a  nearly  ripe  antheridiuin^sf,  its  pedicel ;  to,  the  wall, 
two spermatozolds.    "    *  .-    •      -v.. 


Varionsly  magnilled.    2>  x  800.— After  Sachs. 


A 


gemmae,  when  full-grown,  fall  to  the  ground,  and  grow  di- 
rectly into  new  plants.     In  some  cases  the  gemmae  are  much 


Pig.  882.- Developmont  of  the  antheridia  of  Riccia  glauca.    A,  longitudinal  flection 
throagh  the  spex  or  the  thalla<* :  «.  apical  cell  of  the  thallus  :  b,  scale-like  l<'aves,  in 
•ection;  a,  a  very  yonng  antheridinm;  of,  an  older  antheridinm,  surrounded  by  a 
"  thallns  tissue,  w.    B,  a  young  antheridinm,  a,  overarched  by  a  growth  oi 


growth  of  I 
the  thallus. 
meister. 


C^  an  older  antheridium,  in  longitudiuMl  section,    x  500.— After  Hnf. 


simpler  than  those  just  described  ;  in  the  Jungermanniaceae, 
for  example,  they  consist  of  a  few  cells  which  are  spontane- 
ously detached  from  the  tissues  in  the  margins  of  the  leaves. 


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346  BOTANY. 

460. — The  sexual  organs  are  situated  in  depressions  in 
the  upper  side  of  the  thallus,  or  upon  the  sides  or  ends  of 
the  stems,  and  are  surrounded  by  peculiarly  developed  leaves 
{perichcBtium)  in  the  leaf-bearing  forms. 

461. — The  antheridium  is  a  more  or  less  globular — usually 
stalked — body,  which  arises  from  a  single  cell  (hence  mor- 
phologically a  trichome)  by  the  repeated  subdivision  of  its 
terminal  cells.  Its  outer  wall  consists  of  a  single  layer  of 
cells  (C,  Fig.  231,  w)^  and  its  cavity  is  filled  with  a  large 
number  of  sperm-cells,  each  of  which  contains  a  single 
spermatozoid.  The  sperm-cells  escape  by  the  breaking  of 
the  antheridium  wall,  and  in  the  water  in  which  this  always 
takes  place  they  rupture,  and  the  spermatozoids  are  set  free. 
Each  spermatozoid  is  a  spirally  curved  slender  thread  of 


Pw.  888.  Fio.  281 

Pig.  888.— Development  of  the  antherfdla  of  MarehanHa  poiymcrpha,  in  a  section 
of  ayoung  antheridial  disc.  r.  the  growing  anterior  margin  of  tbediK;  from  r  to 
the  left  are  shown  the  antheridla  (a,  a,  a,  afiu  four  etages  of  development;  at  «>,  /m. 
8p,  are  ^bown  the  stages  of  development  of  the  stomata  above  ihe  air  cavities  be- 
tween the  antherfdla.     x  800.— After  Hofmelstcr. 

Fig.  284.—^,  longitudinal  section  of  the  apex  of  the  Ihallnn  of  INecia  giauca.  or, 
arcbegonmm:  e.  germ-cell.  B,  the  unripe  sporogoniam,  sg,  snrroanded  by  the  caljrp- 
tra.  which  still  bears  the  neck  of  the  archegoiilam,  or.  ^  x  660 :  i?  x  80a— After 
Hofmcistcr. 

protoplasm, 'provided  at  the  anterior  end  with  two  long 
cilia  {D,  Fig.  231). 

452. — In  some  cases  the  antheridia  are  developed  singly 
upon  the  upper  surface  of  the  thallus,  as  in  Biccia  (Fig. 
232).  In  this  particular  case  the  antheridium  is  developed 
directly  from  an  epidermal  cell  {A,  Fig.  232,  a),  and  so  is 
at  first  external;   it,   however,   soon  becomes  overarched 


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HEP  A  TIC  jS, 


347 


l)y  the  rapid  growth  of  the  surrounding  tissue  of  the  thallus 
(A,   By    and    C, 
Fig.    232).       In 
other    cases    the 

antheridia  are  de-  I 

veloped   in   great  9 

numbers  upon 
fipecial  branches, 
as  in  Marchantia, 
which  has  a  large 
*'antheridialdisc" 
{A  and  B,  Fig. 
231,  hu),  in  whose 
upper  surface  are 
to  be  found  many 
imbedded  anther- 
idia. That  the  an- 
theridia are  actu- 
ally external  in 
this  case  also,  be- 
coming apparent- 
ly internal  by  the 
growing  up  of  the 
surrounding  tis- 
sues, is  well  shown 
in  Fig.  233.  In 
still  other  cases 
{e.g.,  in  Junger- 
manniacem)  the 
antheridia  are  in 
the  axils  of  the 
leaves,  and  occur 
singly  or  in  groups. 
453.— The  ar- 
chegonium  first 
appears  as  a  simple 
papilla,  composed 
of  a  single  cell, 
which,  by  subdi- 
vision in  va"'ous 


Fij?.  S85.— The  arctaegonla,  and  origin  of  the  sporopro. 
ninm  ot Marchantia  polymorpha.  I.  and  //.,  yonnK  arche- 

fonia  ;  e,  jcerm  celi ;  »,  lowest  cell  of  axial  row  of  celU. 
11.  and  /K.,  the  same  after  the  formation  of  a  central 
canal  by  the  absorption  of  the  axial  row  of  cells  in  the 
neck.  V.y  the  same  when  hiatnre  and  ready  for  fertiliza- 
tion. VI.,  the  ba^e  of  a  fertilized  archeeoniam.  the 
germ-cell,  /,  divided  into  two  culls  by  adia^^onal  partition. 
VII.,  later  stage  of  the  same,  showing  farther  division  of 
the  germ-cell,  /.  and  the  beginning  of  the  growth  of  a 
perianth,  pp.  VIII.,  still  later  stagu  of  the  same,  the 
perianth,  pp,  now  enclosing  the  archegoniam ;  a;,  the 
withered  neck  of  the  archeeoniam.  IX.,  the  anripe  sporo- 
goniam,  enclosed  in  the  old  walls  of  the  archegonium, 
now  called  the  calyptra,  a ;  /.  wall  of  sporogonium  ; 
ai,  the  short,  nndeveloped  stalk  of  the  sporogonium. 
Inside  of  the  sporogoninm  are  the  yoang  elaters  arranged 
radially,  and  between  them  are  the  spores.  /.  to  VIII. 
X  800 ;  IX.  aboat  80.— Alter  Sachs. 

directions,  gives  rise  to  a  more  or  less 


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348  BOTANY. 

flask-shaped  body;  this  in  its  first  state  is  composed  of  a 
layer  of  cells  surrounding  and  enclosing  an  axial  row  of 
cells,  but  by  the  change  of  most  of  the  latter  into  mucilage, 
and  their  consequent  solution,  the  structure  becomes  tubular 
above.  The  lower  cell  of  the  axial  row  is  the  germ -cell  (^, 
Fig.  234 ;  r,  and  c,  e,  e,  Fig.  235) ;  it  is  a  rounded  naked 
mass  of  granular  protoplasm.  In  Anthoceros  the  archego- 
nium  is  very  simple;  a  row  of  cells  perpendicular  to  the 

surface  of  the 
thai  1  us  becomes 
filled  with  proto- 
plasm ;  the  low- 
er develops  into 
a  germ-cell,  and 
.  the  others  dis- 
solve, forming 
thus  a  tubular 
opening  to  the 
germ-cell. 

454.  —  After 
fertilization  the 
germ-cell  divides 
successively  in 
several  direc- 
tions, giving  rise 
to  a  tissue,  which 
undergoes  differ- 

iij?.  286.— ^nMocww  Urf>U.     fo,  th«»  yonnir  tporogonlnm  d^  ^        modifica- 

tnt  vertically  ;  L.  the  iuvolucre,  winch  U  a  portion  of  the  fir^na   in    tho  A\f 

thailua  developed  so  as  to  form  a  kln.lof  sheath  :  c»  o,the  '-l^uo   1"    "'e  Ull- 

columella ;«,  the  spores,    x  160.— Alter  Hofmeibter.  f e rent  Orders  but 

which  becomes  in  every  case  a  sporogonium  (called  in  descrip- 
tive works  a  capsule)  of  some  kind.  In  Riccia  it  is  a  simple 
globular  case  filled  with  spores  ( J9,  Fig.  234,  sg) ;  in  Anthoce- 
ros it  is  an  elongated  body,  with  a  single  circular  layer  of 
spores  (Fig.  236),  while  in  other  cases  its  structure  is  quite 
complex.  In  Marchantia,  the  sporogonium,  when  mature,  is 
a  short-stalked,  rounded  body,  filled  with  spores  and  radially 
placed  thin- walled  cells,  the  elaters,  each  of  which  contains 
one  or  more  spiral  fibres  (/X.,  Fig.  235,  and  Fig.  240) ;  it  is 


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UEPATICjS.  349 

here  surrounded  by  a  perianth,  a  loose  bag-like  sheath,  which 
grows  up  from  below  the  base  of  the  youni;  sporogonium,  at 
length  completely  enclosing  it  ( VII,  and  VII I.  ^  Fig.  235, />/?). 
466. — The  archegonia  of  the  Liverworts  occur  singly,  as 
in  Ricciay  Anthoceros,  etc.,  or  grouped  together,  as  in  Mar- 
chantia,  Jungermanniay  and  their  allies.  In  Marchantia 
they  grow  in  several  clusters  of  four  to  six  upon  the  under 
surface  of  the  spreading  top  (the  fertile  receptacle)  of  a 
special  branch  of  the  thallus  (Fig.  237).     In  many  cases  the 


Pio.  287.  Pio.  238. 

Fig.  287.~Fertile  receptacle  of  Marehantia  polymorpha,  seen  fh>m  below,  ft,  Mb 
•talk,  cariously  grooved  ;  gr,  one  of  the  rays  or  the  star-shaped  receptacle  ;  /,  one  of 
the  sporogonia ;  pc^  pc,  perichietla,  which  surround  several  sporogonla.  x  6.— After 
tktchs. 

Fig.  288.— Plant  of  naffioehUa  a$plenioi(U»,  with  the  bilateral  leafy  axis  below,  p, 
the  perianth  through  whose  top  the  Bporoffoniom  or  capsule  has  pushed ;  a,  an  an- 
ripe  sporogonium ;  o,  a  ripe  sporogonium  split  open  to  permit  the  escape  of  the  spores. 
—After  Prantl. 

sporogonium  is,  even  when  fully  mature,  sessile,  or  nearly  so, 
there  being  but  a  very  short  stalk  developed;  but  in  the 
JungermanniacecB,  when  the  sporogonium  is  ripening,  the 
tissue  at  its  base  increases  rapidly,  and  gives  rise  to  a  long 
slender  stalk,  which  pushes  the  spore-case  through  the  dried- 
up  wall  of  the  old  archegonium,  and  raises  it  to  the  height 
often  of  several  centimetres  (Fig.  238). 

466. — There  are  various  ways  in  which  the  spores  are  set 
free  from  the  ripe  sporogonium  or  capsule.     In  Rivcia  it 


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350 


BOTANY. 


takes  place  simply  by  the  decay  of  the  sporogonium ;  in 
Anthoceros  the  long  sporogonium  splits 
vertically  into  two  long  valves  (Fig. 
239),  while  in  the  greater  part  of  the 
class  it  splits  regularly 
into  a  definite  number 
(four  to  six)  of  recurv- 
ing segments ;  in  the 
latter  the  elaters,  which 
are  present,  doubtless 
aid  in  setting  the 
spores  free.  The  struc- 
and  development  of  the  elaters  are 


Fig.  880.— Plaot  of  Ar^- 
Ihoeerat  kevU.  K.  on  the 
right,  Bporogonia  on- 
opened  ;  K^  on  the  left, 
»poro2onia  opened.'After 

ture 

shown  in  Fig.  240. 


the 


The  following;  are  the  principal  orders  of 
Hepaticse : 

Order  Ricciacesd. — Cons'iBtin^  of  terrestrial  or 
aquatic  annual  plants  of  small  size  ;  the  plant- 
body  is  a  dichotomously  branched  thalloid  stem, 
which  bears  a  row  of  scale-like  leaves  upon  the 
under  side.  The  sexual  organs  occur  sinj^rly  on  the 
upper  side  of  the  stem,  and  the  sessile,  spherical 
sporogouia  (capsules)  are  immersed  in  it  or  sessile 
upon  it ;  the  capsule  breaks  irregularly  upon  the 
decay  of  its  walls  ;  and  there  are  neither  perianth 
nor  elaters. 

Order  Anthocerotead.  —  Terrestrial  annual 
plants  with  an  irregularly  branched  thallus.  The 
sexual  organs  are  imbedded  in  the  upper  surface 
of  the  frond,  and  are  of  very  simple  structure ;  the 
sporogonia  are  long  and  narrow,  and  dehisce  by 
splitting  into  two  valves  ;  perianth  none  ;  and  the 
elaters,  when  present,  imperfect  and  rudimentary. 

Order  Marchantiacesd.  —  Terrestrial  perennial 
plants,  with  a  thick,  creeping,  and  dichotomously 
branched  stem,  furnished  beneath  with  numerous 
scale-like  leaves  and  root-hairs  ;  above,  the  stem  is 
provided  with  a  well-developed  epidermis,  and  pe- 
culiar stomata  of  a  complex  structure,  communi- 
cating with  lozenge-shaped  cavities  (Figs.  78  and 
79,  pp.  91-2).  The  sexual  organs  are  developed  on 
special  erect  branches,  and  they  may  occur  on  the 
same,  or  on  distinct  plants  ;  the  sterile  or  antheridial  branches,  which 


Fig.  240.— Two  ela- 
ters in  different  Bti 
of  development  ' 
one  on  the  leftl»E___ 
to  bean  elongated  cell 
with  no  trace  aa  yet 
of  the  spiral  thicken- 
ing of  its  wall.  By  its 
side  are  i*everal  yoang 
spores.  The  elatcr  on 
the  right  is  mature.  It 
is  composed  of  the  spi- 
rally thickened  por- 
tions of  the  wall,  the 
intervenin/  portions 
having  broken  away. 
A^  A,  are  mature 
spores  magnified.— 
From  Le  Maout  and 
Decaisne. 


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MU8CL  361 

are  sometimes  very  short,  bear  flattened  discs  in  whicli  the  antheridia 
are  immersed ;  the  fertile  or  archegonial  branches  bear  spreading^ 
discs,  upon  the  under  side  of  which  the  dependent  arcliegonia  are  clus- 
tered. The  ripe  sporogonium  (capsule)  is  enclosed  in  a  perianth ;  it 
opens  bj  splittin>;  fiart  way  down  from  the  top  into  several  segments, 
and  contains  two-fibred  eiaters  mixed  with  the  spores. 

MarcharUia  polymorplM^  a  common  species,  is  used  by  quacks  as  a 
medicine. 

Mne/iaTUia  occurs  in  the  Tertiary  (Eocene)  of  Europe,  but  has  not 
been  detected  in  North  America. 

Order  JungermanniaceaB.— Plants  composed  of  a  thallus,  a  thalloid 
stem,  or  a  stem  with  two  or  three  rows  of  leaves  ;  when  there  are  three 
rows  the  third  row  is  ou  the  under  side  (constituting  the  amphigastria). 
The  sexual  organs  are  distributed  mono&ciously  or  diceciously  ;  in  the 
thalloid  species  tliey  occur  much  as  in  the  Marehantittcem ;  in  the 
foliose  forms  the  antheridia  "  are  usually  in  the  axils  of  the  leaves, 
either  siugly  or  in  groups,"  and  the  arche^onia  are  moBt  frequently 
clustered  upon  the  summits  uf  the  shoots,  and  are  generally  concealed 
by  the  leaves.  The  ripe  sporofronium  (capsule),  which  is  usually  long 
stalked,  opens  by  splitting  into  four  parts  from  the  apex  to  the  base  ; 
it  contains  one.  or  two-fibred  eiaters  mixed  with  the  spores.  Many 
species  are  common  on  rocks  and  the  bark  of  trees. 

The  modern  genera  Jungermannia,  Frallania,  and  L'jeunia  were 
represented  in  the  Tertiary  (Miocene). 

§  II.  Class  Musci, 

467. — The  adult  plant-body  in  this  class,  which  includes, 
besides  the  Sphagnums,  all  the  true  Mosses,  is  always  a  leafy 
stem,  which  is  rarely  bilateral.  It  is  fixed  to  the  soil  or  otlier 
substratum  by  means  of  articulated  root-haii-s,  or  rhizoids, 
which  grow  out  from  the  sides  of  the  stem.  The  leaves  are 
sessile,  usually  composed  of  a  single  layer  of  cells,  And  either 
nerveless,  or  traversed  longitudinally  by  a  single  rib,  rarely 
by  two  ;  they  are  arranged  in  two  or  three  straight  or  spirjd 
rows,  and  are  usually  inserted  more  or  less  obliquely  to  the 
stem. 

468. — The  tissues  of  the  Mosses  present  a  considerable 
advance  upon  those  of  the  Liverworts.  In  the  stem  there  is 
usually  a  considerable  thickening  of  the  outer  layer,  or  layers, 
of  cells,  constituting  a  kind  of  imperfect  sclerenchyma.  In 
8ome  cases  {Leucobryum,  Barbula,  etc.)  the  remainder  of 
the  stem  is  composed  of  thin-walled  tissue  (parenchyma). 


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852  BOTANY. 

but  in  others  {Funaria,  Mnium,  Bryum,  etc.)  there  is  an 
axial  bundle  of  very  narrow  thin-walled-cells  ;  in  still  others 
{Atrichum,  Polytrichnm,  etc.)  the  cells  of  the  central  bundle 
are  considerably  thickened,  and  in  the  last-named  genus 
there  are  extra-axial  bundles.  In  a  few  cases  there  have 
been  observed  bundles  of  thin-walled  cells  extending  from 
the  leaves  obliquely  through  the  tissues  of  the  stem  to  the 
central  bundle.  From  the  foregoing  statements  it  cannot 
be  doubted  that  the  Mosses  possess  rudimentary  fibro- vascu- 
lar bundles.  Stomata  resembling  those  of  the  higher  plants 
occur  on  the  capsules  ;  they  are  not  found  upon  the  leaves 
or  stems.     The  stem  always  grows  from  an  apical  cell. 

469. — Mosses  are,  for  the  most  part,  aerial  plants,  growing 
upon  moist  earth  or  rocks,  or  even  upon  the  sides  of  trees, 
a  comparatively  small  number  of  species  being  aquatic ;  they 
range  in  size  from  less  than  a  millimetre  to  many  centimetres 
in  length,  the  most  common  height  being  from  two  to  four 
centimetres.  They  are  all  chlorophyll-bearing  plants,  and  are 
generally  of  a  bright  green  color ;  occasionally,  however,  they 
are  whitish  or  brownish. 

460. — The  sexual  organs  of  Mosses  consist  of  antheridia 
and  archegonia ;  they  are  usually  found  upon  the  end  of  the 
leafy  axis,  and  generally  occur  in  considerable  numbers. 
Most  of  the  species  are  either  monoecious  or  dioecious,  while 
some  are  hermaphrodite.  There  is,  however,  but  little  value 
to  be  attached  to  the  kind  of  inflorescence,  as  it  is  often  dif- 
ferent in  genera  which  are  certainly  near  allies.  Even  in 
the  same  genus  some  of  the  species  may  be  dioecious,  while 
others  are' monoecious  or  hermaphrodite  ;  and  occasionally,  as 
in  the  genus  Brytim,  the  three  kinds  of  inflorescence  are 
found ;  rarely  a  species  is  itself  variable  in  this  respect — 
e.g.,  Bryum  crudtim,  which  is  mostly  hermaphrodite,  but 
sometimes  dioecious. 

461. — The  antheridia  are  generally  club-shaped,  stalked 
bodies  (spherical  in  Sphagnacem),  with  a  wall  composed  of  a 
single  layer  of  cells  enclosing  a  mass  of  sperm-cells,  each  of 
which  contains  a  bi-ciliate,  spirally  coiled,  thread-shaped  sper- 
matozoid  (Fig.  242,  B).  When  the  antheridium  is  mature  its 
wall  ruptures  when  wet,  and  the  sperm-cells  escape  in  a  mass 


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MU8CL  353 

of  mucilage ;  the  walls  of  the  sperm-cells  break,  and  the 
epermatozoids  are  set  free  (Fig.  242).  The  antheridia  are 
frequently  intermingled  with  variously  shaped  hairs  {para* 
physes),  and  about  the  cluster  there  may  be  one  or  more 


Fio.  241.  Pig.  ^42. 

Pig.  841.— Female  reprodnctive  organs  of  a  mo88,  Funa^ia  hygrometrioa.  A,  apex 
of  the  stem  ;  a«  arcbegonia :  6,  leaves.  J?,  archegoniom ;  6,  oase ;  A,  neck  ;  m, 
mouth.    C^  month  of  fertilizea  arcbegonlnm.    A  x  100,  B  X  560.— After  Sachs. 

Fig.  94S.— Male  reproductive  organs  of  the  same  moss.  A^  antheridinm  open  and 
permitting  the  spermatozoids  a  to  escape.  B^  h,  sperm-cell  of  another  moss  {Poly- 
hichum),  with  contained  spermatozoid ;  c,  spermatozoid  free,  with  two  cells  at  the 
pointed  extremity.    A  x  860,  B  x  800.— After  Sachs. 

whorls  of  leaves  or  bi'acts,  giving  to  the  whole  much  of  the 
appearance  of  a  flower  of  the  Phanerogams. 

462. — The  archegonia  are  elongated  flask-shaped  bodies, 
with  a  swelling  base,  and  a  long,  slender  neck  (Fig.  241, 
B).     The  wall  is  composed  of  a  single  layer  of  cells,  except 


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364  BOTANY. 

below,  where  there  are  two  layers.  The  neck  of  the  arche- 
gonium  at  first  contains  an  axial  row  of  cells,  but  these 
become  dissolyed  and  transformed  into  a  mucilaginous  mass 

just  before  the  time  of 
fertilization.  The  germ- 
cell  lies  in  the  lower 
swollen  portion  of  the  ar- 
chegonium  ;  it  consists  of 
a  naked  rounded  mass  of 
protoplasm.  At  the  time 
of  fertilization  the  upper- 
most cells  of  the  neck  of 
the  archegonium  diverge 
from  one  another,  and 
thus  form  an  open  chan- 
nel to  the  germ-cell. 

4e3.-7-Fertilization 
takes  place  in  the  water, 
or  in  the  presence  of  a 
considerable  amount  of 
moisture.  The  spermato- 
zoids,  which  are  produced 
in  great  numbers,  move 
through  the  water  by 
means  of  their  vibratile 
cilia,  and  some  of  them 
find  tlicir  way  down  the 
channels  of  the  archego- 

^i'ti'lBevelapment  of  the  sporogonlnm  ^^^^  ^^^^^  ^^^^J  ^^^^^^  ^^^'^ 

of  l^naHahygrxmuMca.AAon^t^^  SUbstaUCC  with  the  gcrm- 
tion  of  the  archegoniam,  ft,  6,  shortly  after  fer-  i       *     i  • 

tilization  ;  A,  neck  ;  /.  aplciil  portion  of  yoang  cells.  As  a  rCSUlt  of  thlS 
eporogonlam  ;  Z'.  baau  portion  of  young  sporo-  ,  .. 

eoninm.  2?,  vertical  section  of  a  female  flower ;  UniOU,  the  germ-CCU  SUT- 
7,  yoanfif  sporogon  lam  eloneatlng,  and  carrying?  -i      *.     -••       •.'•  i-i 

up  the  remains  of  the  old  Mche|3ninm,o  (bow  rOUUds    itsclf  With  a  Wall 

called  the  calyptra) ;  A,  neck  of  old  archego-  ^*  «^ii„i^„«    ^^A  «r>^,%  «« 

nlum.    C,  a  later  sla^  of  the  same.    In  2?  aiid  01  CelluloSC,  and  SOOU  Un- 

^:^'tS^'T^l!^re.^\tYe.f:^^^^^       ^ergoes  division  in  various 

600;  5  and  C7much  less.-After  Sachs.  directions,  giving  risC  to  a 

many-celled  mass,  the  young  sporogonium  (/,  /,  Fig.  243, 
A).  In  most  Mosses  tiie  young  sporogonium  elongates  rap- 
idly, and  while  its  upper  end  carries  up  the  remains  of 


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MU8CL 


355 


the  old  archegonium  (/*,  Fig.  243,  B  and  (7),  the  lower  eud 
penetrates  into  the  tissues  of  the  leafy  axis  ;  the  upper  end 
develops  into  a  spore-case,  while  the  remainder  becomes  a 
filiform  stalk  (seta)  of  greater  ^ 

or  less  length.  In  the  Sphag- 
nacecBy  however,  the  sporogo- 
nium  does  not  greatly  elongate, 
but,  on  the  contrary,  remains 
quite  short,  while  the  end  of 
the  leafy  axis,  soon  after  the  fer- 
tilization of  the  archegonium, 
elongates  into  a  slender  leafless 
stalk  {pseudopodium)y  which 
caiTies  up  the  developing  sporo- 
goninm  upon  its  upper  expand- 
ed end  (v,  pSy  Fig.  244,  B  and 
C).  Essentially  the  same 
structure  is  found  in  Andrm- 
acecB  and  PhascacecB, 

464.  —  The  ripe  sporogo- 
nium  (capsule,  theca,  or  spore- 
case)  is  of  various  shapes,  but 
generally  more  or  less  cylindri- 
cal or  globose  ;  it  differs  much 
in  its  particular  structure  in 
the  different  orders,  but  in  all     Fie.  244.-Deveiopinent  of  the  sporo- 

'        ,  Konlum  of  SphaqnwH  aeutifolium.    A, 

Certam    internal     cells    become  longitudinal  section  of  a  female  flower: 

,i  n  1  •   V      T     ar,  archegonia ;  cA.  young  pericba;tial 

spore    mother-cells,    which    dl-  lenvee;   y.  upper  leaves  or   the  shoot 

Vide  into  four  daughter-cells,  'ZT^h^T^'^.L^S^^f^TP^] 
the  spores.    The  capsule,  when  ^revi^U^c3"tS^/a"r?^^^^^^ 
ripe,  opens  by  the  falling  off  of  li^Sl^rSXt^i^     tp^rSi'X 

a      terminal     lid      (operculum)  "Poroeonlum.    in  ibe  centre  of  the  spo- 

j^  -'^  '  rogonlnm    is    the  columella  and   the 

(SphagnaceCB  and  BryaceCB),  or  cnrvcd  row  of  spore  mother^sells.     (7, 

.  m  ,  t"!,.  Sp/M(piumtquarromtm.    «9,  ripe  sporo- 

in  a  few  cases   by  splitting  Ver-  gbnlum ;  d,  opercnlam ;  c,  torn  calyp- 

,.      -ii        /AT  \        •       J.1  tra;   ^«,  the  elongated  p(*eadopodium : 

tlCally     (AnarceaceCB)  ;     in    the  cA.  perlcbaetial  leares.    All  magnlfled.-- 

small  order  Phascacece  the  cap-  ^^'Schimper. 
sule  is  indehiscent,  and  the  spores  are  set  free  only  by  its 
decay  or  irregular  rupture.      The  ripe  spores  are  roundish 
or  more  or  less  angled,  and  have  a  roughened  or  granulated 


^l 


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356  BOTANY. 

exospore,  which  is  generally  yellow  in  color.  Internally 
the  spores  contain,  in  addition  to  the  protoplasm,  oil-drops 
and  chlorophyll  granules. 

466. — In  the  germination  of  the  spores,  tlie  exospore  is 
ruptured,  and  the  endospore  protrudes  as  a  tubular  filament, 
which  elongates  by  the  continued  growth  of  an  apical  cell ; 
partitions  form  at  close  intervals,  and  the  threads  branch 
freely,  giving  rise  to  a  green  Conferva-like  mass,  the  pro- 
tonema  (Fig.  245,  B).  In  the  Sphagnacece,  however,  the 
protonema  is  a  flattened  mass,  somewhat  like  the  plant-body 


Fig.  345.— Development  of  Funariahygrometrica.  ul,  eermf nating  pporee  ;  «,  rnp- 
tnrod  exospore  ;  tr,  ir,  younfif  root  hairs— on  the  oppot^ite  side  of  the  spore  Ik  tne 
beginning  of  the  protonema  ;  r,  vacuole  in  a  germinating  spore.  B,  part  of  a  proto- 
nema three  weeks  after  germination  ;  A,  a  primary  shoot  with  brown  walls— from  it 
arise  several  lateral  branches  b.  JT,  a  young  bud  or  rudiment  of  a  leaf-bearing 
axis  ;  w,  a  small  root  hair.    A  X  560  ;  i?  X  70.— After  Sachs. 

of  the  lower  Liverworts.  After  a  greater  or  less  period  of 
vegetation,  there  arise  upon  the  protonema  small  buds,  which 
develop  into  leaf-bearing  axes  (Fig.  245,  B,  K).  These  buds 
originate  from  single  cells,  which  repeatedly  divide  them- 
selves by  diagonal  partitions ;  the  apical  cell  thus  formed 
in  each  case  becomes  the  apical  cell  of  the  bud,  and  the 
new  axis.  The  leafy  axes  thus  formed  sooner  or  later  bear 
the  sexual  organs,  thus  completing  the  round  of  life. 

466. — Mosses  reproduce  themselves  asexually,  sometimes 
in  a  manner  quite  similar  to  that  of  the  Liverworts — e,g,y  in 


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SPUAQNACE^.  357 

Teir aphis  pellucida,  where  the  leafy  axis  frequently  bears 
a  terminal  cup-shaped  receptacle,  containing  many  lenti- 
form  stalked  gemmaB ;  these  separate  spontaneously,  and 
give  rise  to  a  kind  of  protonema,  and  upon  this  buds  after- 
ward arise,  from  which  leafy  axes  are  developed.  Many 
Mosses  reproduce  themselves  by  the  formation  of  a  pro- 
tonema from  the  leaves  and  the  root-hairs,  and  from  buds 
formed  upon  such  a  protonema  new  plants  may  arise.  Even 
the  protonema  is  capable  of  an  asexual  reproduction  of  itself  ; 
sometimes  its  individual  cells  become  rounded,  spontane- 
ously separate  themselves,  become  thicker  walled,  and  then 
remain  inactive  for  a  time ;  they  thus  remind  one  of  the 
conidia  of  some  Thallophytes. 

There  are  four  well-marked  orders  of  Mosses,  as  follows  : 

Order  Sphagnacesd. — The  plants  of  this  order  are  large,  soft,  and 
usnallj  pale  colored ;  they  inhabit  bogs  and  swampy  placet,  and  are 
known  as  the  Peat  Mosses.  The  protonema  is  a  flat  thallus,  or  com- 
posed of  branched  filaments,  accordinulj  as  it  has  developed  upon  a 
solid  substratum  or  in  water ;  the  leafy  axis  is  usually  much  elongated, 
and  as  it  dies  away  below  it  grows  at  the  summit ;  the  leaves  are  usa- 
ally  five-ranked,  and  are  composed  of  two  kinds  of  tissue,  viz.,  (1)  one 
made  up  of  small  chlorophyll -bearing  cells,  and  (2)  one  made  up  of 
large  perforated  cells ;  the  latter  are  usually  filled  with  water,  and  to 
them  is  due  the  well-known  power  possessed  by  the  Peat  Moes'S,  of 
retaining  moisture  for  a  great  length  of  time .  Root-hairs  (rhizoids)  are 
present  only  in  young  plants,  their  place  being  taken  by  the  reflexed 
branches,  which  are  always  abundant.- 

The  inflorescence  is  monoecious  or  dioecious;  the  rounded  (almost 
spherical)  antheridia  occur  singly  by  the  sides  of  the  leaves  of  catkin- 
like branches  (not  axillary,  as  stated  in  some  books)  ;  the  archegonia 
are  developed  upon  the  ends  of  certain  branches  (A,  Fig.  244).  The 
ripe  sporogonium  (capsule  or  spore-case)  is  globose,  or  nearly  so  ;  its  seta 
is  short,  but  it  is  borne  upon  a  more  or  less  elongated  pseudopodium, 
which  resembles  a  seta.  The  old  archegonium  (calyptra)  is  ruptured 
irregularly  by  the  g^wing  sporogonium,  and  forms  only  a  very  imper- 
fect cap  to  the  spore-case.  In  the  development  of  the  spores  the  cells  of 
a  layer  parallel  to  the  surface  of  the  upper  half  of  the  capsule  become 
modified  as  spore  mother-cells  (j?.  Fig.  244).  At  maturity  a  circular 
portion  of  the  apex  of  the  capsule  spontaneously  separates  as  a  lid 
(opereulum),  and  allows  the  spores  to  escape  (C,  Fig.  244,  d). 

The  order  contains  but  a  single  genus.  Sphagnum,  represented  in 
the  United  States  by  twenty-seven  species.  These  are  of  some  eco- 
nomic account,  as  they  furnish  a  most  excellent  material  for  "  pack- 
hig"  in  the  transportation  of  living  pln-nts. 


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358  BOTANY. 

The  genus  Sphagnum  was  represented  in  the  Tertiary  (Miocene)  of 
Europe. 

Order  AndrsBaceaB. — In  this  small  order  the  little  plants  of  which. 
it  is  composed  have  a  short-stalked  sporogonium,  raised  upon  a  pseudo- 
podium,  as  in  the  8phagnace<B  ;  the  sporogonium  contains  a  layer  of 
spore-forming  tissue,  disposed  as  in  the  preceding  order ;  but  the  ripe 
capsule  opens  by  splitting  into  four  lon^tudinal  valves,  in  this  remind- 
in  ir  one  of  the  JungermanniacecB.  In  the  growth  of  the  sporogonium 
the  old  archegonium  is  torn  away  at  its  base,  and  carried  up  as  a  cap 

(calypira),  which  covers  the  apex  of 
the  capsule. 

The   principal  genus  is  Andraa^ 

represented  in  the  United  States  by 

?  a  f^w  alpine  or  sulMilpine  species  of 

brownish  or    blackish    rock  -  loving^ 

Mosses. 

Order  Phascacess.— These  small 
Mosses  are  peculiar  in  having  but 
a  little  development  of  leafy  axis,  and 
in  their  pfrsistent  protonema.  The 
sporogonium  is  short-stalked,  or  seeu 
sile,  and  the  pseudopodium  is  very 
short,  or  entirely  wanting.  The 
spores  are,  in  the  simplest  ^enns  (Ar- 
cliidium),  developed  from  a  single 
mother-cell,  while  in  the  higher  ones 
'  they  develop  from  a  layer  of  mother- 

T^.m.-F«»aHahv(nvmeMca.    A,  S!!}^'  '"«<=}'  *"  }''J^?    "«*   ""'f 
a  yoan?  leafy  plant,  a,  with  (>porogo-  The  capsule  is  mdehiscent,  and  the 
nium  Kt  11  covered  with  the  calypira,  o.  annr*»a  ara  RAt  fi-i-A  nnlv  hv  Uj*  HArwv 
A  leafy  plant,  g,  with  nearly  npe  bpo-  spof^s  are  set  tree  only  oy  its  aecay. 
rogonium, /;  c,  the  calypira;  «.  seta.  The  old  archegonium  persists  as  a 
C,  looffitudinal  section  of  a  capsnle ;  «„i„«*^   ywx«-o.-;««.  «v.<%  «»»o.,1a 
Ctf.  columella;  d,  operculum  6r  lid,  calyptra  covermg  the  capsule, 
which  will  Reparate  from  the  remainder      The  principal  genera  are  Archidi-- 
of  the  capsule  at  a :  p,  peristome ;  «,  n^  j    r>       s.  •  mi 

spore-beaVinK  layer  ;/C  air  cavity  surl  ^^i,  Phftscum,  and  Bruchva.  The 
rounding  the  columella,  and  crossed  by  species  are  terrestrial,  and  many  are 
confervoid  filaments ;   U  inferior  con-    '^        ,  •' 

nection  of  the  columella  with  the  tissues  annuals. 

of  the  capsule.  ^  and  2?  slightly  mng-  i^  the  Tertiary  (Miocene)  of  Eu- 
nifled  ;    V  about  40  diameters.— After  .      ..  .         -   ^, 

Sachs.  rope  a  fossil  species  of  Fhascum  has 

been  found. 

Order  Bryacesd.  —  The  plants  of  this  order  constitute  the  true 
Mosses.  They  are  usually  bright  green  (in  a  few  genera  brownish), 
and  in  the  great  majority  of  instances  live  upon  moist  ground  and 
rocks,  or  upon  the  bark  of  trees ;  in  a  comparatively  small  number 
of  cases  the  species  live  in  the  water. 

In  the  development  of  their  tissues  and  the  complex  structure  of 
their  sporo^onia  the  Bryacese  clearly  stand  at  the  head  of  the  Bryo- 
phyte  Division.    The  tissues,  as  indicated  above  (paragraph  458),  attain 


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BRYACEJS. 


359 


in  some  cases  a  development  which  foreshadows  the  differentiation  of 
tlie  Btem  into  the  epidermal,  fibro- vascular,  and  f  andamontal  systems  of 
tie  higher  plants.  In  Folytriehum,  for  example,  there  can  be  no  doubt 
that  the  axial  and  extra^xial  bundles  of  elongated  cells  with  thickened 
walls  found  in  the  stem  represent  the  fibro-vascular  bundles  of  the 
Pteridophytes  and  Phanerogams  ;  the  bundles 
of  elongated  thin- walled  cells  which  pass 
downward  through  the  stem  from  the  base  of 
the  leaf,  in  Spiaclmum,  must  also  be  regarded 
as  representing  rudimentary  foliar  bundles. 

While  these  higher  Mosses  cannot  properly 
be  classed  with  vascular  plants,  their  tissues 
in  some  cases  reach  so  high  a  development  as 
to  show  that  there  is  no  abrupt  change  in  pass- 
ing from  the  so-called  non-vascular  plants  to 
the  vascular  ones. 

The  inflorescence  of  Bryaceae  is  hermaphro- 
dite, monoecious,  or  dioecious.    The  sexual  or- 


Fie.  847.— Two  capsules 
of  Bryum  arffenUum.  The 
one  on  the  left  ie  still  per- 
fect ;  at  its  apex  i«  ahown 


gans  are  situated  on  the  apex  of  the  main  the  lid  or  operculmn;  the 
stem  (Acrocarpae),  or  of  short  lateral  branches  ftS^operc^um,  expJ«ine  the 
(Pleurocarpae).  The  sporogonium.  in  its  de-  ^^^^"^^  ^  *  hlfj  °*^ 
velopment,  carries  up  the  old  arche^onium  as 

a  calyptra,  which  quickly  falls  away  in  some  genera  {e.g.,  Bryum, 
Bartramia,  etc.),  while  in  others  (e.g.,  Polytrichum,  Pogonatum^  etc.)  it 
persists  as  a  closely  fittins:  covering  of  the  capsule  ;  between  these 
two  extremes  there  are  all  gradations. 

The  sporogonium  is  usually  long  stalked  (Fig. 
246,  B),  The  capsule  is  generally  more  or  less 
ovoid  or  cylindrical.  It  is  at  first  composed  of  pa- 
renchymatous tissue,  which  entirely  fills  up  its 
interior ;  as  it  enlarges,  however,  an  annular  in- 
tercellular air  cavity  forms,  separating  a  cylin- 
drical axial  portion  from  the  outer  portion,  which 
forms  the  wall  of  the  capsule.  The  axial  cylin- 
der remains  in  connection  with  the  remainder 
Fie  848— Ad  leal  ®^  *^'®  capsule  at  its  top  and  bottom  (<,  Fig.  246, 
wit  of  the  capsnle  of  6'),  and  it  is,  moreover,  slightly  connected  with 
a^^l'howi^^  the  capsule  walls  by  chlorophyll-bearing  confer, 
double  peristome.  The  void  filaments,  which  pass  across  the  air  cavity, 
of  ^tL^S^the  i^cr  o?  '^''®  rather  dense  tissues  below  and  surrounding 
dtto.  Magnified.  the  air  cavity  in  the  immature  capsule  are  com- 

posed of  chlorophyll-bearing  cells,  and  the  epidermis  covering  these 
portions  is  supplied  with  stomata.  The  spores  are  developed  from  a 
layer  of  cells  (the  third  or  fourth  from  the  outside)  in  the  axial  cylinder 
(<,  Fig.  246,  C)  ;  and  each  cell  of  the  spore-bearing  layer  produces  four 
spores.     The  portion  of  the  axial  cylinder  within  the  spore-bearing 


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360  BOTANY. 

layer  is  called  the  columella  (<;,  c\  Fig.  246,  C\  wliile  the  two  or  three 
layers  of  cells  exterior  to  it  constitate  the  spore-sac. 

In  all  the  meml>ers  of  this  order,  the  capsule,  when  ripe,  opens  bj  the 
falling  awaj  of  a  lid  (opercvlum),  which  is  composed  for  the  most  part 
of  the  epidermis  covering  the  apical  portion  (Fig.  247).  In  most  of  the 
genera,  wlien  the  operculum  falls  off,  one  or  two  rows  of  teeth  (the 
peristome)  are  exposed,  surrounding  the  opening  of  the  capsule  (Fi^c. 
248).  These  teeth,  wliich  are  always  some  multiple  of  four  (4,  8, 16, 
82,  or  64),  are  in  most  cases  formed  respectively  of  the  thickened  outer 
and  inner  walls  of  rows  of  cells  which  lie  beneath  and  parallel  to  the 
wall  of  the  operculum,  and  converge  toward  its  centre.  Each  tooth 
is  thus  made  up  of  parts  of  several  cells,  and  the  transverse  lines  seen 
upon  it  are  the  thickened  transverse  walls  which  formerly  separated 
the  original  cell  cavities. 

The  peristome  of  Polytrichum  and  its  allies  is  composed  of  bundles 
of  thickeued  cells,  hence  they  are  much  firmer  than  in  those  genera  in 
which  they  are  made  of  fragments  of  cell  membranes. 

The  Bryaceae  include  many  genera,  which  are  widely  distributed 
throughout  the  world.  The  genera  arrange  themselves  under  two 
groups  (sub-orders),  according  as  the  sporogonia  are  terminal  or 
lateral,  with  reference  to  the  main  axis  ;  the  first  constitute  the  Aero- 
earpce,  including  FunaHa,  Bryum,  Mtiium^  PolytrWium^  etc.  ;  those 
with  lateral  sporogonia  constitute  the  Pleurocarpa^  and  include  FonU- 
noLiSf  Climadum,  Hypnum,  etc. 

In  the  Tertiary  of  Europe  the  order  is  represented  by  an  Eocene  spe- 
cies of  Hfuscitea,  and  Miocene  species  of  the  modern  genera  FontinalU, 
Bicranum,  Barbvla,  Polytrichum,  Hypnum,  etc.  A  single  si>ecie8  of 
Hypnum  from  the  Tertiary  of  Colorado  is  the  only  American  fossil  of 
this  order  yet  dietected. 


The  most  valuable  systematic  works  for  the  student  of  the  Brjo- 
phytes  of  this  country  are  "  Musci  and  Hepaticse  of  the  Eastern  United 
States,"  by  W.  8.  Sullivant,  1871;  "  Icones  Muscorum."  by  the  same 
author,  1864-74 ;  and  "Catalogue  of  Pacific  Coast  Mosses,*'  by  L.  Les- 
quereux,  1868;  "Manual of  the  Mosses  of , North  America,"  by  Leo 
Lesquereux  and  Thomas  P.  James,  1884;  "Descriptive  Catalo^^ue  of 
the  North  American  Heputicse  North  of  Mexico^"  by  L.  M.  Under- 
wood, 1884. 


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CHAPTER    XIX. 

PTERIDOPHYTA. 

467. — ^The  plants  of  this  Division  constitute  the  so-called 
Vascular  Cryptogams.  They  present  an  alternation  of  sexual 
and  asexual  generations,  much  as  in  the  Byrophytes,  but  in 
the  higher  orders  it  shows  signs  of  disappearing.  The  first 
generation  proceeds  directly  from  the  germination  of  the 
epore  ;  it  is  made  up  of  simple  tissues,  and  is  usually  short- 
lived ;  it  bears  the  sexual  organs,  and  hence  is  called  the 
sexual  generation.  The  second  generation,  which  results 
from  the  fertilization  of  a  germ-cell  developed  upon  the 
preceding  one,  is  long-lived,  and  made  up  in  most  cases 
of  tissues  of  a  high  order,  and  the  plant-body  is  differen- 
tiated into  root,  stem,  and  leaves  ;  upon  this  second  genera- 
tion spores  arise  asexually  year  after  year,  and  from  these 
spores  the  sexual  generation  is  again  produced. 

468. — The  sexual  generation,  called  the  Prothallium,  is 
generally  a  flattened  thallus-like  growth,  somewhat  resem- 
bling the  plant-body  of  the  lower  Bryophytes.  It  is  always 
small,  and  composed  throughout  of  parenchyma  disposed  in 
one,  or  at  most  a  few  layers  ;  on  its  under  surface  it  generally 
produces  root-hairs  (rhizoids),  which  serve  to  fix  it  to  the 
ground,  and  doubtless  also  serve  as  organs  of  nutrition. 
The  cells  of  the  prothallium  are  in  most  cases  richly  sup- 
plied with  chlorophyll,  by  means  of  which  they  elaborate 
material  for  its  growth. 

469. — When  the  prothallia  have  become  sufficiently  large, 
they  develop  the  sexual  organs,  the  antheridia  and  arche- 
gonia.  These  are  formed  in  essentially  the  same  manner  as 
they  are  in  the  two  lower  orders  of  Hepaticae  {Ricciaceo  and 
Anthocernfew),     They  are  more  or  less  imbedded  in  the  sur- 


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362  BOTANY. 

face  of  the  prothallium,  and  consist  of  masses  of  cells,  enclos- 
ing in  each  case  a  single  cell,  which  develops  into  one  germ- 
cell  (in  the  archegonia),  or  a  number  of  sj)erm-cells  (in  the 
antheridia).  The  sperm-cells  produce  spirally  coiled  sperma- 
tozoids,  which  fertilize  the  germ-cell  by  passing  down  the 
canal  in  the  neck  of  each  archegonium.  In  many  of  the 
plants  of  this  division  there  is  a  strong  tendency  toward 
dioBciousness  in  the  prothallia,  and  in  the  higher  genera  it 
becomes  the  invariable  rule. 

470. — The  result  of  fertilization  is  the  formation  of  a 
young  plant,  by  the  growth  and  successive  division  of  the 
fertilized  cell.  In  its  first  stages  the  new  plant  is  usually 
quite  simple,  but  it  soon  becomes,  in  the  greater  part  of  the 
Division,  a  leafy  plant  with  highly  developed  tissues.  After 
a  greater  or  less  period  of  vegetation  the  new  plant  produces 
spores  by  the  internal  cell-division  of  certain  mother-cells, 
each  of  the  latter  producing  four  spores.  The  particular 
structure  of  the  spore-bearing  organs  and  the  place  of  their 
appearance  are  quite  different  in  the  different  classes.  In 
many  cases  they  are  produced  upon  the  surface  of  the 
ordinary  green  leaves,  in  other  cases  upon  modified  leaves, 
while  in  still  others  upon  the  bases  of  the  leaves,  in  their 
axils.  The  spores  are  in  most  cases  of  one  kind,  but  in 
certain  genera  there  are  large  spores  (macrospores),  and  small 
ones  (microspores). 

471. — ^True  roots  first  make  their  appearance  in  this 
division.  A  root  is  developed  upon  the  young  plant,  but 
this  never  attains  a  great  size,  and  others  form  in  acropetal 
order  upon  the  stem,  and  even  occasionally  upon  the  leaves. 

472. — In  the  Pteridophytes  the  three  tissue  systems — epi- 
dermal, fibro-vascular,  and  fundamental — attain  a  good  de- 
gree of  development.  The  epidermis  is  distinct,  and  con- 
tains stomata  similar  in  form  and  position  to  those  of  the 
Phanerogams,  In  many  cases  there  is  a  strong  development 
of  trichomes,  as  in  the  Ferns,  where  the  young  leaves  are 
usually  densely  covered  with  scurfy  hairs.  The  fibro-vascu- 
lar bundles  are  always  closed,  and  generally  are  what  De 
Bary  calls  concentric  bundles ;  in  Mi «  "Rquisetinae,  however, 
collateral  bundles  occur,  and  t      ^g|.  4inaB  radial  bundles. 


EqUISETINJS.  363 

The  bundles  vary  considerably  as  to  the  tissues  they  contain, 
but  they  generally  possess  tracheary  and  sieve  tissues  ;  the 
iormer  is  usually  well-developed  as  spiral,  scalariform,  or 
pitted.  Sieve  tissue  is,  as  a  rule,  not  so  well  developed  as 
the  former,  consisting  for  the  most  part  of  thin-walled, 
-elongated  cells,  in  which  the  characteristic  sieves  are  less 
regularly  formed.  Fibrous  tissue  occurs  only  to  a  limited 
extent  as  a  constituent  of  the  fibro- vascular  bundles.  Paren- 
<3hyma  is  also  found  in  them,  but,  like  the  former,  it  is 
usually  not  abundant.  The  fundamental  system  of  tissues 
includes  various  forms  of  parenchyma  and  sclerenchyma ; 
the  latter,  however,  is  frequently  wanting.  CoUenchyma  and 
laticiferous  tissue  are  not  found  in  the  greater  part  of  the 
Division  ;  but  the  former  occurs  in  Marattiace«.  in  which  or- 
der, according  to  Sachs'  observations,  there  are  also  indica- 
tions of  a  rudimentary  laticiferous  tissue. 

§  I.   Class  Equisetin^. 

478. — In  the  plants  of  this  class  the  plant-body  (of  the 
asexual  generation)  consists  of  a  hollow  elongated  and  jointed 
axis,  bearing  upon  each  node  a  whorl  of  narrow  united  leaves, 
which  form  a  close  sheath  («,  Fig.  249) ;  the  stem  is  always 
^ooved  or  striate,  and  is  usually  rough  and  hard  from  the 
large  amount  of  silica  deposited  in  the  epideimis.  The 
branches  arise  by  the  side  of  the  axils  of  the  leaves  consti- 
tuting the  sheaths,  and  consequently  they  are  in  whorls. 
Both  the  main  axis  and  the  branches  are  in  most  cases  richly 
supplied  with  chlorophyll-bearing  parenchyma ;  in  some  of 
the  species  (c.^r.,  Equisetum  Telmateia  and  E,  arvense)  the 
fitems  which  bear  the  spores  are  destitute  of  chlorophyll. 
All  the  species  develop  numerous  colorless  branching  under- 
ground stems,  which  bear  roots  and  rudimentary  sheaths, 
and  which  each  year  send  up  the  vegetating  and  spore- 
bearing  stems.    Both  root  and  stem  grow  from  an  apical  celL 

474. — In  common  with  most  members  of  th^'s  division, 
the  Equisetinae  are  perennial  plants.  In  some  species  the 
underground  portions  only  persist,  the  aerial  stems  dying  at 
the  end  of  each  year,  as  is  the  case  in  E,  Telmaleia,  E,  arvense. 


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364  BOTANY. 

E.  Bylvaticurtiy  E.  Umosum,  and  some  other  species.  In 
other  species^  as  E,  hyemaUy  E.  IcBvigatuniy  the  aerial  stems 
also  persist;  the  latter  are  hence  known  as  perennial- 
stemmed. 

475. — The  prothallia  are  irregularly  branched  thallus-like 
growths,   composed  of  chlorophyll-bearing  parenchymatous 
cells  arranged  in  one  or  more  layers.     Upon  the  under  side 
they  bear  root-hairs,  which  fix  them  to  the  ground.    They 
are  usually  small  in  size,  ranging  from  two  or  three  to  ten  or 
twelve  mm.  in  length.     In  most  species  the  prothallia  are 
dioecious,   bearing  but  one  kind  of 
sexual  organ  upon  each,  and  in  such 
cases  it  always  happens  that  those 
which  bear  the  antheridia  are  much 
smaller  than  those  which  bear  arche- 
gonia.     Both   kinds  live  but  for  a 
short  time,  the  whole  period  of  their 
existence  usually  not  extending  be- 
yond a  few  months ;  the  male  pro- 
thallia appear  to  endure  for  a  some- 
what shorter  period  than  those  which 
bear  archegonia. 
Fig.  240.-Portion  of  the  up-       476. — The  antheridia  occur  upon 
ttX.r^\i^;!Trint.  the  ends  or  margins  of  the  prothal- 
lf^tir^^l:'t.i^'^c^.  lia;    they  ai-ise  from  the  repeated 
r?nil2dS*St>StVtheiX^  division  of    a    marginal  cell,   thus 
arate  apices  (teetii) ;  a,  a',  a",  forming  an  inner  mass  of  cells  rich 

basal     internodes     of     lateral    .  .       ,  ^  .         , 

branches.— After  Sachs.  in  protoplasm,  and  a  covei'ing  layer 

{an\  Fig.  250,  A),  By  the  continued  division  of  the  inner 
cells  100  to  150  cubical  cells  are  formed,  each  of  which  con- 
tains a  single  sperm-cell ;  somewhat  later  the  walls  of  the 
cubical  cells  dissolve,  and  the  sperm-cells  become  free  in  the 
antheridial  cavity,  from  which  they  are  soon  allowed  to  es- 
cape by  the  separation  of  the  apical  cells  of  the  enveloping^ 
layer  {an.  Fig.,  250,  A),  At  this  time  each  sperm-cell  con- 
tains a  spermatozoid,  which  soon  escapes  by  the  rupture  of 
the  cell-wall.  Each  spermatozoid  is  a  thick,  spirally  coiled 
filament  of  protoplasm,  tapering  anteriorly,  where  it  is  pro- 
vided with  numerous  cilia,  which  give  it  motility. 


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EqUISETIN^,  365 

477. — The  archegonia  arise  upon  the  anterior  edge  of  the 
prothallium,  from  the  division  of  single  cells.  The  mother- 
cell  of  the  archegonium  undergoes  several  divisions,  result 
ing  in  the  formation  of  a  germ-cell,  surrounded  by  one  or 
more  layers  of  cells.  The  germ-cell  lies  at  a  considerable 
depth  beneath  the  general  surface  of  the  prothallium,  above 


Fig.  SSO.— il,  fragment  of  a  prothallinm  of  EqnUetum  limosum  (In  the  middle  of 
July) ;  a,  an  apical  cell  of  a  growing  point ;  an,  a  ripe  antheridiiim,  with  eecaping 
aperm-celle  ;  an^  a  young  antheridinm.  B,  longitudinal  section  of  an  archegonium 
of  EquUeium  arvenie  immediately  after  the  opening  of  its  apex,  showing  the  germ- 
cell  in  the  cavity  below,  surrounded  by  the  parenchyma  of  the  j>rothallium.  C,  longi- 
todinal  section  of  the  germ-cell,  or  rudimentary  embryo,  of  £.  arvenM^  shortly  after 
fertilization  ;  it  is  seen  to  be  already  divided  into  four  parts,  and  the  whole  is  sur- 
rounded by  the  parenchyma  of  the  prothallium.  ^  X  200 ;  ^  and  C  X  800.— After 
Hofmeister. 

which  the  surrounding  tissue  of  the  archegonium  is  pro- 
longed into  a  four-sided  tube.  At  the  period  of  maturity  of 
the  archegonium,  the  projecting  cells  diverge  from  each 
other,  and  form  an  open  channel  to  the  germ-cell  {B,  Fig. 
250). 
478. — After  fertilization  the  germ-cell  undergoes  division 


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366  BOTANY. 

into  four  cells  (C,  Fig.  250),  and  from  these  the  young  plant 
of  the  asexual  generation  is  developed.  The  young  plant  is 
quite  simple,  having  small  internodes,  bearing  sheaths  which 

contain  but  three  leaves  ;  lar- 
ger shoots  soon  arise,  with  lar- 
2  ger  internodes  and  sheaths  hav- 

ing more  leaves,  and  these  are 
followed  by  others  still  larger, 
B  until  at  last  the  full   size  is 

^  reached. 

V^g^  479.  —  The   spores   of    the 

^y^B^^B/  EquisetinsB  are  produced  either 

^^^^P  u}X)n  the  ordinary  green  stems, 

^^^  as  in  Equisettim  Umosum  and 

^flft  E,  hyemaUy  or  upon  colorless 

hW^^  or  brownish  stems,  which  de- 

WJw^^  velop  early,  and,  after  bearing 

w^  the  spores,  die  and  disappear, 

as   in    E.    Telmateia  and  E, 
^        A  arvense.      The  sporangia  are 

^^Stg  developed    upon     modided 

^^^g  leaves,  upon  the  ends  of   the 

stems.  The  spore  -  bearing 
leaves,  like  the  ordinary  ones, 
are  in  whorls ;  each  leaf  is, 
however,  peltate  in  form,  and 
bonie  upon  a  short  stalk  (*/, 
Fig.  251,  B).  These  peltate 
leaves  (usuallv  called  the  pel- 
np^^r>?Aof^fmne^  tatc  scales)  are  collected  into 

SSmTveTlt^rnui^^^^^^^^^^  cone-shaped   clusters,   and  by 

S?et&'^'^iut;1SS^;Si^^^^^  ^l^^ir    °^"^^al    pressure    each 

been  cut  off ;  «,  i»ectioii  of  the  rachis  of  gcalc  bcCOmCS  morC  Or  IcSS 
the  Fpike.     B,   peltate   Bcales,   «, «.  in 

various   poeiUons    (Plightlv  magnified) ;  hCXagOUal    lU    OUtllUe.        Upon 

«9, the  sporangia  borne  on  the  under  side  .it  -  •  i, 

of  the  scales  ;  at,  t>t,  the  pediceU  of  the  the  UUdcr  SUrfaCC  of  Cacll  SCale 

8calet».— After  Sachs.  ,1  •        /j        i.         •  i. 

there  arise  five  to  nine  or  ten 
cellular  masses,  which  enlarge  and  become  sac-shaped  spo- 
rangia ;  certain  inner  cells  become  spore  mother-cells,  and 
from  each  of  these  four  spherical  spores  are  produced.     The 


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EqUISEXm^,  367 

sporangia,  when  mature,  appear  as  nearly  cylindrical  sacs 
attached  by  one  end  to  the  under  surfaces  of  the  peltate 
scales  (sg^  Fig.  251,  By,  they  open  at  maturity  by  a  slit  along 
the  inner  face — i.e.,  the  side  next  to  the  pedicel  of  the  pel- 
tate scale. 

480. — In  their  development  the  spores  acquire  three  con- 
centric coats,  and  as  they  approach  maturity  the  outer  one, 
which  has  previously  become  spirally  thickened,  splits  from 
two  opposite  points  into  four  narrow  spiral  filaments,  which 
are  united  with  one  another  and  the  spore  at  a  common 
point.  These  filaments  are  hygroscopic,  and  they  roll  and 
unroll  with  the  slightest  changes  in  the  moisture  of  the  air : 
when  moistened  they  wrap  tightly  around  the  spore,  but 
w^hen  dry  they  unroll  and  become  more  or  less  reflexed.  By 
the  changes  of  position  which  they  undergo,  they  move  the 
spores  very  considerably,  and  are  doubtless  useful  in  empty- 
ing the  sporangia  after  dehiscence — hence  they  have  been 
called  Elaters. 

481. — The  spores  germinate  soon  after  falling  upon  water 
or  moist  earth  ;  they  first  enlarge,  and  then  divide  by  a  par- 
tition into  two  paits  of  unequal  size,  the  larger  of  which 
contains  chlorophyll  granules,  while  the  smaller  one  is  color- 
less ;  the  latter  grows  rapidly  into  an  elongated  root-hair. 
The  larger  cell  divides  first  into  two  cells,  and  then  usually 
one  of  these  divides  again,  and  so  on,  giving  rise  to  a  simple 
prothallium,  composed  of  a  single  layer  of  cells ;  this  en- 
larges and  increases  in  size,  until  it  reaches  the  stage  in 
which  it  bears  the  sexual  organs  (paragraph  475). 

482.  Tissues. — The  epidermis  is  remarkable  for  the  large 
quantity  of  silica  which  it  contains,  mainly  in  the  outer 
walls  of  the  cells.  The  epidermal  cells  are  mostly  narrow 
and  elongated,  and  are  arranged  in  vertical  rows.  The  sto- 
mata,  which  are  present  in  all  the  chlorophyll-bearing  parts 
of  the  plant,  are  arranged  with  more  or  less  regularity  in 
longitudinal  rows  ;  on  the  stem  they  occur  in  the  channels 
between  the  numerous  ridges.  They  resemble  pretty  closely 
the  stomata  of  the  Phanerogams  in  their  structure.  The 
fibro-vascular  bundles  of  the  stem  are  disposed  in  a  circle,  as 
seen  in  a  cross-section,  and  they  run  through  the  funda- 


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368  BOTANY. 

mental  tissues  from  node  to  node,  parallel  with,  but  inde- 
pendent of,  one  another.  At  the  nodes  they  split  into  two 
branches,  which  unite  right  and  left  with  corresponding 
branches  of  other  bundles,  and  thus  form  the  bundles  of  the 
next  internode.  The  bundles  of  successive  intemodes  thus 
alternate  with  one  another.  Each  leaf  of  the  leaf-sheaths 
sends  down  a  bundle,  which  joins  a  bundle  in  the  stem  at 
the  point  where  two  descending  branches  of  contiguous  bun- 
dles from  the  upper  internode  unite  to  form  a  bundle  in  the 
lower  internode.  The  bundles  are  thus  seen  to  be  of  the 
" common"  t)'pe — i.e.,  they  are  common  to  both  stem  and 
leaves.  As  to  their  construction,  they  are  collateral,  and 
contain  tracheary,  sieve  and  fibrous  tissues  (paragraph  139, 
and  Fig.  99).  The  remainder  of  the  stem  (the  fundamental 
portion)  is  made  up  for  the  most  part  of  parenchyma ;  in  the 
cortical  portion  of  the  vegetating  shoots  it  contains  an 
abundance  of  chlorophyll,  and  it  is  here  frequently  pene- 
trated by  large  longitudinal  canals  (Z,  Fig.  249) ;  in  the 
medullary  portion  a  great  central  canal  soon  appears  by  the 
rapid  growth  causing  a  rupture  of  the  tissues  (/*,  Fig.  249). 
There  are  frequently  found  in  the  hypodermal  portions  of 
the  fundamental  systems  bands  of  thick- walled  tissue,  which 
are  either  sclerenchymatous  or  fibrous. 

(a)  This  class  contains  but  one  living  order,  the  EQUiSETACSiB,  hav. 
ing  the  characters  of  the  class  as  given  above.  In  ancient  geological 
times  the  Calamites  and  their  allies  constituted  a  dietinct  order,  the 
CalamariccB,  now  extinct ;  they  differed  from  the  Equisetacea  in  hav- 
ing fibro- vascular  bundles  which  increased  exogenously.  The  CctUi- 
mariecB  were  represented  in  the  Devonian  by  a  species  of  AtAercphyU 
lUe$.  In  the  Carboniferous  period  there  were  many  species  of  the  gen- 
era Calamites,  Calamodadns,  CcUamostachys,  SphenophyUum,  etc.  In 
the  Permian  the  order  became  extinct. 

(&)  The  order  Equisetaeea  includes  but  a  single  genus,  Equisetum, 
which  contains  about  twenty-five  species.  None  of  the  species  attain 
a  great  size,  the  URual  height  being  from  20  to  100  cm.  (8  to  40  inches)  ; 
one 'species  (E,  giganteum)  in  tropicnl  South  America  attains  a  height 
of  9  to  10  metres  (80  feet  or  more),  but  it  is  very  slender,  being  no  more 
than  20  to  25  mm.  (1  inch  or  less)  in  diameter.  The  silicious  stems  of 
E,  hyemale,  a  common  species,  are  sometimes  used  for  scouring  knives 
and  other  articles. 

(c)  The  germination  of  the  spores  of  Equisetin©  may  be  studied  by 


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FILICINJS.  369 

placing  fresli  Bpores  in  water,  or  upon  moist  earth  or  moist  pieces  of 
porous  pottery.  It  must,  however,  be  borne  in  mind  that  within  a  few 
days  after  reaching  maturity  the  spores  lose  their  power  of  germinating. 
((2)  The  oldest  genus  of  this  order  is  Equisetites,  represented  in  the 
Carboniferous  by  several  species.  Equisetum  extends  from  the  lower 
Secondary  (Triassic)  to  the  present. 

§  11.  Class  Filicin^. 

488. — ^The  plant-body  of  the  asexual  generation  in  this 
class  consists  of  a  solid  stem,  bearing  roots  and  broadly  ex- 
panded leaves,  the  latter  usually  on  long  petioles.  The 
stems  are  mostly  horizontal  and  underground,  but  in  some 
cases  they  rise  to  a  considerable  height  vertically  in  the 
air.  The  leaves  arise  singly  upon  the  stems,  and  grow  up- 
ward from  the  rhizome  (horizontal  stem),  or  are  borne  as  a 
crown  upon  the  more  or  less  elongated  upright  stem.  The 
leaves  are  in  nearly  all  cases  supplied  with  fibro-vascular 
bundles,  which  run  as  veins  through  the  parenchjrma  ;  there 
is  usually  a  prominent  midrib,  upon  each  side  of  which  the 
parenchyma  is  permeated  with  small  veins,  which  are  free 
(running  more  or  less  parallel  from  the  midrib  to  the  margin), 
or  reticulated. 

484. — The  Filicinae  are  for  the  most  part  terrestrial  plants 
of  considerable  size,  a  few  only  being  small  or  of  an  aquatic 
habit  They  are  all  richly  supplied  with  chlorophyll,  and 
none  are  in  any  degree  parasitic.  Nearly  all  the  species  are 
perennial,  in  some  cases,  however,  dying  down  to  the 
ground  at  the  end  of  the  summer,  the  underground  portions 
alone  surviving  the  winter. 

485. — The  prothallium  in  the  Filicinae  is  a  small  cell- 
ular body,*  composed  in  most  cases  of  chlorophyll-bear- 
ing parenchyma.     It  is  frequently  somewhat  heart-shaped, 


♦  Dr.  Farlow,  in  a  paper  on  **  An  Asexual  Growth  from  the  Pro- 
thallus  of  Pteris  cretica,"  in  Prne,  Am.  Acad.  Arts  and  Sciences,  1874, 
and  Qr,  Jour.  Mic.  Science,  1874,  described  certain  prothallia  in  which 
scalariform  vessels  were  found  by  him.  These  abnormal  prothallia 
produced  new  plants  directly,  without  the  intervention  of  the  usual 
process  of  fertilisation  ;  the  scalariform  vessels  of  the  prothallia  were 
in  every  case  continuous  with  those  in  the  new  plants. 


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370  BOTANY. 

and  is  generally  provided  with  root-hairs  on  its  under  sur- 
face, by  means  of  which  it  secures  nourishment  for  its  inde- 
pendent growth  (Fig.  252).  In  the  Rhizocarpece  the  pro- 
thallium  is  so  reduced  as  to  be  only  a  small  outgrowth  of  the 
germinating  spore. 

486. — Both  kinds  of  sexual  organs  usually  occur  upon  the 
same  prothallium.  The  antheridia  consist  of  a  few  or  many 
sperm-cells,  which  may  or  may  not  bo  surrounded  by  a  wall 


m 


Fig.  252.  Fie.  858. 

Fig.  252.— A  prothallium  of  a  fern,  seen  from  tho  under  side,  h,  the  root-haiw  grow- 
ing iTom  the  oaeal  end  of  the  prothallium  ;  an,  the  antheridia  scattered  among  the 
root-hairs  ;  ar,  archegonia  near  the  apex,    x  10.— After  Prantl. 

Fig.  258.— Mature  anlheridium  of  AdiarUum  CapUlw-  Veneris,  p.  cells  of  prothal- 
lium :  a,  wall  of  antheridium— the  sperm-cells  are  seen  escaping,  in  each  a  sperma- 
tozoid  is  coiled  up ;  «,  the  spermatozoids ;  d,  the  protoplasm  of  the  sperm-ceUs  still 
attached  to  the  spermatozoids.    x  560.— After  Sachs. 

of  other  cells.  In  the  Ferns  {Filices)  they  are  few-celled 
bodies,  which  project  from  the  basal  portion  of  the  under 
surface  of  the  prothallium  ;  one  of  the  interior  cells  becomes 
divided  into  sperm-cells,  in  each  of  which  is  a  spirally  coiled 
spermatozoid  (Fig.  253).  In  the  other  orders  the  antheridia 
are  not  confined  to  the  under  surface  of  the  prothallium,  and 
in  some  of  the  Rhizocarpece  nearly  the  whole  of  the  contents 
of  a  microspore  is  developed  into  one  antheridium  filled 
with  sperm-cells. 


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FILICINJE,  371 

487. — The  archegonia  of  the  Ferns  are  cellular  projec- 
tious  from  the  anterior  portion  of  the  under  surface  of  the 
prothallium.  The  germ-cell  is  sit- 
uated at  the  base  of  an  axial  row 
of  cells ;  the  latter  dissolve,  and  thus 
form  a  canal,  which  becomes  open 
by  the  separation  of  the  apical  ceils 
of  the  archegonium  wall  (Fig.  254). 
The  archegonia  of  the  other  Fili- 
cinae  do  not  differ  much  as  to  struc- 
ture, but  like  the  antheridia,  they 

are  not  confined  to  the  under  sur-     pi„  2m.— Yonng  archegonium 
face  of  the  prothallium.  tx^'oT^^^liS^^^^^^i^l 

488. -After    fertilization     the  Ij^chioro^^^^^^^^^ 

eerm-cell    divides     (in     the    known    with  dense  and  granulated  pro- 
°  ^   .  .  ^  .        _       .     toplanm.      Highly    magnified.— 

cases)  into  four  parts,  as  in  Equi-  After  sachs. 
setincBy   and  by  the  growth  and  development  of  these  the 
young  plant  of  the  asexual  generation  is  produced.     The 
young  plant  is  at  first  very  simple,  the 
\  first  leaves  being  much  smaller  and  less 
divided   than   those  which  appear  later 
(Figs.  255  and  25G). 
489. — The  spores  are  developed  upon 
)  the  leaves.     They  are  contained  in  spo- 
j  rangia,  which  occur  singly  or  in  clusters 
upon  the  surface,  or  on  the  margins  of 
the  more  or  less  modified  leaves ;  in  one 
order,  the  OphioglossacecB,  the  single  spo- 
rangia occur  in  the  tissues  of  the  greatly 
modified  leaves.    The  spores  are  all  of  one 
Fiff    2»— Prothai-  ''^"^»  excepting  in  the  Rhizocarpeo,  in 
Mum  *and  young  plant  of  which  there  are  two   sizes,  viz.,  micro- 


eris.  Been  from  below,  sporcs  and  macrosporcs.  The  sporangia 
Siot-haire'of  orothSilum;  of  the  truc  Fcms  {FUices)  have  a  ring  of 
piaSr^  J',  the^flrernlo?  cclls  belonging  to  their  walls,  peculiarly 
SJe^^nd°foSl*°  X  t-  thickened,  forming  an  elastic  ring,  which 
After  Sachs.  ruptures  the  mature  sporangium  ;  in  the 

other  orders  there  is  no  such  elastic  ring,  and  the  dehiscence 
is  usually  by  the  simple  splitting  of  the  dried  wall. 


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372 


BOTANY, 


Fig.  2S6.— Prothallinm  and  yoang  plant  of  Adi- 
antum  CapUltts- Veneris,  seen  in  vertical  longitudinal 
eection.  2>,p,  the  prothallinm;  a.  archegonia:  A,  root- 
hair  ;  E^  the  voui^  plant ;  tr,  its  first  root ;  6,  its  first 
leaf.    X  aboat  10.— After  Sachs. 


490. — The  Filicinse  may  be  here  arranged  under  four 

orders,  as  follows  :* 
/.    Isosporew, — 
Spores    of     one 
kind. 

Order  1.  Filioes, 
the  true  Perns. 
Sporangia  compos- 
ed of  modified  tri- 
chomes,  each  de- 
veloped from  a  sin- 
gle epidermal  cell,  produced  in  clusters  on  the  surface  of  or- 
dinary or  slightly  modified 
leaves.  Each  sporangium 
with  an  elastic  ring.  No  stip- 
ules. 

Order  2.  Marattiaceee,  the 
Eingless  Ferns.  Sporangia 
produced  from  a  group  of  epi- 
dermal cells ;  the  ring  either 
rudimentary  or  wanting.  The 
large,  much  -  branched  leaves 
with  stipules. 

Order  8.  OphioglossaoeeBy 
the  Adder-Tongues.  Sporan- 
gia formed  by  groups  of  cells 
in  the  interior  of  a  modified 
branch  of  the  sheathing  leaf. 
The  ring  is  absent. 
//.  HeterosporecB.-SvoreB  ^^^^^JSuSt^X^^ 

of  two  kinds.  vascular  bundles ;  ag,  the  broad  upper 

.        band  of  the  outer  bundle  zone ; 
Order  4.  HhizOCarpeSBy    the    band  of   elongated    thick-walled 


^ 


Fig.  SST.— il,  a  transverse  section  of 
the  stem  (rhizome)  of  Pteris  aguUinOf 
slightly  enlarged,  r,  brown  sclerenchv- 
ma,  forming  a  hard  feheath  beneath  the 


pr,  a 


ceils, 

T>                    J.         CI                •  sclerenchyma  or  fibrous  tissue— a  second 

r'epperWOrtS.      bporangia  com-  one  occurs  on  the  other  side  of  the  cen- 

posed       of       modified       trich-  fibro-vaScular  bundle^r^^stem^irS 

rkTnna    f^\»   flio    rmVrnaT^nroTio'ia  zome),  W,  and  its  branches,  «<',<<" ;  6, 

Omes   (r)y  tne    microsporangia  bundles  of  the  leaf  stalk ;  w.tt,w.out^ 

containing  many  microspores,  "*»«  °'  ^^«  stem.-After  sachs. 


*  This  arrangement  is  easentiallj  tbat  modification  of  Saclis*  pro- 
posed bj  Professor  McNab.  See  his  *'  Outlines  of  the  Classification  of 
Plants,"  American  edition,  Chapter  VII. 


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FLLIOES. 


373 


the  macrosporangia  asuallj  containing  only  one  macrospore. 
Sporangia  in  clusters^  enclosed  in  modified  leaves  or 
"fruits." 

Order   Filicet,  the  true  Ferns.    The  prothallia  of  the  Ferns  are 
green  thallus-like  stractores,  growing  apon  the  surfaoe  of  the  groand. 


Fiff.  857a.— Longitndinal  eection  of  the  apex  of  the  root  of  PterU  haalata.  v, 
apical  cell ;  o,  o,  epideimis ;  e,  cortical  tiesae  ;  c-c,  c-e,  the  primary  fibro-vaacular 
bandies  ;  n^m.l.  k,  the  root-cap  ;  k,  k,  danghter-celis  recently  cot  off  from  the  apical 
cell.— After  Nfigeli  and  Leitgeb. 

and  composed  at  first  of  but  a  single  row  of  cells,  but  later  of  extended 
layers  of  cells.     Th*^>  are  moooecious,  and  bear  their  antheridia  on  tbe 
basal  portion  of  tbf  ander  surface,  while  the  archeffonia  are  found  near 
the  apical  margin  of  the  same  surface.     After  fer- 
tilization the  germ-cell  divides  into  four  parts,  the 
uppermost  one  (or  two)  of  which  becomes  the  foot, 
or  otfiBLii  which  remains  in  contact  with  the  prothal- 
lium  ;  one  of  the  other  parts  develops  into  the  first 
root,  and  tbe  other  into  the  first  leaf.     The  young 
plant  is  thus  formed  on  the  under  side  of  the  pro-   { 
thallium,  from  which  it  grows  up  as  shown  in  Figs.    I 
256  and  255. 

The  stems  of  Ferns  are  mostly  short,  or  slender 
and  creeping  in  our  species,  but  in  the  tropics  they 
are  dflen  of  considerable  height  and  thickness, 
some  tree-ferns  attaining  the  height  of  24  metres 
or  more  (80  feet  or  more).  They  increase  in  length  caisne. 
only,  and  this  takes  place  by  the  continued  division  of  an  apical  cell 
They  contain  flat  fibrovascular  bundles  (Fig.  257,  A  and  B),  which  are 
usually  disposed  in  a  single  circle,  as  seen  in  a  cross-section,  but  in 
some  cases  there  are  bundles  in  the  medullary  portion  also.  On  ac- 
count of  the  presence  of  thick  masses  of  thick- walled  cells,  (scleren. 


Pig.  267A.-Portion 
of  under  surface  of  a 
leaf  of  Polypodiwm, 
Hhowing  eori.— From 
Le    Maout    and    De- 


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374  BOTANY. 

cbjina,  or  fibroas  tissae),  the  Btems  are  freqaently  verj  hard.  The 
fundamental  tissues  frequently  develop  a  good  deal  of  mucilaginous  or 
slimy  matter. 

Both  stems  and  roots  develop  from  a  tbree^ded  apical  cell.  The 
apical  cell  of  tbe  root  continually  nndergoes  fission  not  only  parallel  to 
its  sides,  but  also  parallel  to  its  base— t.^.,  at  right  angles  to  tbe  axis  of 
the  root.  The  daugbter-cells  thus  cut  off  (A:,  k.  Fig.  257a)  constitute  the 
root-cap  (pUearhiza)  with  which  each  root- tip  is  covered. 

The  leaves,  which  unfold  circinately,  are  often  very  large,  and  in 
most  cases  are  more  or  less  lobed  and  divided,  frequently  becoming 
several  times  compound.  Their  development  is  slow,  tbe  rudiment  of 
the  petiole  forming  one  year,  and  that  of  the  blade  the  next,  while  the 
opening  or  unfolding  does  not  take  place  till  tbe  following  year.  Tbe 
growth  is  sometimes  (leriodic,  as  in  Qleichenia  and  Lygodium.     In  tbe 


Fio.  868.  Fio.  250.  Fig.  S60. 

Fig.  268.— Under  side  of  a  fertile  leaflet  of  Aspidium  FUix^mas,  with  eight  sori. 
i,  the  indasinm.    Magnified.— After  Sachti. 

Fig.  250.— A  leaflet  of  Atplenium,  showing  the  elongated  sori,  each  covered  by  a 
laterally  placed  indusium.- From  Le  Maout  and  Decaisne. 

Fig.  280.— A  leaflet  of  Adiantum,  showing  the  sori  covered  by  indasia  formed  by 
reflexions  of  the  margin  of  the  leaflet.— From  Le  Maout  and  Decaisne. 

latter  the  leaf  eventually  becomes  greatly  elongated,   resembling  a 
climbing  stem. 

The  sporangia  are  usually  formed  in  clusters  {sort)  on  the  veins,  on 
the  under  side  of  the  leaves,  or  upon  their  margins.  Tbe  sori  may 
be  distinct  and  rounded  or  more  or  less  elongated,  or  they  may  be 
confluent  over  conBiderable  portions  of  the  surface.  In  some  cases 
tile  sori  are  naked  (as  in  Fig.  2576),  but  quite  frequently  each  one 
is  covered  by  a  cellular  outgrowth  of  the  leaf,  called  the  indimum 
(Figs.  258,  259,  260).  In  some  cases  the  indusium  is  shie]d-shap«Hi,  its 
short  pedicel  arising  in  the  midst  of  the  sporangia  (Fijrs.  258  and  261) ; 
in  others  it  is  more  or  less  elongated,  and  attached  by  one  of  its  edges 
to  the  side  of  the  sorus  (Fig.  259) ;  in  still  others  a  portion  of  the  mar- 
gin of  the  leaf  is  refiexed  in  such  a  way  as  to  form  the  covering  (Fig.  260). 
Many  other  forms  are  common,  and  are  to  be  found  described  in  system- 
atic treatises.    The  sporangia  are  more  or  less  rounded  bodies,  usually 


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FILICE8.  375 

boiae  upon  slender  pedicels.  Morphologically  tbey  are  trlchomes, 
which  ander^ro  a  special  modification.  Each  sporanginm  is  at  first  a 
two-oelled  trichome  ;  the  lower  cell  of  which  develops  into  the  pedicel, 
while  the  other  l>ecoines  divided  by  partitions  parallel  to  its  surface 
into  outer  cells,  which  develop  into  the  sporangial  wall,  and  an  inner 


B 


"FUa.  2R1.—A9pidium  IWm-mtu.  A^  a  section  of  a  leaf  through  a  sorai* ;  «,  «.  the 
gporangia,  borne  upon  an  elevated  mass  of  tiseue.  the  receptacle ;  i,  i,  the  Indusiam. 
8cen  in  section.  £,  a  section  of  a  young  sporangiam,  showing  it8  central  cell  divided 
into  four  ;  r,  one  cell  of  the  ring,  the  section  being  at  right  angles  to  its  plane.  C.  a 
sporanginm  nearly  mature,  seen  laterally  ;  r,  r,  the  ring  of  the  sporanginm ;  d^  a 
glandular  hair— in  the  Interior  of  the  sporangium  are  seen  the  nearly  npe  spores. 
Atagnified.— After  Sac  lis. 

tetrahedral  cell  (the  so-called  central  cell),  rich  in  protoplasm  ;  from  the 
latter  a  numl)er  of  P|)ore  mother-cells  (twelve,  according  to  Reess)  are 
formed,  and  from  each  spore  mother-cell  four  spores  arise  (Fijjs.  261 
and  262).  In  each  sporangium  some  of  the  cells  of  the  wall  are  devel- 
oped into  an  elastic  ring  {annulus),  which  extends  part  way  around  the 


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876 


BOTAHY. 


spore  cavity  (Fi^.  261,  C,  r).  By  the  contraction  of  this  ring  the  ripe 
sporangiam  is  ruptured  and  the  spores  set  free.  In  some  cases,  instead 
of  forming  a  ring,  the  elastic  cells  are  arranged  as  a  group  at  one  aide 
or  end  of  the  sporangium. 

Six  fiamilies  or  suborders  of  the  Ferns  may  be  distinguished,  if  we 
take  into  consideration  the  characters  derived  from  the  asexual  geneia- 
tion.    They  have  been  arranged  as  follows  :  * 

1.  Oleicheniace(B, — Sporangia  sessile,  splitting  vertically,  furnished 
with  a  complete  horizontal  ring.  Sori  composed  of  very  few  sporangia ; 
receptacle  not  elevat«d  (Fig.  268).  Fronds  with  very  distinct  dichot- 
omous  branching.  Genera  two  (Platyzama  and  OUiehenia) ;  species 
thirty,  mostly  confined  to  the  southern  hemisphere. 

2.  HymeTi&phyUoiUm. — 
Sporangia  sessile,  split- 
ting vertically,  famish- 
ed with  a  complete 
horizontal  ring.  Sori 
composed  of  numerous 
sporangia  inserted  on  a 
long  filiform  receptacle 
(Fig.  264).  Leaves  of 
filmy  texture  (usually  of 
a  single  layer  of  cells), 
with  pinnate  branching. 
Genera  two  {Hytneno- 
phyUum  and  Tridioma- 
nes);  species  150  to  200, 
mostly  confined  to  the 
tropics. 

8.  Cyatheacea,  —  Spo- 
rangia nearly  sessile, 
splitting      transversely. 


Fig.  283.— Development  of  the  spores  of  AtfAdium 
FUix-nuu.  /.,  a  mother-cell  cootaining  a  nucleas ; 
II..  the  same  after  the  absorption  of  tne  nacleos ; 
///.,  the  mother-cell,  with  two  larse  clear  nnclei— 
sometimc9  a  line  of  B^paration  is  evident,  as  in  the 
flffore ;  /T.,  the  mother-cell,  with  four  clear  nuclei, 
which  appear  after  the  absorption  of  the  two  in 
///. ;  K.,  the  four  daughter-cells  (young  spores) 
which  form  fmm  IK;  VI,  VII.,  VIII.,  ditferent 
relative  positions  of  the  developing  spores ;  /X,  the 
perfect  spore,    x  550.— After  Sachs. 


*  The  characters  and  arrangement  of  the  suborders  of  ferns  are 
taken  from  the  article  "  Ferns,"  by  W.  T.  T.  Dyer  and  J.  G.  Baker,  in 
the  *'  Encyclopaedia  Britannica,"  ninth  edition.  Vol.  IX.,  p.  104.  For  a 
systematic  account  of  the  Ferns  the  student  is  referred  to  "  Synopds 
Filicum  :  a  Synopsis  of  all  Known  Ferns,"  by  W.  J.  Hooker  and  J.  G, 
Baker,  London,  1878  The  student  may  profitably  consult  the  following 
recently  published  American  works,  viz.,"  The  Ferns  of  North  America," 
by  D.  C.  Eaton,  the  plates  by  J.  U.  Emerton,  now  being  issued  in  parts  ; 
•'Ferns  of  Kentucky  "  by  John  Williamson,  1878  ;  *'  Ferns  in  Th^r 
liomes  and  Oars,"  by  John  Robinson,  1878  ;  and  '*  Ferns  of  the  South, 
west,"  by  D.  C.  Eaton,  in  Lieut.  Wheeler's  "  Report  upon  U.  8.  Geo- 
graphical Surveys  West  of  the  One  Hundredth  Meridian,"  VoL  VI., 
1878  ;  Underwood's  "  Our  Native  Perns,  and  their  Allies,"  188a 


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FILI0E8. 


377 


farniflbed  with  a  usually  incomplete,  nearly  Tertical,  or  ratber  oblique 
ring.  Receptacle  prominent,  barreUsbaped  (Fi^.  265).  Tree-fema. 
Genera  three  {Cyathea,  Hemitdia,  and  AUophila) ;  species  150,  mostly 
tropical  and  subtropical . 

4.  Polypodiaceas.  —  Sporani^ft  stalked,  splitting  transversely,  f ar- 
nisbed  witb  a  usually  incomplete  vertical  ring.     Receptacle  not  prom<- 


Fio.  368. 


Fio.  264. 


J^'io.  886. 


Ffg.  263.— Portion  of  a  leaf  of  GteUhmia,  with  a  soras,  a;  &«  a  sporangiam.— Af- 
ter Hooker. 

Fig.  i64.— Portion  of  a  leaf  of  TrichomaM/t^  a,  with  five  eori ;  6,  a  sporangium.— 
Aft«r  Hooker. 

Fig.  865.— Vertical  section  of  a  sonu.  a,  of  AlsophUa^  showing  the  cylindrical  re- 
ceptacle ;  d,  a  sporangium.— After  Hooker. 

inent  (Figs.  2576  to  261).  Genera  fifty  (AcrosticJium,  Pdypodium, 
Adiantum,  Pteris,  Atfplenium,  Scolopewfrium,  Aspidium,  Cyslopteris, 
etc.) ;  species  2000,  widely  distributed  throughout  the  world. 

5.  OamundaeecB. — Sporangia  stalked,  splitting  vertically,  furnished 
with  only  a  faint  horizontal  bar,  instead  of  a  ring  (Fipf.  266).  Genera 
two  {Osmunda  and  Todea) ;  species  ten  to  twelve,  widely  distributed  In 
north  and  south  temperate  re- 
gions. 

6.  Sch'icpacecB.  —  Sporan- 
gia sessile,  splitting  vertical- 
ly, crowned  by  a  complete 
small  annular  horizontal  ring 
(Fig.  267).  Genera  five 
{SehiziBa^  Anemia,  Lygodium, 
etc.);  ppecies  sixty,  mostly 
natives  of  the  warm  regions 
of  America  and  Asia. 

Economically  the  true  Ferns  are  of  comparatively  little  value.  The 
pulpy  interior  of  tlie  stem  of  a  tree-fern  (Cyatfiea  meduUaris)  growing 
in  the  Pacific  islands  furnishes  an  important  article  of  food  to  the 
natives.  In  Austrniia  the  underground  stems  of  Pteris  aquUina 
supply  an  indifferent  food.  A  few  species  are  of  doubtful  value  as 
astringent  medicines.     The  long  woolly  hairs  of  certain  species  ot 


Fig.  266  Fro.  267. 

Fig.  266.  —  Two  pporangia  of  Ofmundn ;  a» 
with  the  rudimentary  ring  wen  in  front  view  ; 
6,  with  the  ring  seen  in  profile.— After  Hooker. 

Fig.  867.— Lower  portion  of  a  fertile  pinna,  a, 
of  SchiMcea  ;  b,  a  sporangium.- After  Hooker. 


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378  BOTANY. 

Dieksonia  arrowing  in  the  Sandwich  Islands  constitute  the  substanoe 
known  as  Pulu,  used  somewhat  in  upholstery.  Manj  ot  the  spedes 
are  now  largely  grown  as  ornaments. 

Ferns  first  appeared  in  the  Devonian,  in  which  period  no  less  than 
twelve  pfenera  belonging  to  extinct  families  were  represented.  In  the 
Carboniferous  the  genera  and  species  were  exceedingly  numerous,  after 
which  they  decreased  to  the  present.  Many  Tertiary  genera  extend  to 
the  present,  and  are  now  represented  by  living  species. 

Order  Marattiaceao,  the  Ringless  Ferns.  The  prothallia  of  the 
ringless  Ferns  are  thick,  fleshy,  and  dark  green  in  color.  They  bear 
antberidia  in  depressions  upon  both  surfaces,  and  in  these  are  pro- 
duced spermatozoids  bearing  much  resemblance  to  those  of  true  Ferns. 
The  archegonia  are  also  deeply  sunken  in  the  tissue  of  the  prothallium, 
and,  according  to  McNab,  resemble  those  of  the  HhizocarpesB. 

The  asexual  generation  bears  a  close  resemblance  to  that  of  tnie 


Pig.  368.  Pio.  2®. 

Fig.  268.— A  prothalllnm  of  BotryeMum  Lunarian  In  longitudinal  eectfon.  ac^  an 
archegonium ;  an,  an  antheridiom— near  to  it  are  others,  one  not  yet  matore,  and 
three  empty  ones ;  w,  root-hairs,    x  50.--After  Hofmeister. 

Fig.  ^.— A  longitudinal  section  of  the  lower  part  of  a  jonng  plant  of  the  same,  dog 
np  in  6eiitember.    rf,  stem ;  b,  I/,  l/\  leaves,    x  20.— After  HofVneister. 

Ferns.  The  plant-body  is  usually  large  ;  its  stem  is  generally  upright, 
short,  thick,  and  unbranched  ;  the  leaves  are  circinately  developed,  as 
in  true  Ferns,  and  are  mostly  very  large,  with  pinnately  or  palmately 
divided  laminae  ;  they  are  provided  with  stipules,  and  in  their  petioles 
is  fonnd  the  first  collenchyma.  The  stem  develops  from  a  three-sided 
apical  cell,  but  the  root  is  provided  with  a  group  of  cells,  as  in  the 
Phanero^rams. 

The  sporangia  occur  on  lateral  veins  upon  the  under  side  of  the 
leaves,  and  are  usually  confluent  into  one  body,  the  eorus  (often  called 
erroneously  the  sporangium).  In  Angiopteris,  however,  the  sporangia 
are  distinct.  The  spores  develop  from  many  mother-cells  in  each  spo- 
rangium, instead  of  from  one,  as  in  true  Ferns. 

The  MarattiacesB  are  essentially  tropical,  extending  somewhat  into 
the  warmer  parts  of  the  temperate  zones.  Four  genera  are  known, 
viz. ,  Danasa,  restricted  to  tropical  America ;  Kaulfussia  and  Angiopteris, 


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0PHi0QL088ACEjS.  379 

• 

found  in  the  tropica]  regions  of  the  eastern  hemisphere ;  and  MaratHa, 
which  is  represented  in  the  New  and  Old  World.  The  whole  number 
of  species  probably  does  not  exceed  twenty-five. 

The  oldest  members  of  this  order  oc- 
cur io  the  Permian  strata. 

Order  Ophioglossaceas,  the  Adder- 
Tongues.  The  prothallia  of  these  fern- 
like  plants  are  thick  masses  of  paren- 
chyma, which  are  destitute  of  chloro- 
phyll ;  they  develop  underground,  and 
are  difficult  to  study,  lience  they  are 
known  for  but  few  of  the  species.  In 
Botrychium  Lunaria,  according  to  Hof- 
meister,*  the  prothallium  is  **an  oval 
mass  of  firm  cellular  tissue,  whose  larger 
diameter  does  not  exceed  a  millimetre 
<one  twenty- fifth  of  an  inch),  and  is  often 
less"  (Fig.  268).  He  discovered  them 
in  the  {ground  at  a  depth  of  from  two 
and  a  half  to  seven  and  a  half  centim- 
etres (one  to  three  inches).  The  an- 
theridia  occur  for  the  most  part  upon 
the  upper  surface,  and  the  archegonia 
upon  the  lower. 

The  mature  plant  (asexual  generation) 
consists  of  a  short  erect  underground 
stem,  which  bears  annually  one  or  more 
stipulate  and  erect  {i.e.,  not  circinate)f 
leaves  (Fig.  269,  6'  and  6'',  and  Fig. 
270).  The  leaf  is  usually  divided  into 
two  portions,  one  of  which  is  ^reen  and 
expanded  (Fi^.  270,  6),  while  the  other 
is  contracted  into  a  spore-bearing  organ 
(Fig.  270,  /) ;  in  some  cases  each  seg- 
ment is  simple,  whiM  in  others  it  is  one  ' 
or  more  times  compound. 

The  spores  of  the  Ophioglossofta  are 
produced  from  mother-cells  developed  in      p^g,  ^.-Piant  of  Bo^ehiwn 
the  tissue  of  the  fertile  segment  of  the   Xwnarlo,  nat.  size.  «^,  «/,  the  phort 

1     •     X ^     «i 11  J         -^    -J     ^4   stem:  «,  r  otn;  6*.  theleaf  pialk; 

leaf;  hence  the  so-called  sporangia  of  «»,  po^nt  where  the  leaf  branched 
this  order  are  morphologicallv  quite  into  the  sterile  part  (6)  and  the  fer- 
j.«        ^-         ,,  ],  u*       '  tUeorspoie-bearing  portion  (/ ).— 

dmerent  from  those  of  true  berns.  After  Sachs. 


*  **  On  the  Germination,  Development,  and  Fructification  of  the 
Higher  Cryptogamia,*'  etc.,  by  Dr.  Wilhelm  Hofmeister.  Translated 
by  Frederick  Currey,  I^ondon,  1862. 

I  The  vernation  of  our  species  of  BotrycJdum  is  well  worked  out  in 


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380 


BOTANY. 


The  stems  are  developed  from  a  triangular  apical  cell,  while  the 
roots,  like  those  of  Marattiacece,  possess  no  apical  cell,  but  a  group 
of  cells  instead.  The  fibro-vascular  bundles  are  arranged  in  a  cylinder 
(a  circle  in  cross-section),  and  they  form  a  network  by  their  anastomos- 
ing with  each  other.  According  to  De  Bary,  they  belong  to  the  '*  ool- 
lateral "  series. 

These  plants  are  usually  of  small  size,  rarely  exceeding  80  centime* 


Fig.  271.— il,  vertical  Bectlon  of  an  archegonium  and  the  rndimentary  prothallioxa 
of  JPUiilaria  globulifera  :  w,  tc,  part  of  the  ruptured  wall  of  the  macrocpore  :  p,  p 
the  rudimentary  prothallicro,  merging  above  into  the  archegoninm  ;  g^  the  germ-cell 
ready  for  fertibzation  ;  «c,  the  cavity  of  the  macrot»pore.  x  500.  5,  a  microspore- 
of  the  same  burst  open  and  allowing  the  escape  of  8perm-cell8.  «.  from  which  sper- 
matozoids  aro  escaping,  x  600.  C,  Tongitodinal  section  of  a  macrocpore  of  Salvinia 
natans  at  the  commencement  of  germination  ;  jp,  theyonsg  prothalliam.  x  90.  Z>, 
a  very  young  prothallium  of  the  same,  detached,  with  a  fragment  of  the  Inner  spore- 
membrane  iffi)  adhering  to  it— top  view,  x  900.  E,  a  vertical  longitudinal  section  of 
J>.  X  aOO.  F  a  similar  section  of  a  more  advanced  prothallium  of  the  same  ;  g.  the 
young  germ-cell.  X  200.  <?,  vertical  section  of  an  unfertilized  archegonium  of  the 
same,  surrounded  by  cells  of  the  prothallium  ;  g,  germ-cell ;  or,  canal  of  the  arche- 
gonium.   X  800.— After  Hofmeii^ter. 

tres  (1  foot)  in  height ;  in  one  Ceylonese  species  {Ophioglosgum  pendu^ 
lum)  the  slender  pendent  leaves  are  sometimes,  according  to  Hooker, 
nearly  three  metres  long  (15  feet). 

There  are  three  genera,  viz.,  Ophioglossum,  Botrychium,  &nd  Selmiiu 
thostacliys  ;  the  latter  is  confined  to  the  southern  hemisphere,  the  others 

G.  E.  Davenport's  paper,  Vernation  in  Botrychia,  in  the  Bulletin  of 
the  Torrey  Botanical  Cluh,  1878;  it  is  illustrated  by  figures. 


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BfflZOCABFEJE.  381 

are  coflmopolitaxL    All  told,  there  are  probably  not  more  than  eighteen 
or  twenty  distinct  species,  of  which  we  have  six  within  the  limits  of 
the  United  States. 
A  species  of  Ophiogloshum  has  been  discovered  in  the  Tertiary  strata. 
Order   Shizocarpeae,   the   Pepperworts.     The  prothallia  of   the 
'^' '  1.    -t  ^^  ^^^  developed 

e  mac>  ospares  and 
icularly  described 
)  simple,  and  con- 
B^rowths  from  the 
Salvinia  and  Azol' 
)ntents  of  the  mi- 
iiularia.  Fig.  271, 
jpirally  coiled,  and 
a  are  produced  in 
I  in  each  antherid. 
produce  archego- 
ttain  a  size  large 
gh   the  ruptured 
p.  Fig.  271,  A). 
ose  of  true  Ferns, 
tissues  of  the  pro- 
After  fertiliieatiou 
vision,  and  giveb 
turned  plant,   th« 
i  with  roots  (ex- 
cept in  JScUvin- 
ia).     The  stem 
is      horizontal, 
and  floats  upon 
the    water     or 
runs     through 
the  mud  at  the 
bottom  of  shal- 
low  water.  The 
leaves  are  cir- 
cinately  devel- 

„      , oped,    and    are 

Pio.  272.                                          ViQ.  273.  .       ,                 J 
"*  *'^  simple  or  quad- 
Pig.  272. -Plant  of  Marailia  9alvcarix.    K,  apex  of  the  stem  ;  .«  ,  /«.      n^oi 
6.  6.  leaves  ;  /,  /,  /,  the  flraits  epriuglng  /rom  the  petiolefi  %t ».  ^ina  \v  iff.  AiC). 
One  half  nat.  rize.— After  Sachs.                           ^   ,       ^    ^  The    stem   and 
Fig.  278.  —  Longltadinal  secuon  through  three  fruits  (the  fer-  /lAv«ln« 
tile  apicee  of  a  waier-leaf)  of  i^aivinia  nataru.     i,  i,  two  fruits  root        aeveiop 
containing  microsporangia ;  a,  one  with  macrosporangia.    x  10.  from   an   apical 
-After  Sachs.  ^^,^    ^^^^^     j^ 

two  or  three-sided  in  the  stem,  and  triangular  in  the  root. 

The  sporangia,  which  are  usually  of  two  kinds,   are  produced  in 
••fruits"  or  receptacles,  which  are  modified  parts  of  leaves.    These 


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382  BOTANY. 

fruits  are  one-celled  in  ScUviniacecB,  and  several-celled  in  Marnliacea. 
Id  Saltinia  (Fig.  278)  the  microsporangia  are  small  and  numerous,  and 
are  contained  in  separate  fruits  from  the  macroeporangia,  which  are  few 
in  number ;  each  of  the  former  contains  many  microspores,  and  the 
latter  a  single  macrospore  (by  the  abortion  of  three,  as  four  are  formed 
at  first).  In  Marnlia  and  PUularia  the  two  kinds  of  spores  occur  in 
the  same  fruit,  and  in  the  former  in  the  same  sporangium. 

Four  genera  are  known  ;  these  are  arranged  under  two  suborders  or 
families,  the  SalviniaeecB,  which  includes  JSalvinia  and  AzoUa,  and  the 
ifar«tfuw5e<»,  which  includes  JfarsUia  and  FUtdaria,  The  whole  num. 
ber  of  species  is  sixty-four,  of  which  forty  belong  to  Marnlia,  the 
others  being  unequally  divided  between  the  remaining  genera.  All 
the  species  are  of  small  size,  rarely  exceeding  a  few  centimetres  in 
height ;  they  grow  in  ditches  and  other  wet  phices.  Half  a  dozen 
species  occur  in  the  United  States. 

Rhizocarps  have  been  found  as  fossils  in  the  Secondary  (Jurassic)  and 
Tertiary  strata. 

§  III.   Class  Lycopodik^.* 

491._The  plant-body  of  the  asexual  generation  consists 
of  a  solid,  dichotomously  branched,  leafy,  and  generally  erect 
stem.  The  leaves,  which  have  a  central  fibro-vascular  bundle, 
or  midnb,  are  small,  simple,  sessile,  and  imbricated,  and 
usually  bear  a  considerable  resemblance  to  those  of  Mosses. 
The  roots  are  mostly  slender  and  dichotomously  branched. 

The  LycopodiniB  are  for  the  most  part  terrestrial  peren- 
nials. They  are  usually  of  small  size,  rarely  exceeding  a 
height  of  15  or  20  centimetres  (6  or  8  inches). 

492, — ^The  spores  of  the  LycopodinsB  are  produced  in  spo- 
rangia which  are  generally  (if  not  always)  axillary  appen- 
dages of  the  leaves.  In  four  of  the  genera  {Lycopodium, 
Fsilotum,  Tmesipteris,  and  Phylloglossum)  the  spores  are 
of  one  kind  ;  while  in  the  two  remaining  genera  {Selaginella 
and  Isoetes)  they  are  of  two  kinds,  the  macrospores  and  the 
microspores. 

493._The  prothallium  or  sexual  generation  is  scarcely 
known  in  the  isosporous  genera ;  it  appears,  however,  to  be 
a  thickish  mass  of  tissue,  which  develops  underground,  and 

*  Sachs  calls  this  class  the  Dichotomy,  but  as  long  as  we  have  the 
EquUetincR  and  FUicincp^vre  may,  for  tbe  sake  of  uniformity,  retain  the 
old  name  i^ven  above. 


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LTCOPODINJE.  383 

bears  both  kinds  of  sexual  organs.  In  the  heterosporous 
genera  the  macrospores  produce  small  prothallia,  which 
project  slightly  through  the  ruptured  spore- wall,  and  upon 
these  several  or  many  archegonia  are  formed-;  the  micro- 
spores produce  very  small  rudimentary  prothallia,  each  of 


Pio.  274. 

Fig.  374.— if,  londtudinal  section  of  a  young  protliallium  of  Lycopodium  anruh 
Unum;  an,  two  aotberidia.  not  matare— upon  )t«  lower  surface  are  f>een  the  root- 
hairs.  X  150.  B,  lonsttudinal  section  of  a  protba]liam«p,  of  the  same,  after  termi- 
nation of  the  yoang  plant ;  «,  ntem  of  yonng  plant ;  r,  its  young  root ;  f.  the  foot,  or 
portion  of  the  yonng  plant  which  remains  m  contact  with  the  proihalli'um.  Slightly 
magnified.— After  Fankhauser. 

Fig.  275.— Plant  (asexual  generation)  of  Lycopodium  elawOum;  horizontal  stem 
with  rootM  and  leaves,  the  erect  branch  bearing  fertile  spikes,  «.  One  half  natural  size. 
—After  Prantl. 

which  bears  a  single  antheridium,  in  which  there  are  de- 
Teloped  a  few  spermatozoids. 

494. — Three  orders  of  Lycopodinae  may  be  distinguished, 
as  follows : 

/.  IsosporecB. — Spores  of  one  kind  ;  no  ligules. 

Order  1.  Lyoopodiaoeae,  with  small  leaves,  commonly 
moss-like. 

//.  HeterosporecB, — Spores  of  two  kinds  ;  ligules  present. 

Order  2.  Selaginellae,  with  small  moss-like  leaves. 

Order  3.  Isoeteae,  with  elongated  grass-like  leaves. 


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884  BOTANY. 

Order  LycopodiaceeB.— The  prothalliom  is  known  onlj  in  one  c 
viz.,  Lycopodium  annatinum.  It  was  discovered  andergroand  by 
Fankliauser  in  1872,  who  described  it*  as  a  yellowisli  wbite,  irreg- 
nlarlj  lobed  body,  sparingly  furnished  on  its  under  surface  with  small 
root-hairs  (Fi^.  274,  A),    In  its  upper  surface  the  prothallium  bears 

^  antheridia,    which    are 

deeply  sunken  in  its  tis- 
sue {an,  Fiflr.  274,  A); 
the  spermatozoids,  which 
are  numerous,  are  stout 
and  slightly  twisted. 
The  archegonia  were 
only  seen  after  the  young 
plants  had  grown  con- 
siderably (Fig.  274,  B) ; 
they  are  likewise  devel- 
oped upon  the  upper 
surface  of  the  prothal- 
Hum,  and  appear  to  bear 
a  considerable  resem- 
blance to  those  of  the 
0phiog1o8(uea, 

The  young  plant  which 
results  from  the  growth 
of  the  fertilized  germ- 
I  cell  is  quite  simple,  but 
it  soon  takes  on  the  form 
of  the  mature  plant. 
The  leaves  are  crowded 
in  Lycopodium,  but  are 

Fig.  276-Gennlnation  of  the  spores  of  Selaqinella.  less  so  in  the  other  gen- 

1,  lonsrltadinal  section  of  a  macronpore  of  S.  Marten-  __.         ?_    ^.-nv-    anAriAA 

Hi.  above  the  line  d  is  theprothallinm,  below  it  the  ®"^-       ^°   ™*^J^   species 

*'  endosperm ;"  «,  e',  two  embnros,  the  laiger  one  with  the  sporangia  are  borne 

its  suspsnsor  projecting  into  the  neck  of  the  archego-  .       .,  .,        -  ., 

nium;  atthelift  of  the  larger  embryo  is  a  young  ar-  '^   ^"^  ""«  ^^  *"®  O'" 

chegonium  ;  several  root-hairs  are  also  shown.     2,  a  dinary    leaves,    but     in 

young  archegonium  of  the  wime  species,  not  yet  open,  ^.i  ^„  ^r..  i«o«.4»o  »li;^li 

8,  an  archegoninro  of  the  name  species,  with  the  germ-  oiuers  me  leaves  wuicn 

cell  fertilized  and  divid- d  into  iwo.    ^,  a  microspore  bear  sporangia  are  col- 

of  5.  oat//ew«/w,  rendered  transparent,  showing  the  df-  .     ^    ,    ,   ^  vi. 

vision  of  the  contents  into  the  primordial  cells;  the  lected  into   cone-like  or 

small  lower  cell  is  the  rudimenrary  pW>tballinm.  A  anike  -  like  structures, 
later  stage  of  the  same,  showing  the  large  antheridinm      \  ,  ,  ,  . 

filled  with  sperm-cells ;  r.  the  rudimentary  prothal-  which  terminate  certam 

Hum.    All  magnified.- After  Pfcffer.  branches  (Fig.  275).  The 

sporangia  are  more  or  less  globose  bodies,  which  are  short-stalked 
or  sessile ;  they  contain  large  numbers  of  email  spores,  which  escape 
by  an  apical  slit  in  the  sporansrium. 

*  J.  Fankhauser :  "  Ueber  den  Vorkeim  von  Lycopodium,"  in  Botar^ 
itche  Zeitung,  1878,  No.  1. 


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8ELAQINELLJS, 


385 


Foar  genera  belong  to  tbis  order,  viz.,  Lyeopodium^  which  is  common 
in  the  wooded  portions  of  the  United  States ;  Pnlotum,  foand  in 
florida;  TmesipterU  and  PhyUoglouum,  of  Aostralia.  The  species 
number  from  115  to  120,  of  which  about  100  belong  to  the  genus 
Lyoopodium. 

The  spores  of  Lyeopodium  davatum  are  gathered  in  Europe  and 
sold  for  various  minor  uses.  Manj  species  have  a  high  ornamental 
▼alue. 

Tliis  order  was  represented  in  the  Devonian  by  species  of  Arctapo- 
dium.    In  the  Carboniferous  the  genus  Lyeopodium  first  appeared. 

The  closely  related  extinct  order  Lepidodendreffi  first  appeared  in  the 
Devonian,  in  which  it  was  represented  by  two  known  species  of  L^pu 
dodendron  ;  in  the  Carboniferous  this  genus  was  represented  by  sixty  or 
more  species,  many  of  gi- 
gantic size,  and  the  order 
by  many  other  genera— e.g., 
Lepidophloio$,  Lepidostro- 
hru^  Ealonia,  etc  In  the 
Permian  tlils  order  became 
extinct. 

Another  order— the  Sigll- 
lariesB — was  represented  by 
many  species  of  SigiUaria 
in  tlie  Carboniferous  period. 
Like  the  preceding,  tliis  or- 
der became  extinct  in  the 
Permian. 

Order    SelaginellsB. — 
The  prothallia  are  dicecious. 


T\g.  ftn.—I.t  two  yotm?  plaDts  of  SelagineUa 
MarUnHi  growing  fh>in  the  Bame  spore ;  at  the 
top  of  the  spore  maj  beseen  the  projecting  pro- 
thallium,  p.    //..  a  voung  plant  drawn  out  of  the 
spore,  showing  the  foot,  /,  on  the  left  below,  and 
the  young  root,  r,  on  the  ri<;ht.    ZT/.,  a  joong 
plant  whose  first  leaves  (cotyledons)  hare  been  re- 
rvi»ua«i lA  arc uiucviuuB.    moved,  leaving  ouIt  their  stipules, « ;  between  the 
rm*^^  »ut»v.  ;rio,,r^i^r.  #*^«n    UtteT  is  secu  tuc  dfcbotomously  dividing twnT^mi 
Those  which  develop  from   w^^rfotfoni*;  p,  the  prothaUium  Isolated  ^m  the 


spore, 
meister. 


the  macrospores  consist  of  a 
concavo-convex  many-celled 
structure,  which  develops  upon,  and  has  its  concave  side  applied  to,  the 
convex  surface  of  the  spore.  Upon  its  convex  surface,  which  protrudes 
through  the  ruptured  wall  of  the  spore,  are  a  few  root-hairs  and  many 
deeply  sunken  archegonia  (Pig.  276, 1,  2,  3).  The  microspores  develop 
only  the  smallest  rudiments  of  prothallia.  In  germination  a  single 
cell  {%  Fig.  276,  D)  is  first  of  all  cut  off ;  this  undergotfs  no  further 
change,  and  is  doubtless  to  be  regarded  as  the  prothallium.  The  re- 
mainder of  the  spore  becomes  divided  in  a  regular  way  into  a  few 
large  primordial  cells  (Fig.  276,  A\  and  from  these  great  numbers  of 
sperm-cells  are  produced  (Fig.  276,  D). 

After  fertilization  the  germ-cell  divides  at  right  angles  to  the  axis 
of  the  archegonium  (Fig.  276.  8) ;  from  the  upper  cell  so  formed  a 
iuspefhior  is  developed  (Fig.  276. 1),  while  the  lower  develops  into  the 
embrya     The  embryo,  by  its  rapid  growth,  comes  eventually  to  occupy 


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386  BOTANY. 

the  caritj  of  the  spore  itself,  in  which,  by  bending  upon  itself,  it  lies 
at  right  angles  to  the  axis  of  the  arcbegonium.  The  new  plantlei 
bears  some  resemblance  to  the  embryo  in  the  Dicotyledons ;  it  has  an 
elongated  stem,  bearing  at  its  summit  two  small  leaves  (cotyledons), 
having  between  them  a  growing  bud  (plumule) ;  at  the  lower  end  of 

the  8tem  there  is  a  rudimentary 
root,  and  the  structure  known 
as  tlie  foot,  which  is  common  to 
all  Pteridophytes  (Fig.  277,  //.). 
The  young  plant  grows  from 
the  spore  with  its  cotyledons  fore- 
most (Fig.  277,  /.  and  //7.) ;  this 
is  only  possible  by  the  great 
bending  of  the  embryo  upon 
itself,  for  at  first  its  cotyledon- 
ary  extremity  points  directly  to- 
ward the  centre  of  the  spore — 
i.e.,  away  from  the  opening  in 
the  spore. wall.  Usually  but  one 
plantlet  grows  from  each  pro- 
thallium  but  occasionally  two  or 
more  may  be  developed  (Fig. 
277,  /.) 

The  adult  plant  of  the  asex- 
ual generation  is  densely  leafy 
throughout.  The  leaves  are 
small,  moss  like,  and  are  gen- 
erally  placed  in  four  rows,  of 
which  two  opposite  ones  are 
composed  of  large  leaves,  and 
the  two  intermediate  ones  of 
small  leaves.  EacU  leaf  has  a 
small  scale-like  body,  the  ligule, 
on  its  upper  surface  at  its  base. 
The  sporangia  occur  singly  in 
the  axils  of  certain  leaves,  gen- 

Plg.  278.— -4,  a  fertile  branch  of  6Wo<7in«ffa   erally  in  those  which  form  the 
incequifolia^  with  the  qaadrangnlar  foore-  ...     .^.  .,      ,.  ,.-3. 

bcanne  epike  at  the  apex  ;  B,  vertical  sec-  narrower"  fruitmg  spikes  (Fig. 
tion  of  the  Hpike,  showing  the  microsporan-  278,-4).  Macrosporangia.  con- 
gla  containing  microspores  on  the  left,  and        »   .  #  j 

the  macrosporangia  with  macrospores  on  taining  four  macrospores  in 
the  right-A  x  2 ;  ^  X  15. -After  Isachs  ^^^^^  usually  occur  in  some  defi- 
nite portion  of  the  spike,  as  nearer  the  base,  or  upon  one  side  (Fig. 
278,  B).  The  microsporangia  contain  many  microspores,  and  usually 
also  occupy  definite  positions  in  the  spike. 

But  one  genus,  Selaginella,  is  known  in  this  order ;  it  includes  384 
species  of  mostly  delicate  plants,  which  are  mainly  tropical,  not  more 


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ISOETEjE.  387 

than  six  or  seven  species  occurring  within  tlie  limits  of  tbe  United 
States.     Many  are  cultivated  as  ornaments. 

Order  Isoetece,  the  Qui!  i  worts.  The  prothallia  of  the  Isoetese  are  dioe- 
cious, and  resemble  closely  those  of  S&agineUa.  The  macroftpores  give 
rise  to  small  prothallia,  which  project  through  the  triangular  slit  in  the 
spore- wall,  and  bear  several  or  manj  sunken  archegonia  (Fig.  279).  The 
microspores,  in  their  germination,  first  cut  off  a  small  cell  («,  Fig.  280« 
A  to  C),  which,  as  in  Sektginella,  represents  the  prothallium ;  the  re. 
mainder  of  the  spore  contents  becomes  divided  into  four  cells  (tbe 
primordial  cells),  and  these  give  rise  to  the  sperm-cells  (Fig.  280,  A  to 


T1g.S79.— 1,  Longltndiii.ll  eection  of  a  profhnlHum  ot  Isoetes  lacuAris,  toxxr  weeks 
after  flowing  the  epore :  ar,  an  archegoniam.  2,  a  portion  of  the  apex  of  a  prothal- 
Uam  cat  through  longi'udlDally,  with  two  archegonia,  ar»  ar,  still  in  process  of  dfvel- 
opment ;  0r,  gr,  the  germ-cells  of  the  archegonia.  8,  longitudinal  section  of  an  arche- 
ffonium  rfiady  for  fertilization.  4,  longitudinal  eection  of  a  fertilized  archegonium, 
enowing  the  germ-cell  transversely  divided.  6,  a  section  similar  to  the  last ;  in  the 
lower  cell  of  the  cmbryo-rudinient  preparation  for  division  has  been  made  by  the  ap- 
pearance of  two  nuclei.    1  x  40 ;  2  and  8  X  900  ;  4  and  5  X  400.— After  Hoftnelster. 

0).  The  spermatozoidd  are  elongated  and  provided  with  cilia  at  both 
ends  (Fig.  280,/). 

Tne  germ-cell,  after  fertilization,  undergoes  transverse  division 
(Fig,  279,  4  and  5),  as  in  S^lagineUa,  and  its  subsequent  development 
is  essentially  the  same. 

The  adult  plant  of  the  asexual  generation  consists  of  a  very  short, 
thick,  tuber-like  stem,  which  bears  numerous  long,  narrow,  grass-like 
leaves,  which  are  sheathing  at  the  base.  There  are  also  numerous 
roots.  The  sporangia  are  produced  in  grooves  on  the  inner  side  of  the 
bases  of  the  leaves  ;  those  attached  to  the  outer  leaves  contam  macro- 


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388 


BOTANY. 


8pores»  while  tbe  interior  ones  contain  microepores.     Both  macroepcret 
and  microBpores  are  produced  in  ^reat  numbers  in  the  sporan^a. 

Tlie  Quillworts  are  for  the  most  part  aquatic  plants  ;  they  are  found 
chiefly  in  the  north  temperate  and  warm  regions.     The  spedes,  of 


71)?.  380.— Oerminatloii  of  the  mlcrosporefl  of  Itoetu  laewtris.  ^,  a  microspore, 
side  view.  JB,  the  same,  ventral  view  ;  the  spore  contents  have  divided  Into  a  few 
cells,  of  which  v  in  each  flf^rure  represents  the  radlmentary  prothalliom  ;  /?,  /9  are  the 
Tentral,  and  J  fi  the  dorsal  cells.  (7,  a  side  view  of  microspore  ;  the  four  cells,  p^  fi^ 
6,  d,  have  disappeared,  and  spermatosoids  have  formed.  2>,  ventral  view  of  (7;  a  to 
/,  development  of  spermatozoids.    e  and/  x  TOO,  the  others  X  660i— After  MlUardet. 

which  there  are  from  forty  to  fifty  or  more,  all  belong  to  the  single 
genus  lioeies;*  we  have  representations  of  about  fourteen  within  the 
United  States. 
Two  species  of  hoetes  occur  as  fossils  in  the  Tertiary  (Miocene). 

♦  The  North  American  species  of  Pteridophytes  are  well  described 
in  ** Our  Native  Ferns  and  their  Allies,"  by  L.  M.  Underwood.  (Holt, 
1888.) 


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CHAPTER    XX. 

PHANEROGAMIA,  OR  ANTHOPHYTA. 
§  I.   General  Characters. 

495. — In  this  Division  the  alternation  of  generations 
which  is  so  well  marked  in  Bryophytes  and  in  most  Pterido- 
phytes  disappears.  We  have  seen  that  in  the  higher  FilicinsB 
and  LycopodinaB  there  is  a  great  reduction  in  the  size  and 
importance  of  the  prothallium  (the  sexual  generation) ;  in 
EquisetacecB  and  Filices  it  is  a  large  growth,  which  soon  be- 
comes entirely  independent  of  the  spore  from  which  it  origi- 
nates ;  in  Ophioglossacem  and  Lycopodiacew  it  is  of  consid- 
erable size,  but  it  is  less  capable  of  leading  an  independent 
existence ;  in  Rhizocarpem  and  SelaginellcB  it  is  reduced  to  a 
small  outgrowth  of  the  spore  ;  and  in  Isoetem  the  reduction 
is  still  greater,  the  small  prothallium  being  little  more  than 
the  transformed  spore  contents. 

With  the  decrease  in  the  structural  importance  of  the 
prothallium  in  these  orders  of  the  Pteridophyta,  there  is  a 
noticeable  increase  in  the  differentiation  of  the  spore  before 
its  separation  from  the  parent  plant ;  thus  in  the  three  last- 
named  orders  the  spores  have  differentiated  into  (1)  small 
ones,  microspores, which  are  strictly  male  as  to  their  functions, 
and  {2)  larger  ones,  macrospores,  which  are  as  strictly  female. 

496. — In  the  Phanerogamia  the  changes  begun  in  the 
Pteridophyta  proceed  a  step  further.  The  differentiation 
into  male  and  female  organs  of  reproduction  is  carried  back 
far  beyond  the  formation  of  the  microspores  (pollen  grains) 
and  macrospores  (embryo  sacs) ;  the  macrospore  does  not 
sever  its  connection  with  the  parent  plant,  but  continues  to 
be  nourished  by  it  until  after  the  embryo  is  formed;  and  as 


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390  BOTANY. 

a  consequence  of  its  maintaining  its  structural  connection 
with  the  parent  plant,  the  prothallium  (endosperm)  is  but 
feebly  developed.  The  prothallium  is  essentially,  as  to  its 
function,  a  nourishing  structure,  which  is  rendered  necessary 
in  the  Pteridophji^s  by  the  fact  that  the  reproductiye  bodies 
separate  from  the  parent  plant  before  they  are  ready  for  fer- 
tilization ;  and  just  as  this  separation  is  delayed,  or,  in  other 
words,  just  as  the  parent  plant  bestows  more  care  upon  the 
bodies  which  are  to  give  rise  to  the  embryo,  so  the  prothal- 
lium  is  less  necessary,  and,  being  less  necessary,  is  less  de- 
veloped. Thus  we  find  a  much  smaller  prothsilium  in  the 
heterosporous  orders  of  Pteridophytes  than  in  the  isosporous 
ones,  and  in  Phanerogams,  where  parental  care  extends  until 
after  the  formation  of  the  embryo,  there  is  generally  only 
the  smallest  rudiment  of  a  prothallium. 

497. — The  leafy  plant  (which  corresponds  to  the  asexual 
generation  of  the  Pteridophytes)  produces  two  kinds  of  re- 
productive cells,  viz.,  pollen  grains  and  embryo  sues,  the 
homologues  respectively  of  microspores  and  macrospores. 
The  pollen  grains  are  for  the  most  part  single  cells,  which 
develop  from  mother-cells  in  the  interior  of  phyllome  struc- 
tures (modified  leaves) ;  they  soon  become  free,  and  are  then 
more  or  less  spherical  in  shape  ;  they  have  two  coats,  an  outer 
thick  one,  the  extine,  and  a  delicate  inner  one,  the  intine, 
and  they  contain  a  granular  protoplasm,  in  which  oil  drops 
and  starch  granules  generally  occur.  The  embryo  sacs  are 
thin-walled  cells  which  arise  axially  in  the  ovules,  structures 
which  appear  to  be  homologous  to  the  macrosporangia  of 
Pteridophytes  ;  they  do  not  become  free,  but  continue  to  be 
m  organic  connection  with  the  cells  of  the  surrounding  tis- 
sues. Each  embryo  sac  develops  in  its  interior  a  larger  or 
smaller  mass  of  cells,  the  endosperm,  which  is  the  homo- 
logue  of  the  prothallium,  and  in  which  nourishing  matters 
are  deposited ;  it  also  develops  one  or  more  germ-cells,  the 
homologues  of  the  germ-cells  of  the  archegonia  in  Pterido- 
phytes. 

498. — The  portions  of  the  plant-body  which  produce  pol- 
len grains  and  embryo  sacs  are  in  general  considerably  modi- 
fied ;  thus  the  axis  is  generally  short,  the  leaves  delicate  or 


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PHANEROGAMIA,  391 

otherwise  difEerent  from  foliage  leaves,  and  containing  little 
or  no  chlorophyll ;  they  are  usually  of  some  other  color  than 
green,  from  the  presence  of  soluble  coloring-matters  in  their 
cells.  These  modified  parts,  together  with  the  organs  more 
immediately  connected  with  the  male  and  female  reproduc- 
tive cells,  constitute  what  is  known  as  the  flower. 

499. — The  ovule,  in  its  development,  becomes  surrounded 
by  one  or  two  thin  cellular  coats,  which  grow  from  its  base, 
and  almost  completely  enclose  it,  a  little  orifice  only,  the 
micropyUy  being  left  at  its  apex.  In  the  lower  Phanero- 
gamia  (the  Gymnosperms)  the  ovule  enclosed  in  its  single 
(rarely  double)  coat  is  otherwise  naked,  while  in  the  higher 
classes — viz.,  the  Monocotyledons  and  Dicotyledons — it  is  en- 
closed within  the  cavity  of  the  ovarj%  a  phyllome  structure, 
or,  as  it  is  commonly  described,  a  modified  leaf,  which  is 
folded  involutely  so  as  to  form  a  cavity. 

500. — In  the  fertilization  of  the  germ-cell  there  are  no 
spermatozoids  developed ;  instead  of  producing  these,  the 
pollen  grain  develops  a  long  slender  tube,  the  pollen  tube, 
which  penetrates  the  tissue  of  the  ovule,  and  comes  in  con- 
tact with  the  germ-cell  in  the  embryo  sac.  The  result  of 
fertilization  is  always  the  formation  of  a  suspensor  (some- 
times called  the  pro-embryo)  essentially  like  that  in  the 
Selaginellm  and  Isoetem,  and,  at  the  lower  end  of  this,  an 
embryo,  consisting  of  a  short  stem,  bearing  generally  one  or 
more  rudimentary  leaves  {cotyledons)  at  one  extremity,  and 
a  rudimentary  root  at  the  other.  The  embryo  grows,  at  the 
expense  of  the  endosperm,  upon  which  it  gradually  en- 
croaches, and  in  many  orders  entirely  displaces.  While  the 
embryo  is  forming,  the  ovule  becomes  greatly  enlarged,  and 
its  outer  coat  generally  much  thickened  and  hardened  ;  it  is 
now  called  the  seed,  and  soon  separates  at  its  base  from  the 
parent  plant. 

501. — After  a  longer  or  shorter  period  of  rest  the  seed 
germinates,  the  root  and  stem  elongate,  and  the  former 
pushes  out  through  the  micropyle  ;  in  those  seeds  in  which 
much  of  the  endosperm  remains,*  or  in  which  the  cotyle- 

*  Seeds  wbicU  contain  endosperm  are,  in  the  ordinary  descriptive 


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392  BOTANY. 

dons  are  greatly  thickened,  the  latter  remain  for  some  time 
inside  of  the  seed  ;  in  other  cases,  however,  they  soon  with- 
draw themselves,  and  become  expanded  as  the  first  leavea 
of  the  plantlet  The  young  plant  is  quite  simple  at  first, 
but,  with  the  development  of  each  succeeding  internode,  it 
becomes  more  like  the  adult  plant. 

502. — ^The  three  tissue  systems  are  generally  well  de- 
veloped in  Phanerogamia.  The  epidermis  is  copiously  sup- 
plied with  stomata,  and  itself  consists  of  one  or  (rarely)  more 
layers  of  cells,  whose  external  walls  are  generally  somewhat 
thickened,  and  whose  cell  contents  rarely  contain  chloro- 
phyll. Trichomes  of  various  forms  are  abundantly  de- 
veloped. The  fibro- vascular  bundles  are  of  the  form  called 
by  De  Bary  collateral  bundles,  the  only  exception  being  the 
first  formed  one  in  the  root,  which  is  of  the  radial  type. 
The  bundles  are  symmetrically  arranged  in  the  stem,  through 
which  they  pass  vertically  parallel  to  each  other.  They  are 
mostly  common — i.e.,  they  extend  from  the  leaves  into  the 
stem  ;  but  some  are  strictly  cauline — i.e.,  they  are  found 
only  in  the  stems  and  have  no  connection  with  the  leaves. 
All  the  kinds  of  tissues,  with  the  exception  of  collenchyma, 
may  occur  in  the  bundles  ;  but  they  are  mainly  made  up  of 
tracheary,  sieve,  and  fibrous  tissues.  In  the  larger  perennials^ 
as  the  trees,  the  great  mass  of  tissue  in  the  woody  stems  is 
principally  made  up  of  the  tracheary  and  fibrous  tissues  of 
the  fibro-vascular  bundles.  In  succulent  plants,  especially 
those  growing  in  water,  the  bundles  are  usually  smaller  and 
more  simple,  being  sometimes  reduced  to  a  thread  of  trache- 
ary or  sieve  tissue. 

In  the  fundamental  tissues  parenchyma,  in  its  various 
forms,  is  by  far  the  most  common.  The  hypodermal  por- 
tions are  frequently  composed  of  collenchyma  or  scleren- 
chyma.  Laticiferous  tissue  is  common  in  the  fundamental 
system  of  certain  orders. 

503. — By  far  the  greater  number  of  Phanerogams  are 
chlorophyll-bearing  plants,   comparatively  few  only  being 

books,  said  to  be  albuminous,  while  tliose  in  which  it  is  wanting  are 
said  to  be  ezalbnminous. 


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QTMNOSPERMJE.  393 

parasitic  or  saprophytic.  They  range  from  minute  plants 
one  or  two  centimetres  in  height,  and  living  but  a  few  days 
or  weeks,  to  enormous  trees,  which  continue  to  grow  for 
many  hundred  years,  and  which  attain  a  diameter  of  ten, 
and  a  height  of  one  hundred  metres. 

604. — The  Phanerogams  are  separable  into  two  classes, 
s&  follows  :* 

Class  I.  Gyninospermad  (the  ArchespermcB  of  Strasbur- 
ger).  The  ovules  are  not  enclosed  in  an  ovary.  The  en- 
dosperm arises  before  fertilization,  and  forms  rudimentary 
archegonia  ("corpuscula"),  in  which  the  germ-cells  origi- 
nate. The  contents  of  the  pollen  grains  divide  before  the 
growth  of  the  pollen  tube,  forming  a  rudimentary  pro- 
thallium,  much  as  in  SelaginellcB  and  Isoetem, 

Glass  n.  Angiosperm®  (the  Metaspermm  of  Strasburger). 
The  ovules  are  enclosed  in  an  ovary.  The  endosperm  is 
formed  after  fertilization.  The  contents  of  the  pollen  grain 
remain  undivided  before  and  during  the  growth  of  the  pollen 
tube. 

Sub-Class  Monocotyledones.— The  first  leaves  produced  by  the 
embryo  (the  cotyledons)  are  alternate  ;  the  endosperm  is  usually  large 
And  the  embryo  small. 

Sub-Glass  Dicotyledones.— The  first  leaves  of  the  embryo  form  a 
^whorl  of  two  (i.0.,  they  are  opposite);  the  endosperm  is  very  often 
Todimentary  or  entirely  wanting,  and  the  embryo  is  generally  large. 

•      §  IF.  Class  Gymnosperm^. 

606. — The  plants  of  this  class  have  solid  stems,  which 
l)ear  in  most  cases  small,  simple,  narrow  leaves  having  a 
parallel  venation.  The  xylem  portions  of  the  fibro-vascular 
bundles  of  the  stem  are  closely  compacted  into  a  single  dense 
woody  cylinder,  which  is  surrounded  by  a  looser  mass  of 
tissues,  the  so-called  bark,  composed  of  the  united  phlofim 
portions  of  the  bundles.     The  woody  cylinder  increases  its 

*  This  is  essentially  Sachs'  arrangement,  in  his  **  Lehrbuch,"  4te 
Auf.  The  terms  Archespermss  (from  the  Greek  apxh,  beginning,  and 
therefore  properly  Archesperme,  instead  of  Archispermse)  and  Meta. 
spemiflB  (from  fitrd,  after  or  later)  are  those  proposed  by  Strasburper ; 
**  Die  Coniferen  und  die  Gnetaceen,"  1872,  p.  289. 


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394  BOTANY, 

diameter  centrifugally,  and  the  sheathing  envelope  of  bark 
eentripetally,  by  the  growth  of  new  tissues  between  these 

two  portions. 

Gy  mnosperms  are  all  ter- 
restrial, chlorophyll-bear- 
ing plants ;  none  are 
aquatic,  and  none  are  par- 
asitic. Most  of  them  are 
large  trees,  a  few  only 
being  shrubs  or  under- 
shrubs. 

506.  —  The  flowers  of 
Gymnosperms  are  much 
simpler  than  those  of  the 
remaining    Phanerogams. 

They  are  always  diclinous 
Fig.  281.— i4,  ft  male  flower  of -/IW/'wi^'r/ln/i-         ,  ,,  *^ ,  ,     . 

to  .' 2>,  bracts ;  a, stamens.    J?,  pollen  grain  ;  ^  — I.e.,    tlie     male  and    le- 

extlne,  with  Its  large  vesicular  proirnsions,   _     , ..„«„   « :«    Alft^^ 

«;  <,lntine;  y,  cell  in  the  interior  of  the  pol-  male  Organs  are  in  dltier- 

itSSSKtS?fe'^^^^^  ent  flowers.     They  consist 

^A  after  Sachs;  ^  after  schacht.  essentially  of  ouc  or  more 

yariously  shaped  pollen-producing  organs  (stamens)  on  the 
one  hand,  and  naked  ovules  on  the  other ;  both  kinds  of  or- 
gans are  in  most  cases  in  structural  connection  with  scale- 
like bodies,  which  serve  as  acces- 
sory organs  of  reproduction. 

507.  —  The  male  flower  in 
Abies  pectinata  consists  of  an 
elongated  axis,  upon  which  are 
borne  a  large  number  of  spirally 
arranged  stamens  (a.  Fig.  281, 
A),  Each  stamen  is  morpholog- 
ically a  phyllome,  which  is  here 
modified  into  a  body  consisting  ,.       •   ^    ,^^ 

^  T-      i.      i.   n     /  ^7  A\  Fig.  282.-A  catkin  or  spike  of  the 

of  a  short  stalk   {filament)  sup-   male   flowers  of  Pinvs  nylvestrU.— 
i.  i  11  /.I  From  Le  Maoat  iind  Decalsne. 

porting  two  pollen  sacs  (the  an- 
ther).     The  pollen  grains  are  developed  from  mother-cells, 
each  of  the  latter  giving  rise  to  four  grains.     The  pollen- 
mother-cells  themselves  arise  from  the  interior  parenchyma 
of  the  stamen  by  the  differentiation  and  enlargement  of  cer- 


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OTMNOSPERMjE, 


395 


Fig.  283.  — A  Bta- 
meu  from  the  flower 
of  Finus  sylvesiriSt 
showing  the  two  jaol- 
len  eacs.  Magniflcd. 
— From  Le  Maoat  and 
Decaisne. 


tain  cells.     Each  pollen  grain  is  at  first  a  single  cell,  but  by 

the  time  it  escapes  from  the  anther  it  is  a  several-celled  body, 

by  the  formation  of  partitions  within  its  cav- 

i^  {q,  y,  Fig.  281,  B).     The  daughter-cells 

thus  formed  are  doubtless  the  homologues  of 

the  prothallium  of  the  higher  Pteridophytes. 

Each  mature  grain  has  a  double  wall,  of 

which  the  outer  one  (the  extine)  is  hard 
and  thick,  while 
the  inner  one  {in- 
title)  is  thin  and 
delicate  {e  and  /, 
Fig.  281,  B).  In 
this  case  (as  indeed  is  common) 
there  are  two  vesicular  protru- 
sions of  the  extine  (bl.  Fig.  281, 
B),  which  give  the  grain  the  ap- 
pearance externally  of  being  three- 
celled. 

The  nuJe  flowers  of  Pinus  syU 
vestris  are   collected  into  catkins 

Pig/ssi'.-^,  male  flower  of  ^^  spikes  (Fig.  282).       They  are 
Taxua  baooata;  o.  the  pollen  structurally  similar  to  thoso   dc- 

■acs.     Bt  a  stamen,  seen  from  .,     -i       t  rr^^ 

K^i^«    r, .  ^. * .  -»^« —    scribed  above.      Ihe  stamens  are 

short  and  broad,  and  each  bears  on 
its  back  or  outer  surface  two  elon- 
gated pollen  sacs  (Fig.  283).  The 
pollen  grains  are  similar  to  those 
of  Abies. 

In  Taxus  baccata  the  male  flower 
differs  from  those  described  above 
only  in  the  shape  of  the  stamens, 

r«"p;i^Td«wJ?%riinV        which  are  peltate  and  lobed  (Fig. 

ottl'?^:i^:^AlV;^S^!?t  ^^^^^)'     They  bear  attached   to 

:S[il'ranJlf';5?/^VdfieX^^  the  under  surface  three  to  eight 

aril    between    the    upper    hcale    poUen-SUCS,     which    COUtaiu    maUV 
leaves)  and  the   ovale.    All    the    ^_  '  .  -^ 

figures  magnifled.— After  Sachs.      globoSC  poUcU  graiUS. 

These  examples  will  ^erve  to  illustrate  the  general  struc- 
ture of  the  male   flower,   which,   with  minor  variations. 


7 


below.  (7,  a  piece  of  a  foliajce- 
shoot,  •,  with  a  leaf,  6,  in  whose 
axil  is  a  scaly  axis  (the  fe- 
male flower),  which  is  terminated 
by  an  ovule,  gJb;  a,  the  scnles. 
i>,  longitudinal  section  of  the  fe- 
male fl«>wer  in  C,  more  magnified ; 
i,  integumfut  or  coat  of  ovule ; 
kk,  the  body  or  "  nucleus'*  of  the 
ovule ;  m,  aril ;  a?,  a  rudimentary 
axillary  ovule.  (J3^  By  an  error 
of  the  t-ngraver  the  hair  line  from 
X  is  carried  aboat  1  mm.  too  high 
in  the  figure.)  E,  longitudinal 
section  or  an  older  ovule,  but 
before   fertilization ;    i,   integU' 


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396  BOTANY. 

is  in  nearly  all  the  class  essentially  like  the  ones  described. 
The  exceptions,  which  are  in  the  order  Gnetaceae,  will  be  de- 
scribed further  on.  It  may  be  pointed  out  here  that  in  pass- 
ing up  through  the  three  orders  of  the  class,  the  pollen  sacs, 
which  in  the  first  resemble  sporangia,  become  more  nearly 
like  the  anthers  of  the  Monocotyledons  and  Dicotyledons. 


Pio.  285.  Fig   266.  Fio.  287. 

Fig.  S8Sk— ^,  pollen  grnins  of  Biotn  orientalis  before  their  escape  from  the  pollen 
eac  ;  L.ttesh ;  //.  and  ///.,  after  lying  in  water,  the  extlne,  «,  having  been  stripped 
off  by  the  swelling  of  the  intine,  t ;  the  protoplasmic  contents  are  seen  to  consist 
of  two  cells,  a  large  nucleated  one,  and  a  smaller  one.  B,  pollen  grains  of  Finua 
pinader.  before  their  escape  from  the  pollen  sac ;  «,  extine,  with  its  vesicolar  protm- 
sions,  N;  /F.,  side  view  ;  V..  dorsal  view— the  protoplasmic  contents  are  oivided 
similarly  to  those  in  A.    Magnified.— After  Sachs. 

Fis.  286. — i4,  a  pollen  grain  of  Cupresttu  semperrireiu,  showing  the  envelopes  (ex- 
tine  and  intine),  and  the  nidimeutary  prothallium  as  a  small  cell  cnt  off  from  the 
cell  contents.  B,  a  germinating  pollen  grain  :  e,  the  fragmenta  of  the  ruptured  and 
exfoIiat«d  extine  ;  <,  intine  ;  (p,  the  base  of  the  pollen  tube.    X  400.— After  Schacht. 

Fig.  287.— Pollen  grains  of  Ceratozamia  longifolia.  A,  before  srerinination  ;  y, 
a  three-celled  body,  the  rudimentary  prothallium.  B.  s  jrerminatin?  ixtllen  grain  ;  «, 
the  ruptured  extine;  />»,  the  pollen  inbe ;  y,  rudimentary  prothallium.  Magnified. 
—After  Jur&nyl. 

508. — The  pollen  grains,  like  the  male  flowers  themselves, 
are  essentially  alike,  although  differing  considerably  in  ex- 
ternal appearance.  The  vesicular  protrusions  of  the  ex- 
tine {bly  Figs.  285,  B,  and  281,  B),  which  are  common  in 
certain  genera  of  the  order  Coniferm^  at  first  sight  hide  the 
close  similarity  which  exists  between  the  pollen  grains  in 
many  cases.    (Compare  -4,_/.,  in  Figi  285,  with  B,  IV.  of  the 


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QTMNOSPEBMjE.  397 

same  figure.)  In  all  cases,  unless  possibly  the  GnetaceaB  fui> 
nish  some  exceptions,  the  pollen  grains  become  more  than  one- 
celled  before  the  formation  of  the  pollen  tube  (Figs.  281-5- 
^7).  When  the  pollen  grains  germinate — t.c.,  send  out  their 
tubes — they  always  swell  up  and 
burst  the  extine  (which  slips  oflE 
in  the  Goniferse),  and  the  intine 
is  then  prolonged  into  a  tube, 
which  is  continuous  with  the 
cavity  of  the  grain,  and  into 
which  the  protoplasmic  con- 
tents pass  (Figs.  286  and  287). 
The  small  cells  take  no  active 
part  in  the  formation  of  the 
tube,  and  from  their  similarity, 
both  in  structure  and  function, 
to  the  small  cells  in  the  germi- 
nating microspores  of  the  SeU 
aginellcBy  there  can  be  no  doubt 
that  they  are  to  be  regarded 
as  constituting  a  rudimentary 
prothallium. 

609. — The  female  flower  is 
in  most  cases  a  similar  elon- 
gated axis,  upon  which  are  ar- 
ranged spirally  a  considerable 
number  of  phyllomes,  each 
bearing  two  or  more  naked  ov- 
ules.    Thus  in  Abies  pectinata 

the  female  flower  is  the  young     ng.  288.-.!,  a  bract,  c,  detached 
cone,  which  consists  of  an  axis  ^nX'J^uh^g/SSSI.r^^^^^^ 
{sp,  Fig.  288,  B)  bearing  nar-  V^Z^^^^^^^'^^-^^^l^^^^^^ 
row  bracts  (c),  which,  in  turn,  i•;?.'^o^^W^^^^^^^ 
develop  thick  scales  {s,  s)  upon  ^i^f^^}:  itg'^'i^^^X^^i 
their  upper  surface.    The  scales  schacht. 
are  at  first  quite  small  (as  in  A)y  and  it  is  only  as  the  cone 
becomes  older  that  they  grow  larger.      Each  scale  bears  on 
its  inner  face  two  inverted  ovules  {sk,  Fig.  288,  A). 

In  Pinus  sylvestris  the  structure  is  essentially  the  same  as 


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398 


BOTANY. 


Fio.  289. 


Fie.  290. 


Fio.  292. 


Fio.  898. 


Fig.  289.— A  ripe  cone  (female  flower)  of  Plnui  svlvestri». 

Fig.  290.— Partial  section  of  a  cone,  tq,  »q\  tne  scales;  g,  the  seeds;  0m,  the 
embryo  in  the  seed. 

Fig.  291.— A  detached  scale  of  a  ripe  cone,  seen  from  above,  bearing  two  seeda. 
M.  micropyle ;  c*,  chalasa. 

Fiff.  292.— A  detached  »tcale  of  a  young  cone,  seen  from  the  back,  showing  the  tri- 
anirular  bract.    Majrnlfled. 

Fig.  293— The  same  as  Fig.  291 ,  ^een  from  the  front,  showing  the  two ovoles. 
Magnified. 


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QTMNOSPERMjE, 


399 


Pig.  204.— Female  flower  of  CWW- 
tria  quadrivalvia.  d^  d,  decossatiiig 
carpel larv  leaves;  Kb^  bIx  ovules. 
Magnifled.— After  Sachs. 


in  the  foregoing.     The  bract  is  smaller,  however,  aad  the 
scale  attached   to  it  soon  becomes  very  large,   thick,  and 
woody  (Figs.  289,  290,  and  291).     The  bract  and  scale  in 
this  case  have  nearly  the  same  relative  proportions  when 
young  as  they  have  in  the  mature 
cone  of  Abies  pectinata,    (Com- 
pare Fig.  288  with  Figs.  292-3.) 
In  other  cases,  as  in  Callitris 
quadrivalviSy  the  axis  is  short, 
and  the  phyllomes  (d.  Fig.  294) 
which  bear  the  ovules  are  only 
four  in  number  (Fig.  294,  Ks, 
the  ovules).     In  Tazus  haccata 
the  flower  is  still  more  simple. 
It  appears  in  the  axil  of  a  foliage 
leaf,  and  is  a  scaly  axis,  resembling  a  small  cone  (C,  Fig. 
284).     The  lower  scales  do  not,  however,  bear  ovules,  and 
at  the  top  of  the  axis  is  a  single  naked  ovule  {D  and  E,  Fig. 
284).     This  simplicity  is  carried  a  step  further  in  Ginkgo, 
where  the  female  flowers  are  merely  naked  axes,  which  bear 
-  no  bracts  or  scales, 

and  produce  but  two 
ovules  at  their  sum- 
mits (Fig.  295,  8k)* 
The  female  flower 
of  Ci/cas  revoluta  is 
a  rosette  of  phyl- 
lomes, which  bear 
some  resemblance  to 
foliage  leaves,  being, 
however,  smaller, 
Fig.M6.-A  Bhoot  of  Ginkgo  bUoba,    a*,  ovnies  brownish,  and  hairy. 

in  pairs  at  the  end"  of  naked  axes;  above  and  on  f  he  Al^T^rr  fl>/i  IrxnrA** 
right  are  shown  fragments  of  two  leaven,  which  -^iWUg  tne  1  O  W  e  r 
are  seen  to  be  broad.    Nat  size. -Alter  Sachs.  p^p^    ^f    ^YiQiT   mar- 

gins they  produce  a  number  of  spherical  naked  ovules  {sk, 

♦  The  morpbology  of  the  flowers  of  Ginkgo^  as  here  jfiven.  is  by  no 
means  satisfactorj.  Instead  of  the  ovules  being  borne  upon  naked 
axes,  it  is  probable  tliat  they  are  in  reality  upon  foliar  organs— f.«.» 
either  modified  leaves,  somewhat  as  in  Gyca*^  or  upon  elongated  homo- 


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400  BOTANY. 

Fig.  296).    These  structures,  which  may  be  called  carpeU 
lary  leayefifi  show  their  relationship  to  ordinary  foliage  leaves 


BhAlf).   /. 

dereloped 


ctureof 

I  necepsi- 
Tannea. 


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QYMNOSPERM^  401 

the  female  flower  of  the  Gymnosperms.     The  only  consider- 
able departure  from  the  plan  of  the  flower,  as  here  given,  is 
foond  in  the  order  GnetaceWy  which  will  be  described  further 
on. 
610. — ^The  ovule  is  at  first  a  minute  protuberance  of 


Fig.  297.— it,  loDgltadinal  Bectlnn 
cone  Jastopened  ;  c,  the  coat  of  the 
the  ovnle^  this  includes  all  the  flgnr 
yoang  embryo  sac.  B,  a  similar  tkrct 
tranco  of  the  pollen  tube?,  pi^  into  th 
of  the  ovule— the  apper  portion  lac 
shown);  t0,  the  wall  of  the  embryo  si 
tp^  ep^  two  corpne>culii ;  n,  the  neck 
tne  pro-embryo,    ii  x  100 ;  B  x  80.- 

small-celled  tissue  ;  a  littl 
base,  and  rises  as  a  sheath 
finally  more  or  less  comple 
second  integument  forms  ( 
tain  stage  of  its  growth  on 
grows  larger  than  the  oth 
(em.  Fig.  297,  ^) ;  in  it 


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402  BOTANY. 

which  multiply  by  fission,  and  eventually  unite  into  a  con- 
tinuous tissue  (in  reality  a  false  tissue),  the  endosperm  (en. 
Fig.  297,  B).  In  this  mass  of  endosperm  cells  several  near 
the  micropylar  end  grow  larger  than  the  surrounding  ones, 
and  become  filled  with  granular  protoplasm.     These  are  the 

corpustmla  of  Brown,  the 
archego7iia  of  Sachs,  or 
the  secondary  enibryo  sacs 
of  Henfrey  {cp,  cp,  Fig. 
297,  B).  In  some  cases 
they  are  placed  singly  at 
short  distances  from  each 
other,  while  in  others  they 
are  clustered  together 
(1  and  2,  Fig.  298).  Each 
corpusculum  is  at  first  a 
single  cell,  but  when  fully 
developed  it  consists  of  an 
elongated  cell,  the  germ- 
cell  proper,  and,  in  many 
cases  at  least,  one  or  more 
neck-cells,  the  whole  sunk- 
en deeply  into  the  sub- 
pig.  298  —1.  Three  corpnpcnia.  ep.  of  jtmi-  stance  of  the  endosperm. 

peruf  communi*,  cJr>Be  together,  and  seen  In  a  _,.  i    •     ^  j  il     ^.i. 

Jongliudinal  section  of  theovnlc  ;  H,  the  flr»t  ihC  UeCK  IS  lOrmed  by  the 
Buspenifur  ccHb  of  two  fertilized  corpnscnla—         ...  cm      •  i.«  • 

at  flie  upper  end  of  the  corpa^cula  are  hhown  CUttmg  Oil   01  a  pOrtlOU  OI 

ll;Se°"J'^'Sifc;'4crn"u\".1,"«'HS.*eC?'!  the  original  cell  of  thecor- 
SnJof'thSaT;?m'TL?w\^^^^  in  8om«  cases 

cleus,"  A*,  of  the  ovule,  shown  In  outline ;  «,  othcrS   it  di vidcs    SO    aS  tO 

endosperm  in  enlarged  embryo  (•ac  ;  f',  portion  .  i*      i  j 

of  endosperm  broken  up ;  ep,  three  corpus-  form    a  Vertical    rOW,    and. 

cula,  from  the  lower  ends  of  which  the  suspen-  •  .  v  m 

sora,  ».  grow  ;  o,  pollen  tube.    1  and  2  x  a)0 ;  m   OtncrS  a  lOUr-   Or  CVen 

«  X  100 ;  4  X  68:-Aaer  Hofmei.ter.  ^j^j^^  .  ^^||^^        traUSVCrse 

plane  (see  Fig.  298,  1) ;  the  latter  arrangement  has  been 
termed  a  rosette. 

511. — If  we  now  review  the  structure  of  the  ovule  its  ho- 
mologies can  be  readily  made  out.  The  ovule  itself  plainly 
corresponds  to  the  macrosporangium  of  the  higher  Pterido- 
phytes,  and  the  embryo  sac  is  to  be  regarded  as  the  homo- 


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QTMNOSPERMjE.  403 

logne  of  a  macrospore,  which  here  is  not  freed  from  the 
parent  plant.  The  endosperm  clearly  bears  the  same  rela- 
tion to  the  embryo  sac  as  the  prothallium  of  Isoetes  does  to 
the  macrospore ;  and  the  corpuscula  are  slightly  modified 
archegonia.  In  some  corpuscula  the  resemblance  to  arche- 
gonia  is  very  marked,  the  germ-cell  below  being  surmounted 
by  a  short  neck ;  Strasburger  has  even  discovered  a  rudi- 
mentary axial-cell,  thus  completing  the  correspondence  of 
these  organs  to  those  of  the 
higher  Pteridophytes. 

512. — Fertilization  is  effect- 
ed   by    means    of    the  pollen, 

which   comes  in   contact  with 

the  apex  of  the  ovule.     It  is 

transported    from     the    male  . 

flowers    mostly   by    the   wind, 

which    accounts  for    the    im- 
mense   quantity   produced. 

When  the  ovule  has  reached  the 

proper  stage  the  micropyle  is 

filled  with  a  fluid,  which,  dry- 

ing,  carries  the  adherent  pollen  .r^^oT^A'^S^ijT^Lru^fxi^l 

grains  into  contact  with    the  ^V°,Se;  t;./?hl^X^;U^Tt^^^^^^ 

apex   of  the  ovule  body,  where    or''nucleu8"of  theovale;  <,the  em- 
^  ,  •»    •  ,      bryo  sac,  fllled  wlih  endosperm  ;  c.  c, 

they  cermmate  and  form  pol-  two  corpuscula  shown  AUea  with  pro- 

,       -^    °  1 V      1   xi.  J.     X      toplasm ;  A,  the  neck  cell  of  one  cor- 

len  tubes ;  the  latter  penetrate  puscuium;  p,  two  poiien  grains  ap- 

.1  #1   i  •  ^  xt-  1  J    plied  to  the  apex  of  the  ovule  body, 

tne  soft  tissue  OI  tne  ovule  and    into  which  they  have  pent  two  pollen 

eventually    reach    the  corpus-  tubes,  •.  ..-Alter  Pranti. 
cula  (Fig.  299).     In  those  cases  where  the  corpuscula  are 
separated  from  one  another  each  pollen  tube  comes  in  c^"- 
tact  with  only  one  corpusculum  (Figs.  297,  B,  and  299) ; 
when  the  corpuscula  are  close  together  a  single  pollen  t 
may  come  in  contact  with  all  of  them  (Fig.  298,  1  and 
The  union  of  the  protoplasm  of  the  pollen  tube  with  thai 
the  germ-cell  appears  to  take  plaee  by  diffusion  through 
wall  of  the  former,  as  no  openings  in  it  have  been  disco vei 
After  fertilization  the  protoplasm  in  the  germ-cell  becoi 
more  turbid  and  granular,  and  soon  at  the  base  a  transvi 
partition  is  formed,  cutting  off  a  cell,  which  is  the  rudim 


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404  BOTANY. 

of  the  suspensor.  By  the  growth  and  fission  of  this  first 
cell  an  elongated  toiluous  filament — the  suspensor — is  at 
length  formed,  which  develops  at  its  lower  extremity  a  rudi- 
mentary embryo  (c6,  Fig.  298,  3).  Sometimes  each  suspen- 
sor splits  into  several  parallel  ones,  each  of  which  forms  a 
rudimentary  embryo,  but  in  such  cases  it  rarely  happens 
that  more  than  one  continues  to  grow.  While  the  embryo 
is  growing  the  ovule  increases  greatly  in  size,  and  its  coat 
becomes  hardened  or  otherwise  modified.  Internally,  the 
endosperm  in  the  embryo  sac  grows  still  more  rapidly,  and 
finally  entirely  replaces  the  other  tissues  of  the  ovule.  The 
endosperm-cells  at  this  stage  are  filled  with  nutrient  materials 
for  the  support  of  the  embryo. 

613. — The  stem  of  the  embryo  develops  upon  the  lower 
end  of  the  suspensor  as  a  very  short  cylindrical  mass ;  the 
end  opposite  to  the  suspensor  is  a  growing  point  {punctum 
vegetationis),  and  this  produces  two  or  more  cotyledons  as 
lateral  members  ;  lastly,  upon  the  end  of  the  axis  next  to, 
and  under,  the  suspensor  a  rudimentary  root  forms,  covered 
with  a  few-celled  root  cap.  The  fully  formed  embryo  has 
thus,  (1)  an  axis  (called  also  the  hypocotyledonary  stem,  cau- 
licle,  and  erroneously  the  radicle) ;  (2)  the  cotyledons;  (3)  a 
growing  point  above  the  whorl  of  cotyledons  (called  also  the 
plumule) ;  (4)  a  rudimentary  root,  which  is  the  true  radicle, 
and  to  which  alone  the  term  should  be  applied. 

514. — ^When  the  ovule  and  its  contained  embryo  reach  the 
stage  last  described  above  they  constitute  the  Seed.  The 
growth  of  the  embryo  is  suspended,  and  the  tissues  which 
maintained  organic  connection  between  the  ovule  and  the 
parent  plant  are  absorbed,  thus  setting  the  seed  free.  Under 
proper  conditions  the  suspension  of  the  growth  of  the  em- 
bryo may  be  pmlonged  for  some  years  without  the  loss  of 
its  power  of  resuming  it  again  ;  this  latter,  or  the  germina- 
tion of  the  seed,  takes  place  whenever  the  necessary  amounts 
of  heat  and  moisture  are  present.  The  first  stage  in  germina- 
tion is  the  swelling  of  the  endosperm,  which  ruptures  the 
hardened  integument  (testa) ;  this  is  followed  by  the  rapid 
elongation  of  the  axis  (caulicle)  of  the  embryo,  by  which  the 
growing  root  is  pushed  out  (Pig.  300,  77.) ;  the  latter  forms 


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QYMN08PERMJE,  405 

the  first  root  of  the  new  plant,  and  eventually  gives  rise  to 
its  whole  root  sys- 
tern.  The  cotyle- 
dons having  thus 
far  been  in  contact  I 
with  the  endo- 
sperm, which  fur- 
nished them  with 
nourishment,  now 
elongate  and  push 
out  their  bases,  and 
in  some  cases  even- 
tually withdraw  ^ 
themselves  entirely 
from  the  seed  coat 
(Fig.  300,  ///.). 
The  apex  of  the 
axis  (plumule)  be- 
gins a  rapid  growth, 
which  gives  rise  to 
a  leafy  stem  resem- 
bling that  of  the 
parent  plant,  al- 
though usually 
somewhat  simpler. 

616.— The  tis- 
sues of  the  Gymno- 
sperms  are  individ- 
ually but  little  high-  B  c*^  D 
er  than  those  of  the 
Pteridophytes,    but 

in  the  mode  of  their  Fie*  SOO.— Secda  of  Pinu»  Plnea  In  different  {>Uige8  of 

.,  germination.    /.,  ripe  seed  in  loni^itndiual  section;  «, 

aggregation          they  the  seed  coat ;  tf,  endosperm  ;  w,  the  hyp««coiyledoiiary 

"■         i                J.           J  axis  of  embryo  ;  c,  cotyledons  ;  y,  the  inlcropylar  end 

present     great     and  of  the  seed,  with  the  root  of  the  embryo  directed  to- 

;r«>T^/^i.fn«^4>         /i;iT/^^  wards  It.    //.,//.,  four  views  of  the  bqrinning  of  ger- 

impoicant         ainer-  mination;  a,  external  view;  li,  with  half  of  the  seed 

f^nona    in    fliia  laff^r  c^^t   removed;     C,  in    longitudinal  section;    i>,    in 

euuca,  III    tins  mLLtr  transverne  section ;  n,  seed  coat ;  r,  red  membrane  lln- 

resnect     bearinfir      a  *°l?  ^^®  ^^  coat;   «,  endosperm;   c,  cotyledons;   tc, 

•    ^                          S  root ;  X,  ruptured  embryo  sac.    ///.,  germination  com- 

Close  resemblance  to  P'ete,  the  cotyledons,  c,  unfolding,  and  the  hypoctyle- 

,,        ,.                  *     .1  donary  stem.  A«,  elongating ;  w,  the  main  root,  devel- 

the    tissues    of     the  oplug  lateral  roots, «(/.— After  Sachs. 

Dicotyledons  among  tlie  Angiosperms.    The  three  tissue  sys- 


\ 


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406 


BOTANY. 


terns  are  well  defined,  and  include  most  of  the  tissues  de- 
scribed  in  Chapter  VI.  (page  69  et  seq.). 

The  epidermal  system  consists  of  one  or  more  layers  of 
epidermal  cells,   which    are   frequently  much  thickened; 


Fig.  801.— Diagrammatic  cross-sections  of  the  stem  of  Gymnof^penns.  A,  jomg 
stem  with  the  flbro-vaf»cular  bundles. /&,  widely  separated  ;  p,  the  phlo€m;  »,  the 
xylem  ;  /«,  tiraiics  of  the  fundamental  system  ;  e,  epidermis.  B^  a  similar  sectioa  of 
an  older  stem,  the  cambium  layer,  0,  extended  tnrongh  the  fundamental  fyvtein 
from  bondle  to  bundle.  C,  section  of  a  three-year-old  stem,  showing  the  manner  of 
increase  in  the  xylem  and  phlofim ;  pc,  primary  cortex  (phlo€m) ;  ae,  secondaiycor 
tex  (phlofim) ;  c,  cambium  layer ;  «i>,  secondary  wood  (xylem) ;  pto,  primary  wooa 
(xylem) ;  p,  pith  ;  pl^  pS,  j^S,  eel,  cb2,  cbS,  corresponding  phlo(Sm  and  xylem  portions 
of  each  yearns  growth  of  the  bundle. 

stomata  are  common,  and  in  general,  are  quite  regularly  dis- 
posed in  lines  ;  the  outer  surface  is  occasionally  covered  with 
well-developed  trichomes ;  in  general,  however,  they  present 
themselves  as  rough  points,  which  give  a  harshness  to  the 


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QTMNOSPERMJS.  407 

surface.    In  many  cases  oil  or  resin  receptacles  occur  in,  or 
immediately  beneath,  the  epidermis. 

516. — The  fibro- vascular  bundles  are  for  the  most  part 
of  the  collateral  form,  and  in  the  young  stem  they  are  ar- 
ranged so  as  to  form  an  inner  xylem  cylinder  ensheathed  by 
a  phloem  cylinder  (Fig.  301).  The  xylem  of  these  first- 
formed  bundles  is  composed  of  an  inner  mass  of  annular  and 
spiral  vessels,  which  gradually  pass  outwardly  into  tracheldes. 
The  phloem  is  mostly  composed  of  an  outer  mass  of  bast 


Fig.  Wla.— Crora-eectlon  thronsrh  the  new  wood  (A-A),  camblam  (x-x),  and  bark 
{b-h)  of  the  stem  of  Juniperv§  eommunis^  made  at  the  end  of  September,  rriy  m,  me* 
dnllary  rays.  In  the  bark  are  shown  the  layers  of  bast  fibres,  b,  6,  b.  Magnified.— 
After  De  Bary. 

fibres,  which  is  bordered  internally  by  a  mass  of  sieve  tissue 
(latticed  or  cambiform  cells)  and  parenchyma.  Between  the 
xylem  and  the  phloem  a  layer  of  cells  always  remains  as  a 
meristem  tissue  ;  this  constitutes  the  cambium  layer  of  the 
bundles  (c.  Fig.  301,  B.,  and  X-X,  Fig.  301a). 

617. — The  increase  in  the  diameter  of  the  stem  takes 
place  by  the  multiplication  of  cells  in  the  cambium  layer ; 
the  cambium  cells  undergo  longitudinal  fission  by  the  forma- 
tion of  partitions  at  right  angles  to  the  radii ;  these  new  cells 


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408  BOTANY. 

are  developed  on  the  one  hand  into  tracheWcs,  which  com- 
pose the  secondary  wood,  and  on  the  other  into  parenchyma 
and  fibrous  tissue,  composing  the  secondary  cortex  {sw  and 
8Cy  Fig.  301,  6').  There  always  remains  a  layer  of  meristem 
tissue  between  the  secondary  wood  and  cortex  thus  formed, 
so  that  the  next  year  an  additional  increase  is  made  again  in 
exactly  the  same  manner.  Thus  it  happens  that  the  new 
growth  takes  place  between  the  xylem  and  phloem  portions 
last  formed,  and  that  the  corresponding  xylem  and  phloem 
parts  of  any  year's  growth  come  at  last  to  be  separated  by 
the  similar  parts  of  all  the  subsequent  years'  growths  (/i, 
Fig.  301,  C). 

The  tracheldes  are  much  elongated,  with  somewhat  tape^ 
ing  ends  ;  their  walls  are  thickened,  and  are  more  or  less 
copiously  supplied  with  bordered  pits.    (See  Fig.  15,  p.  25.) 
618. — The  fundamental  system  of  tissues  in  the  stem  be- 
comes divided  into  two  portions  by  the  development  of  the 
fibro-vascular  cylinder  described  above.     The  inner  portion, 
the  pith,  which  occupies  the  axis  of  the  stem,  is  composed  of 
parenchyma,  which  soon  loses  its  vitality,  and  persists  as  a 
mass  of  thin-walled  and  generally  cmi)ty  cells.     The  outer 
portion,  the  primary  cortex,  consists  of  parenchyma,  which 
is  usually  chlorophyll-bearing,  and  a  greater  or  less  amount 
of  sclerenchyma  or  collenchyma.     There  is  frequently  a  con- 
siderable development  of  cork  in  the  primary  cortex,  and 
not  rarely  the  whole  of  the  primary  cortex  undergoes  a 
corky  degeneration.      Between   the   fibro-vascular  bundles 
there  are  broader  or  narrower  plates  of  tissue,  composing  the 
so-called  medullary  rays,  which   in  the  young  stems  are 
parenchymatous,  but  in  older  ones  they  are  sclerenchyma- 
tous  (Fig.  301a,  in,  in).     In  that  portion  of  each  medullary 
rftv  lying  between  the  cambium  layers  of  two  contiguous 
o-vascular  bundles  there  is  a  layer  of  meristem  tissue,  the 
ibium  of  the  medullary  rays,  or  the  inter-fascicularcaffi- 
m.     As  this  is  continuous  with   the  cambium  of  the 
idles,  there  is  thus  formed  a  cylinder  of  cambium,  sepa- 
ng  not  only  the  fibro-vascular,  but  also  the  fundamental 
tions  of  the  stem,  into  two  parts  {B,  Fig.  301).    By  the 
nation  of  new  cells  by  fission  in  the  inter-fascicular  cam- 


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OTMNOSPERM^,  409 

binm  at  the  time  of  activity  in  the  cambium  of  the  fibro- 
Tascular  bundles,  there  is  an  annual  addition  made  to  the 
fundamental  tissues  of  the  stem  corresponding  to  the  addi- 
tion made  in  the  fibro-vascular  bundles. 

619. — By  this  internal  increase  of  tissues  in  the  stem  the 
epidermis  is  at  length  ruptured,  and  the  primary  cortex  be- 
comes exposed,  and  eventually  broken  up  and  destroyed. 
The  phloem  portions  of  the  fibro-vascular  bundles,  and  the 
subsequent  external  additions  to  the  fundamental  tissues 
made  by  the  inter-fascicular  cambium,  constitute  what  is 
called  the  Bark  of  the  stem.  There  are  usually  in  it  corky 
developments,  which  often  very  considerably  change  the 
character  and  alter  the  relations  of  its  parts.  The  paren- 
chyma frequently  becomes  somewhat  sclerenchymatous,  while 
in  other  cases  it  undergoes  a  peculiar  degeneration. 

620. — Most  Gymnosperms  have  intercellular  canals  in 
their  stems,  either  in  the  fibro-vascular  or  the  fundamental 
portions ;  these  contain  a  turpentine  in  which  is  dissolved  a 
resin.* 

621. — There  are  three  quite  well-marked  orders  of  Gym- 
nosperms, which  may  be  separated  as  follows  : 

1.  CycadesB,  the  Cycads.  Stem  simple,  or  rarely  branched, 
not  resinous  ;  pith  large  ;  leaves  large,  pinnately  compound, 
crowded  upon  the  stem. 

2.  ConifercB,  the  Conifers.     Stem  branched,  usually  resin- 

*  The  distribution  of  tliese  canals  has  been  made  out  bj  Van  Tie^hem 
(Ann,  des  8ci.  Nat^  1872)  to  be  as  follows  for  the  principal  genera  of 
Coniferm : 

1.  No  canals  in  root  or  stem — TaxiLS, 

2.  Canals  in  the  Etem  onlj. 

(a)  In  the  cortical  parenchyma — Taxodium,  Podocarpus,  Tor^ 
rcya,  Tavga,  etc. 

(6)  In  the  pith  also — Ginkgo. 
8.  Canals  in  both  stem  and  root. 
In  the  cortical  parenchyma  of  the  stem — Cedrus,  Al4e»,  etc. 

(a)  In  the  xylem  of  the  fibro-vascular  buudles  of  r«)ot  and 

stem — Pinun,  Larix,  Picea,  P»eudolarix, 

(b)  In  the  phloem  of  the  fibro-vascular  bundles  of  root  and 

stem — Th^iya,  Cuprekmt*^  Biota,  Araucaria,  etc. 


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410  BOTANY. 

ous ;  pith  slender ;  leaves  small,  simple,  mostly  crowded 
upon  the  stem,  sometimes  scattered. 

8.  GnetacesB,  the  Joint-Firs.  Stem  branched,  not  resin- 
ous ;  pith  slender ;  leaves  small,  opposite,  upon  elongated 
internodes,  or  large  and  only  two  on  a  short,  thick  stem. 

Order  GycadeaB.— Tbe  Cycads  are  large  or  email  trees,  with  much 
the  general  appearance  of  the  palms  and  tree-fernfi.  Tkej  are  of  alow 
growth  and  are  long-lived  ;  the  stem  elonjzates  by  a  nlowly  unfolding 
terminal  bud,  which  gives  rise  to  a  crown  of  widely^preading  pinnate 
leaves,  which  are.  constantly  renewed  above  as  they  die  and  fall  away 
below. 

}^\ne  gQneTK(CJyeai,  EncephAlartoa,  Hficrazamia,  Zamia,  Ceratotamia, 
etc),  and  from  fifty  to  sixty  species,  are  known ;  they  are  all  tropical  or 
sab-tropical,  and  are  about  equally  distributed  in  both  the  Eastern  and 
Western  continents.  Three  species  occur  within  the  United  States  (in 
Florida),  viz.,  Zamia  integrifolin ,  Z.  pumila,  Z.  Floridana. 

Many  species  contain  considerable  quantities  of  starch  in  their  thick 
stems  ;  from  this  a  kind  of  sago  is  made.  In  some  cases  the  seeds  also 
are  nutritious. 

Order  Ck>xiifer89. — The  Conifers  are  for  the  most  part  trees  of  a  con- 
siderable size,  with  branching,  spreading,  or  spiry  toi>8.  They  are 
generally  of  rapid  growth,  and  in  many  cases  attain  a  great  height  and 
diameter.  In  the  greater  number  of  species  tbe  leavt- s  are  persistent, 
and  the  trees,  consequently,  evergreen. 

The  order  contains  thirty-three  genera  and  about  three  hundred  spe- 
cies, which  are  distributed  mainly  in  the  cooler  climates  of  the  globe. 
Fifty  or  more  species  occur  within  the  limits  of  the  United  States. 

The  disposition  of  the  genera  may  be  understood  from  tbe  following 
arrangement,  which  is  essentially  that  of  Parlatore  in  De  Candolle's 
"Prodromus": 

Tribe  J.  Taxin€€e, — Flowers  dioecious  or  rarely  monoedous; 
fruit  fleshy  ;  non-resinous  trees  or  shrubs. 

Gen.  Oinkgo  (SalMuria),  PhyUocladuB,  Podoearpus,  T&rreya,  Taxu4, 
etc. 

The  seeds  of  Oinkgo  are  eaten  in  Japan  as  a  dessert.  Many  species 
furnish  valuable  timber,  which  is  generally  very  durable.  The  wood 
of  tbe  yew(Taxu9  baccata)  of  Europe  and  Asia  is  almo.«»i  indestructible 

Species  of  Podoearpus  in  Java,  Australia,  And  New  Zealand  attain  a 
great  height,  and  afford  good  timber  ;  allied  species  in  the  West  Indies 
and  South  America  are  equally  valuable. 

Ginkgo  is  now  planted  in  this  country  as  an  ornamental  tree. 

Tribe  II,  Abietinece* — Flowers  monoecious  or  dioecious ;  fruit  a 
woody  cone  (excepting  in  Juniperus).    Resinous  trees,  a  few  shrubs. 


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CONIFKRJE.  411 

Siib-Tribe  L  CupresaecB, — Scales  of  the  cone  four  or  more»  decus- 
flatelj  opposite,  or  three  or  four  in  a  whorl,  persistent.  Leaves  nsu. 
ally  scale-like,  persistent,  opposite  or  whorled. 

Gen.  Juniperus,  Cupresaus,  Chamaseyparis,  Thuya,  Libocedrus,  CallU 
tris,  etc. 

The  fleshy  cones  (the  so-called  berries)  of  Juniperut  eommunis  are 
used  in  medicine,  as  are  also  the  leaves  of  /.  Sabina  ;  from  the  former 
an  oil  is  obtained  by  distillation. 

The  wood  of  most  of  the  species  is  valuable. 

From  Juniperua  Virginiana  of  North  America  and  J,  Bermudiana 
of  the  Bermudas,  the  wood  is  obtained  for  making  lead  pencils. 

Cupresstta  aempercirena  is  the  Cypress,  a  native  of  the  Levant ;  its 
wood  is  nearly  indestructible.  C.  macrocarpa  is  the  beautiful  "  Mon. 
terey  Cypr«»ss  "  of  California. 

Chamctcyparia  apluxroidea^  the  White  Cedar  of  the  Eastern  United 
State;*,  is  used  in  the  manufacture  of  pails,  tubs,  etc  Several  allied 
species  from  Japan  are  cultivated  under  the  name  of  Retinospora. 

Thvya  oecidentalia,  the  Arbor  Y itse  of  the  Eastern  United  States,  sup- 
plies enduring  posts,  etc.  ;  its  congener  of  California  and  Oregon  (T. 
gigantea)  is  an  immense  tree  80  to  60  metres  (100-200  ft.)  high. 

Libocedrtta  decurrena,  nearly  related  to  the  last  named,  is  another 
large  Californian  tree. 

Sub-Tribe  II,  Taxodiea,  —  Scales  of  the  cone  spirally  arranged 
(whorled  in  one  genus),  persistent.  Seeds  three  to  nine  upon  each 
scale.     Leaves  usually  linear,  arranged  spiruUy,  or  in  two  ranks. 

Gen.  Taxodium,  Sequoia,  Sciadopytia,  etc.  Taxodium  diatichum,  the 
Bald  Cypress  of  the  Southern  United  States,  is  valuable  for  its  durable 
timber.  S  quoia  gigantea,  the  Giant  Redwood,  or  Big  Tree  of  Califor- 
nia, grows  only  on  the  western  slo{>es  of  the  Sierra  Nevada  Mountains. 
It  attains  a  height  of  more  than  100  metres  (300  ft.),  and  a  diameter  of 
6-10  metres  (20  to  30  ft.).  Its  wood  is  red  in  color,  and  yeij  durable.  8^ 
aempervirena,  the  Redwood  of  the  Coast  Range  Mountains,  is  a  some- 
what smaller  tree  ;  its  durable  timber  is  mucli  used  for  making  shingles, 
weather-l>oarding,  fences,  etc.  Sciadopytia  vertieiUcUa  and  Cryptomeria 
Japonica,  large  trees  of  Cliina  and  Japan,  furnish  valuable  timber. 
They  are  now  considerably  grown  in  the  United  States. 

Sub- Tribe  HI,  Pinecs. — Scales  of  the  cone  spirally  arranged,  usually 
persistent.  Seeds  two  upon  each  scale.  Leaves  linear  (or,  in  some  cases, 
scale-like  on  the  primary  shoots),  spirally  arranged. 

Gen.  Tauga,  Abiea,  Picea,  Larix,  Pinua,  etc.  Tauga  Canadenaia,  the 
Hemlock-Spruce  of  the  Eastern  United  States,  and  T.  Dauglaaii  (Paeu- 
dotauga  Dotiglaaii  of  Carri^re),  the  Douglas  Spruce  of  Oregon  and  Cal- 
ifornia, are  valuable  timber  trees.  The  former  attains  a  height  of  80 
metres  (100  ft.), and  the  latter  of  nearly  100  metres  (800  ft.).  Both  are 
valuable  for  making  the  frames  of  houses  and  sliips. 


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412  BOTANY. 

The  genua  Abie%  contains  the  BalMim  Fir,  A.  baUamea,  of  Eastern 
United  States,  the  Silver  Fir  of  Europe,  A.  peetincUa,  the  Giant  Silver 
Fir,  A,  grandis,  of  Oregon  and  California,  hesides  many  others.  All 
furnish  valuable  timber,  and  from  the  first  is  obtained  a  fine  turpentine 
known  as  Canada  Balsam. 

Picea  excelsa,  the  Norway  Spruce  of  Northern  Europe,  is  a  large  tree 
80  to  60  metres  (100-150  ft.)  high,  from  wliich  white  deal  timber  Is  ob- 
tained ;  from  its  turpentine  Burgundy  pitch  is  made.  P.  *  Iba,  the 
White  Spruce  of  Canada,  and  P.  SUchenm  and  P.  pungem  of  the 
Western  United  States,  are  valuable  for  timber,  and  are  planted  for 
ornamental  purposes. 

Larix  Ametieana,  the  Tamarack  or  American  Larch  of  Eastern 
North  America,  and  L,  Europaa,  the  Larch  of  the  mountains  of  Cen- 
tral Europe,  are  valuable  timber  trees  ;  from  the  latter  Venice  turpen- 
tine is  obtained. 

The  genus  Pinna  contains  many  important  trees  ;  they  may  be 
grouped  as  follows  : 

(«)  Leaves  in  fives. 

P.  Strobus,  the  White  Pine  of  Eastern  North  America ;  this  is  our 
most  valuable  species,  as  it  furnishes  the  greater  part  of  the  pine 
''lumber"  used  in  the  Northern  States ;  it  often  attains  a  height  of 
60-00  metres  (160-200  ft.). 

P.  Lambertiana,  the  Sugar  Pine  of  California,  is  like  the  preceding^ 
but  of  greater  size,  being  from  60  to  90  metres  high  (200-800  ft.}. 

(b)  Leaves  in  threes. 

P.  au  tralii,  the  Yellow  Pine  of  the  Southern  United  States,  fur* 
nishes  a  durable  timber,  used  for  flooring,  shipbuilding,  etc.  Its  tur- 
pentine, which  is  obtained  by  cutting  into  the  trees,  yields  spirits  of 
turpentine  by  distillation ;  the  residue  is  ro^in.  Tar  is  obtained  by 
slowly  buminfr  the  wood  In  kilns  ;  and  by  evaporating  the  volatile 
matters  from  tar,  pitch  is  produced. 

P.  ponderosa^  the  Yellow  Pine  of  the  Rocky  Mountain^  and  California^ 
is  similar  to  the  former,  but  of  greater  size,  being  80-100  metres  high 
(100-800  ft.). 

(c)  Leaves  in  twos. 

P.  iylvestris,  the  "  Scotch  Fir,"  or  "  Scotch  Pine,"  is  a  native  of 
Northern  Europe  and  Asia.  Its  timber  is  extensively  used  in  England 
under  the  names  of  Dantzic  Fir  and  Riga  Fir,  in  the  building  of  ships, 
docks,  houses,  etc. 

P.  larido  is  a  less  valuable  tree  of  Southern  Europe  ;  it  is  known  io 
this  country  as  Austrian  Pine,  and,  with  the  preceding,  is  commonly 
planted  with  us  for  ornamental  purposes. 

P.  rmnosa,  the  Red  Pine  of  Canada,  is  a  tall  and  slender  tree,  much 
nsed  for  making  masts  and  spars. 

(d)  Leaves  single. 

P.  monophyllos,  the  Nut  Pine  of  the  Utah-Arizona  district,  is  pecu- 


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QNETACEuS!.  413 

liar  in  its  single  leaves.  Its  seeds  are  large  and  constitute  an  impor- 
tant article  of  food  for  the  Indians. 

Sub^Tribe  IV.  Araveiruff .Settles  of  tlie  cone  spirally  arranged, 
deddooos.  Leaves  flat  or  four-angled,  often  broad,  sub-opposite,  or 
spirally  arranged. 

Gen.  Dammara,  Araucaria,  Dammara  austraUs  is  the  Kauri  Pine 
of  New  Zealand,  which  attains  a  height  of  60  metres  (200  ft),  and  is 
much  used  for  making  masts.  From  D,  cUba  of  the  Malay  Islands 
Dammar  resin  is  obtained. 

The  genus  Aratccaria  contains  large  pyramidal  trees  of  sinjnil&r 
beauty.  A,  exeelsa,  the  Norfolk  Island  Pine  of  the  South  Pacific  Ocean, 
is  45  to  60  metres  high  (150-200  ft.),with  horizontal  verticillate  branches, 
forming  a  pyramidal  head.  The  timber  is  valuable.  This  species 
and  A,  imMeata  from  Chili,  and  A.  BidwiUi,  of  Australia,  are  now 
grown  for  ornamental  purposes  in  California. 

Order  Qnetacess. — The  Joint-flrs  are  undershrubs,  or  small  trees, 
with  usually  jointed  rush-like  stems,  and  opposite  setaceous  or  oval 
leaves  (the  exceptional  Welicitschia  will  be  described  below).  The 
flowers  differ  from  those  of  the  other  Gymnosperms  in  always  having  a 
perianth — i.e.,  a  floral  envelope  ;  in  some  cases  this  is  single  and  bifid, 
while  in  others  it  is  composed  of  two  or  more  bract-like  bodies  (phyl- 
lomes).  The  stamens  are  single  (in  Gnetum),  or  six  to  eight  united 
into  a  tube  or  column.  The  ovules  are  single  in  each  flower,  and  are 
provided  with  one  or  two  envelopes  ;♦  in  the  former  case  the  single 
integument,  and,  in  the  latter,  the  inner  one,  is  prolonged  beyond  the 
body  of  the  ovule  into  a  style-like  process,  which  is  occasionally  ex- 
panded above  into  a  stigma-like  body. 

The  flowers  are  disposed  in  the  axils  of  the  opposite  bracts  of  short 
lateral  branches  (aments  or  catkins),  which  spring  from  the  axils  of 
the  leaves  upon  the  main  stems. 

Three  genera  of  Gnetacese  have  been  described,  viz.  :  (1)  Gnetum, 
with  from  fourteen  to  eighteen  species,  mostly  confined  to  the  East  In- 
dian islands  and  the  tropical  porti<iU8  of  South  America  ;  (2)  Epiudra, 
with  about  as  many  species,  widely  distributed  in  temperate  and  trop. 
ical  regions  (five  species  occur  in  the  southwestern  part  of  the  United 
States) ;  (3)  WehoiUclUa,  with  but  one  South  African  species. 

♦  In  Gnetum  Gnemon-  there  are  three  envelopes  surrounding  the 
bfidy  of  the  ovule,  but  it  is  probable  that  the  outer  one  is  to  be  re- 
garded as  l}elonging  to  the  perianth.  Some  botanists  reject  the  idea 
that  any  of  these  are  proper  ovule  integuments,  and  regard  the  inner 
one  as  a  true  ovary,  and  the  outer  one  or  two  as  belonging  to  the  peri- 
anth or  stamlnal  whorl.  This  is  the  position  taken  by  Parlatore  in 
De  Candolle's  '*  Prodromus  ;"  by  Beccari,  in  *•  Nuovo  Giomale  Botan- 
ic© Italiano,*'  Jan.,  1877  (Delia  Organogenia,  etc.,  dd  Gnetum  Gnemon)\ 
and  by  Dr.  Gray,  in  "  Bot.  Text-Book."  6th  ed.,  1879,  vol.  1,  p.  269. 


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414  BOTANY. 


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QNETACE^,  415 

The  most  remarkable  member  of  the  order  is  WelwiUcJiia  mirdbilis 
(Fig.  802)  discovered  by  Dr.  Welwitsch  in  1860,  and  described  by  Dr. 
Hooker  in  1862.*  It  consists  of  a  sbort,  thick,  woody  stem  rising 
80  cm.  (1  ft.)  above  the  ground,  and  having  a  diameter  of  from  80  to 
50  cm.  (12  to  20  in.),  and  even  attaining  in  some  cases,  according  to  the 
dlBcoverer,  a  diameier  of  1.4  metres  (4f  It.).  From  tlie  lower  portion 
of  this  stem  a  stout  tap-root  passes  downward,  branching  more  or  less 
at  its  lower  end.  The  top  of  the  stem  is  nearly  flat,  there  being  usu- 
ally a  slight  depression  across  its  diameter.  Tliere  are  only  two  leaves 
attached  to  this  curious  stem,  and  from  the  study  of  the  young  plants 
it  seems  probable  that  they  are  the  persistent  cotyledons.  They  arise 
in  two  deep  grooves  in  the  circumference  of  the  upper  part  of  the  stem, 
and  as  tUey  continue  to  grow  at  their  bases  they  eventually  attain  a 
great  length,  being  nearly  two  metres  long  (6  ft.)  in  full  grown  plants. 
They  are  thick  and  leathery  in  texture,  and  their  fibro- vascular  bun- 
dles are  all  parallel  and  free  from  each  other,  running  from  the  base  of 
the  leaf  to  its  split  and  frayed  apex.  From  the  circumference  of  the 
stem,  above  and  close  to  the  bates  of  the  leaves,  spring  stout  branching 
peduncles,  which  bear  clusters  of  scarlet  cones  (Figs.  802  and  803). 
These  cones  are  composed  of  numerous  opposite  bracts  arranged  in 
four  rows.  In  the  axil  of  each  bract  there  is  a  single  flower,  consist- 
ing  in  the  male  cones  of  a  perianth  of  two  pairs  of  decussating  bracts 
enclosing  a  ring  of  partly  united  stamens  ;  within  these  is  a  rudimen- 
tary, abortive  ovule,  whose  sinjrle  coat  is  curiously  prolonged  so  as  to 
resemble  a  pistil  with  style  and  expanded  stigma.  In  the  flowers  of 
the  female  cones  the  perianth  is  a  compressed,  winged  tube,  lying 
within  the  broad  scales.  There  are  no  rudiments  of  stamens ;  and  in 
the  centre  of  the  perianth  there  is  placed  a  single  erect  ovule  with  one 
elongated  integument. 

It  will  thus  be  seen  that  the  cones  of  WelioiUeJiia,  while  bearing 
some  external  resemblance  to  those  of  Coniferse,  are  not  homologous 
with  them  ;  \nWeltiiUchia  they  are  phort,  flower-bearing,  bracted  axes  ; 
in  Coniferse  they  are  stamen-beariug  or  pistil-bearing  axes,  in  other 
words,  each  cone  is  a  multistaminate  or  multiovulate  flower. 

Fossil  Gymnosperms. — Oymnosperms  first  appeared  in  the  Devo- 
nian,  in  which  they  were  represented  by  species  of  Prototaons,  Cladoxy- 
Ion  and  Schizoxylon,  doubtfully  referred  by  Schimperf  to  the  Coniferae. 
True  conifers  were  present  in  the  Carboniferous,  in  the  Permian  they 
were  abundant,  and  in  the  Tertiary  exceedingly  so.  Araucaria  was 
represented  in  the  Jurassic  by  several  species.  Pinus,  Abies,  Cedrus 
and  Sequoia  onginhied  during  the  Cretaceous  period,  and  were  repre- 

♦  "  On  Welwitschia,  a  new  Genus  of  Qnetaceae/'  by  J.  D.  Hooker, 
in  "  Transactions  of  the  Linnean  Society/'  Vol.  XXIV. 

t  ••  Traits  de  Pal^ntologie  V^getale,"  par  W.  Ph.  Schimper,  Paris, 
186^1874. 


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416  BOTANY, 

sented  by  many  species  during  the  Tertiary.  It  is  interesting  to  not© 
that  the  present  small  and  restricted  genus  Sequoia  was  during  Cre- 
taceous and  Tertiary  times  large  and  widely  distributed  throughout  the 
northern  hemisphere.  In  this  country  two  Cretaceous  species  are  re- 
corded from  Nebraska  and  Kansas,  and  eight  species  from  the  Tertiary 
of  Colorado,  Utah,  Montana,  and  the  region  westward. 

The  Cycads  originated  in  the  Carboniferous,  and  increased  in  num- 
bers to  the  Jurassic,  in  which  twenty  or  more  genera  were  richly  repre- 
sented in  species.  A  Cretaceous  species  of  Pterophyllum  from  Nebraska, 
and  a  tertiary  Zamiostrobus  from  Colorado  have  been  described. 

Two  species  of  Ephedra  from  the  Tertiary  of  Europe  are  the  only 
known  fossil  Gnetacese. 

§  III.    Class  Angiosperm^. 

622. — This  class  includes  the  great  mass  of  the  so-called 
flowering  plants.  The  principal  characters  which  set  these 
off  from  the  preceding  small  class  of  the  Phanerogams 
(Gymnospermae),  are  (1)  the  development  of  an  ovary,  and 
(2)  the  aggregation  of  the  reproductive  organs  into  a  defi- 
nite and  distinct  flower. 

623. — The  plants  of  this  class  have,  in  most  cases,  more 
or  less  elongated  stems ;  these  are  solid  at  first,  and  in  the 
great  majority  of  cases  they  remain  so.  They  usually  bear 
ample  leaves  with  a  parallel  (in  the  Monocotyledons),  or 
netted  venation  (in  the  Dicotyledons).  The  disposition  of 
the  fibro-vascular  bundles  in  the  stem  is  either  like  that  in 
the  Gymnosperms  (in  most  Dicotyledons),  or  they  run 
through  the  fundamental  tissues  parallel  to,  but  independent 
of,  one  another  (in  most  Monocotyledons).  In  the  former 
case,  the  stems  of  the  perennial  species  increase  in  diameter, 
in  the  same  way  that  they  do  in  Gymnosperms,  and  there  is 
here  also  a  well-marked  division  into  pith,  wood  and  bark  ; 
in  the  latter  case  there  is  usually  no  increase  in  the  diameter 
of  the  stem  after  it  has  elongated,  and  in  \i\Q  few  cases  of 
considerable  increase  it  takes  place  by  methods  very  different 
from  that  described  in  the  pi'cceding  class. 

Most  Angiosperms  are  terrestrial  and  chlorophyll-bearing 
plants  ;  there  are,  however,  many  aquatic  and  aerial  species, 
and  a  considerable  number  of  parasites.  They  range,  also, 
in  size  and  duration,  from  minute  annuals,  a  millimetre  in 


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ANGI08PERMJE.  417 

extent,  to  enormous  trees,  60  to  100  metres  high,  and  often 
several  or  many  centuries  old. 

624.  —The  flowers  of  the  Angiosperms,  while  sometimes 
80  reduced  as  to  be  quite  simple,  are  in  all  cases  much  more 
complex  than  those  of  Gymnospenns.     In  most  cases  they 
ai*e  monoclinous  (hermaphrodite),  r.^.,  the  male  and  female 
sexual  organs  occur  in  the  same  flower ;  in  such  case  each 
flower  consists  essentially  of  an  axis  bearing  one  or  more 
pollen  -  producing     organs 
{antherSy  Fig.  304,  «),  and 
one  or  more  ovule-contain- 
ing organs    {ovaries,  Fig. 
304,  F).     These  are,  when 
more  than  one,   generally 
arranged  upon  the  axis  in 
one  or  more  whorls  ;   the 
staminal  whorls    normally 
arise  below  the  ovaries.  Be- 
sides these  essential  organs, 
there  are  usually  secondary 
or  accessory  organs,  such  as 
the  delicate,  and  frequent- 
ly colored  floral  leaves  {pet-       Fig.  an.— masrwmnittlc  section  of  an  an- 
«7«    ^-     «^>«^7«      r^  ^^A     I'«      giospermouB  flower,    if^  calyx;  if,  corolla ; 
alS    or    SepalSy  A    and   A  e,   7,  the  filament,  and  a  the  anther  o^  the  eta- 
Fig.  304),  the  honey  glands,   X^'in'^tSrettt  TtSe  SvS^  ;Tt"e 

p4-p  Ptyle,  and  n  the  stigma  of  the  piatil— the 

^  ^'  ovary  contains  one  ovule,  which  has  a  einele 

526. — The    axis    of     the  <^®*J'  <, enclosing  the  ovule  body,  S:  em,  Die 

embryo  sac  ;  E,  germ  cell  or  g»*rminal  vesi- 

flower    (the     Torus    or    Re-  cle;/w,  apollen-tuhe  ponetrating  thestyle, 

_  ;  ,,  .  and  reaching  the  gi>rm-cell  through  the  mi- 

Ceptacle),     usually    remains  cropyle  of  the  ovule.-Alter  Prautl. 

very  short,  so  that  the  different  organs  of  the  flower  are 
closely  approximated,  and  thus  distinctly  set  off  from  the 
other  parts  of  the  plant.  The  axis  is,  moreover,  but  very 
rarely  prolonged  beyond  the  flower,  all  growth  ceasing  in  it 
when  the  floral  organs  are  developed.  In  most  cases  the  re- 
ceptacle is  conical  or  hemispherical  in  shape  ;  in  other  cases 
it  develops  into  various  shapes,  the  principal  ones  of  which 
will  be  noticed  hereafter. 

626. — The  lower  portion  of  the  flower  axis  generally  bears 
one  or  more  whorls  of  modified  leaves  (phyllomes),  which 


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418  BOTANY. 

constitute  the  floral  envelopes,  or,  technically,  the  perianth. 
Frequently  there  is  a  strong  difference  between  the  outer  and 
inner  whorls,  and  in  such  cases  the  former  is  distinguished 
as  the  calyx,  and  the  latter  as  the  corolla. 

627. — The  whorl  of  stamens  (technically  the  Andrmcium) 
develops  above  the  upper  whorl  of  the  perianth.  Each 
stamen  generally  consists  of  a  slender,  thread-like  stalk  (fila- 
ment), bearing  upon  its  upper  extremity  from  one  to  four 
pollen-sacs ;  this  pollen-containing  portion,  whether  one  or 
more  celled,  is  known  as  the  anther.  In  its  development 
the  stamen  at  first  bears  a  close  resemblance  to  a  rudimentary 
leaf,  both  in  structure  and  position,  and  there  can  be  no 
doubt  that  it  is  a  phyllome,  modified  into  a  pollen-produc- 
ing organ.  Whether  the  anther  is  to  be  regarded  as  an  out- 
growth of  the  phyllome,  or  as  its  modified  upper  portion,  is 
doubtful ;  analogy  would  indicate  the  probability  of  the 
former  view.  There  can  be  but  little  doubt  that  the  pollen- 
sacs  are  to  be  considered  homologous  with  the  microspo- 
rangia  of  the  higher  Pteridophytes,  and  the  latter  are  clearly 
outgrowths  (trichomes  ?)  upon  phy Homes. 

628. — The  pollen-grains  are  developed  here  as  in  Gymno- 
sperms.  from  pollen  mother-cells ;  the  latter  are  differentiated 
parenchyma  cells,  lying  in  or  near  the  axis  of  the  pollen- 
sacs.  Each  mother-cell  undergoes  two  divisions  (by  fission), 
producing  four  parts,  which  become  as  many  pollen-gi*ains. 
The  mature  pollen-grain  is  a  single  cell,  and  consists  of  a 
mass  of  protoplasm  mixed  with  oil-drops,  starch  granules, 
etc.,  surrounded  by  two  investing  membranes,  an  outer  hard 
and  firm  one  (the  extine)^  and  an  inner  thin  and  delicate  one 
(the  intiTte),  In  the  germination  of  the  pollen-grains,  they 
always  remain  single  cells,  there  being  no  formation  of  in- 
ternal cells  (rudimentary  prothallium)  as  in  the  Gymno- 
sperms.  The  development  of  the  pollen-tube  takes  place  as 
in  Gymnosperms,  by  a  prolongation  and  growth  of  the 
intine,  but  here  the  extine  is  not  slipped  off  in  the  process, 
but  only  pierced  in  certain  thin  areas  of  its  surface.  Usually 
but  one  tube  issues  from  each  pollen-grain,  but  in  some 
cases — e.g.,  (Enothera — two  or  more  are  sometimes  found. 

629. — The  female  reproductive  organs  (individually  the 


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'  ANOIOSPERM^.  419 

pistils,  and  collectively  the  Oyncecium)  normally  develop 
upon  the  uppermost  portion  of  the  flower-axis,  and  within 
the  whorl  of  stamens.  They  consist  of  one  or  more  infolded, 
ovuliferous  phyllomes  {carpophylla)  whose  margins  are 
united  so  as  to  form  separate,  or  more  or  less  united  cavi- 
ties (ovaries).  The  apical  portions  of  the  carpophylla  are 
usually  extended,  terminating  in  a  mass  of  loose  pai-enchy- 
matous  tissue,  the  stigma.  The  ovules  arise  as  outgrowths 
(trichomes,  in  the  broader  sense  of  the  term)  upon  some 
portion  of  the  interior  surface  of  the  ovary ;  they  most  fre- 
quently develop  upon  the  margins  of  the  carpophylla, 
although  they  are  by  no  means  confined  to  them.  In  some 
cases  there  is  but  a  single  ovule  in 
each  ovary,  in  others  they  range 
from  a  few  to  several  hundred.  In 
many  cases,  especially  when  the 
ovules  are  numerous,  the  ovulifer- 
ous portion  of  the  ovary  is  devel- 
oped into  a  thickened  mass  of  tis-     fi?.  sos.— very  voang  ovules  of 

sues,  the  placenta,  which    projects    8iicce>.Mve?tage«ordevelSpmen? 

more  or  less  into  the  ovary  cavity.  ;?Je^V:f/e2JorSote' 
630.-Each   ovule  is  at  first  a  2^^ t^^J^'.ht  .l;;.:?'c<^?'?SS 

homogeneous  mass  of  parenchyma-  •ecandlne)  l«  ju»t  beginning  to  de- 

,  ,r  i^i       •  n        1      1  velopagarintf,«o;  In  i?  there  are 

toUS  tissue,   COnstltutmg   the   body  two  rings,  the  npper  being  the  ru- 

/  TTj  ^        \     M  A.\.  1  dimenrar?  secundine.  the   lower 

(or  so-called  nucleus)  of  the  ovule  ;  the  prlmino.     x  140.-After  Da- 

a  little  later  a  circular  ridge  arises  *^*'**"'"* 
upon  the  ovule  body  ;  this  grows  upward,  and  forms  an  in- 
tegument ;  a  second  integument  generally  forms  in  exactly 
the  same  way  outside  of  the  first  (Fig.  305,  A  and  B).  From 
their  position  when  fully  formed,  these  coats  have  received 
the  names  primine  and  secundine,  the  former  being  applied 
to  the  outer,  the  latter  to  the  inner.*  The  coats  never  com- 
pletely enclose  the  body  of  the  ovule,  there  always  remaining 
a  small  opening  (the  micropyle)  over  its  apex  {m,  Fig.  306, 

*  These  terms  were  so  applied  by  Mirbel,  who  was  not  acquainted 
with  the  order  of  development  of  the  coats.  Schleiden  applied  them 
in  exactly  the  opposite  way,*  which  has  led  to  some  conf^ion.  Mir- 
bel's  use  of  the  terms*  although  not  as  good  as  Schleiden's,  is  the  pre. 
▼ailing  one. 


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420 


BOTANY. 


A).  In  their  development  most  ovules,  although  straight 
(Fig.  306,  -4)  at  first,  become  afterward  more  or  less  curved 
upon  themselves  (Fig.  306,  B  and  C). 

The  development  of  the  embryo  sac  takes  place  in  a  much 
simpler  way  in  Angiosperms  than  in  Gymnosperms.*  An 
axial  cell  enlarges  greatly,  becoming  thus  the  young  embryo- 
sac  (Fig.  306,  em).  In  preparation  for  fertilization,  it  divides 
into  a  row  of  several  (3-6)  cells,  the  uppermost  of  which 
forms  four  nuclei,  one  of  which  becomes  the  germ-cell. 
By  the  absorption  of  the  cell  wall,  the  upper  cell  fuses 
with  the  second  (which  may  or  may  not  contain  four  nuclei), 
forming  a  common  cavity  containing  many  nuclei  or  young 


Fig.  806— Diagrammatic  longitadinal  sections  of  omles.  A^  the  straif^ht  ovnle  (or- 
thoiroponf) ;  k^  the  body  of  the  ovule,  with  its  embryo  eac,  em  ;  ai,  the  outer  ovale 
coat  cprimine)  ;  ii^  the  Inner  coat  (rtcandine) ;  m,  the  mlcropyle  ;  c,  the  base  of  the 
ovule,  where  the  coats  arise,  called  also  the  chalaza;  /,  the  ovale  stalk  or  funicnlus. 
J9,an  inverted  ovule  (anatropoofn) :  the  Ions  fanicnlas,/,  has  fused  with  the  primine  of 
one  side  of  the  ovule  and  lormed  the  raph6,  r.  (7,  a  bent  ovule  (campy  lot ropous).— 
After  Prantl. 

cells,  several  of  which,  including  the  Germ-Cell,  remain  at 
the  top,  the  others  (Antipodal  Cells)  occupying  the  lower 
part.     No  endosperm  is  to  be  seen  at  this  stage,  f 

The  fertilization  of  the  germ-cell  involves  two  operations, 
viz.,  Pollination — i.e.,  the  deposition  of  the  pollen  upon  the 
stigma,  and  Fertilization  proper. 

*  See  *•  Nouvelles  Recherches  sur  le  developpement  du  sac  embryon- 
naire  des  Phanerogames  angiospermes/'  by  Julien  Vesque,  in  Annates 
des  Sciences  NatureUes,  1879. 

t  The  endosperm,  which  here  forms  after  fertilization  of  the  germ- 
cell,  may  be  regarded  as  a  belated  piothallium.  It  is  here  no  longer 
necessary  for  the  prothallium  to  precede  the  formation  of  the  germ- 
cell  ;  there  is  consequently  a  considerable  retardation  in  its  develop* 
ment. 


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ANQIOSPERMjS.  421 

581.  Pollination. — As  the  pollen-grains  are  entirely  want- 
ing in  means  of  locomotion,  they  are  dependent  for  trans- 
portation to  the  stigma,  upon  (1)  the  wind  (anemophilous 
flowers)  ;  (2)  certain  contrivances,  by  means  of  which  insects 
(or  rarely  birds)  are  made  to  carry  the  pollen  from  anther  to 
stigma  (entomophilous  flowers)  ;  (3)  the  favorable  position  of 
the  anthers  and  stigmas,  bringing  the  pollen  in  the  open- 
ing anther  into  contact  with  the  stigmatic  surface  {auto- 
gamous flowers).  The  grasses  and  sedges,  and  the  oaks, 
beeches,  chestnuts,  walnuts,  birches,  and  their  allies,  and  a 
few  others,  have  anemophilous  flowers.  In  these  the  pollen 
is  produced  in  great  abundance,  and  the  flowers  are  small, 
uncolored,  and  destitute  of  nectar  (honey).  An  immense 
number  of  plants  have  entomophilous  flowei^s  ;  these  are,  as 
a  rale,  large,  colored,  and  provided  with  nectar-secreting 
glands;  the  nectar  acts  as  a  bait,  and  the  showiness  as  a 
guide  to  honey-loving  insects,  which,  by  various  structural 
contrivances  in  the  flowers,  are  made  to  come  successively 
in  contact  with  the  anthers  of  one  flower  and  the  stigmas  of 
the  next,  in  the  first  dusting  their  bodies  with  pollen,  which 
in  the  second  adheres  to  the  stigmas.  Autogamous  flowers 
are  much  less  numerous  than  either  of  the  foregoing,  and  it  is 
doubtful  whether  there  are  any  species  of  plants  all  of  whose 
flowers  exhibit  constant  autogamy.  There  are  a  good  many 
plants,  however,  which  have  two  forms  of  flowers,  viz.,  large, 
showy,  nectar-bearing,  entomophilous  ones,  and  small,  in- 
conspicuous autogamous  ones,  generally  with  a  rudimentary 
perianth.  FlowerG  exhibiting  this  form  of  autogamy  are 
said  to  be  cleistogamous.     Examples  are  to  be  met  with  in 

Viola^  Lithospermum,  Impatiens,  etc.  ;  early  in  the  season 
these  have  large  flowers,  which  are  entomophilous,  but  later 
only  small  cleistogamous  ones  appear,  and  in  some  species  of 

Viola  these  are  subterranean.  Without  doubt  it  frequently 
happens  that  the  pollen  of  anemophilous  and  entomophilous 
flowers  falls  upon  their  stigmas,  resulting  in  accidental  auto- 
gamy, but  too  frequent  a  recurrence  of  this  is  guarded  against 
by  various  structural  devices.* 

*  Upon  this  interesting  subject  the  student  is  referred  to  Mr.  Dar- 
win's works.  "  The  Various  Contrivances  by  which  Orchids  are  Fertil- 


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422 


BOTANY, 


682.  Fertilization. — Fertilization  takes  place  as  follows : 
The  pollen  grain,  resting  upon  the  moist  surface  of  the 
stigma,  absorbs  moisture  and  germinates,  sending  out  a  tube 
which  penetrates  the  soft  tissues  of  the  stigma  and  style, 
finally  reaching  the  cavity  of  the  ovary,  where  it  enters  the 
micropyle  of  an  ovule  (Fig.  307,  A).  Here  it  comes  in  con- 
tact with  the  apex  of  the  ovule  body,  through  whose  tissues 
it  forces  its  way  until  it  reaches  the  embryo  sac  ;  in  some 

cases,  however,  the 
embryo  sac  has  grown 
out  through  the  apei 
of  the  ovule  body 
I  into,  and  occasionally 
through  the  micro- 
pyle, thus  meeting  the 
pollen  -  tube.  The 
transfer  of  the  con- 
tents of  the  pollen- 
tube  to  the  germ-cell 
has  never  been  ob- 
served, but  doubtless 
it  takes  place  by  diffu- 
sion through  the  pol- 
len-tube and  embrya 
sac.  The  first  result 
of  fertilization  is  the 

•  py1ar  end»  and  namerons  freeendoi'penn  celU  at  the  formation  of  a  Wall  of 
other.    B^  apex  of  embryo  sac.  e  (mach  more  mag-        ,,    ,  j      v 

nifled) :  e6,  very  younK  embryo  of  two  cells, support-  CCllulOSe  around  the 
ed  by  a  two-celled  saspeiisor.     (7,  the  aame,  farther  „        ^,       ,   ,. 

advanced.    All  the  figures  highly  magnified.— After  germ-CCll  ;     the  latter 

^*^***'  soon     divides    trans- 

versely one  or  more  times,  and  thus  gives  rise  to  a  row  of 
cells,  the  suspensor,  at  the  free  extremity  of  which  a  rudi- 
mentary embryo  is  soon  formed  by  the  fission  of  cells  in 
three  planes  (Fig.  307).     Simultaneously  with  the  foregoing 


B 


Fig.  807.—^,  a  longitudinal  section  of  the  anatro- 
pous  ovule  of  Viola  tricolor^  after  rertilization.  p/, 
the  placenta ;  to,  the  raphd,  swollen  at  this  point ;  a, 
the  outer  coat  of  the  ovule  ;  i,  the  inner  ;  o,  the  pol- 
len-tabe  which  \\wi  entered  the  micropyle ;  e,  em* 
brvo  sac,  with  the  very  young  embryo  at  the  micro- 
yla        *        '  '  *  .... 


ized  by  Insects  ; "  "  The  Effects  of  Cross  and  Self-Fertilization  in  the 
Vegetable  Kingdom  ; "  "  The  Different  Forms  of  Flowers  on  Plants  of 
the  Same  Species."  Also  Lubbock's  "  British  Wild  Flowers  Considered 
in  Relation  to  Insects,"  and  Dr.  Gray's  "  How  Plants  Behave." 


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ANQIOSPERMJE, 


423 


development  in  the  apical  portion  of  the  embryo  sjic,  there  is 
a  corresponding  one  in  the  basal  portion.  The  protoplasm 
gathers  about  certain  points,  and  gradually  condenses  so  as 
to  form  as  many  free  and  naked  cells  (Fig.  308).  These 
soon  become  covered  with  cell- walls,  and  they  then  multiply 

rapidly  by  fission,  until  they  ^  ^ 

fill  up  the  embryo  sac  with  a 
continuous  tissue,  the  endo- 
sperm. (Consult  p.  41,  and 
Fig.  33,  A  and  j5.) 

533.   The  Development  of      Fig.  a06.-Poaterior  part  of  the  em. 

the  Embryo.  (Figs.  309  and  X'Vfhrt:Tt^^/y<l!l1,r^^^ 
310).-As  stated  above,  one  of  ^?rpTaim,  15?^'  m^lx^'S^^.i^.tl 
the  first  results  of  the  fertili-  ^^^^  sachs. 
zation  of  the  germ-cell  is  the  formation  of  a  row  of  from 
two  to  many  cells,  the  suspensor  or  pro-embryo,  the  first  or 
proximal  cell  of  which  is  attached  to  the  wall  of  the 
embryo  sac  close  to  the  miciopyle  of  the  ovule  ;  its  distal,  or 
free  end,  always  grows  toward  the  interior  of  the  ovule,  and 


Pig.  900.— Embryos  of  Allium  cepti.  /..  very  yonnsr  "tuce  ;  c,  h.  oells  of  Bnppenior ; 
o,  the  pingle  cell  conetitatfng  the  embryo ;  »,  an  unfertillxcd  germ-cell.  //.,  an  older 
stage,  the  embryo  now  two-celled  ,  es,  the  wall  of  the  embryo  gac.  ///.,  a  still  later 
stage.    Mnch  magnified.— After  Sachs. 

its  last  cell  becomes  transformed  by  successive  fissions  into  a 
several-celled  surface  (/.,Fig.  310) ;  by  a  continuation  of  the 
process  a  many-celled  solid  body  is  formed  (77.,  Fig.  310) ; 
partitions  then  arise  in  the  cells  parallel  to  the*  surface,  and 
the  external  layer  of  daughter-cells  thus  formed  constitutes 
the  dermatogen   or    primary  epidermis   (777.,    Fig.    310), 


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424 


BOTANY. 


About  this  time  there  is  inmost  cases  a  slight  differentiation 

of  the  inner  cells, 

/^^/f^J^^ffe^^  /^y=lF<^  * '       foreshadowing  the 

future  tissue  sys- 
tems (///.  and 
/r.,  Fig.  310).  A 
little  later  the  cot- 
yledons (one  or 
two)  appear ;  in 
the  Monocotyle- 
dons, in  one  side  of 
the  thallus  -  like 
structure  a  depres- 
sion forms,  which 
becomes  the  punc- 
tum  vegetationis  of 
the  embryo,  and 
marks  the  limits  of 
the  stem  and  single 
cotyledon  ;  in  the 
Decotyledons  two 
cotyledons  grow 
out  symmetrically 
from  the  distal  end 
of  the  thallus-like 
structure,  and  the 
depression  between 
them  becomes  the 
punctum  vegeta- 
tionis ( F.,  Fig. 
310).  The  root  is 
the  last  portion  of 
the  embryo  form- 
ed ;  its  cap  (the  pil- 
eorhiza)  is  develop- 
ed from  a  layer  of 
cells  resulting  from 
the  successive  fis- 


Plg.  810.— Development  of  the  embryo  of  Cfapselia 
Burttii-pcutoris  {hlgtilY  masiiifled).  /..  r.  cu^pensor,  or 
pro-embryo  of  five  cells,  and  terminated  by  a  rour-celled 
embryo :  1-1,  the  longinidinal  wall  which  divided  the 
first  emnryo-cell  Into  two  cells;  ^2,  transverse  wall 
which  divided  each  cell  of  the  two-celled  embryo,  mak- 
ing it  foar  celled.  //.,  c  suspensor;  A,  the  hypophysis, 
the  basal  part  of  the  embryo  formed  by  the  division  of 
the  end  cell  of  the  suspensor  ;  the  shaded  portion  of  the 
embryo  Is  the  dermatogen  or  primary  eplaermis  ///., 
embryo  further  advanced ;  the  inner  shaded  cells  con- 
stitute the  plerome.  between  these  and  the  dermatogen 
Ut  the  right  and  left  are  the  cells  of  the  periblem  ;  the 
hypophysis  is  divided  into  two  cells,  A,  A'.  JV.,  still 
oloer  condition.  F.,  embryo  considerably  advanced  ; 
e.  c.  cotyledons  ;  «,  apex  of  stem  ;  the  dermatogen,  peri- 
blem, and  plerome  shown  as  before ;  to,  the  rudiment- 
ary root,  and  root-cap  formed  from  the  cell  A'  of  ///. 
and  /F.— After  Hanstein. 


sion  of  the  penultimate  cell  of  the  suspensor,  the  hypophy- 


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ANOIOSPERMJE.  425 

sis  [hy  Fig.  310,  //.,  7/7.,  7F.,  F.).  The  growing  points  of 
both  root  and  stem  develop  in  all  cases  from  masses  of 
small  cells,  and  never  from  single  apical  cells. 

The  development  of  the  embryo  may  be  studied  by  selecting  the 
youngs  ovaries  of  CapseUa  Bursa-pastoris,  or  Lepidium  intermedium,  and 
dissecting^  out  the  ovules  in  a  solution  of  potassic  hydrate,  and  after- 
wards transferring^  them  to  a  solution  of  glycerine  and  water.  Speci- 
mens prepared  in  this  way  show  clearly  the  embryo  sac  with  the  con- 
tained suspensor  and  embryo  when  examined  by  means  of  a  magrnify- 
ing  power  of  from  one  hundred  and  fifty  to  four  hundred  diameters. 
When  they  have  been  made  too  transparent  by  this  treatment,  their 
walls  may  be  rendered  more  opaque  by  the  addition  of  a  dilute  solution 
of  alum.  The  young  embryo  may  sometimes  be  separated  from  the 
ovule  by  a  gentle  pressure  upon  the  top  of  the  cover-glass. 

534.  The  Endosperm. — During  the  early  part  of  the  de- 
velopment of  the  embryo,  just  described,  the  formation  of 
endosperm  cells  within  the  embryo  sac  takes  place  with  great 
rapidity  ;  in  most  cases  th«  growth  of  the  endosperm  is  so 
great  as  to  displace  the  gi'eater  part  or  even  the  whole  of  the 
surrounding  tissues.  The  cells  of  the  endosperm  contain 
large  quantities  of  nutrient  matters,  which  are  at  first  in  so- 
lution, but  which  later  may  pass  into  a  less  soluble  condition. 
The  growing  embryo  is  imbedded  in  the  endosperm,  and  as 
the  former  increases  in  size,  the  latter  is  displaced  and  ab- 
sorbed. In  many  cases  the  growth  of  the  embryo  is  arrested 
before  the  endosperm  is  all  absorbed — e,g,y  in  Ranunculaceae, 
Violacese,  Solanaceae,  Euphorbiacea3,  Palmaceae,  Liliacese, 
Gramineae,  etc.  ;  in  other  cases  the  embryo  continues  to  grow 
until  it  has  entirely  absorbed  the  endosperm — e,g,y  Cruciferae, 
RosacesB,  Myrtaceae,  Compositae,  Salicaceae,  Cupuliferae, 
Alismaceae,  etc. 

535.  The  Perisperm. — It  rarely  occurs  that  the  endo- 
sperm develops  but  slightly,  and  in  such  cases  there  is  a  con- 
siderable development  of  the  tissues  of  the  ovule  surround- 
ing the  embryo  sac,  constituting  the  perisperm  ;  in  such 
cases  nutrient  matters  are  contained  in  tlie  latter,  which 
functionally  replaces  the  endosperm.  Examples  of  this 
structure  occur  in  NymphaBaceae,  Piperaceae,  and  Cannaceae. 

536. — During  the  growth  of  the  embryo  the  ovule  and 
ovary  undergo  considerable  changes.     The  outer  coat  of  the 


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426  BOTANY. 

ovule  becomes  hardened  by  the  conversion  of  parenchyma 
into  sclerenchyma,  thus  forming  the  testa  ;  in  other  cases  it 
becomes  more  or  less  pulpy,  as  in  MagfioUa,  Pceonia,  etc. 
The  outer  coat  is  liable  to  be  much  modified  in  form  also, 
being  sometimes  developed  into  thin  wings,  or  a  tuft  or 
covering  of  hairs,  as  in  Bignonia,  Asclepias,  Gossypium,  etc. 
The  inner  coat  usually  undergoes  little  change,  generally  be- 
coming thin  and  dry.  The  ovary  in  many  cases  becomes 
hard  and  dry — e.g.y  in  Cupuliferas  and  Leguminosae ;  in 
others  it  is  more  or  less  pulpy,  as  in  the  Cherry,  Plum, 
Blackberry,  etc.  Both  ovule  and  ovary  at  maturity  (now 
called  seed  and  pericarp  respectively,  and  the  latter,  with  all 
its  contained  seeds,  the  fruit)  spontaneously  separate  from 
their  supporting  parts,  by  the  breaking  away  of  the  walls  of 
certain  layers  of  cells. 

The  development  of  the  flower  as  a  whole,  or,  as  it  is  termed,  the  Or- 
ganogeny of  the  flower,  is  an  important  and  instructive  subject  of 
study.  The  law  of  greater  structural  similarity  in  the  earlier  stages  of 
organisms  becomes  very  evident  when  we  look  carefully  into  the  de- 
velopment of  flowers.  Very  many  flowers  which,  when  fully  formed, 
have  little  resemblance  to  each  other,  are  found  to  be  exactly  alike  in 
their  earlier  stages.  Relationships  are  thus  indicated  where  they 
would  otherwise  hardly  be  detected. 

Without  entering  further  upon  this  subject,  which  would  require 
several  volumes  for  its  full  treatment,  it  need  only  be  said  here  that 
all  the  floral  organs  are  essentially  alike  in  form  and  structure  upon 
their  flrst  appearance ;  tlie  sepals,  petals,  stamens,  and  pistils  appear 
at  first  as  small  papillae,  and  it  is  only  after  they  have  grown  somewhat 
that  the  nature  of  the  nascent  organ  can  be  determined  by  its  shape. 
Moreovt'r,  it  is  found  (as  has  so  often  been  seen  in  the  development  of 
animals)  that  the  rudiments  of  some  organs  which  are  wanting  in  the 
fully-formed  flower  are  present  in  its  earlier  stages,  a  fact  of  no  less 
significance  in  the  comparative  anatomy  of  plants  than  of  animals. 

The  general  appearance  of  the  parts  of  the  very  young  flower,  and 
their  development,  are  well  shown  in  the  accompanying  figures  from 
Hofmeister  (Figs.  811-313).* 

Glo88olog:y  of  Angiosperms. — The  great  number  of  species  of  An- 
giosperms  and  the  multitude  of  forms  assumed  by.  different  parts  of 

*  The  student  who  wishes  to  study  this  subject  further  may  profit- 
ably consult  Hofmeister's  '*  Allgemeine  Morphologie  der  Qewachse,' 
Leipsie,  1868,  and  Payer's  *'Organog€nie  de  la  Fleur/'  Paris,  1857. 


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ihe  plant,  ba 
principal  one 

Infloresce 
in  groups  U] 
The  brancliii 


Fig 


F\gB.  811-18.- 
iRota  canina). 
carpels  or  pistili 

podial,  a  few 

dicbotomons. 

Monopodia] 

tnase,  referrec 


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428  BOTANY, 

cence  the  flowers  «.re  p'X}perly  lateral  upon  the  main  axis,  or  the  sec. 
ondary  axes.  The  Jiowers  develop  in  acropetal  (centripetal)  order,  and 
when  the  axis  contint^  to  grow  the  cluster  may  become  indefinitely 
extended,  whence  it  is  called  indeterminate.  In  Cymose  inflorescence 
every  flower  is  properly  terminal  upon  a  main  axis  or  one  of  the  sec- 
ondary ones.  In  every  flower  cluster  the  main  axis  is  first  terminated 
by  a  flower  ;  lateral  benches  (secondary  axes)  tlien  arise  at  some  dis- 
tance below  the  apex,  and  each  of  these  is  terminated  by  a  flower ; 
lateral  branches  termiuated  by  flowers  arise  on  the  secondary  axes,  and 
so  on.  The  flowers  thus  develop  in  ba^ipetal  (centrifuji^al)  order.  From 
the  fact  that  every  axis  is  terminated  by  a  flower,  such  clusters  are 
often  called  determinate.  This  distinction  into  indeterminate  and  deter- 
minate is,  however,  a  misleading  one,  for  some  botryose  inflorescences 
are  in  fact  determinate — e.g.,  the  Umbel  und  Head  ;  while,  on  the  other 
hand,  most  of  the  cymo?e  flower  clusterfc.  are  capable  of  indefinite  ex* 
tension,  ^  is  notably  the  case  witli  the  Belicoid  And  Scorpioid  formic. 
It  not  iiifrequently  happens  that  in  large  flower  clusters  a  part  of  th<* 
branching  is  of  one  type  and  the  remainder  ot  the  other  ;  all  such  case# 
may  be  considered  as  examples  of  mixed  inflorescence. 

The  most  important  of  the  terms  in  common  use  are  nfiven  in  tb^ 
following  table  of  inflorescences  : 

A,  B0TRYO8K  Inflorbscbncb. 

I.  Flowers  solitary  in  the  axils  of  the  leaves — 

e.g.,  Vinea *. Solitary  Axillar7* 

II.  Flowers  in  simple  groups. 

1.  Pedicellate. 

(a)  On  an  elongated  axis :  pedicels  about 

equal — e.g„  Mignonette Baceme. 

(6)  On  a  shorter  axis  ;  lower  pedicels 

longer — e.g.^  Hawthorn Corymb. 

(c)  On  a  very  short  axis ;  pedicels  about 

equal— tf.^r..  Cherry UmbeL 

2.  Sessile. 

(a)  On  an  elongated  axis — e.g.,  Plantain.&pike, 
Var.  /3.  Drooping,  and  scaly  bracted — 

e.g.,  Popla/ Catkin. 

Var.  y.  Thick  and  fleshy— tf.^.,  Indian 

Turnip Spadix. 

(6)  On  a  very  short  axis — e.g.,  Clover. .  .Head. 
IIL  Flowers  in  compound  groups. 
!•  Regular. 

(a)  Racemes  in  a  raceme— «.^.,  Smiladna.Compound  Baceme* 

(6)  Spikes  in  a  spike— e.^..  Wheat Compound  Spike. 

(c)  Umbels  in  an  umbel — e.g.,  Parsnip., CompoMnd  UmbeL 


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GLOSSOLOGY  OF  ANGI08PERM8,  429 

(d)  Heads  in  a  raceme— «.^.,  Ambrosia.  .Heads  Bacexnose. 

(0)  Heads  in  a  spike — e.g.^  Liatris Heads  Spicate, 

And  so  on. 
2.  Irregular. 

Racemosely  or  corymboselj  compound — 

e,g,,  Catalpa Panicle. 

Compound  forms  of  tlie  panicle  itself  are  common — e,g.,  pamcied 
heads  in  many  Compositse,  panicled  spikes  in  many  grasses. 

B,  Cymosk  Inflorescence. 

L  Flowers  solitary ;  terminal — e.g.,  Anemone 

nemorosa Solitary  TerminaL 

IL  Flowers  in  clusters  (Cymes). 

1.  Lateral  branches  in  all  parts  of  the  flower 

cluster  developed — e.^r.,  Cerantium Forked     Cyme,     or 

Dichasium. 
(This  is  the  Bipa/rous,  and  so-called  DUIiotomous  Cyme  of  authors.) 

2.  Some  of  the  lateral  branches  regularly  suppressed. 

(a)  The  suppression  all  on  one  side — e,g,y 

HemerocaUis Helicoid   Cyme,  or 

Bostryx. 
(&)  The  suppression  alternately  on  one 

side  and  the  other — e.g.,  Drosera. .  .Scorpioid  Cyme,  or 

Cicizinus. 
(The  last  two  are  frequently  not  distinguished  from  one  another,  and 
are  called  Monochasia,  Uniparous  Cymes,  or  False  Racemes,) 

C,  Mixed  Inflorescence. 

1.  CymO'Botryose,  in  which  the  primary  in- 
florescence is   botryose,   while  the  sec 
ondary  is  cymose,  as  in  HorsecJusinut,,  .Cymo-Botrys. 
(This  is  sometimes  called  a  Thyrsus,) 

3.  Botryo-Cymose,  in  which  the  primary  in- 

florescence is  cymose,  while  the  sec- 
ondary is  botryose — e,g,,  in  many  Com- 
positcs Botry-Cyme. 

Floral  Symmetry. — The  parts  of  the  flower  are  mostly  arranged 
in  whoris,  which  are  distinctly  separated  from  each  other  {cyclic  flow- 
ers) ;  in  some  cases  they  are  arranged  in  spirals,  with,  however,  a  dis- 
tinct separation  of  the  different  groups  of  organs  {Tiemicydic  flowers) ; 
in  still  other  cases  the  arrangement  is  spiral  throughout,  with  no 
separation  of  the  groups  of  organs  {acyclic  flowers). 


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430  BOTANY. 

In  cyclic  flowers  there  are  moet  frequently  four  or  five  wliorls,  viz. : 

1.  The  CalyXy  comi>o8ed  of  (mostly)  green  sepals, 

2.  The  Corolla,  composed  of  (mostly)  colored  petals. 

3.  (4.)  The  AndrcBcium,  composed  of  one  or  two  whorls  of  stamens. 
4  or  5.  The  OyruBcium,  composed  of  carpels. 

These  whorls  usually  contain  definite  numbers  of  organs  in  each ;  in 
many  cases  the  numbers  are  the  same  for  all  the  whorls  of  the  flower 
(uomerous  flower) ;  when  the  numbers  are  diff*erent  the  flower  is  said 
to  be  heteromerous. 

The  terms  which  denote  these  numerical  relations  are :  monocydie, 
applied  to  a  flower  having  only  one  cycle ;  hieyclic,  two  cycles  ;  tricyclic, 
three  cycles ;  tetracyclic^  four  cycles ;  penta  yclic,  five  cycles,  etc. ; 
monomerous,  applied  to  flowers  each  cycle  of  which  contains  one  mem- 
ber ;  dimerous,  two  meml>ers  ;  trimerous,  three  members ;  tetramerous, 
four  members  ;  pentamerous,  five  members. 

These  relations  can  be  briefly  indicated  by  using  symbols  and  con- 
structing floral  formulae,  as  follows  : 

Ca»,  Co»,  An 6,        Gn»  =  a  tetracyclic  pentamerous  flower ; 
Caa,  Cos,  Anj  +  s,  Gnj  =  a  pentacyclic  trimerous  flower. 

Most  commonly  the  members  of  one  whorl  alternate  with  those  of 
the  whorls  next  above  and  below ;  in  a  few  cases,  however,  they  are 
opposite  (or  superposed)  to  each  other.  These  relations  may  be  indi- 
cated by  a  modification  of  the  floral  formulae  given  above,  as  follows, 
where  the  members  are  alternate  : 

Gn  

An  

An 

Co  

Ca  

B  

When  they  are  opposite  the  arrangement  is  as  follows : 

•     Gn     

An     

Co      

Ca      

B  

In  both  these  formulsB  the  position  of  the  parts  of  the  flower  with 
respect  to  the  flowering  axis  is  indicated  by  the  position  of  the  bract 
B,  which  is  always  on  the  anterior  side,  while  the  axis  is  always  pos- 
terior. 

When  all  the  members  on  each  whorl  are  equally  developed,  having 
the  same  size  and  form,  the  flower  may  be  vertically  bisected  in  any 
plane  into  two  equal  and  similar  halves;  it  is  then  aetinamorphie 
(=  regular,  and  polysymnietrical).    When  the  members  in  each  whorl 


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GLOSSOLOGY  OF  ANGIOSPERMS  431 

are  unlike  in  size  and  form,  and  the  flower  is  capable  of  bisection  in 
onlj  one  plane,  it  is  zygommphic  (=  irregular,  and  monosjnimetrical). 
In  tlie  latter  there  is  generally  more  or  less  of  an  abortion  of  certain 
parts — i.e.,  one  or  more  of  the  sepals,  petals,  stamens,  or  pistils  are  but 
partially  developed,  appearing  in  the  flower  as  rudiments  only.  Some- 
times this  is  so  marked  as  to  result  in  the  complete  suppreseion  of  cer- 
tain parts. 

It  not  infrequently  happens  in  lK>th  actinomorphic  and  zygomorphic 
flowers  that  entire  whorls  are  suppressed  ;  this  gives  rise  to  a  number 
of  terms,  as  follows : 

When  all  the  whorls  are  present  (not  necessarily,  however,  all  mem' 
ber»  of  all  the  whorls)  the  flower  is  said  to  be  ctrmpUte  ;  when  one  or 
more  of  the  whorls  are  suppressed,  the  flower  is  incomplete. 
As  to  ita  perianth,  the  flower  is  said  to  be 
DichlamydeouB^  when  lx)th  the  whorls  of  the  perianth  are  present , 
M(tnocJilamydeous,  when  but  one  (usually  the  calyx)  is  present ; 
Apetalous,  when  the  corolla  is  wanting  ; 

Achlamydeuus^  ornaked,  when  both  calyx  and  corolla  are  wanting; 
As  to  its  sexual  organs,  the  flower  is 
Bisexual  (or  hermaphrodxte)  when  stamens  and  pistils  are  present ; 
Unisexual,  when,  of  the  essential  organs,  only  the  stamens  are  pres- 
ent (then  staminate),  or  only  the  pistils  (then  pistillate) ; 
Neutral,  when  both  stamens  and  pistils  are  wanting ; 
Collectively,  bisexual  flowers  are  said  to  be  mow  clinovs  ;  unisexual 
flowers,  diclinous  ;  while  in  those  cases  where  some  flowers  are  bisex- 
aal  and  others  unisexual  they  are,  as  a  whole,  said  to  be  j)olygamous. 
Diclinous  flowers  are  further  distinguished  into 
Monoecious,  when  the  staminate  and  pistillate  flowers  occur  on  the 

same  plant,  and 
DueHous,  when  they  occur  on  different  plants. 
The  Perianth. — In  a  large  number  of  flowers  the  parts  of  the 
calyx  and  corolla  (sepals  and  petals)  arc  distinct — i.e.,  not  Ht  a)I  united 
to  one  another  ;  such  are  said  to  be  cliorisepalous*  as  to  the  calyx,  and 
c?ioripetalou«  as  to  the  corolla.    The  terms  polysepalous  and  polypttaU 
uus  are  the  ones  most  commonly  used  in  English  and  American  books 
on  botany,  although  they  manifestly  ought  lo  be  used  as  numerical 
terms.     Eleutheropetalous  f  and  dialypetalous  f  are  also  somewhat  used, 
especially  in  German  works. 
The  numerical  terms  usually  employed  are  monO',%  di-,  tri-,  tetra-, 

*  From  Greek  xf^P'Cftv,  to  sever,  to  separate. 

t  From  Greek  eAev^epoc,  free. 

J  From  Greek  dia'/.veiv,  to  part  asunder. 

§  The  terms  moncsepalous  and  monopetalous  were  formerly  used  with 
a  difl*erent  meaning  from  that  given  here ;  they  were  applied  to  the 
forms  now  called  gamosepalous  and  gamopetalous.     This  use,  errone- 


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432  BOTANY. 

penta-sepaUms,  etc. ,  and  mono-,  di-,  tri-,  tetra-,  penta-petalous,  etc,  mean. 
ing  of  one,  two,  three,  four,  five  sepals  or  petals  respectively.  Potysepa- 
hut  9iiid  polypetaUms  are  properly  used  to  designate  **  a  considerable  but 
unspecified  number  "  of  sepals  or  petals.* 

In  some  flowers  the  sepals  or  petals,  or  both,  are  united  to  one 
another,  so  that  the  calyx  and  corolla  are  each  in  the  form  of  a  single 
tube  or  cup.  This  union  of  similar  parts  is  called  cocUeaeence,  The 
terms  gamosepaltms  f  and  gamopeta^ous  (or  sympetalous)  are  used  in  such 
cases.  MonosepaUms  and  monopeicUotts,  still  used  in  this  sense  in  many 
descriptive  works,  should  be  reserved  for  designating  the  number  of 
sepals  or  petals  in  calyx  and  corolla  respectively. 

Not  infrequently  the  calyx  and  corolla  are  connately  united  to  each 
other  for  a  less  or  greater  distance.  This  union  of  dissimilar  whorls  is 
termed  adnation,  aud  the  calyx  and  corolla  are  said  to  be  adnate  to 
each  other. 

The  Androecium. — The  number  of  stamens  in  the  flower  or  the 
andrcecium  is  indicated  by  such  terms  as 

MonaTidrous,  signifying  of  one  stamen ; 

Diandraus^  of  two  stamens ; 

THandrotis,  of  three  stamens ; 

Tetrandrous,  of  four  stamens — when  two  of  the  stamens  are  longer 
than  the  other  two,  the  andrcecium  is  said  to  be  didynamous; 

Pentaiidrous,  of  five  stamens ; 
*    Hcxandrous,  of  six  stamens ;  when  four  are  longer  than  the  remain- 
ing two,  the  andrcecium  is  said  to  be  tetradynamows. 

Other  terms  of  similar  construction  are  used,  as  hej^TidrauSy  seven 
stamens ;  octandrousMg^i^' ;  enneandr<ms,mvke ;  decand/r<ms,  ten ;  dodeO' 
androuSf  twelve ;  and  polyandrous,  many  or  an  indefinite  number  of 
stamens. 

The  stamens  may  be  in  asinjrle  whorl  {monocyelic),  in  which  case,  if 
agreeing  in  number  with  the  rest  of  the  flower,  the  andrcecium  is  said 
to  be  isostemonous ;  they  are  often  in  two  whorls  (hycyelic),  and  when 
each  whorl  agrees  with  the  numerical  plan  of  the  flower,  the  andrce- 
cium is  diplostemonous. 

The  various  kinds  of  coalescence  require  the  use  of  special  terms. 
When  there  is  a  coalescence  of  the  filaments  the  andrcecium  is 

Monadelphoua,  when  the  stamens  are  united  into  one  set ; 

Diadelpfious,  when  united  into  two  sets  ; 

TriaddplwuSt  when  united  into  three  sets,  etc. 

ouB  as  it  obviously  is,  has  not  yet  been  abandoned  in  works  on  descrip- 
tive  botany. 

*  Dr.  Gray  throws  the  weight  of  his  authority  in  favor  of  this  use  of 
these  terms  (**  Structural  Botany,"  1879,  p.  244). 

\  From  Greek  yayuoS,  union. 


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GLOSSOLOGY  OF  ANGIOSPEMMS.  433 

Wlieu  there  is  a  coalescence  of  the  anthers  the  androecium  is  syn* 
genenous  or  synantherous. 

The  stamens  maj  be  adnate  to  the  petals,  when  they  are  epipetcUoua; 
in  some  cases  thej  are  adnate  to  the  style  of  the  pistil,  as  in  the 
Orchids ;  such  are  said  to  be  gynandraus. 

The  principal  terms  which  designate  the  structural  relation  between 
the  anther  and  filament  in  individual  stamens  are : 

Adnate,  applied  to  anthers  which  are  adherent  to  the  upper  or  lower 
surface  (anterior  or  posterior)  of  the  filament ;  when  on  the  upper 
surface  the  anthers  are  introrse;  when  on  the  lower,  extrorse. 

Innate,  applied  to  anthers  which  are  attached  laterally  to  the  upper 
end  of  the  filament,  one  lobe  being  on  one  side,  the  other  on  the  oppo. 
site  one.  The  part  of  the  filament  between  the  two  anther-Iobes  is 
designated  the  connective;  it  is  subject  to  many  modifications  of  form, 
and  often  becomes  separable  by  a  joint  at  the  base  of  the  anther  from 
the  rest  of  the  filament. 

Versatile  is  applied  to  anthers  which  are  lightly  attached  to  the  top 
of  the  filament,  so  as  to  swing  easily  ;  these  may  also  be  introrse  or 
extrorse. 

The  Oynoeciiun. — The  Qynoecium  is  made  up  of  one  or  more  carpels 
{earpids  or  carpophylla)—i.e.,  ovule-bearing  phyllomes,  and  it  is  said  to 
be  mono-,  di-,  tri-,  tetra-,  penta-,  etc..  And  poly  carpellary,  according  as  it 
has  one,  two,  three,  four,  five,  to  many  carpels.  In  old  books  the 
terms  monogynotis,  digynovs,  trigynous,  etc.,  meaning  of  one,  two,  three^ 
etc.,  carpels,  are  used  instead  of  the  more  desirable  modern  ones.  When 
the  carpels  are  more  than  one  they  may  be  distinct,  forming  the  apo- 
carpous gyncdcium  ;  or  they  may  be  coalescent  into  one  compound  or- 
gan, the  syncarpous  ^noecium.  In  the  former  case  the  term  pistU  is 
applied  to  each  carpel,  and  in  the  latter  to  the  compound  organ.  Pis- 
tils are  thus  of  two  kinds,  simple  and  compound  ;  the  simple  pistil  is 
synonymous  with  carpel ;  the  compound  pistil  with  syncarpous  gynoe- 
cium. 

In  the  simple  pistil  the  ovules  actually  ^row  out  from  the  united 
margins  (the  rtentral  suture)  of  the  carpophyllum  ;  the  internal  ridge  or 
projection  upon  which  they  are  borne  is  the  placenta.  Sometimes  the 
ovules  are  erect-^i.e.,  they  grow  upward  from  the  bottom  of  the  ovary — 
and  when  single  appear  to  be  direct  continuations  of  the  fiower  axis 
(Fig.  804).  Suspended  ovules— i.«. ,  those  growing  from  the  apex  of  the 
ovary  cavity — are  also  common. 

In  compound  pistils  the  coalescence  may  be,  on  the  one  hand,  of  closed 
carpels,  and  on  the  other  of  open  carpels.  In  the  former  case  the  pis- 
til has  generally  as  many  loculi  (cavities  or  cells)  as  there  are  carpels  ; 
this  is  expressed  by  the  terms  uni-,  hi-,  tri-,  quadri-^  and  so  on  to  multi- 
locular.  Such  pistils  have  axile  placenta— i.6. ,  they  are  gathered 
about  the  axis  of  the  ovary,  e.g.,  Hypericum,  In  the  case  of  compound 
pistils  formed  by  the  coalescence  of  open  carpels,  the  margins  only  of  the 


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434  BOTANY. 

latter  unite,  fonning  a  common  ovary  cavity  ;  here  the  placentae  gener- 
ally  occar  along  the  sutures,  and  are  said  to  be  parietal — i.e,,  on  the 
walls.  Between  such  unilocular  pistils  and  the  multilocular  ones 
described  above  there  are  all  intermediate  g^radations.  In  one  series  of 
gradations  the  placentae  project  farther  and  farther  into  the  ovary  cav- 
ity, at  last  meeting  in  the  centre,  when  the  pistil  becomes  multilocular 
with  axile  placentae.  On  the  other  hand,  a  multilocular  pistil  sometimes 
becomes  unilocular  by  tlie  breaking  away  of  the  partitions  during 
growth.  In  such  a  case  the  placentae  form  a  free  central  column, 
commonly  called  2k  free  central  placenta. 

In  other  cases  a  free  placental  column  of  an  entirely  different  origin 
occupies  the  axis  of  a  unilocular,  but  evidently  |>olycarpellary  pistil. 
In  Anagallia,  lor  example,  the  placental  column  grows  from  the  base 
of  the  ovary  cavity,  and  there  is  at  no  time  a  trace  of  partitions  (see 
illustrations  of  the  Order  Primulaceae,  p.  507). 

The  Gynoecium  may  be  free  from  all  the  other  organs  of  the  flower, 
which  are  then  said  to  be  hypogynoue*  and  the  gynoecium  itself  tu- 
perior.  Sometimes  the  growth  of  the  broad  flower-axis  stops  at  its 
apex  long  before  it  does  so  in  its  marginal  portions  ;  a  tubular  ring  is 
thus  formed,  carrying  up  calyx,  corolla,  and  stamens,  which  are  then 
said  to  he  perigynou9,\  and  the  gynoecium  half  inferior.  These  terms 
are  used  also  in  the  cases  where  the  gynoecium  is  similarly  surrounded 
by  the  tubular  sheath  composed  of  aduate  calyx,  corolla,  and  androe- 
cium.  In  some  nearly  related  cases,  in  addition  to  the  structures  de- 
scribed above  as  perigynous,  there  is  a  complete  fusion  of  the  calyx, 
corolla,  and  stamen -bearing  tube  with  the  gynoecium.  so  that  the  ovule- 
bearing  portion  of  the  latter  is  below  the  rest  of  the  flower,  e.g..  Com- 
positae.  The  perianth  and  the  stamens  are  said  to  be  epigynotuii  in  such 
flowers,  and  tlie  ovary  is  inferior.  Some  cases  of  epigyny  are  doubtless 
to  be  regarded  as  due  to  the  ad  nation  of  the  calyx,  corolla,  stamens, 
and  ovaries  ;  in  others,  the  ovaries  are  adnate  to  the  hollow  axis  which 
bears  the  perianth  and  stamens  ;  in  still  others,  it  seems  probable  that 
the  hollow  axis  is  itself  ovule-bearing,  and  that  the  true  carpels  are 
borne  on  its  summit. 

Certain  terms  descriptive  of  relations  between  the  stamens  and  pis- 
tils which  have  recently  come  into  use  require  explanation  here. 

In  many  flowers  the  stamens  and  pistils  do  not  mature  at  the  same 
time,  such  are  said  to  be  dichogamous  ;  when  the  stamens  mature  be- 
fore the  pistils  the  flower  is  proterandrous  ;  and  when  the  pistils  ma- 
ture before  the  stamens  they  are  proterogynous. 

In  some  species  of  plants  there  are  two  or  three  kinds  of  flowers, 

♦  From  Greek  v»r<f,  under,  and  ywrj,  female— f.«.,  the  pistil, 
f  From  the  Greek  irepi^  about,  etc. 
X  From  the  Greek  knl,  upon,  etc. 


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GLOSSOLOQF  OF  ANQI08PERM8,  435 

differing  as  to  tbe  relative  lengths  of  the  stamens  and  styles ;  these  are 
called  heterogenous*  or  heieroslyled.  When  there  are  two  forms,  viz., 
one  in  which  the  stamens  are  long  and  the  styles  short,  and  the  other 
with  short  stamens  and  long  styles,  the  flowers  are  said  to  be  dimorph* 
ou$,  or  more  accurately  htterogonou$  dimorpfums,  and  the  forms  are 
distinguished  as  short-styled  and  long-sty'ed  When,  as  in  some  spe- 
cies of  Oxalis,  there  are  three  forms,  viz.,  long-,  mid-,  and  short-styled, 
the  term  trimorph4>us  (or  better  heterogonous  ttimorphous)  is  used. 

The  Fruit. — The  fruit  may  include  (1)  only  the  ripened  ovary  withits 
contained  seeds — eg.,  the  bean  ;  or  (2)  these  with  an  aduate  calyx  or  re- 
ceptacle— e.g. ,  th^AppleC  Many  changes  frequently  take  place  in  ripen- 
ing,  such  as  (1)  an  Increase  in  the  number  of  cells  by  tbe  formation  of 
false  partitions,  or  (2)  a  decrease  in  their  number  by  the  obliteration  o( 
some  ;  (3)  the  growth  of  wings  or  prickles  upon  the  exterior  of  the  ovary ; 
(4)  the  thickening  and  formation  of  a  soft  and  juicy  pulp ;  (5)  the 
hardening  of  some  yiortions  of  the  ovary  wall  by  the  development  of 
sclerenchyma ;  (6)  the  thickening  and  growth  of  the  calyx  or  recep- 
tacle. 

In  cases  where  in  the  ripening  the  ovary  walls  remain  thin,  and 
eventually  become  dry,  the  fruits  are  said  to  be  dry — e.g.^  in  the  bean; 
where  the  walls  become  thickened  and  more  or  less  pulpy,  they  are 
fieshy — e.g.,  the  peach.  These  terms  are  also  used  in  reference  to  the 
fruit  when  it  includes  an  adnate  calyx  or  receptacle.  In  many  fleshy 
fruits  (developed  from  carpels)  the  inner  part  of  the  pericarp  wall  is 
hardened  ;  the  two  layers  are  then  distinguished  as  (Xt)cnrp  and  endo- 
carp  ;  when  there  are  tiiree  layers  the  middle  one  is  the  memX'irp. 

The  opening  of  the  fruit  in  order  to  permit  the  escape  of  the  seeds  is 
called  its  dehiscence,  and  such  fruits  are  said  to  be  dehiscent ;  those 
which  do  not  open  are  indehistent.  In  fruits  developed  from  single 
carpels  dehiscence  is  generally  through  the  ventral  or  dorsal  suture,  or 
both ;  in  those  developed  from  compound  pistils  the  partitions  may 
split,  and  thus  resolve  each  fruit  into  its  original  carpels  (septicidal 
dehiscence) ;  or  the  dorsal  sutures  may  become  vertically  ruptured, 
thus  opening  every  cell  (loculus)  by  a  vertical  slit  (loculicidal  dehis* 
eence).  Among  the  other  forms  of  dehiscence  only  that  called  circum- 
cissile  and  the  i,  regular  need  be  mentioned  ;  in  the  former  a  transverse 
slit  separates  a  lid  or  cap,  exposing  the  seeds  ;  in  the  latter  an  irregu- 
lar slit  forms  at  a  certain  place,  and  throutrh  this  the  seeds  escape. 

The  principal  fruits  may  be  distinguished  by  the  brief  characters 
given  in  the  following  table  :t 

♦  Proposed  by  Dr.  Gray,  Am.  NaiuralitU  Jan.,  1877. 

f  This  is  based  upon  Dr.  Dickson's  classification  as  modified  by 
Professor  Balfour  in  the  article  **  Botany  "  in  the  ninth  edition  of  the 
*'  Encyclopaedia  BriUnnica,"  Vol.  IV.,  p.  153. 


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436  BOTANY. 

A,  Monogynaeial  fruits,  formed  by  the  gynoeciam  of  one  flower. 

L  Capsulary  fruits.     Dry,  debiBoent,  formed  from  one  pistil. 

1.  Monocarpellary. 

(a)  Opening  by  one  suture— «.^.,  CaUha Follicle. 

Q})  Opening  by  both  sutures — eg,.  Pea Leoumb. 

2.  Bi-polycarpellary— €.^.,  Viola Capsxtlb. 

Var.  a.  Dehiscence  circumcissile—e.^.,  .dna- 
gaUis Pyxis. 

Var.  h.  Dehiscence  by  the  falling?  away  of 
two  lateral  valves  from  the  two  per- 
sistent parietal  placent»  —  e.g.,  Mus^ 
tard Silique. 

II.  Schizocarpic  fruits.    Dry,  breaking  up  into  one-celled  inde- 
hiscent  portions. 

1.  Monocarpellary,  dividing  transversely — e.g..  Dee- 

modium Lomknt. 

2.  Bi-polycarpellary. 

(a)  Dividing  into  achene-Iike  or  nut-like  parts 
{ntUleU)^  no  forked  carpophore— e.^.,  Lith' 
oepermum Carcbrulus. 

(&)  Dividing  into  two  achene-like  parts  {meri' 
caips),  a  forked  carpophore  between  them 
— e.g.,  UmbelUfera Cremocabp. 

m.   Achenial  fruits.    Dry,  indehiscent,  one-celled,  one  or  few 
seeded,  not  breaking  up. 

1.  Pericarp  hard  and  thick — e.g..  Oak Nut. 

2.  Pericarp  thin — e.g. ,  Sunflou)er.p Achbnb. 

Var.  a.  Pericarp  loose  and  bladder-like — e.g., 
Chenopodium Utricle. 

Var.  b.  Pericarp  consolidated  with  the  seed — 

e.g.,  ChrasHS Caryopels. 

Var.  c.  Pericarp  prolonged  Into  a  wing — e.g.. 
Ash Samara. 

IV.  Baccate  fruits.    Fleshy,  indehiscent ;  seeds  in  pulp. 

1.  Rind  firm  and  hard— «.^.,  PwmpAan Pbpo. 

2.  Rind  thin— e.^.,  Oooeeheriy Bbrbt. 

V.  Drupaceous  frxdts.    Fleshy,  indehiscent ;  endocarp  indurated 
usually  stony. 

1.  One  stone,  usually  one-celled — e.g..  Cherry Drupe. 

2.  Stones  or  papery  carpels,  two  or  more — e.g., 

Apple Pome. 

VI.  Aggregate  fruits.    Polycarpellary ;  carpels  always  distinct 
The  forms  of  these  are  not  well  distinguished.    In  many  Ranuncu 


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TISSUES  OF  ANG10SPERM8,  437 

lactate  there  are  numeroaB  acbenes  on  a  prolonged  receptacle  ;  in  Mag- 
nolia numerous  follicles  are  similarly  arranged  ;  in  the  raspberry  many 
drupelets  cohere  slightly  into  a  loose  mass,  which  separates  at  maturity 
from  the  dry  receptacle ;  in  the  blackberry  similar  drupelets  remain 
closely  attached  to  the  tleshy  receptacle ;  in  the  strawberry  there  are 
many  small  achenes  on  the  surface  of  the  fleshy  receptacle ;  finally,  in 
the  rose  several  to  many  achenes  are  enclosed  within  the  hollow  and 
somewhat  fleshy  receptacle. 

B,  Polygynacial  fruits,  formed  by  the  gynoecia  of  several  flowers. 

1.  A  spike  with  fleshy  bracts  and  perianths — e.g.. 

Mulberry SoROSis. 

2.  A  spike  with  dry  bracts  and  perianths — e.g.. 

Birch Strobile. 

8.  A  concave  or  hollow,  fleshy  receptacle,  enclosing 

many  dry  gyuoecia — e.g,.  Fig. Syco^sUS. 

Tlie  Seed. — Many  of  the  terms  used  in  the  description  of  the  ovule 
are  applied  also  to  the  seed.  However,  the  modifications  which  most 
of  the  parts  undergo  render  necessary  some  additional  terms.  Thus 
the  outer  integument  is  generally  so  thickened  and  hardened  that  it  is 
commonly  called  the  tesUi,  The  inner  is  sometimes  called  the  tegmen. 
Id  some  seeds  the  outer  coat  becomes  fieshy,  in  which  case  they  are 
baccate  (berry-like) ;  in  others  the  outer  part  of  the  testa  is  fleshy  and 
the  inner  hardened,  so  that  the  seed  is  dru]>e.like  (drupaceous).  Occa- 
sionally an  additional  coat  forms  around  the  ovule  after  fertilization ; 
it  differs  somewhat  in  nature  in  diflTerent  plants,  but  all  are  commonly 
included  under  the  name  aril — e.g.,  May  Apple. 

The  testa  may  be  prolonged  into  one  or  more  flat  extensions  ;  such  a 
seed  is  winged — e.g.,  Catalpa.  Its  epidermal  cells  may  be  prolonged 
into  trichomen,  forming  the  comose  seed — e.g.,  cotton. 

The  embryo  either  occupies  the  whole  of  the  seed  cavity,  in  excUbu- 
minons  seeds,  or  ii;  lies  in  or  in  contact  with  the  endosperm,  in  the 
albuminous  seeils.  It  is  stratght — e.g.,  the  pumpkin;  or  variously 
curved  and  folded — e.g.,  in  Erysimum,  where  the  cotyledons  are  in- 
cumbent, and  in  Arabis,  where  they  are  acctimbent. 

687.— The  Tissues  of  Angiosperms. — The  epidermis  of 
Angiosperms  does  not  differ  in  any  marked  way  from  that 
of  the  Gymnosperms  and  the  Pteridophytes.  The  principal 
differences  are  that,  as  a  rule,  the  stomata  are  more  numer- 
ous, and  the  trichomes,  which  are  much  more  commonly 
present,  show  greater  variations  in  form  and  stnicturo.  It 
is  noticeable,  furthermore,  that  in  both  these  points  the 
Dicotyledons  excel  the  Monocotyledons. 


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438  BOTANY. 

688. — The  tissues  of  the  fundamental  system  in  the  An- 
giosperms  are,  in  general,  sharply  set  off  from  those  of 
the  epidermal  and  fibro-vascular  systems.  In  the  annual 
stemmed  species  the  fundamental  tissues  constitute  the  great- 
er part  of  the  stems,  but  in  perennial-stemmed  species  there 
is  proportionately  less  of  these,  and  more  of  the  fibro-vascular 
tissues ;  in  the  former  the  principal  tissue  in  the  funda- 
mental system  is  parenchyma,  which  occupies  the  interfascic- 
ular spaces,  as  well  as.  the  greater  part  of  that  lying  between 
the  bundles  and  the  epidermis — i.e.,  in  the  cortical  region. 
In  perennials,  on  the  contrary,  the  interfascicular  spaces  are 
in  many  cases  occupied  by  sclerenchyma,  and  the  cortical 
region  either  entirely  disappears  (as  in  Dicotyledons)  or  it 
becomes  filled  with  sclerenchymatous  or  fibrous  tissue. 

In  the  leaves.the  fundamental  system  rarely  includes  more 
than  chlorophyll-bearing  parenchyma,  while  in  the  parts  of 
flowers  a  similar  tissue  is  found,  which  is,  however,  generally 
wanting  in  chlorophyll.  The  succulent  parts  of  fruits, 
whether  phyllome  or  ciaulome  structures,  are  composed  of 
parenchyma  of  the  fundamental  system. 

589. — The  fibro-vascular  bundles  of  the  stems  of  Angio- 
sperms  are  entirely  of  De  Bary*s  ** collateral"  class — that  is, 
each  bundle  in  cross-section  presents  more  or  less  distinctly 
two  sides,  viz.,  xylem  and  phloem.  Each  of  these  sides,  as 
previously  described  (paragraph  147),  generally  contains 
parenchymatous,  fibrous,  and  vascular  tissues,  the  latter 
tracheary  in  the  xylem,  and  sieve  in  the  phloem. 

640. — The  disposition  of  the  bundles  in  the  Angiosperms 
is  for  the  most  part  dependent  upon  the  position  of  the  leaves. 
Nearly  all  the  first-formed  bundles  are  of  the  kind  termed 
"  common  bundles" — that  is,  they  extend  on  the  one  hand 
into  the  leaf,  and  on  the  other  down  into  the  stem.  In 
Fig.  314  there  pass  down  from  each  leaf  three  bundles ;  at 
the  lower  internode  these  are,  on  the  left,  a,  J,  c,  and  on  the 
right,  d,  e,  f.  At  the  next  internode,  where  the  leaves 
stand  at  right  angles  to  the  lower  ones,  there  are  three 
bundles  again,  g,  h,  /,  and  k,  I,  m  ;  these  are  largest  at  their 
points  of  curvature,  and  they  dwindle  in  size  as  they  pass 
downward  and  finally  unite  with  the  bundles  from  the  lower 


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TISSUES  OF  ANQI08PERM8. 


43d 


Fig.  814.~Showing  the  disposition  of  the  llbro-vascultr  bundles  in  the  stem  of  C/«m- 
Qtia  vUUiUa.  a,  6,  c,  —  d,  «./.  the  bundles  from  the  lower  pair  of  leaves;  g.K,i,~- 
k,  I,  m,  the  bundles  from  the  second  pair  of  leaves  ;  n,  o.  p.  —  9.  r,  «,  the  oundles 
from  the  third  pair  of  leaves  ;  ce  and  t,  the  median  bundles  of  the  Iburth  pair  of 
leaves  ;  a,  /3.  —  y,  (5,  pairs  of  rudimentary  leaves  not  yet  supplied  with  bundles.— 
After  NSgeli. 


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440 


BOTANY. 


pair  of  leaves.  The  bundles  from  the  third  internode  pass 
downward,  and  in  like  manner  join  those  from  the  second 
pair  of  leaves,  and  so  on.    Thus  in  such  a  stem  every  bundle 

passes  downward 
through  one  in- 
ternode before 
joining  another, 
and  in  any  inter- 
node all  the  bun- 
dles are  derived 
from  the  leaves  at 
its  summit. 

In  Fig.  315, 
with  a  similar  ar- 
rangement in  tiie 
main,  there  are 
some  complica- 
tions. The  lateral 
leaf-bundles  (J,  c 
in  the  lower  inter- 
node, and  g,  h  in 
the  next  one)  pass 
downward  to  the 
next  node,  where 
they  unite  with 
other  descending 
bundles  ;  and  the 
median    bundles, 

^yfy  h  Oy  ^»  ^>  P^SS 

down  through  two 
intemodes,  and 
then  fork  right 
and  left,  and 
unite  with  other 
descending  bun- 
dles. Thus  in 
any  internode  there  are  bundles  from  at  least  three  leaves. 
This  is  shown  in  the  cross-section  of  the  next  to  the  lower 
internode  (Fig.  316),  in  which  the  bundles  A,/,  g,  k,  %  pass 


Fig.  815.~DiagTmm  showing  the  amngement  of  the 
flbro-va»cnlar  bundles  In  the  stem  of  Lalkyrus  Pteudti- 
phaoa.  The  bundles  nearest  i  he  observer  are  flgared  dark- 
er, those  Cuthest  away  lighter. -After  NftgelL 


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TISSUES  OF  ANQIOSPERMS. 


441 


816.  —  Croeft-sec- 
tloD  of  the  next  to  the 
lower  interaode  of  Fi 
8I6,fhowing  the  arraoffe- 

'""    ^      "    i^the 


^ 


'/ 


into  the  second  leaf — i.e.,  the  leaf  at  the  summit  of  the  in- 
temode  under  consideration  ;  the  bundles 
Z,  w,  n  descend  from  the  leaf  next  above, 
and /?  and  q  from  the  one  still  higher. 

641. — ^We  may  get  a  clearer  idea  of  the 
mutual  relations  of  the  bundles  if  we  con- 
ceive the  bundle-cylinder  to  be  split  down 
on  one  side,  and  spread  out  upon  a  plane. 
In  Fig.  317  we  have  such  a  diagrammatic 
representation  of  the  arrangement  of  the  jower  intornode  of  v\g, 

,-,1         'ii         ^  M    cyi      1  A-     816,ihowingthe«nv««yH- 

bundles  m  the  stem  of  btachys  angusti-  ment  of  the  bundles, 
folius.  Here  each  leaf  sends  down  two  -Aiter^CreU.  ^' 
bundles,  which  pass  through  two  internodes  and  then  unite 

with  other  descending  bundles  at 
their  middle  points.  The  fibro- 
vascular  cylinder  is  thus  compos- 
ed when  complete  of  repeatedly 
branching  bundles.  A  cross-sec- 
tion (Fig.  318)  through  the  stem 
at  some  distance  above  the  lower 
leaves  in  Fig.  317 
shows  that  each 
intemode  c  o  n  - 
tains  bundles 
from  two  pairs  of 
leaves — t.c,  those 
at  its  summit  and 
those  at  the  sum- 
mit of  the  one 
above.  In  Fig. 
318  the  pairs  of 
bundles  marked  c  and  d  descend 
from  the  leaves  c  and  rf,  while 
those  marked  e  and/  pass  down 
from   the  leaves  one    intemode 

FlfT.  817.— Dia<^m  ehowine  the  ar-  llighcr  up. 
raojrement  of  the  flbro-va§cumr  bun-        ▼  ..,.  i-»t 

dies  in  sktctiy  anguttifoiiu*.  a,  ft.      In  a  Similarly  Constructed  dia- 
fi^m%'hlih*Se%uc^8fve^pa^°^  gram  of  the  fibro-vascular  cylin- 

leaveaapring-AfterNftgell.  j^^   ^f    ^^^^.^   ^^^^^^   ^^ig.     319, 

projected  upon  a  series  of  transverse  and  vertical  lines  to 


Fie.  818.  —  CroM- 
eection  of  the  next 
to  the  lower  inter- 
node  in  Fit^.  817, 
showing  the  dispooi- 
tlon  of  the  bundles, 
the  lettering  a**  in 
Fig.  8n.-Aner  Na- 

gen. 


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442 


BOTANY. 


indicate  the  nodes  and  the  vertical  ranks  of  leaves)  the  sin- 
gle bundles  which  descend  from  the  leaves  are  shown  to  pass 
through  from  ten  to  twelve  internodes  before  uniting  with 


Fig.  819.— Diagram  ahowing  the  arrangement  of  the  fibro-Yascnlar  bundles  In  29 
internodes  of  the  atem  of  IberU  amara.—AftAir  NAgeli. 

other  bundles.  It  is  seen,  moreover,  that  there  are  running 
through  the  stem  five  series  of  branching  bundles,  which  are 
not  quite  vertical,  but  slightly  spiral.  In  Fig.  320  is  shown 
the  appearance  of  an  actual  section  of  the  stem  taken  be- 


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TISSl/ES  OF  ANQI08PERM8.  443 

tween  the  fifth  and  sixth  leaves  of  the  preceding  figure.  The 
bundles  are  numbered  as  in  Fig.  319. 

542. — In  a  comparatively  small  number  of  instances  thei-e 
are  fibro-vasculai*  bundles  in  the  stem  which  have  no  connec- 
tion with  the  leaves.     These  are  known  as  cauline  bundles. 

543. — In  the  Monocotyledons  and 
many  herbaceous  Dicotyledons,  the 
fibro-vascular  bundles  are  closed — that 
is,  there  is  no  zone  of  meristem  tissue 
left  between  the  xylem  and  phloem  after 
these  have  passed  over  into  permanent 
tissues.  There  is,  as  a  consequence,  a 
definite  period  of  growth  for  the  bun- 
dles, and  when  any  bundle  haa  fully  Pig.8!».-CroB».secUonof 
formed  all  its  tissues,  no  further  devel-  {??h'e'ttS!1Sk<^'fbove 
opment  can  take  place  in  it  This  gen-  the  iifthiei»f. -After  Nagea. 
erally  results  in  definitely  limiting  the  growth  of  the  inter- 
nodes,  and  in  consequence  such  plants  are  as  a  rule  short- 
lived. The  perennial  woody-stemmed  Dicotyledons,  and 
some  of  the  herbaceous  annuals,  possess  bundles  which  are 
open— that  is,  there  is  left  between  the  xylem  and  the  phloSm 

a  zone  of  meristem  tissue  which 
continues  to  grow  long  after  the 
other  parts  of  the  bundle  have 
passed  over  into  permanent  tis- 
sues. Plants  with  such  bundles 
may  live  and  continue  to  grow  for 
an  indefinite  time. 

544. — A   cross-section   of    the 

stem  of  a  Palm  (Fig.  321)  shows 

it  to  be  composed  of  parenchyma- 

FJg.  8«i.-Cro«8-8ection  of  the  tous  tissuc  traversed  by  myriads 

etem  of  a  palm.    «c,  cortical  zone ;       .     ^,  ,        i        ji  i.*   i_ 

Ig,  the  softer  interior  jwrtion  of  the  of     fibrO-VaSCUlar    DUndleS,   WniCn 

•tern ;  Ig'y  the  harder  peripheral  ,  ,   .  . ,  '»  -, 

portion.-After  Duchartre.  dcSCeud  from  the  CrOWU  Of  ICaVCS. 

Each  leaf  sends  down  from  its  broad  insertion  numerous 
bundles,  which,  in  a  vertical  section,  are  seen  first  to  pass  in 
toward  the  centre  of  the  stem,  and  then  to  cui-ve  downward 
and  finally  outward.  The  centre  of  the  stem  is  thus  softer 
than  the  peripheral  portion,  as  in  the  latter  the  descending 


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444 


BOTANY. 


bundles  are  more  numerous.  In  such  a  stem  it  is  evident 
that  there  can  be  no  considerable  increase  in  thickness  after 
it  is  once  formed,  and  we  consequently  find  that  palms 
take  a  long  time  for  the  formation  of  a  broad  bud  or  growing 
point  {pu7ictum  vegetationis),  and  afterward  push  up  a  cylin- 
drical stem  in  which  little  change  subsequently  takes  j)laco. 

In  the  Dragon  trees 
{Draccena,  sp.)  and 
some  other  Monoco- 
tyledons, there  is  a 
I  thick  layer  of  paren- 
chymatous cortex  be- 
tween the  column  of 
fibro-vascular  bundles 
and  the  epidermis 
(Fig.  322y  r),  and  in 
the  deeper  layers  of 
^  this  a  persistent  meri- 
stem  tissue  is  found 
(Fig.  3^2,  a:).  In  this 
meristeni  there  are 
formed  fibro-vascular 
bundles,  which  lie  par- 
allel to  tliose  already 
formed,  and  in  this 
way  the  stem  slowly 
increases  in  thickness. 
645.— In  tliose  Di- 
«    ««    r.  ...  *  ,v_  cotyledons       whose 

Plff.  822.— Oross-eection  of  stem  of  Draccena.    «,  . 

epidermis;  *,  cork;  r,  cortex;  b,  a  fibro-vascniar  StemS        mcrease       lU 

bnndle  bending  oat  to  a  leaf  ;  m,  parenchyma  of  the  ,  v  •   i             .  i             i 

fandamental  system  :  g.  g,  fibro-vascular  bundles;  tlllCKneSS  there  alWayS 

flj,  meristem  aone  of  the   fuiidarnvntal   system  in  ,i^,,^i^.^«  ««^«    «    T«„«.. 

which  new  bundles  and  Ussues  are  forming.— After  UeVClopS  SOOll   a   layer 

®'^***'  of    meristem    tissue, 

which  connects  the  cambium  layer  of  one  fibro-vascular 
bundle  with  that  of  the  other  (Fig.  323).  This  is  made 
easier  from  the  fact  that  in  most  (but  not  all)  Dicotyle- 
dons the  bundles  lie  at  nearly  the  same  depth  beneath  the 
epidermis  on  all  sides  of  the  stem,  thus  forming  a  cylinder, 
or  in  cross-section,  a  ring,  as  in  Fig.  323.     Both  the  fascicu- 


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TISSUES  OF  ANQI0SPERM8. 


445 


Fig.  8S8.— Diagrtmg  of  dicotyledonous  ctems  as  seen  in  croM-section.  J?,  the  cor- 
tical, if,  the  medallarj  portion  of  the  f nndamental  aystem ;  p,  the  phloem ;  ar,  the 
zylem  ;  6,  5,  6,  gronpe  of  bast  fibres ;  fc,  the  fascicular,  io,  the  interfludcnlar  cank' 
blom.— After  Sachs. 


Pig.  894.^0ro8S-8ection  through  a  young  intemode  of  SamtmeMS  nigra.  P,  P,  cor- 
tical parenchrma ;  p,  p,  parencbTma  of  the  pith  ;  between  r—r  and  P—P,  sieve  tie- 
sne ;  g,  a,  pitted  vessels ;  «,  «,  ana  above,  spiral  vessels ;  c  —  c,  the  cambium  zone,  x 
2S0.— After  De  Bary. 


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446 


BOTANY. 


lar  and  interfascicular  cambium  layers  are  composed  of 
elongated  cells^  which  multiply  by  fission  in  a  tangential  di- 
rection, and  thus  give  rise  to  radiating  rows  of  cells  (Figs. 
324  and  325).  In  a  tangential  section  the  cambium  cells 
present  an  elongated  outline,  and  their  extremities  are 
usually  more  or  less  oblique  (Fig.  326).  From  these  cells 
there  develop  various  tissues.  Thus,  on  the  one  side,  the 
phlo(5m  parenchyma,  sieve  and  fibrous  tissues  may  be  pro- 
duced by  more  or  less  great  modifications  (Fig.  327).  On 
the  other  side  (the  xylem  side)  new  ves- 
sels, fibres,  and  parenchyma  are  also  devel- 
oped (Fig.  328).  The  development  of 
these  tissues  begins  in  the  inner  and  outer 
layers  of  the  cambium,  and  advances  to- 
ward the  central  layers.  It  never  hap- 
pens, however,  that  all  the  cambium  lay- 
ers pass  over  into  permanent  tissues,  there 
always  remaining  one  or  a  few  meristem 
layers. 

646.— A  study  of  Figs.  326-328  will 
show  the  probable  mode  of  development  of 
the  permanent  tissues  from  the  meristem 
tissue  of  the  cambium.  It  is  evident  from 
a  comparison  of  Figs.  326  and  327  that 
the   phloem  parenchyma  is  produced  by 

«.    ^    «^  .  the  formation  of   several  transverse  parti- 

ng. 825.— The  row  of  ^.        .  ,  ,  .  „        1  .1  .         1 

ceiu  marked  a— 1»  In  tions  m  cach  cambium  cell,  and  it  IS  prob- 

rig.  aw :  r,  phloem :  A,      ,  ,      iv    .    •  xi.  •  i-        i. 

xylem  ;atii^  seen  the  able  that  in  many  cascs  there  IS  a  direct 
ceril*!°*x  6(»!^^Aner  couvcrsion  of  cambium  cells  into  sieve 
^^^^'y-  fnhAfl      That  the  cambium  cells  may  be 


tubes. 


converted  directly  into  trache^des  is  evident  from  Fig.  326, 
and  also  Fig.  75  (p.  84).  In  Fig.  328  it  is  plain  that  the 
fibrous  tissue  {If)  and  traclieKdes  (t)  have  the  same  origin, 
and  the  indications  are  that  even  the  large  pitted  vessels 
{gg)  are  formed  from  cambium  cells  by  the  great  increase 
in  the  diameter  of  the  latter,  the  thickening  of  their  vertical 
walls,  and  the  partial  or  complete  absorption  of  their  trans- 
verse walls.    The  origin  of  the  xylem  parenchyma  from  cam- 


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TISSUES  OF  ANGIOSPERMS.  447 

bium  cells  by  the  formation  of  transverse  partitions  is  very 
clear  in  this  figure. 

547. — In  the  trees  and  shrubs  of  cold  climates,  or  of 
those  in  which  there  is  one  annual  period  of  growth,  fol- 
lowed by  a  period  of  rest  or  the  cessation  of  growth,  the 


Fig.  886.  Fio.  8S7. 

Fig.  826.  A  tangential  section  of  the  cambiam  region  of  CyHtu$  Labumwn.  a,  6, 
e,  <f ,  cambiam  cells  enclodnfi  the  section  of  a  medallary  ray ;  A,  A,  tracbeldes  belong- 
Ing  to  the  xylem.    x  145.— After  De  Bary. 

Fig.  827.— Tangential  section  of  the  inner  phlofim  region  of  the  same  stem  as  Fig. 
396.  «,  «,«,  sieve  vessels ;  m,  section  of  a  small  mednllary  ray ;  the  remaining  paris 
of  the  flgare  are  phlo€m  parenchyma,    x  145.— After  De  Bary. 

processes  described  above  take  place  each  year,  giving  rise 
thus  to  an  annual  layer  of  xylem  (wood)  outside  of  the  pre- 
viously formed  xylem  cylinder,  and  an  annual  layer  of 
phloem  (bark)  inside  of  the  phloSm  cylinder.  In  the  wood 
these  layers  are  generally  quite  well  marked,  and  in  cold 
climates  they  enable  us  to  determine  with  accuracy  the  age 


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448  BOTANY. 

of  trees  and  shrubs  (Fig.  329).  The  layers  of  the  bark  are 
rarely  well  marked,  and  they  generally  become  soon  obliter- 
ated by  irregular  corky  growths  in  the  substance  of  the  bark 


Fig.  888.— Tangential  section  of  the  Btem  of  AUanJthm  dhndulotv,  throuKh  the 
tecondary  xylem :  g,  ff,  pitted  vessels  ;  p^  ;>,  zylem  parenctivuia  ;  gt,  H,  mediillar^ 
rays  in  cross-section ;  (f,  flbrooa  tloAue  ^wood  cells) ;  t,  tracheldes.  Highly  magnified. 
—After  Sachs. 

itself.  They  are,  moreover,  ruptured  by  the  increase  in  the 
diameter  of  the  woody  cylinder,  and  soon  decay  and  fall 
away.  It  thus  happens  that  while  the  annual  layers  of  the 
wood  are  constantly  increasing  in  number,  reaching  in  ex- 


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TISSUES  OF  ANeiOSPERMS.  44Vl 

treme  cases  more  than  a  thousand,*  the  bark  rarely  shows 
more  than  a  few  distinct  layers,  and  its  thickness  is  generally 
very  much  less  than  that  of  the  former. 

From  what  has  been  said  it  is  seen  that  a  dicotyledonous  stem  several 
years  old  is  composed  of  a  series  of  larger  and  larger  continuous  woody 
shells  (Fig.  330, 1,  2,  8,  4,  6)  surrounded  by  a  corresponding  series  of 
bark  shells,  which  are  smaller  and  smaller  (Fig.  380,  5',  4'.  8',  2%  l^. 

648.~The  Medullary  Bays.   In  the  young  dicotyledonous 
stems  there  are  thick  masses  of  parenchyma,  which  connect 
the  cortical  with  the  medullaiy  (pith)  portion  of  the  funda- 
mental system  of  tissues  (Fig.  323).     However,  as  the  fibro- 
vascular  bundles  increase, 
these  masses  become  thin- 
ner, until  they  are  mere 
plates,  often  not  more  than 
one  or  two,  or  at  most  a 
few  cells  in  thickness  (Figs. 
326-7-8).     From  their  ap- 
pearance and  position  they 
have  long  borne  the  name 
of    Medullary    Bays.       In 
the  young  stem  their  cells 

may  be    parenchvmatous,  ^^ 

but  in  older  ones  they  are  o.i:'^<^Si^':^S»'^rrt?!4'ry^4"o.'S 
frequently  sclerenchyma-  ^J^^^X^^^XH^'^^^^J^ 
tons.  Viewed  in  a  radial  -After  Duchartre. 
section  of  the  stem,  they  are  generally  seen  to  be  elongated 
in  the  direction  of  the  radius,  having  the  outlines  of  right- 
angled  quadrilaterals.  In  the  increase  of  the  diameter  of  the 
stem  there  is  always  an  increase  in  the  length  of  the  medul- 
lary rays,  both  in  their  bark  and  wood  portions ;  and  when 
from  their  divergence  a  considerable  space  intciTenes  between 
two  rays,  one  or  more  new  ones  arise  between  them  ;  thus 
while  there  may  be  no  more  than  four  or  five  rays  in  the 
young  plant,  it  may  when  old  have  hundreds  of  them  in  its 
circumference  (Fig.  329). 

What  has  been  said  of  the  tissues  of  the  Angiosperms  must  suffice  to 

♦  In  the  Lime  {Tilia  Europaa)  1076  and  1147,  and  in  the  Oak  (Qyier- 
cus  Rdbur)  1060  and  1500,  according  to  De  CandoUe. 


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450  BOTANY, 

•a  •  introduce  the  student  to  tbdi 

Q§  study.    For  further  details, 

^%  he  is  referred  to  De  Bary's 

5p  admirable    treatise,     "Ver 

Zj{  gleicbende     Anatomie     der 

J<  Veflfetationsorgane  der  Phan- 

j  I  erogameu    und    Fame,"    in 

J^«  which  copious  references  are 

•g3  given.    Tbe  publications  of 

[I.-  Russow  will  also  be  found  to 

>^  be  of  great  value  to  the  stu- 

Ig'  dent. 

Ia  649.— The  systematic 

1 1  arrangement  of  the  An- 

u^  giosperms  is  by  no  means 

fell  settled.    The  one  mostly 

kTI  followed  in  England  and 

"^•l  this  country  is  a  modifi- 

•^,5  cation  of  De  Candolle's 

^j  system       (a.d.      1813), 

1|  which  was  itself  a  modi- 

1 1  fication  of  Jussieu's  (a.d. 

^tn  1789),  which  in  turn  was 

«|  based  upon  the  general 

i  I  system  proposed  by  Eay 

:|  (A.D.    1703).       In    the 

ll  *' Genera    Plantarum," 

1 1  now  publishing  by  Ben- 

Bg  tham  and  Hooker,  and 

1"^  in  the  English  edition  of 

*-2  Le  Maout  and  Decaisne's 

g  I  "  General  System  of  Bot- 

|jj  any,'*  we  have  the  most 

1^*  recent  modifications  of 

^^^  the  Candollean  system. 

►«-  On  the  continent  of  Eu- 

|7^  rope  other  systems  have 

ci  been  used  more  or  less, 

I  -  and  it  is  probable  that 

i-  among  these  are  to  be 

/y       /  /^^  \V^^\\  \^^^^^^       E^  found  the  best  groupings 

iw4^548«i*^i2846W4Wi'        §,  of  Angiospcnus  to  ludi- 


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MONOCOTYLEDONES, 


451 


cate  their  real  affinities.  Unfortunately  for  us,  however^ 
none  of  our  systematic  manuals  follow  any  of  the  Continen- 
tal systems  ;  we  are  compelled,  therefore,  to  use  for  the  pres- 
ent the  prevailing  form  of  the  Candollean  system.  In  this 
book  the  sequence  of  the  groups  is  the  reverse  of  that  in 
most  American  and  English  books,  in  order  to  bring  the  ar- 
rangement of  Angiosperms  into  harmony  with  that  of  the 
rest  of  the  vegetable  kingdom. 

Sub-Class  I.  Monocotyledoxes. 

{Endogenm  of  De  Candolle.*) 

650. — ^In  these  plants  the  first  leaves  of  the  embryo  are 

alternate,  hence  we  say 
that  they  have  one  cotyle- 
don. The  venation  of  the 
leaves  is  for  the  most  part 
such  that  the  veins  run 
more  or  less  parallel  to 
one  another,  and  when 
they  anastomose  enclose 
four-sided  areolae ;  rarely, 
however,  their  veins  are 
irregularly  distributed, 
and  they  anastomose  so  as 
to  form  an  irregular  net- 
work. 


Fij^.  SSl.—Londtndlnal  section  of  thQ  seed 
of  Indian  corn  {2ea  Mais),  c.  adherent  wall 
of  the  ovary ;  »,  remahis  or  the  style  ;/*, 
base  of  the  ov&ry  ;  all  the  remainder  6t  the 
ilgare  is  the  true  seed  ;  «y,  eto,  endosperm  ; 
«'.-—«4.  cotyledon  of  embryo:  ^  its  epider- 
mis ;  k^  plumule  <;  w  (below),  the  main  root ; 
tM,  the  root-f heatli :  to  (above),  adventitious 
roots  spriugiufir from  the  first  iuteruodo of  the 
•tern.    X  o.~After  Sachs. 

bas  its  broad  dorsal  Burface  in  contact 


The  genninatioa  of  Monoco. 
tjledons  may  be  illustraied  by 
a  couple  of  examples.  In  tbe 
seed  of  tbe  Indian  com  tbe 
embryo  lies  partly  imbedded 
in  one  side  of  tbe  large  endo- 
sperm (Fig.  331).  Tbe  first  leaf 
of  tbe  young  plant  (tbe  cotyle- 
don or  Bcutellum,  Fig.  831*  te ) 
witb  tbe  endosperm ;  anteriorly 


*  From  tbe  Greek  Mov,  witbin,  and  yevetv,  to  bring  fortb.  Tbe 
name  was  given  under  tbe  false  impression  tbat  tbese  plants  were 
"  inside  growers,"  and  tbe  Dicotyledons  "  outside  growers." 


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452 


BOTANY. 


Fie.  889. 


Fig.  832.— Germination  of  Indian  corn.  /.,  //.,  ///.. 
successive  stages.  A  and  B^  front  and  side  views  of 
a  separated  embryo.  In  the  figures,  w,  the  primary 
root ;  vo9^  its  root-sbeatb  ;  ^^  vf\  adventitious  roots ; 
v}"'^  lateral  roots  springing  from  tbe  main  root ;  ^, 
part  of  seed  filled  with  endosperm  ;  m,  cotvledon  :  r. 
its  open  margins ;  ib,  the  plumule ;  6,  ^,  ly\  leaves  of 
young  plant ;  /.  fragment  of  wall  of  ovary.  Natural 
size.— After  Sachs. 

Fig.  83:).— Germination  of  the  Date  (PAomte  dad^" 
l\fera).  /.,  transvprse  section  of  seed  ;  e,  embryo  :  s, 
endosperm^  //..  ///..  i^ections  of  germinating  i>eeds; 
c,  apex  of  cotyledon  developing  into  an  absorbing  or- 
can  ;  gt,  i>Ulk  of  cotyledon  :  «,  sheath  of  cotyledon ; 
0^,  W,  leaves ;  «0,  root ;  u^^  lateral  roots ;  A,  root-cap. 
IV.  y  young  plant,  natural  size,  the  lettering  as  In  III. 
Ay  section  of  IV.  Kt  x  —  m;  B,  section  at  x— v,  the 
lettering  as  in  ///.  C,  section  at  s — a,  the  lettering  aa 
In  ///.—After  Sachs. 


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QLUMALE8.  453 

it  is  carved  entirely  around  the  remainder  of  the  embrvo.  Under  prop, 
er  conditions  the  main  root  pnsbes  tlirougb  tbe  root  slieatb  (tM,  Figs. 
881,  882).  The  plumule,  consisting  of  a  minute  stem  and  a  few  rudi- 
mentary leaves,  next  pushes  out  tlirou^h  the  upper  end  of  the  curved 
cotyledon  (II.,  Fig.  882).  The  cotyledon  remains  in  contact  with  the 
endosperm  and  absorbs  nourishment  from  it  for  the  sustenance  of  the 
growing  parts.  Lateral  roots  soon  appear  upon  the  main  root,  and 
adventitious  ones  arise  from  the  first  intemodes  of  tbe  stem  (iff"',  W\  v/. 
Fig.  382).  The  first  leaf  above  the  cotyledon  is  quite  small  (6),  and 
each  succeeding  one  becomes  larger  and  larger  until  the  full  size  is 
reached. 

In  the  Date  the  small  embryo  lies  imbedded  transversely  in  the  large 
endosperm.  In  germination  the  cotyledon  elongaten  and  carries  the 
enclosed  root  and  plumule  outside  of  the  seed  (//.  and  III.,  Fig.  888). 
The  apex  of  the  cotyledon  (c)  expands  into  an  organ  through  which 
the  dissolving  endosperm  is  absorbed.  The  root  pushes  downward, 
and  soon  develops  lateral  roots  (w^.  The  plumule  grows  upward,  es- 
caping from  tbe  enclosing  cotyledon,  as  shown  in  /F.,  Fig.  888.  The 
fintt  leaves  above  the  cotyledon  are  here,  as  in  the  Indian  corn,  much 
less  perfectly  developed  than  the  later  ones. 

661. — The  sub-class  Monocotyledones  contains  about  fifty 
natural  orders  of  plants,  which  are  grouped  into  fifteen  co- 
horts.    Of  these  only  a  few  need  be  noticed. 

662.:— Cohort  I.  Gliimales.  Grass-like  plants  with  thd 
flowers  in  the  axils  of  scales,  which  are  arranged  in  spike- 
lets  ;  the  stamens  are  from  one  to  three,  rarely  more ;  the 
single  ovary  contains  but  one  ovule,  and  these  at  maturity 
are  completely  coalesced,  forming  a  caryopsis. 

Order  Oraminess. — The  Grass  Family.  Herbaceous  or  rarely 
woody  plants,  with  round,  jointed,  and  mostly  hollow  stems,  bearing 
alternate  two-ranked  leaves  with  split  sheaths.     (Figs.  884-9.) 

This  very  natural  order  contains  about  4500  species,  which  are  dis- 
tributed in  all  climates.  In  the  tropics  they  are  large  and  almost  tree- 
like (Bamboo) ;  in  the  temperate  climates  they  cover  the  ground  with 
a  close  mat,  while  in  the  colder  countries  they  grow  in  bunches.  Very 
many  of  the  species  are  valuai^le  on  account  of  their  stnrchy  peeds  or 
nutritious  herbage.  None  are  poisonous  (with  possibly  one  or  two  ex- 
ceptions). 

TritiGum  milgare.  Wheat,  a  native  probably  of  Southwestern  Asia, 
has  been  under  cultivation  in  temperate  climates  for  several  thousand 
years.  Bemains  of  wheat  grains  have  been  found  in  the  ruins  of  the 
lake  dwellings  in  Switzerland,  proving  that  it  was  cultivate  in  Europe 
in  prehistoric  times.     By  long  culture  it  has  fonued  many  varieties; 


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454 


BOTANY. 


some  of  these  are  bardj  (winter  wheats),  others  are  tender  (spring 
wheats) ;  some  are  awned,  others  awnless ;   in  some  the  grains  are 

Figs.  884-9.— Inflorxscbmob  of  the  Oat. 


Fio.  830. 


FiQ.  887. 


Fio.  838. 


Fio.  330. 


Fig.  884.— Spikelet. 

Fig.  885.— pikelet  opened.    G,  flames ;  P,  paleto ;  A^  awn  ;  F^  abortive  flower. 

F!g»  338.  —Flower  witli  upper  palet. 


Fig.  887.--Embryo. 

Fig.  388.— Section  ot  gram. 

Fig.  889.— Diagram  oiBpikelet.    Ol,  glumes ;  By  palets ;  A^  abortive  flower. 


dark  in  color  (red  wheats),  in  others  they  are  light  colored  (white 
wheats).  Fahre's  experiments  about  a  quarter  of  a  century  ago  appear 
to  indicate  that  wheat  was  originally  derived  from  a  wild  grass  called 


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QLU MALES.  46.'i 

.^ffHops  atcUa,  From  it,  in  the  course  of  from  ten  to  twelve  years,  be 
succeeded  in  producin^r  the  form  known  as  cultivated  wheat.  (See 
Oardener^B  Ohronide,  July,  1852.) 

JSecale  eereale,  Rye,  is  probably  a  native  of  Southeastern  Europe  and 
Southwestern  Asia.  It  has  l>een  cultivated  for  ages  and  is  still  much 
grown  in  temperate  climates. 

Ebrdeum  milgare,  Barlfy.  A  native  probably  of  the  same  region  as 
Rye  ;  has  also  been  long  under  cultivation.  One  or  two  other  species 
are  also  grown. 

Avena  saliva,  the  Oat,  was  formerly  much  used  as  food  for  man., 
especially  in  cool  climates,  where  it  succeeds  best.  It  is  now  less  used. 
Its  native  country  is  not  certainly  known,  but  it  was  probably  northern 
Europe  or  Asia. 

Oryza  scUiva,  Rice,  has  been  long  under  culture  in  Southeastern 
Asia,  of  which  country  it  was  probably  a  native.  It  is  now  cultivated 
also  in  Egypt,  Italy,  Brazil,  and  the  Southern 
United  States.  It  furnishes  food  to  more  human 
beings  than  any  other  single  plant. 

Zea  Mais,  Maize  or  Indian  Com,  a  native  of 
the  warmer  parts  of  the  New  World,  was  culti- 
vated by  the  aborigines  of  both  North  and  South 
America  before  the  advent  of  Europeans.  It  is 
one  of  the  most  valuable  of  the  cereals,  and  is 
now  cultivated  almost  all  over  the  world.  Of  its 
numberless  varieties  the  larger  are  grown  in  the 
hotter,  and  the  smaller  in  the  cooler  climates. 

The  more  important  forage  grasses  are  the  fol-  heM^ndJSr^flS^  S 
lowing :  Rice* 

PIdeum  pratense,  Timothy  or  Herd's  Grass,  a  native  of  Europe  is  val- 
uable on  rich  soils. 

Agrostis  vulgaris.  Red-top,  a  native  of  Europe,  grows  well  on  moist 
soils. 

Dactylis  glomerata.  Orchard  Grass,  a  native  of  Europe,  is  valuable 
because  of  its  growing  well  in  the  shade,  and  so  furnishing  hay  and 
pasture  in  orchards  aud  woodlands. 

Poa  pratensis,  Kentucky  Blue  Grass,  a  native  of  the  Eastern  United 
States  and  of  Europe,  is  in  the  latitude  of  Kentucky  the  best  of  all  our 
pasture  grasses.    In  drier  regions  it  is  small  and  harsh. 

Muhlenbcrgia  glomertUa  and  M,  Mexieana  constitute  the  "  Fine 
Sloagh  Grass  "  of  the  Mississippi  valley  prairies.  They  furnish  val- 
uable hay. 

Several  species  furnish  sugar : 

Saecharum  offieinarum.  Sugar  Cane,  a  native  of  the  warmer  parts  of 
Asia,  is  a  large  plant  somewhat  resembling  Indian  com  in  size  and  ap- 
pearance. From  its  sweet  juice  most  of  the  sugar  and  molasses  of  com- 


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456 


BOTANY, 


morce  are  made.     It  is  cultivated  exteDsivel  j  in  the  Southern  United 
States,  Cuba,  Brazil,  and,  in  fact,  in  all  warm  countries  of  the  world. 

Fios.  841-4.— IiiusTRATioMs  or  Cabbx. 


Fio.  841. 


Pro.  843.  Fio.  848.  Fio.  844. 

Fig.  841.— Underground  stem,  ftcnding  up  leafy  and  flowering  eteme. 
FiiC.  848.— Male  flower.    Magnlfled. 
Fig.  848.— Female  flower.    Magnified. 
Fig.  844.— Hectiou  of  seed.    Magnified. 

It  is  a  curious  fact  that  while  the  annual  production  of  cane  sugar  in 
the  world    is   now  about  4,000,000,000   pounds,  yet   five   hundred 


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LILIALE8  457 

jears  airo  it  was  bat  little  known  to  our  European  ancestors,  and  even 
a  centary  and  a  Imlf  a^o  it  was  one  of  the  luxuries.    (Simmonds.) 

Sorghum  viUgare,  Chinese  Sugar  Cane,  a  native  of  India,  has  within  a 
few  years  be^n  brought  into  cultivation  in  the  United  States  for  its 
sweet  juice,  from  which  molasses  and  sugar  are  made.  One  variety  of 
this  species  is  the  Broom  Corn,  used  in  the  manufacture  of  brooms. 

Several  species  of  BHxnhoo  {Bambusa,  sp.)  growing  in  India  become  so 
large  as  to  supply  materials  for  building  the  houses  of  the  natives. 

B.  arundinneta  sometimes  attains  the  height  of  80  metres  (100  ft.). 
Its  uses  are  almost  innumerable. 

Order  Cyperacese. — The  Sedge  Family.  Herbaceous  plants,  with 
three-angled  solid  stems,  bearing  alternate  three-ranked  leaves,  with 
entire  sheaths.     (Figs.  841-4.) 

There  are  about  two  thousand  species  of  sedges,  which  are  distrib- 
uted throughout  the  world.  They  grow  in  tufts,  never  forming 'a  con- 
tinur>u8  mat,  and  generally  prefer  wet  localities.  Tbey  are  of  little 
value  to  man,  and  their  stems  contain  so  little  nutritious  matter  that 
they  are  eaten  only  to  a  limited  extent  by  animals. 

CyperuM  eseulenius,  the  Chnfa,  a  UHiive  of  the  Mediteirauean  region, 
is  somewhat  cultivated  for  its  small,  sweet-tasting  tubers. 

Cyperus  textUis  is  used  in  India  for  making  ropes  and  mats ;  in  Egypt 
other  species  are  used  for  the  same  purpose. 

Papyrus  antiquorum.  Papyrus,  is  a  tall  growing  plant  with  stems  3-8 
cm.  (1  inch)  in  diameter.  It  is  a  native  of  Egypt  and  the  adjacent 
countries,  and  from  it  the  inhabitants  anciently  made  paper  by  slicing 
its  cellular  pith,  and  afterward  hammering  and  smoothing  it. 

663.  Cohort  n.  Bestiales. — This  includes  three  orders  of 
mostly  tropical  plants  bearing  glumaceous  flowers. 

Orders  Bestiaceae,  Eriocaulonacess,  and  Flagellariess. 

664.  Cohort  m.  Commelynales. — Plants  with  a  hexa- 
merous  perianth,  in  two  whorls,  the  inner  colored  and  petal- 
oid. 

Orders  Mayacese,  Xyridacese,  and  Commelyxiacefle. 

The  latter  contains  the  well-known  Spiderwort   Trade^'/iTUia,  sp.). 

655,  Cohort  IV.   Pontederales. — Marsh  plants  with  a 
gamophyllous  petaloid  perianth. 
Orders  Philydrese,  Pontederiacese,  and  Bapatesd. 

666.  Cohort  V.  Liliales. — Plants  with  a  hexamerous 
(rarely  tetramerous)  perianth,  the  parts  united  or  free,  and 
usually  petaloid. 

Order  Juncaceae. — The  Rushes.    Natives  of  temperate  and  cold 


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BOTANY. 


climates.    The  leaves  and  stems  are  woven  into  matting  and  cbair 
bottoms,  and  the  pith  is  used  for  the  wicks  of  candles  (rush-lights). 

Order  LUiacees.— The  Lily  Family.  Perennial,  mostly  herbaceous 
plants,  with  entire  leaves,  and  generally  showy  flowers.  The  species, 
of  which  there  are  about  two  thousand,  are  distributed  in  all  climates. 
Some  of  these  are  valuable  as  fo<Kl,  others  furnish  useful  medicines, 
while  many  are  among  our  finest  ornamental  plants. 

The  more  important  food  plants  are  the  following : 

AUium  Cepa,  the  Onion,  a  native  probably  of  the  Mediterranean  re- 
gion, is  grown  throughout  the  world. 

AUium  Porrum,  the  Leek,  A.  tativum,  Garlic,  A.  cuecUonicum, 

Figs.  845-8.— Illustbationb  or  Fbitillabia. 


Fio.  346. 


Fio.  347. 


Fio.  848 


Fio.  845. 
Fig.  345.— Section  of  flower. 
Fig.  846.— Flower  diagrafa. 
Fig.  347.— Section  of  ovary. 
Fig.  348.— Ovule. 

Shallot,  and  a  few  other  species,  all  natives  of  the  Old  World,  are  con. 
siderably  used. 

Asparagus  officinaUs,  Asparagus,  is  a  native  of  the  Atlantic  and 
Mediterranean  coasts  of  Europe,  and  of  the  sandy  plains  of  Central  and 
Western  Asia.  It  has  been  cultivated  in  England  for  upwards  of  two 
thousand  yeHrs,  but  it  is  an  interesting  fact  that  in  all  that  time  it  has 
exhibited  very  little  variation. 

Among  the  medicinal  plants  may  be  mentioned 

Aloe  vulgaris,  of  the  Mediterranean  region,  and  other  species  in 


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LILIALE8.  459 

Soathem  and  Eastern  Africa,  the  inspissated  Juice  of  whose  leaves  con- 
stitutes the  drug  Aloes. 

Smilax  officinalis,  of  South  America,  and  other  species,  furnish  Sarsa 
parilla  root. 


Fig.  849.— Undergroand  parts  of  Colehicum  autumnaU  at  the  time  of  flowering. 
A^  front  view ;  k,  old  corm ;  a',  9f\  scales  surronnding  flower  stalk.  B^  section  show> 
ing  new  stem,  A^  with  mdlmentary  leaves,  /^  I"  ;  the  very  Ions  tabular  flowers,  b,  ^, 
spring  from  near  the  summit  of  the  new  stem,  hf.    The  folluwing  spring  A'  will  elon- 

Ste  and  carry  the  fruit,  and  leaves  ^,  /",  above  ground  ;  the  lower  part  of  V  will  en- 
rge  into  a  corm  like  f,  while  at  k"  a  new  plant  will  form  as  a  lateral  bud.— After 

SdUa  maritiima  ;  the  sliced  bulb  of  this  Mediterranean  sand  plant  la 
the  drug  SquilL 

VenUrum  album,  the  White  Hellebore  of  the  mountains  of  Centra] 


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460  BOTANY. 

Europe,  and  F.  tiHde,  Green  Hellebore  of  tlie  Eastern  United  Statei^ 
are  poisonous  emetics.     The  rhizome  is  officinal. 
Ornamental  plants : 

AspJiodelus  ItUeus  is  the  Asphodel  of  Southern  Europe. 
AgaparUhm  umbellatus,  the  Love  Flower  of  the  Cape  of  Good  Hope, 
is  a  beautiful  green-house  plant,  bearing  pale  blue  flowers. 

Colehicum  autumnaU,  the  "  Meadow  Saffron  "  or  "  Autumn  Oocus  " 
of  Europe,  is  curious  for  its  producing  leaves  in  tlie  spring,  and  then, 
long  after  these  have  died  dowu,  in  the  autumn  sendinir  up  one  or  two 
long-tubed  pale  flowers,  which  soon  wither  away  ;  the  following  spring, 
by  the  lengthening  of  the  under^rround  stem,  the  setni-pod  is  carried 
up,  along  with  the  green  leaves  (Fig.  849).  The  corms  of  tliis  plant 
were  formerly  in  some  repute  as  medicines. 

CimtaUaTia  mqjaUs,  the  Lily  of  the  Valley,  is  a  native  of  woodlands 
and  shady  places  in  England,  Europe,  and  Siberia. 

Draccma  Draco,  the  Dragon  Tree  of  Western  Africa  and  the  adja- 
cent islands,  is  cultivated  as  a  curiooity  in  ^n^een-houses.  A  tree  of 
this  q>ecie8on  the  island  of  Teneriffe  was,  at  the  time  of  its  destruc- 
tion by  a  hurricane  in  1867,  upwords  of  20  metres  (70  ft.)  high,  and  5 
metres  (16  ft)  in  diameter,  and  from  its  known  slow  growth  it  mu9t 
liave  been  many  hundreds,  possibly  some  thousands,  of  years  old. 

FritiUarvi  imperialis,  the  Crown  Imperial,  a  native  ot  the  south  of 
Europe  and  Western  Asia,  is  a  showy  plant. 

Funkia,  sp.,  and  HemerocaUia,  sp.,  ihe  Day  Lilies,  the  former  from 
China  and  Japan,  the  latter  from  Southern  Europe,  and  Hpacinthtu 
orierUalis,  the  Hyacinth  of  Asia  Minor,  are  in  common  cultivation. 

Lilium — many  specie**.     The  True  Lilies.    Aside  from  our  native 
species,  L.  PkUaddphicum,  L,  Canadense,  and  L,  superbum^  which 
deserve  cultivation,  the  following  are  commonly  found  in  gardens  : 
L.  buRnferum.  the  Orange  Lily,  from  Southern  Europe :  flowers 

orange. 
X.  tigrinum^  the  Tiger  Lily,  from  China  ;  flowers  ornnge-red. 
L,  Pomponium,  the  Turban  Lily,  from  Europe  ;  flowers  red. 
L,  Chalcedonicum^  the  Red  Lily,  from  Asia  Minor ;  flowers  red. 
L,  Martngon,  the  Turk's  Cap  Lily,  from  Europe  ;  flowers  flesh- 

colored. 
L,  apeciosum,  the  Showy  Lily,  from  Japan ;  flowers  rose-colored. 
L.  auraium,  the  Golden  Lily,  from  Japan  ;  flowers  white  and 

golden. 
L.  candidum.  the  White  Lily,  from  Asia  Minor ;  flowers  white. 
X.  Japonieum,  the  Japan  Lily,  from  Japan ;  flowers  white. 
X.  longiflorum,  the  Long  flowered  Lily,   from    Japan ;    flowers 
white. 
MyrmphyUumaapanigMeB,  a  delicate  climber  from  the  Cape  of  Good 
Hope,  is  grown  in  windows  and  conservatories  under  the  name  of 
Smilax. 


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ARALES,  461 

OrnUhogalum  umbeOcUumt  the  Star  of  Betlilehem,  is  a  native  of  Cen- 
tral Earope. 

PoUanthes  taberosa,  the  Tuberose,  a  native  probably  of  the  East 
Indies,  bears  a  tall  spike  of  fragrant-  white  flowers.  It  is  sometimes 
placed  in  the  order  Amaryllidacee. 

Ruscus  ctculecUtis,  the  Batcher's  Broom  of  England  and  Soathern 
Earope,  a  carious  ^hrub,  with  flat  leaf-like  branches,  is  rarely  cultivated 
with  us. 

Triioma  uvaria,  of  the  Cape  of  Good  Hope,  bears  a  tail  spike  of  red 
flowers,  and  hence  receives  in  cultivation  the  name  of  the  **  Red-Hot 
Poker  Plant." 

TuUpa  Oesneriana,  the  Tulip,  is  a  native  of  tbe  Levant.  It  was 
brought  into  Europe  about  three  hundred  years  ago,  and  originally 
bore  yellow  flowers,  but  under  long  culture  it  has  developed  number- 
less varieties.  To  the  Dutch  we  owe  much  of  the  improvement  in  this 
flower  ;  in  the  first  halt  of  the  seventeenth  century  throughout  Holland 
so  much  attention  was  ^iven  to  its  culture,  and  such  high  prices  paid 
for  single  bulbs  of  the  finer  varieties,  that  a  speculative  mauia  (known 
aa  the  "  tulipomania*')  anjse,  resembling  the  wildest  of  modern  grain 
or  stock  manias. 

Yticea,  of  several  species,  known  by  the  name  of  Adam's  Needle, 
Spanish  Bayonet,  Bear  Grass,  etc.,  is  a  genus  of  fine  ornamental 
plants,  natives  of  the  warmer  parts  of  America.  The  strong  fibres  are 
sometimes  made  into  cordage.  The  roots  contain  saponin^  and  are 
used  by  the  Mexicans  instead  of  soap  for  washing. 

Xanthorrhcsa  includes  the  curious  Grass  Gum  Trees  of  Australia. 

667.— Cohort  VI.  Arales.— A  group  of  dissimilar  plants, 
some  being  large  trees,  and  others  microscopic  floating  herbs. 

Order  Lemnacess.— The  Duckweeds.  These  smallest  of  Phanero- 
gams consist  of  floating  disks  (thalli),  with  no  distinction  of  leaf  and 
stem,  bearing  one  or  several  roots  beneath  (in  Wolffla,  however,  no 
roots).  They  are  parenchymatous  throughout,  or  with  only  rudimenu 
ary  vascular  tissues.  Their  flower-clusters  are  sunken  into  pits  in  the 
top  or  edge  of  the  disks,  and  consist  of  one  or  two  stamens  and  a  single 
pistil,  representing  as  many  reduced  flowers.  There  are  about  twenty 
species,  widely  distributed  throughout  the  northern  hemisphere.  We 
have  eight  or  ten  species  in  the  United  States.    (Figs.  850-2.) 

Order  Aroide8B.~The  Arum  Family.  Herbs  often  large  and  palm- 
like in  appearance,  with  large  leaves  having  reticulated  venation.  In- 
florescence  generally  surrounded  by  a  spathe.  Of  tlie  Aroids  there  are 
about  1000  species,  distributed  mostly  in  tropical  countries,  where  they 
sometimes  attain  a  height  of  several  metres  (6-12  feet) ;  in  temperate 
climates  they  are  much  smaller.  They  possess  an  acrid  juice,  which 
may  be  poisonous. 


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Some  of  the  species  have  been  used  in  medidne,  among  which  are 
the  Indian  Turnip  (Arisama),  and  Sweet  Flag  {Aconis). 

Calacasia  antiquorum,  a  large  plant  of  the  tropics,  is  there  grown  for 
its  fleshy  farinaceous  conn.     It  is.  grown  with  us  for  its  fine  foliage. 

Richardia  Afiieana,  the  so-called  Calla-lily,  or  Ethiopian  Lily,  a  na- 
tlve  of  the  Cape  of  Good  Hope,  is  a  common  green-house  plant. 

Symplocarpus  fcUidus,  the  Skunk-cabbage  of  the  Northern  United 
States,  is  remarkable  for  the  mephitic  odor  of  its  bruised  leaves. 

Amorp?iophaUtL8  Titanvm,  an  Aroid  discovered  in  1878  by  Beccari  in 

F1G8.  850-S.— Illubtbationb  of  Lkmma. 


Fio.  850. 


Fio.  861. 


Fxo.  858. 


Fig.  860.— Two  plants  of  L.  minor.    Magnified. 
Fig.  351.— Three  flowers  in  a  spatbe. 
Fig.  862.- Section  of  pistil. 

Sumatra,  has  an  enormous  spathe,  1.7  metres  (6  feet)  in  depth,  and  83 
cm.  (2f  leet)  in  diameter. 

Order  Typhacese,  represented  by  the  two  genera  Typha  and  Spar- 
ganium. 

Order  PandanaceeB.— Mostly  tropical  plants,  some  ot  them  of  a 
tree-like  aspect. 

Pandanus  includes  the  Screw  Pines  of  the  East  Indies,  so  called  from 
the  spiral  arrangement  of  their  clustered  leaves. 

Carludomca  palmata,  a  Central  American  plant,  with  palmate  radical 

'""•"*-  ^'^-ne  on  petioles  three  metres  (8-10  feet)  long,  is  important  as 

:  the  material  from  which  the  famous  Panama  hats  are 

Cohort  Vn.    Palmales.— Shrubs  or  trees  with  di- 
trely  simple)  leaves.     Flowers  in  a  spadix. 


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PALMALE8. 


463 


Orders  NipacesB  and  PhytelephasiesB,  both  of  tbe  tropics.  In 
the  latter,  Phytelephas  macrocarpa,  of  Central  America,  is  remarkable 
for  tbe  ivory-like  endosperm  in  its  large  seeds ;  hence  its  name  of 
Ivory  Nut. 

Order  PalmacesB. — The  Palm  Family.  Trees,  shrubs,  or  woody 
climbers  ;  natives  almost  exclusively  of  the  torrid  zone,  or  the  adjacent 

Fies.  353-d.— Illustrations  op  Palmacba. 


Fig.  354. 


Pxo.  353. 


F\g.  3S3.~Fmit  of  Cocoa-nut.    a,  ezocarp ;  6,  endocarp ;  c,  testa  ;  d,  endosperm ; 
«,  embryo  ;  /,  milk  cavity. 
Fig.  354.— Cocoa-nnt  seen  from  below. 
Fig.  855.— Vertical  section  of  a  Dale.  Bhowing  seed  inside. 
Fig.  356.— Seed  of  Date  in  cross-section,  showing  embryo. 

hotter  portions  of  the  temperate  zones,  being  rarely  found  beyond  40* 
North  and  t^^  South  latitude.  The  arborescent  species  are  among  the 
most  striking  and  majestic  of  plants ;  their  lon^  cylindrical  stems  fre- 
qaently  rise  to  the  height  of  thirty  metres  (100  feet),  liearing  at  their 
summits  spreading  crowns  of  large  leaves,  and  drooping  clusters  of  fruit. 
The  whole  number  of  known  species  is  not  far  from  one  thousand. 
The  economic  value  of  the  Palms  is  very  great ;  in  fact  it  may  l>eques- 


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464  BOTANY. 

tioned  whether  any  other  order  of  plants  (the  Qrasees  poesiblj  excepted) 
approaches  them  in  the  importance  of  the  products  they  lumish.  Every 
species  appears  to  be  useful,  and  the  uses  of  some  of  the  species  may 
he  reckoned  by  hundreds.  In  some  countries  every  want  of  man  is 
supplied  by  one  or  another  of  tlie  fialms. 

/•  Tribe  Ctwoint  ce. — AtcUea  Juntftra  is  a  Brazilian  species  of 
stout-growing  trees,  whose  fibrous  leaves  are  used  in  makinfz:  ropes, 
mats,  and  coarse  brooms.  The  nuts,  known  as  Coquilla  nuts,  are  seven 
to  eight  cm.  (3  inches)  long,  very  hard,  and  are  used  for  making  door- 
handles, bell-pulls,  etc 

Cocoa  nuc\fera,  the  Cocoa-nut  Palm,  is  a  native  of  the  coasts  of  tropi- 
cal Africa,  India,  Malay,  and  islands  of  the  Indian  and  Pacific  Oceans. 
It  is  now,  however,  cultivated  throughout  the  tropics.  The  tree  varies 
In  height  from  fifteen  to  thirty  metres  (50  to  100  feet),  and  bears  long 
pinnate  leaves.  The  nuts,  which  are  borne  in  clusters  of  seven  to  ten 
or  more,  are  the  well-known  cocoa-nuts  of  commerce.  As  a  new  cluster 
is  pushed  out  every  month,  the  annual  yield  of  a  single  tree  may  be 
from  100  to  150  or  more  nut»,  and  this  may  continue  for  forty  years.  In 
some  parts  of  India  and  other  countries,  the  white  albumen  of  the  nut 
forms  nearly  the  entire  food  of  the  natives,  and  the  milk  serves  them 
for  drink.  In  this  country  great  quantities  are  used  as  a  delicacy  and 
for  culinary  purposes. 

In  cocoa-nut  countries  the  uses  of  the  root,  stem,  leaves,  and  fruit  are 
said  to  be  as  numerous  as  the  days  in  the  year,  sufficing  for  all  the  wants 
of  the  inhabitants.  The  root  is  used  as  a  masticatory  ;  the  stem  is  used 
for  the  most  diverse  purposes,  while  the  hard  case  of  the  base  is  used 
for  making  drums,  and  in  the  construction  of  huts,  the  tender  termi- 
nal bud  is  highly  prized  as  an  article  of  food.  The  juice  of  the 
flower-stems  is  rich  in  sugar,  and  this,  by  fermentation,  produces  an  ex- 
cellent wine,  and  by  distillation  yields  a  spirit  called  arrack.  From  the 
sheaths  and  leaves  the  natives  construct  roofs,  fences,  baskets,  buckets, 
ropes,  mats,  brooms,  and  numerous  other  articles.  The  fibre  from  the 
leaves  and  sheaths  is  imported  into  this  country  and  made  into  "  coir" 
ropes,  floor-matting,  brushes,  and  brooms,  and  used  also  for  stuffing 
cushions.  Even  the  hard  shell  is  of  use  in  the  manufacture  of  cups 
and  ornaments. 

Meets  guineensis,  of  West  Africa,  produces  annually  large  quantities 
of  pulpy  fruits,  each  containing  a  hard  nut.  From  these  palm  oil  is 
obtained,  which  is  uped  in  Europe  and  the  United  States  for  making 
candles,  for  the  manufacture  of  soap,  and  also  to  some  extent  for  lubri- 
eating  purposes. 

//•  Tribe  Coryphineoe.—Copemica  cerifera,  the  Wax  Palm  of 
Brazil,  attains  the  height  of  twelve  metres  (40  feet),  with  a  diameter  of 
stem  of  thirty  cm.  (1  foot).  The  hard  wood  takes  a  fine  polish,  and  is 
used  for  veneering.  The  young  leaves  are  coated  with  a  waxy  secre- 
tion which  is  used  in  England  for  making  candles. 


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PALMALES.  465 

Phanix  dactylifera,  the  Date  Palm,  is  a  native  of  Nortliern  Africa 
and  Western  Asia,  now  naturalized  in  tbe  south  of  Europe.  The  tree 
is  dioecious,  and  grows  to  the  height  of  ten  to  twelve  metres  (40-^ 
feet),  bearing  a  crown  of  leaves,  each  leaf  being  four  to  six  metres  (15- 
20  feet)  long.  The  fruit  is  produced  in  large  bunches,  containing  from 
twenty  to  thirty  dates.  Dates  constitute  a  large  portion  of  the  food  of 
the  Arabs  of  the  African  and  Arabian  deserts.  They  are  largely  im- 
ported into  the  United  States.  They  are  prepared  by  gathering  before 
they  are  quite  ripe,  and  tlien  drying  in  the  sun. 

The  cultivation  of  the  date  palm  has  fur  ages  been  an  object  of  first 
importance  in  Arabia  and  Northern  Africa.  The  trees  are  hereditary, 
and  are  sold  as  estates,  constituting  the  chief  wealth  of  the  inhabi- 
tants. 

8ah<U  PcUmett ».  the  Cabbage  Palmetto,  8.  serrvlata,  the  Saw  Palmetto, 
S.  Adansonii,  the  Dwarf  Palmetto,  and  Chamarops  Hyitrix,  the  Blue 
Palmetto,  all  of  the  southeastern  United  States,  and  Wcuhiaotonia  JU- 
iferat  of  California  and  Arizona,  are  our  principal  native  palms. 

III.  Tribe  BoraHsinem.—Borasms  flabflUformis,  the  Palmyra 
Palm,  is  a  native  of  nearly  all  Southern  Asia.  It  has  large  fan-shaped 
leaves,  anda  cylindrical  stem  rising  to  the  height  of  fifteen  to  thirty  me- 
tres  (50  100  feet).  Wine,  or  toddy,  and  sugar  are  made  from  the  juice  ; 
the  young  sprouts  of  the  fiowering  branches  u.re  used  for  food  in  the 
same  manner  as  asparagus.    From  the  stem  is  obtained  Palmyra  wood. 

J^phmne  ihebaica,  the  Doum  or  Gingerbread  Palm,  is  a  branching 
species  of  the  upper  Nile  region.  It  produces  fruits  of  the  size  of  an 
apple  and  with  the  fiavor  of  gingerbread.  A  resin  derived  from  this 
tree  is  known  as  E^ryptian  Bdellium. 

Lodaicea  secheUarum,  the  Double  Cocoa-nut  of  the  Seychelle  Islands 
in  the  Indian  Ocean,  is  a  giant  among  the  palms.  It  attains  the  height 
of  thirty  metres  (100  feet),  its  stem  being  forty-five  to  sixty  cm.  (1^  to  2 
feet)  in  diameter.  It  produces  large  oblong  nuts,  which  have  the  ap- 
pearance of  being  double,  and  which  weigh  from  thirty  to  forty  pounds. 
They  are  borne  in  bunches  of  nine  or  ten  in  number,  so  that  a  whole 
bunch  will  often  weigh  400  pounds.  It  takes  ten  years  to  ripen  the 
fruit,  the  albumen  of  which  is  similar  to  that  of  the  common  cocoa-nut, 
but  it  is  too  hard  and  homy  to  serve  as  food.  The  leaves  are  made  into 
hats,  baskets,  etc.  The  demand  for  the  leaves  for  these  uses  has  become 
so  great  that  the  trees  are  cut  down  in  order  to  obtain  them,  and  as  no 
care  is  taken  to  form  new  plantations,  it  is  feared  that  this  palm  will 
eventually  become  extinct. 

JF.  Tribe  Caiatnew.—CcUamus  Botang  and  several  other  spe- 
cies include  the  Rattan  or  Cane  Palms  of  India  and  the  Malayan 
Islanda  They  have  slender  reed-like  stems  which  grow  to  a  great 
length,  often  from  sixty  to  one  hundred  or  more  metres  (200-300  feet), 
and  are  imported  into  Europe  and  the  United  States  for  making  chair- 
bottom'*  umbrella-ribs,  etc. 


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466  BOTANY. 

Calamus  Draco,  of  the  same  region  as  the  prec(*din^,  yields  a  reddish 
resinoua  substance  known  as  Dragon's  Blood,  and  which  is  a  secretion 
coating  the  surface  of  the  small  fruits.  Dragon's  blood  is  used  for  col> 
orlng  Tarnishes  and  for  staining  horn. 

Sagus  ksvis  and  8.  Eumphii,  Sago  Palms,  are  trees  nine  to  fifteen 
metres  (30-50  feet)  high,  natives  of  Siam,  the  Indian  Archipelago  and 
other  islands  of  the  East.  The  sago  is  obtained  by  splitting  the  trunks 
and  extracting  the  soft  white  pith  ;  this  is  thrown  into  tanks  of  water, 
in  which  it  is  repeatedly  washed  and  strained  until  a  pure  pulpy  paste 
is  obtained.  In  this  state,  in  order  to  preserve  it,  the  natives  keep  it 
under  water,  and  it  forms  a  large  proportion  of  their  food.  For  expor- 
tation it  is  dried  and  granulated  through  sieves.  A  tree  fifteen  years 
of  age  yields  from  six  to  eight  hundred  pounds  of  this  nutritious 
material. 

V»  Tribe  Arecinew^—Areca  Catechu,  the  Betel  Palm  of  Cochin 
China  and  the  Malayan  peninsula  and  islands,  produces  a  fruit  of  the 
size  of  a  hen's  egg,  which  is  the  famous  Betel  Nut  or  Pinung  of  the  far 
East.  The  nut  is  cut  into  pieces  and  rolled  up  with  lime,  gambler,  etc., 
in  a  leaf  of  the  betel  pepper,  and  chewed  as  tobacco  is  in  this  country. 

Caryoia  urtns,  of  India,  is  one  of  the  wine  or  **  Toddy"  palms.  It 
grows  to  the  height  of  fifteen  to  eighteen  metres  (5(V-60  feet),  and  has  a 
large  crown  of  compound  winged  leaves.  It  is  said  that  this  tree  will 
yield  one  hundred  pints  of  toddy  in  twenty-four  hours. 

Ccroxylon  andicola,  the  Wax  Palm  of  the  mountains  of  New  Granada, 
is  a  tall  tree,  bearing  large  pinnate  leaves  five  to  six  metres  (15-20  feet) 
long.  It  is  found  on  the  mountain  sides  nearly  to  the  snow  line.  The 
trunk  is  coated  with  a  resinous  wax,  which  is  scraped  off  by  the  natives 
and  used  for  making  candles. 

ChanuBdorca  of  several  species,  climbing  palms  of  New  Granada  are 
interesting  on  account  of  their  stems  being  used  in  forming  suspension 
bridges. 

SagueruB  $acc?iartfer  of  the  Malayan  Archipelago  is  a  valuable  Sago 
Palm.  It  is  twelve  to  fifteen  metres (40-50  feet)  high,  and  bears  enor- 
mous pinnate  leaves  ;  a  tree  grown  in  the  Kew  Gardens  bore  leaves 
twelve  metres  (40  feet)  in  length.  Sugar  is  also  obtained  from  the 
juice  which  flows  from  the  wounded  spadix. 

669.  Cohort  vjljll.  Potamales. — Mostly  herbaceous  wa- 
ter plants,  with  all  of  the  parts  of  the  flower  distinct ;  the 
embryo  large,  and  endosperm  wanting. 

Order  Naiadacese. — The  Pond-weeds. 

Order  AlismaceeB.— The  Water  Plantain  Family.  This  order  is 
interesting  from  the  fact  of  its  evident  relationship  to  the  Ranales 
(Cohort  86)  among  Dicotyledons,  as  long  a^ro  suggested  by  Adanson, 
and  insisted  upon  by  Lindley.    (Figs.  357-9.) 


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NARCIS8ALES.  467 

AJUma  and  Sagittaria  are  two  common  genera. 

660.  Cohort  IX.   TriuraleSy  with  one  small  and  little 
known  order. 

Order  Triuridees. — Delicate,  almost  colorless  herbs  of  the  tropica. 

661.  Cohort  X.  Dioscorales. — Climbing  herbs  or  under- 
shrubs,  bearing  reticulately  veined  leaves. 

Order  DioscoreaceeB.— -The  Yam  Family.  Several  species  of  Jhos* 
eorea  produce  edible  tubers. 

i>.  saiiva,  D,  aculeata,  and  other  species  of  India  are  extensively 
grown  there  and  in  the  West  Indies  as  potatoes  are  grown  in  cooler 
climates. 

D,  Batatas  and  D.  Japonica  are  known  as  Chinese  Yams. 

TeBtudinaria  elepharUipes,  of  the  Cape  of  Good  Hope,  is  a  curious 

Fl08.  857-9.— iLLVSTBATIONff  OV  AlISMA    PtAMTAGa 


Fio.  857.  Fio.  858.  Fio.  866. 

Fig.  857.— Flower  cnt  vertically.    Magnifled. 

Fig.  858.-Seed.    Magnified. 

Fig.  809.--SectioQ  of  seed.    Magnified. 

g^en-house  plant,  having  a  lar^e,  woody,  above-ground  corm-stem, 
from  which  spring  every  year  slender  twining  stems. 

662.  Cohort  XI.  Narcissales. — Plants  with  narrow,  often 
equitant  leaves,  having  parallel  venation ;  seeds  containing 
endosperm. 

Order  HaBmodoracead. — The  Blood- wort  Family. 

Order  AmaryllidaceaB.— The  Amaryllis  Family.  Distinguished 
from  the  next  order  by  having  six  stamens,  and  leaves  which  are  not 
equitant.  The  four  hundred  species  are  herbs  of  temperate  and  trop. 
ical  climates ;  many  possess  a  narcotic  and  poisonous  principle. 

Agave  Americana,  the  Century  Plant  of  Mexico,  is  now  much  grown 
!n  conservatories,  and  is  said  to  be  naturalized  in  Southern  Europe.  In 
California  and  its  native  country  it  blooms  at  the  age  of  from  ten  to 


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468  BOTANY. 

fifteen  years,  but  in  cool  climates  it  requires  from  thirty  to  seventy  or 
more.  The  mature  plant  has  a  cluster  of  thick,  sharp-pointed  radical 
leaves,  each  about  2  metres  (6  ft.)  long,  from  the  centre  of  which  it 
sends  up  a  fiowering  stem  10-15  cm.  (4-6  in.)  thick,  and  5-6  metres 
(16-20  ft.)  high,  bearing  hundreds  of  yellow  flowers.  The  Mexicans 
cut  out  the  central  bud  just  before  the  lengthening  of  the  flowering 
stem,  and  from  the  juice,  which  flows  out  in  great  abundance,  obtain 
by  fermentation  the  drink  called  '*  Pulque,"  or  by  distillation  the  more 
generally  used  *'  Mescal."  The  subterranean  stems  possess  a  detergent 
principle,  and  under  the  nume  of  "  Amole  "  are  much  used  by  the 
Mexicans  in  washing.  The  strong  fibres  in  the  leaves  are  used  for 
cordage. 

HcBmanth'UB  toxicaria^  of  So*y^  Africa,  has  a  poisonous  bulb,  which 
Is  used  by  the  Hottentots  for  ^.s^'Idoning  their  arrows. 
Many  species  are  grown  for  the  beauty  of  their  flowers ;  among  these 
may  be  mentioned : 

Amaryllis,  of  many  ppecies,  mostly  from  South 
Africa  and  South  America. 

QalanViuB  nivalis,  the  Snowdrop,  of  Europe. 
Leueqjum  f^emum,  the  Snowflake,  of  Europe. 
Narcissus,  of    many  species ;   this  includes  the 
Daffodil,  Jonquil,   Polyanthus,  etc.,  all  natives  of 
Europe. 

diagram  'oT  irSa^  Order  Irldaceae. — The  Iris  Family.  The  sta- 
cete.— After  Sachs.  mens  are  only  three  (by  the  abortion  of  an  inner 
whorl.  Fig.  360),  and  the  leaves  are  equitant.  The  order  contains  five 
hundred  species,  which  are  mainly  found  in  tlie  south  temperate  clim- 
ates, a  smaller  number  occurrinjr  in  north  tem]>erate  regions.  They 
contain  a  purgative  principle,  which  has  been  used  in  medicine. 

Crocus  vermis  and  other  species  are  commonly  ^rown  for  their  early 
spring  flowers  ;  the  dried  stiprnias  of  C.  sativus  constitute  the  drug  Cro- 
cus or  Saffron  used  in  medicine  and  also  in  dyeing. 

Gladiolus  psittacinus  and  other  species,  imm  the  Cape  of  Good  Hope, 
are  deservedly  popular  as  ornamental  plants. 

Iris  Oermanica,  of  Europe,  and  many  other  Old  World  species,  are 
common  in  frardens. 

Our  native  /.  versicolor,  I.  cristata,  and  others,  are  also  worthy  of 
culture. 

663.  Cohort  Xn.  Taccades. — This  includes  two  small 
tropical  orders  of  herbaceous  plants. 
Orders  TaccaceaB  and  Burmanniaceed. 

564.  Cohort  XTTI.  Orchidales. — Herbs  with  a  hexaraer- 
ous  (rarely  trimerous)  zygomorphic  perianth  ;  the  stamens 
and  style  more  or  less  confluent  into  a  common  column,  and 


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0RCHIDALE8, 


4G9 


the  minute  seeds  containing  a  rudimentary  embryo  and  no 
endosperm. 

Order  ApostasiacesB,  a  small  order  of  East  Indian  plants,  which  are 
Interesting  because  of  their 
evident  relationship  to  the  ** 

Orchids,  from  which  thej 
differ  in  having  the  style 
partially  free  from  the  sta- 
mens. 

Order  Orchidaceao.  — 
The  Orchids.  Terrestrial 
or  epiphytic  plants,  whose 
stamens  and  style  are  com- 
pletely united  into  a  com- 
mon column  or  gynoste- 
mium.  The  three  thousand 
species  are  found  in  *'aI1 
climates  and  in  all  situa- 
tions but  maritime  and 
aquatic."    (Hooker.) 

This  order  has  long  been 
highly  esteemed  for  the 
many  curiously  shaped  and  ^ 

colored  flowers  it  affords, 
and  many  hundreds  of  its 
species  are  to  be  found  in 
cultivation  in  conservato- 
ries. They  are  interesting 
also  from  the  fact  tliat  none 
of  them  are,  unaided,  capa- 
ble of  fertilizing  tlieir 
ovules,  and  appear  in  every 
case  to  be  dependent  upon 
insects  for  the  transport  of 
the  pollen  and  its  deposition 
upon  the  stigma. 

This  great  order  is  usu- 
ally   divided     into     seven       y\s.  9ii.-0rchh  mncuJntn.    A,  a  symmetrical 
tribes   as  under  vertical  section  of  a  rt«iwer  bud.  D.  irant«vor!«e  »i*c- 

_,  V.        y      Vf       -^  ***^"  of  the  bud.     C,  traneven«e  section  ol  ovury. 

iTIoe   /•      Lfypripe-    2>,  mature  flower,  with  one  sepal  removed  :  x, 

die^.with  two  pollinifer-  Vt^.t^^^l^^^  Ixl'^Va'^^t^:  ^^.t 
0U8  Stamens  containing  mass;  A.  its  viscid  di8c  ;  gs,  the  colnmn  (1:^0- 
<ynLnnlnp  nollnn  fPin.  QA<>\  stominm);  near  gs  is  the  bil^m  which  projects 
granular  pollen  (1?  ig.  363).  jo^a^d  h ;  /,  inferior  ovary,  twisted  In  D ;  $t,  sta- 
in this  the  genus  GypH'  mlnodes.— After  Sachs. 
pedvum,  which  contains  our  native  LadyVSlippers,i8  the  most  important. 
Some  of  the  species,  notably  C.  t^ec'abUe  and  C.  acauk,  are  greatly  ad- 
mired in  cultivation. 


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470 


BOTANY, 


Tribe  II.  Neottiece,  with  a  single  dorsal  antber,  containing: 
two  or  four  soft  pollen  masses  attacbed  to  a  viscid  disc.  Our  principal 
genus  is  Spiranthes. 

Tribe  IJI.  ArethuseiBf  with  a  single  terminal  anther,  contain- 
ing two  or  four  powdery  pollen  masses. 

Our  native  Arethusa  and  Calvpogon  are  fine  representatives  of  this 
tribe.  The  Vanilla  plant  {Vanilla  planijolia,  and  other  species)  of 
tropical  America,  a  climbing  epiphyte,  producf  s  flesby  capsules  12  to 
25  cm.  (5-10  in.)  long,  which  are  highly  aromatic,  and  much  used  in 
the  manufacture  of  confections,  beverages,  medicines,  etc.  Wben  first 
introduced  into  the  East  Indies,  where  it  is  now  mucb  grown,  it  failed  to 

perfect  fruit ;  artificial  p  Uination  hav> 
ing  been  resorted  to,  however,  the  dif- 
culty  at  once  disappeared.  (Fig.863.) 
Tribe  IV.  Ophrytlece^  with  a 
single  anterior  antber,  containing  two 
stalked  pollen  masses,  each  attached  to 
a  viscid  disc  (Fig.  861). 

Our  pretty  little  Orchis  fpectabiHt, 
and  many  species  of  Uabenaiia,  are 
our  principal  representatives  of  this 
tribe.  From  the  tubers  of  Orchis  mas- 
cula  and  other  European  and  Asiatic 
species,  the  starchy-mucilaginous  and 
highly  nutritious  substance  '*  Salep/* 
is  obtained. 

Tribe  V.  Vandece,  with  a  single 
terminal  or  dorsal  anther,  containing 
waxy  pollen  masses  attacbed  to  a  vis- 
cid disc. 

We  have  no  native  representatives 

_  of  this  tribe.     Many  of  the  tropical 

Btunen  or  Btamlnode ;  n,' stigma.--    species  are  of  wonderful  forms;  indeed, 

as  Mr.  Darwin  says  of  them,  they  «re 
Orchids."    In  some  genera  they  assume 


Pig.  862.  —  Sexual  organs  of  the 
flower  of  Cypripedivm  oaicedus.  the 
periaoth, »,  removed.  A ,  side  view. 
B,  back  view.  C,  front  view.  /,  the 
Inferior  ovary  ;  g§,  the  column  or  cy- 
nosteminm ;  aa,  Btaroene ;  s,  stenJe 
stamen  or  s  * 
After  Sachs. 

**  tbe  most  remarkable  of  all 
the  most  curious  forms,  resembling  insects  of  various  kinds,  birds,  etc, 
etc.  In  Catasetum  saccatum,  a  diclinous  South  American  species, 
when  certain  Bensitive  parts  of  the  column  of  the  male  flower  are 
toucbed  by  an  insect,  the  pollen  masses  are  by  a  peculiar  contrivance 
thrown  out  forcibly  in  such  a  direction  as  to  strike  the  insect,  to 
which  it  adheres  by  a  viscid  disc,  and  is  thus  carried  to  and  brought  in 
contact  witl)  the  stigma  of  the  female  flower. 

Tribe  VI.  Epidendrece,  with  a  single  tenuinal  anther,  contain- 
ing stalked,  wnxy  pollen  masses,  these  not  attached  to  a  viscid  disc.  To 
this  tribe  belong  iu  tbe  United  States  Tipularia,  Bletia,  and  JEpideiu 
drum,  the  latter  an  epiphyte,  occurring  only  in  the  Southern  States. 


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AMOMALES,  471 

Of  the  exotics,  Ccdogyne,  Lalia^Cattleya,  etc.,  are  to  be  seen  in  conserva- 
tories. 

Tfdbe  VII.  MalaoGidecBf  with  a  single  dor- 
sal, terminal,  or  anterior  anther,  which  contains  four 
stalkless,  waxj  pollen  masses,  not  provided  with  a 
viscid  disc. 

CcUypao,  Liparis,  CoraUorhizd,  and  other  genera 
occur  in  the  United  States  ;  the  last  named  appears 
to  be  parasitic.  Among  the  many  exotics  may  be 
mentioned  BulhophyUumy  Dendrobium,  Malaxis, 
etc. 

565.  Cohort  XIV.  AmomaleB. — Herbs 
(some  almost  arbores- 
cent) with  hexamerous 
and  mostly  zygomor- 
phic  perianth ;  sta- 
mens six,  generally 
from  one  to  five  only 
polliniferouR. 

Order '  BromeliaceaB. 

— The  Pine-apple  Family. 
Distinguished  from  the 
next  by  the  regular  flow- 
ers and  six  perfect  sta- 
mens. About  two  hundred 
species  of  almost  entirely 
tropical  plants  constitute 
this  order.    But  one  genus 

(rtKand«a)i8  represented  Jlfo^SiiiXpMl'^ 
in  the  Southern  United  anasaa  eativa)  terminated 
States  ;  of  the  eight  or  ten  ^^  *  ^^'^  «'  1«»^««- 
native  species,  the  Long  Moss  (71  usneoides)  of  the 
Southern  Atlantic  coast  is  the  best  known.  It  is 
used  in  upholstery  and  in  the  manufacture  of  mat- 
tresses. 

Ananassa  sativa,  the  Pine-apple,  supposed  to  be 

a  native  of  Brazil,  is  now  cultivated  throughout  the 

world.     In  cool  climates  it  is  grown  in  hot-houses, 

and  it  is  said  that  these  are  much  better  than  those 

grown  out  of  doors  in  warm  climates.     The  fleshy 

Truitsare  aggregated  into  solid  cone-like  masses  (Fig. 

Pig.  868.— Ripened   364),  the  well-known  Pine-apples  of  commerce. 

SpJ5?ii^dThSilSig?^e       Order  ScitaminesB.— The  Banana  Family,  with 

**^*'  zygomorphic  perianth,  and  one  to  five,  very  rarely 

six,  perfect  stamens.    Three  sub-orders  are  well  marked. 


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472  BOTANY, 

Sub'Order  MuscBf  with  five  polliniferons  stamens  (rarelj  six). 

The  genus  Mum.  contains  several  exceedinj;Iy  valuable  plants,  if. 
sapientum,  the  Banana,  and  M.  paradisiaca,  the  Plantain,  of  the  trap- 
ics  everywhere,  are  large  herbs,  3-5  metres  (10-15  ft.)  high,  with  the 
sheathing  petioles  of  their  larg^  leaves  forming  a  tree-like  stem. 
Their  well-known  fruits  constitute  almost  the  sole  article  of  food  for 
millions  of  people  in  the  tropics,  and  are  also  largelj  exported  to  all 
countries.  It  has  been  calculated  that  from  twenty-five  to  sixtj-six 
tons  of  bananas  can  be  grown  upon  an  acre  of  ground,  supplying  more 
nourishment  to  man  than  is  afforded  by  any  other  plant.  They  are 
considerably  grown  in  hot-houses,  both  as  ornaments  and  for  their 


Fig.  865.— Part  of  a  flowering  plant  of  the  Banana,  showing  the  unfolding  flower- 
bad  and  the  young  fruits. 

fruits.  From  their  leaves  and  petioles  a  good  fibre  is  obtained,  and 
from  the  allied  if.  textilis  of  the  East  Indies  is  obtained  "Manilla 
Hemp,*'  so  much  used  in  the  manufacture  of  various  textile  fabrics. 

StrelUzia  Begincp,  of  the  Cape  of  Good  Hope,  is  a  common  conserva- 
tory plant. 

Sub~Order  Zingibers,  with  one  polliniferous  stamen,  bearing 
a  two-celled  anther.    Several  of  these  tropical  plants  are  important. 

Cvrettma  longa,  of  the  East  Indies  and  tropical  Pacific  islands,  has 
a  yellow  colored  rhizome,  which  constitutes  the  well  known  dye, 
"Turmeric." 

Zingiber  officinale,  the  Ginger  Plant,  probably  a  native  of  India,  is 
now  grown  in  most  tropical  countries  for  its  aromatic  rhizomes,  which 


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DIC0TTLEB0NE8,  473 

when  dried  and  powdered  constitute  the  ginger  of  commerce.  That 
from  the  West  Indies,  called  Jamaica  Ginger,  is  considered  the  best. 

Sub'-Order  Cannm,  with  one  poUiniferons  stamen,  bearing  a 
one-celled  anther.  Aside  from  Canuay  with  its  many  ornamental  spe- 
cies  now  common  in  gardens,  one  other  plant  deserves  mention,  viz. : 

Maranta  arundinacea,  a  native  of  tropical  America,  now  grown  ex- 
tensively for  its  fleshy  rhizomes,  from  which  a  starch  known  as  "Arrow- 
root "  is  obtained. 

566.  Cohort  XV.  Hydrales. — Small  aquatic  plants,  with 
a  hexamerous  regular  perianth,  and  stamens  three,  six,  nine, 
or  twelve. 

Order  HydrocharidesB.— This  contains  the  Eel  Grass.  VaUiaruria 
spiralis,  and  Water  Weed,  Anacharis  Canadensis, 
common  in  oar  ponds  ;  the  latter  is  naturalized  in 
England,  where  it  chokes  up  streams. 

FoMil  Monocotyledons.— The  earliest  Mono- 
cotyledon, so  far  as  known  at  present,  was  a  Tri- 
assic  species  of  YuceUes,  doubtfully  referred  to  the 
Liliacese.  In  the  Jurassic  the  Graminese,  Cyper- 
aceae,  LiliaceaB,  Naiadacess,  and  Pandanacese  were  pjg  afl6.— Diajntun 
represented  by  a  lew  species.  In  the  Cretaceous  the  of  the  flower  of  Can- 
t^  Tx«  1    T^  1  J         'w*.  phowing  tbooreti- 

CauDse,    Dioscoreacetc,   aud   Palmaceee   appeared.       cai  structure.  —  Alter 

A  species  of  the  last-named  order  has  been  discov-  S^l^s- 
ered  in  the  Cretaceous  of  Western  Kansas.  In  the  Tertiary  most  of  the 
modem  orders  of  Monocotyledons  were  represented  (liowever,  no  orders 
of  Cohorts  II.,  III.,  and  XIII.  have  yet  been  found).  Fifteen  species 
of  palms  have  been  descrilsed  from  the  Tertiary  of  the  Great  Plains 
and  the  Rocky  Mountain  region,*  extending  as  far  north  as  northern 
Dakota  and  Vancouver's  Island.  Their  remains  are  also  abundant  in 
the  Tertiary  of  Mississippi. 

Sub-Class  II.   Dicotyledones. 

{ExogencB  of  De  Candolle.f) 

567. — In  the  plants  of  this  sub-class  the  first  leaves  of  the 
embryo  are  two  and  opposite,  hence  they  are  said  to  have 
two  cotyledons.     The  venation  of  the  leaves  is  for  the  most 

♦  "  Contributions  to  the  Fossil  Flora  of  th«  Wp«tern  Territories. 
Part  II.  The  Tertiary  Flora,"  by  Leo  Lesquereux.     Washington,  1878. 

t  From  the  Greek  i^u,  outside,  and  yiveiv,  to  bring  forth.  The 
name  is  no  longer  a  proper  one,  as  we  now  know  that  thesu  plants 
are  not,  strictly  speaking,  "  outside  growers ;  '*  on  the  contrary,  they 
Increase  in  thickness  by  the  growth  of  an  internal  meristem  layer. 


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474 


BOTANY, 


part  such  that  the  veins  rarely  are  parallel  to  each  other,  and 
in  their  anastomosing  they  form  an  irregular  net-work. 

The  germination  of  Dicotyledons  may  be  illustrated  by  a  couple  of 
examples.  In  the  seed  of  the  Windsor  Bean  (Fig.  867)  the  embryo 
entirely  fills  up  the  seed-cavity,  the  endosperm  having  all  been  ab- 

FlOB.  867-^.— OERinNATION  OF  DiOOTTLBDONS. 


Pio.  867. 


Fio.  368. 


Fig.  367.— Fiola /fffta.  X,  peed  with  one  cotyledon  removed  ;  o,  remaining  cotyle- 
don ;  ibi,  the  plumule  to,  the  radicle  ;  t,  seed-cuat.  B,  germinating  seed  :  f.  aeed- 
coat,  uartl^r  torn  away  at  /;  n,  the  hilum  ;  *f,  petiole  of  one  of  the  cotyledons;  *, 
cnrvea  epicotyledonary  stem ;  A«,  short  hypocotyledonary  stem  ;  h,  main  root ;  «;«, 
its  apex  ;  *n,  hud  in  the  axil  of  one  of  the  cotyledons.— After  Sachi*. 

Fig.  2IS%.—RiciniL9  commuMa,  /..  longitudinal  section  of  the  ripe  seed.  //.,  ger- 
minating seed  with  the  cotyledons  still  inside  of  the  seed-coat  (f*hown  more  distinct- 
ly in  A  and  B).  s,  seed-coat ;  f,  endosperm  ;  c,  cotyledon  ;  he.  hypocotyledonary 
stem  ;  w,  primary'  root ;  w'.  branches  of  root ;  to,  camucl^,  a  peciiliiir  appendage  to 
the  seeds  of  SuphmMaoece,— After  Sachs. 

sorbed.  The  thick  cotyledons  lie  face  to  face,  and  are  attached  below 
to  the  small  stem  of  the  embryo  plant.  The  stem  extends  upward  a 
short  distance  between  the  cotyledons,  bearing  a  few  rudimentary 
leaves  and  itself  ending  in  a  punetum  vegetationis  (Figf.  869,  m),  the 
whole  constituting  the  plumule.  The  downward  prolongation  of  the 
stem  (commonly  but  erroneously  called  the  radicle,  for  it  is  not  a  little 


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DICOTTLEDONES, 


475 


root)  ends  in  a  very  short  root,  which  is  continuous  with  the  item.* 
Under  ihe  proper  conditions  of  heat  and  moisture,  the  root  elongates 
and  pushes  out  through  the  micro- 
pjle  of  the  seed-coat ;  at  the  same 
time,  the  stalks  of  the  cotyledons 

elongate  and  thus  bring  the  plumule  ^ 

outside  of  the  seed-coat,  the  cotyle- 
dons alone- remaining.  During  the 
first  few  days  of  its  growth  the 
young  plant  is  nourished  by  the 
starch  in  the  cotyledons,  which  in 
this  species  remain  during  the  whole 
process  of  germination  beneath  the 
ground  enclosed  in  the  seed-coat.  In 
the  common  Field  Bean  {Plmseolus) 
the  germination  is  the  same,  except- 
ing that  the  hypocotyledonary  stem 
elongates,  and  brings  the  cotyledons 
which  have  slipped  out  of  the  seed- 
coat  above  the  ground. 

The  seed  of  Rieinus  (the  Castor 
Oil  Plant)  contains  a  large  embryo 
surrounded  by  a  thin  layer  of  endo- 
sperm (Fig.  868,  /).  In  its  germina- 
tion the  root  and  hypocotyledonary 
stem  elongate,  and  thus  bring  the 
seed-coat  with  the  contained  coty- 
ledons above  the  ground  (Fig.  368, 
//.).  The  cotyledons  remain  within 
the  seed-coat  until  they  have  absorb- 
•ed  all  of  the  endosperm  ;  when  this 
is  accomplished  the  empty  seed-coat 
falls  away,  and  the  freed  cotyledons 
expand  and  assume  to  some  extent 
the  function  of  ordinary  foliage 
leaves.  ^ 

The  venation  of  the  leaves  of  Di- 
cotyledons  is  easily  studied  by  mac- 
erating  them   so  as  to  remove  the 

parenchyma     (mesophyll),     leaving    or  cotyledons ;  i,  the  tfrst  internode; 
only    the     fibro-vascular     bundles.    ^jJ^^  petioles  of  the  first   folia 
While  there  is  as  a  rule  a  general 
likeness  between  them,  there  is  yet 
an  almost  infinite  diversity  in  the 


Fig.  SfiO.-Lonifitndlnal  section  of  the 
axiH  of  the  embryo  in  the  ripe  need  of 
Phaseolus  multi^orWy  parallel  to  the 
cotyledons,  m,  apex  of  the  stem  ;  tog, 
of  the  root ;  cf,  swelling  near  insertion 
of  cotyledons ;  i,  the  lira 
oft,  the  petioles  of  the  flrst  foliage 
leaves ;  «.  «,  r  procambium  of  the 
flbro-vascular  bandies  ;  he,  hypocoty- 
ledonary portion  of  the  t^tem  (the  brace 
is  too  long  in  the  figure),  x  80. —After 
Sachs. 


*  In  some  old  books,  and  even  a  few  recent  ones,  a  structure  called 
the  collar  or  eoUum  is  spoken  of.     Dr.  Gray  very  properly  defines  it  as 


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476  BOTANY. 

details.    Tlie  general  disposition  of  the  smaller  veins  is  well  illustrated 
by  Fig.  369a.* 

668. — The  Bub-class  Dicotjledones  is  composed  of  thirty- 
six  cohorts,  containing  in  all  from  150  to  200  natural  orders. 
For  convenience,  the  cohorts  are  separated  into  three  artifi- 
cial groups — the  Apetalae,   Gamopetalae,  and   Choripetalae 
(Polypetalae) — an  arrangement  which  does  violence  to  nature, 
separating  widely  many  orders  which  are  evidently  closely 
related  to  each  other. 
I.  APETAL^.     Plants  whose  flowers  generally  have  but 
a  single  floral  envelope  (calyx), 
this  even,  in  some  cases,  wanting. 

669.  Cohort  1.  — Santalales. 

Herbs,  shrubs,  or  trees,  mostly 
parasitic,  with  inferior  ovary, 
generally  naked  ovules — i.e.,  no 
integuments — and  seeds  usually 
containing  endosperm. 

Order  Balanophoreed.  —  Fleshf 
leafless  parasites,  mostly  of  the  trop- 
ics. One  species,  Cynomorium  eoccin- 
eum,  of  the  Mediterranean  region,  is 
sometimes  eaten. 

Order  SantalaceaB.— Leafj  herbs. 

Jig.  869a.— Prapneiit  of  a  lea.'  of  a  shrubs,  or  trees,  mostly  parasitic,  num- 
Df cotyledon  (P»oralea  biluminwa).    ,      .  u     *.    on/\  •  u*  \. 

ihowing    reticulated    venation,    r.    bering  about   200   species,  which  are 
mw-gin  of  leaf,     x  40.-After  De   distributed   in  temperate  and  tropical 

regions. 

Comandra  unibeUfUa,  a  perennial  herb,  is  our  most  common  repre- 
sentative of  the  order. 

Santalum  albftm,  tlie  Sandalwood  Tree  of  South  Asia,  attains  a  height 
of  seven  to  eight  metres  (25  feet).  Its  dark  red  wood  is  used  in  cabinet- 
making,  and  for  burning  incense  in  Buddhist  temples.  Other  species 
from  the  Pacific  islands  also  furnish  sandalwood. 

The  Quandang  Nut  of  Australia  is  the  edible  fruit  of  a  small  tree, 
Fusanus  acuminatum, 

"  the  name  of  an  imaginary  something  intermediate  between  primary 
stem  and  root." 

*  The  student  who  wishes  to  study  this  subject  fully  should  consult 
the  papers  of  Dr.  Ettingshausen,  published  in  Denkschriften  and 
Sitzung^erichte  Wien.  Kais,  Akad.  Wissen.  They  are  excellently  il- 
lustrated with  many  **  nature  printed  "  plates. 


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qUERNALES.  47; 

Order  LoranthaceeB.  The  Mistletoe  Family.  Evergreen  sUrabs, 
parasitic  opon  other  Dicotyledons.  About  450  species  are  known ; 
these  are  mostly  tropical. 

VxKum  Mum,  the  Mistletoe  of  England,  Europe,  and  Northern 
Asia,  grows  abundantly  upon  the  apple  and  many  other  trees,  rarely, 
however,  upon  the  oak.  The  viscid  fruits  are  usied  in  makin^i:  bird- 
lime, and  its  twigs  and  branches  are  much  used  in  Christmas  decora, 
tions  in  England.  It  was  held  sacred  by  the  Druids,  who  made  use  of 
it  in  their  religious  ceremonies. 

PTioradeTidron  flave»cen$,  the  American  Mistletoe  of  the  Southern 
United  States,  Is  well  known.  On  the  Pacific  coast,  a  variety  of  this 
species  is  common  on  the  oaks. 

Six  species  of  AreetUhobium,  small  brown  branching  parasites  on 
Conifers,  are  known  in  the  United  States.  A,  ptmllum  occurs  in  the 
Northern  States. 

570.  Cohort  n.—Quemale8.  Trees  and  shrubs,  not  at 
all  parasitic,  with  diclinous  flowers,  mostly  in  catkins,  infe- 
rior ovaries,  and  seeds  destitute  of  endosperm. 

Order  Cupidiferess.  The  Oak  Family.  Trees  or  shrubs  with 
simple  leaves  ;  fruits  (nuts),  one-celled,  one-seeded,  one  to  three  en- 
closed in  an  involucre.  This  valuable  order  contains  about  800  species, 
which  are  distributed  mainly  in  the  Nortliern  Hemisphere  ;  in  the  South- 
em  Hemisphere  they  occur  in  Chili,  New  Z«^land,  and  the  mountains 
of  South  Australia.  Most  of  the  species  are  astringent,  which  is  due 
to  the  tannin  they  contain. 

The  order  is  of  great  economic  importance  on  account  of  its  valuable 
wood,  which  is  used  not  only  as  a  fuel,  but  still  more  in  the  manufac- 
ture of  implements  and  utensils,  and  in  the  construction  of  houses, 
ships,  etc  It  is  divided  into  two  sub-orders,  which  are  sometimes  re- 
garded  as  orders. 

Sub- Order  Corylece.    Shrubs  and  small  trees. 

Carpinus  Americana,  the  Blue  Beech,  or  Hornbeam,  is  a  small  native 
tree  with  white,  fine-grained,  hard  wood.  As  the  European  (7.  betultis 
is  used  in  turnery,  doubtless  our  species  mi^ht  be  also. 

Corylus  AveUana,  the  Filbert,  is  a  shrub  growing  wild  in  Europe  and 
Western  and  Northern  Asia,  and  now  cultivated  in  Europe  and  the 
United  States.  It  is  grown  principaUy  for  its  edible  nuts,  although  the 
straight  rod-like  branches  are  lar^rely  used  in  making  hoops,  crates  for 
merchandise,  etc.  White  Filberts,  Red  Filberts,  Cob-nuts,  and  Bar- 
celona-nuts  are  some  of  the  cultivated  varieties.  C.  Americana,  the 
common  wild  Hazel-nut  of  the  Eastern  United  States,  is  much  like  the 
preceding,  but  smaller  in  size  of  shrub  and  nuts.  Its  nuts  are  gath- 
ered and  eaten,  and  are  occasionally  found  in  the  markets. 

Ostrya  Virginica,  the  Ironwood  of  the  Eastern  United  States,  is  a 
small  tree  having  a  hard,  fine-grained  wood,  which  is  valuable  for  fueL 


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478 


BOl'AJVr, 


AlthougL  capable  of  many  uses  in  the  arts,  it  baa  been,  to  a  great  ex- 
tent,  neglected.  Tbe  trunks  of  the  young  trees  are  much  used  for 
levers  in  saw-mills  and  log-yards,  hence  one  of  its  popular  names. 
Lever-wood. 

Sub-Order  Quercinew.    Mostly  large  trees. 

Oastanea  tesca,  tbe  so-called  Spanish  Chestnut,  is  a  native  of  Asia 

Figs.  870-74.— Illustbatiohi  of  Qukbous  Bobub. 


Fia.872L 


Fxe.  973. 


Fig.  870.  Fio.  874. 

Fig  870.— Male  and  female  branches,  with  a  ripe  frnit  at  the  side. 

Fig.  871.— Male  flower.    Magnified. 

Fig.  87S.— Female  flower.    Magnified. 

Fig.  878.— Female  fiower,  in  vertical  section.    Magnified. 

Fig.  874.— Vertical  section  of  fruit. 

Minor  and  tbe  region  eastward  to  the  Himalayas.  It  is  found  in  Cen- 
tral  and  Southeastern  Europe,  but  it  was  probably  introduced  from  the 
East  2000  or  more  years  ago.  It  furnishes  a  valuable  coarse-grained 
timber,  and  its  fruils  are  the  "Spanish  Chestnuts  "of  the  markets. 


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QUERN  ALES.  479 

Several  yarieties  occur  in  North  Africa,  Japan,  and  Nortli  America.  C, 
vesea,  var.  Amerieanat  our  native  Chestnut,  of  the  Eastern  United 
States,  is  a  large  tree,  with  smaller  and  sweeter  nuts  than  the  Old 
World  variety.  Its  wood,  which  is  light,  coarse-grained  and  easily 
worked,  is  highly  prized  for  making  doors,  cases,  certain  kiuds  of  fur- 
niture, etc. 

Fagxis  aylvatiea,  the  Beech  of  Europe  and  Western  Asia,  supplies  a 
hard  wood  much  used  in  chair-making,  turnery,  and  in  the  manufac- 
ture of  wooden  shofS.  Purple  Beech,  often  cultivated  as  a  curiosity, 
is  a  variety  of  this  species. 

F,  ferruginea,  the  common  Beech  of  the  Eastern  United  States,  is  a 
large  spreading  tree  ;  its  wood  is  reddish  in  color,  and  of  great  hard- 
ness when  dry,  and  is  used  in  making  carpenters'  tnols,  and  for  other 
purposes.  Its  nuts,  known  as  Beech-nuts  or  Beecli-Ma^t,  are  nutritious, 
and,  where  abundant,  are  used  for  fattening  swine. 

In  Southern  South  America,  New  Zealand  and  Australia,  there  are 
six  or  seven  evergreen  species  of  this  genus. 

The  genus  QuerctiS  includes  the  Oaks,  in  all  alx)ut  250  species,  which 
are  widely  distributed  in  the  Northern  Hemisphere ;  none  occur  lie- 
yond  the  equator.  De  Candolle  {Prodivmus^Yol.  XVI.)  divides  tlie 
genus  into  six  sections,  four  of  which  are  exclusively  Southeastern^ 
Asiatic. 

Section  I. — The  Scaly-Cupped  Oaks.  These  include  the  common 
oaks  of  Europe  and  America.  Tliey  are  again  subdivided  into  two  sub- 
sections— viz.,  the  White  Oaks  and  the  Black  Oaks. 

(a)  White  Oaks. 

Quercus  Hobur,  the  British  Oak,  of  England  and  tbe  Continent  of 
Europe.  It  is  a  stately  tree,  supplying;  a  most  valuable  timber  for  all 
kinds  of  constructive  purposes,  in  naval,  civil,  and  military  engineering. 
It  is  considered  to  be  superior  to  all  otiier  kinds  of  oak  for  its  timber. 
The  bark  contains  tannin,  and  in  much  used  in  tanning.    (Figs.  370-4.) 

Q.  LuifUaniea,  var.  infectoiia,  of  tiie  Levant,  produces  the  Nutgalls 
of  commerce  ;  these  are  morbid  growths  on  the  petioles  or  midribs  of 
the  leaves,  resulting  from  punctures  made  by  an  Hymenopterous  insect 
of  the  genus  Cynips,    Their  value  lies  in  the  tannin  they  contain. 

Q.  alba,  the  White  Oak  of  the  Eastern  United  States,  stands  next  to 
Q.  Robur  in  the  value  of  its  timber,  which  is  used  in  this  country  as 
British  Oak  is  in  Europe. 

Q.  tirena,  the  Live  Oak  of  the  Southeastern  United  States,  and  ex- 
tending westward  to  Texas,  is  a  large  tree,  twelve  to  twenty  metres 
(40-60  feet)  high,  with  spreading  branches,  bearing  small  entire  ever- 
green leaves.  Its  hard  and  heavy  wood  is  very  strong  and  durable, 
and  has  been  much  used  in  ship-building. 

Q.  ehrysolepis,  the  Canon  Live  Oak  of  the  canons  and  mountain-sides 
of  California,  resembles  the  preceding  in  many  respects,  being  like  it 
an  evergreen,  and  sometimes  attaining  a  height  of  from  twelve  to  six- 


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480  BOTANY. 

teen  metres  or  more  (40-50  feet).  **It  fumiBlies  the  liardest  oak  wood 
of  tbe  Pacific  Coast,  and  is  used  in  making  ox-bows,  ax-bandles,  etc." 
(Vasey). 

Q.  &uber,  the  Cork  Oak,  is  found  in  Southern  France,  Spain,  Italy, 
Sardinia,  and,  to  a  limited  extent,  in  Northern  Africa.  It  is  a  spread- 
ing topped  tree,  bearing  oval,  dentate  evergreen  leaves.  Certain  lay- 
ers of  cells  in  its  bark  retain  their  power  of  growth  for  a  long  time, 
and  give  rise  to  a  thick  mass  of  cork.  This  is  removed  every  eight  or 
ten  years  by  making  yertical  and  transverse  cuts  in  the  bark,  and  then 
peeling  off  all  but  the  inner  bark  layers.  Most  of  the  supply  of  cork 
comes  from  Spain  and  Southern  France.  The  tree  might  very  profit- 
ably be  grown  in  our  Southern  States  and  in  California. 

Q.  cerris,  the  Turkey  Oak  of  Southeastern  Europe,  is  a  fine  tree  with 
deciduous,  lobed  leaves,  and  bears  a  considerable  resemblance  to  our 
native  Q,  maerocarpct^  from  which  it  differs,  however,  in  requiring  two 
years  to  mature  its  fruits.  Its  timber  is  much  used  for  ship-building 
and  other  purposes. 

(6)  Black  Oaks. 

In  this  are  the  Black  Jack  (Q.  nigra),  the  Red  Oak  (Q.  rybra).  Scarlet 
Oak  (Q.  coccinea).  Quercitron  Oak,  (Q.  cocHvea,  var.  tinctoria),  all  of 
tbe  Eastern  United  States.  The  timber  obtained  from  these  is  coarse- 
grained, and  not  so  durable  as  that  of  the  white  oaks ;  the  two  last  fur- 
nish a  yellow  dye,  Quercitron,  which  is  derived  from  the  bark.  Q.  agrU 
folia,  tbe  Field  Oak  of  California  is  a  broad-topped  evergreen  species. 
Its  wood  is  of  but  little  VMlue. 

Section  II.,  the  Spiny-Cupped  Oak,  includes  but  a  single  spedes, 
found  in  California. 

Q.  densiflora,  the  California  Tan-bark  Oak.  This  is  a  beautiful  tree, 
often  thirty  metres  or  more  in  height  (100  feet),  with  curious  chestnut- 
like fruits. 

The  remaining  sections  contain  eighty  to  ninety  Fpecies,  confined  en- 
tirely to  India,  China,  Japan,  and  tbe  Malay  Islands.  They  differ  in 
many  respects  from  our  oaks. 

Order  Juglandacesd.— The  Walnut  Family.  Trees  and  shrubs 
with  pinnately  compound  leaves  ;  fruit  a  dry  drupe,  containing  a  bard, 
one-seeded  nut  (Figs.  880-382).  This  family  includes  about  thirty  spe- 
cies, about  equally  divided  between  North  America  and  Asia.  They 
possess  an  acrid  aromatic  principle,  which  has  been  used  in  medicine. 

Juglana  regia,  the  Walnut  of  the  Old  World,  is  a  native  of  Asia 
Minor  and  tbe  country  eastward,  but  long  cultivated  in  all  parts  of 
Europe,  and,  to  some  extent,  in  this  country.  The  light  brown  wood  is 
highly  prized  in  England  for  cabinet-making,  the  manufacture  of  fur- 
niture, piano-cases,  gun-stocks,  etc.  Its  thin-shelled  nuts  are  highly 
esteemed,  and  are  imported  from  Europe  in  large  quantities  under  the 
name  of  •  *  English  Walnuts. "    (Figs.  875-82.) 

J.  nigra,  the  Black  Walnut  of  the  Eastern  United  States,  is  a  giant 


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qUERNALES, 


481 


tree,  often  forty  to  fifty  metres  (130-160  feet)  in  heipflit.  Its  dark  brown 
timber  is  fully  as  valuable  as  tbe  preceding,  and  is  used  for  tbe  same 
purposes.    It  is  exported  in  considerable  quantities  to  England.     Its 

FlOf .  875-82.— lUiUSTRATIOlVS  OF  JUGLANS  BSGIA. 


Fio.  880. 


Fia.  881. 


Fio.  382. 


Pig.  375.— Female  flower  claster.  Fig.  376.  Female  flower.    Magnifled. 

Pig.  877.— Female  flower  cut  vertically.    Magnified. 
JJg.  878.— Male  flower.    Magnified.  iTg.  379.— Male  fiower  clnster. 

Pig.  880.-Ripe  fruit  Fig.  881.-Endocarp.  Fig.  888.-Seed. 


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482  BOTANY. 

tbick-sbelled  and  stronger-tasting  nuts  are  occasionally  found  in  the 
markets. 

J.  cinerea,  tLe  White  Walnut  or  Butternut,  of  the  Eastern  United 
States,  is  a  smaller  tree,  furnishing  a  valuable  lighter  colored  timber 
than  tbe  preceding. 

Two  small  species  occur  in  California,  Arizona,  and  Texas. 

Vary  a  a. ha,  tbe  Shell-bark  Hickory,  and  C,  sulcata,  both  large  trees, 
of  the  Eastern  United  States,  furnish  a  white,  tough,  and  hard  timber, 
useful  in  the  manufacture  of  agricultural  implements,  and  for  many 
other  purposes  wliere  great  strength  is  required.  It  is  not  well  adapted 
to  use  in  large  masses,  as  it  is  liable  to  early  destruction  through  decay 
and  the  ravages  of  wood-borinp  insects.  The  fruits,  known  as 
*' Hickory-nuts,"  and  highly  prized  for  eating,  are  found  in  our  mar- 
kets, and  are  also  exported  to  England. 

C,  oliwBfortnis,  a  small  tree  of  the  Southern  States,  furnishes  a  thin- 
shelled  edible  fruit  known  as  the  '*  Pecan-nut." 

Other  species  of  Carya  furnish  valuable  timber,  and  from  the  nuts 
of  this  and  the  preceding  species  valuable  "nut-oils"  used  in  paint- 
ing are  obtained. 

571.  — Cohort  HC.  Asarales.  Herbs,  with  mostly  mon- 
oclinous  flowers,  inferior  ovary,  and  seeds  with  integuments, 
containing  minute  embryo  usually  surrounded  with  endos- 
perm. 

Order  Bafflesiacead. — Parasites  upon  the  stems  and  roots  of  Dicoty- 
leiions.  Twenty  or  more  species  are  known,  distributed  throughout 
.the  hotter  parts  of  the  world. 

Rafflma  Arnoldi,  of  Sumatra,  is  the  most  remarkable  member  of  the 
order.  It  consists  of  a  gigantic  parasitic  flower  nearly  a  metre  in  di- 
ameter (3  ft.),  with  five  mottled-red  spreading  petals.  It  is  parasitic 
upon  a  woody  climbing  plant  {Cisms  anguHifolia)  nearly  related  to  the 
Vine,  and  in  its  growth  forms  scarcely  any  stem,  developing  almost  at 
once  into  a  giant  flower-bud.    It  was  discovered  in  1818  by  Dr.  Arnold. 

Order  AriBtolochiacead. — Mostly  tropical  herbs,  including  about 
200  species.  Three  species  of  Asarumt  and  three  of  Ariitoloehia  occur 
in  the  United  States. 

572.— Cohort  rv.  Nepenthales.  Climbing  shrubs,  with 
diclinous  flowers,  a  superior  three  to  four-ceHed  ovary,  whose 
many  seeds  contain  an  endosperm. 

Order  Nepenthaceae.— Plants  of  the  East  Indies  and  Australia,  of 
ten  or  twelve  species,  all  belonging  to  the  genus  Nepenihes.  The 
leaves  are  prolonged  into  a  slender  tendril-like  organ,  upon  whose  ex- 
tremity there  develops  a  hollow  closed  body,  which  finally  becomes, 
open  by  the  separation  of  its  apex  in  such  a  manner  as  to  form  a 
hinjjed  lid  (Fig.  388,  d,  e,  /).     In  the  cavities  of  these  pitchers,  as  they 


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PIPERALES. 


483 


are  called,  a  watery,  slig^litly  acid  fluid  is  secreted  ;  upon  their  borders 
are  secreted  honey  or  nectar  drops,  which  attract  insects,  and  these  fall- 
ing  into  the  fluid  within  are  soon  dissolved  by  it,  and  then  absorbed  by 
the  plant  for  its  nour- 
ishment. 

573.— Cohort  V. 
Fil>erale8.     Mostly 
herbs,  with   spiked 
flowers  and  superior 
one-celled  and  one- 
seeded  ovary. 
/x-j.-  m — tophyl- 
lerbs  of 
Qemi- 

'antha- 
plants, 
opics. 

icecB. — 
Family. 
>r  small 
ifinedto 
anerally 
nt  and 
rinciple. 
;ie8  are 

species 
he  East- 
Anemi- 
Lthwest- 

98. 

genera, 

Piper  and  Peperomia, 

include  nearly  all  the 

species,  the    first   con-  •n.t^  -«.    m_.    ,            .  ,t      ..            ..    . 

*•   •       flft/i      J  *i  Fig.  888— Two  leayes  of  JV««5/i«%<*a»Mwi//^fl'ri(i.   a, 

taining  620  and  the  sec-  short  petiole ;  6,  blade  or  expanded  part  of  leaf ;  c,  ten- 

ond  aft2  drll-like  prolongation  of  midrib  ;  tf,  «,  pitcher  ;  /,  Its 

ona  oo-c.  ^^^     j^  ^^  ^^^^^  j^^  ^^,^j^  ,g  younger,  the  lid  has  not 

Piper    nigrum    is    a   yet  separated  from  the  apex  of  the  pitcher.— After  Da- 
climbing    East   Indian   *'^"^™- 

plant,  with  heart-shaped  leaves ;  It  bears  spikes  of  berries,  which, 
when  slathered  green  and  dried,  constitute  the  Black  Pepper  of  com- 
merce. The  ripe  berries,  when  dried,  constitute  White  Pepper.  Pep- 
per is  now  grown  in  the  West  Indies. 


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484  BOTANY, 

P.  Cubeba,  whose  dried  anripe  berries  are  known  in  pharmacy  as 
Cubebs,  is  a  native  of  the  East  Indies. 

P.  BeUe,  of  tlie  East  Indies,  is  tlie  Betel  Pepper,  wliose  bitter  arc- 
matic  leaves  are  mixed  witb  Areca-nut  and  lime  to  form  a  masticatory. 
(See  Betel  Palm.  p.  466.) 

From  the  thick  rhizome  of  P.  methygHcum  the  inhabitants  of  many 
of  the  Pacific  islands  make  a  disgusting  drink  whicU  is  very  iotoxica- 
ting. 

574.— Cohort  VI.   Buphorbiales.     Plants  with  mostly 
diclinous  flowers,  with  a  superior  two  to  many-celled  ovary  ; 
seeds  containing  endosperm. 
Order  Lacistemaceae.     Shrubs  of  tropical  America. 

Order  (}eiB80lcme8B,  containing  a  single  shrub,  of  Southwestern 
Africa. 

Order  PensBaeeee.    Evergreen  shrubs  of  South  Africa. 

Order  EuphorbiacesB. — The  Spurge  Family.  This  vast  group  of 
upwards  of  8000  species  can  not  be  defined  by  any  one  character.  They 
may  generally  be  distinguished  by  their  three-celled  ovaries  and  milky 
juice,  although  neither  of  these  characters  is  universal  throughout  the 
order.  The  species  range  in  size  from  small  herbs  to  gigantic  trees, 
and  are  distributed  throughout  all  climates  except  beyond  the  Arctic 
Circle.  They  are  much  more  abundant,  however,  in  tropical  countries 
than  elsewhere.  With  few  exceptions  they  possess  an  acrid  principle, 
which  is  often  poisonous. 

Many  of  the  species  are  of  economic  importance,  a  few  of  which  only 
can  be  mentioned  here. 

Maniliot  palmafa  and  M,  utUissima,  slender  plants  of  tropical  Amer- 
ica, and  now  cultivated  in  many  tropical  countries,  have  thick  starchy 
roots.  The  starch,  separated  and  washed,  is  imported  under  the  name 
of  Brazilian  Arrowroot.  Tapioca  is  prepared  by  heating  the  separated 
and  washed  starch  upon  hot  plates.  Cassava  is  made  from  the  crushed 
roots  by  drying  tlie  pulp  without  separating  the  starch.  These  three 
substances  are  highly  nutritious,  and  are  much  used  as  food  by  the 
natives,  and  are,  moreover,  largely  imported  into  this  country.  Their 
value  is  all  the  more  remarkable  from  the  fact  that  the  root  of  the 
second  named  species  above  is  in  its  raw  state  deadly  poisonous. 

RieinvB  communis,  the  Castor  Oil  plant,  a  native  of  India,  is  now 
widely  ^p^wn  for  its  oily  seeds,  from  which  Castor  Oil  is  obtained  by 
pressure.  It  is  extensively  grown  in  the  Mississippi  Valley.  In  Ger- 
many it  is  ffrown  for  its  leaves,  which  are  fed  to  silkworms.  It  is  a 
l)eautiful  ornamental  plant,  and  when  grown  for  this  purpose  is  called 
the  Palma  Christa. 

Croton  Oil  from  Croton  Tiglium,  and  Pinhoen  Oil  from  Jatrapha  Cur- 
cos,  are  drastic  medicines.    Qum  Euphorbium,  the  dried  milky  juice 


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EUPHORBIALES.  485 

of  variouB  African  and  Indian  species  of  Euphorbia^  Gascarilla  Bark  and 
Melambo  Bark  from  species  of  Croton  in  tropical  America,  are  more  or 
less  known  in  pharmacy. 

Hevea  Ouianensia  and  other  species  of  the  genus,  natives  of  the 
northern  part  of  South  America,  furnish  the  important  substance 
Caoutchouc,  or  India  Rubber.  The  trees  are  from  fifteen  to  thirty 
metres  in  hei^rht  (50  to  100  ft.),  and  bear  trifoliate  leaves  resembling 
those  of  the  Scarlet-runner  bean  in  size  and  shape.  The  natives  make 
incisions  into  the  trees,  from  which  th»  milky  juice  exudes,  and  this 
evaporated  constitutes  the  crude  Caoutchouc.  By  heating  the  crude 
product  with  sulphur  it  is  hardened,  and  is  then  known  as  "  Vulcan- 
ized rubber." 

Eecaearia  sebifera,  the  Tallow  tree  of  China,  now  cultivated  in  the 
warmer  parts  of  America,  has  its  seeds  coated  with  a  white  greasy  sub- 
stance,  which  yields  a  valuable  tallow  from  which  candles  are  made. 

Aleurites  Moluccana,  the  Candle  Nut  tree  of  India  and  the  Pacific 
islands,  produces  a  large  oily  fruit,  which  is  itself  burned  and  used  as 
a  candle,  or  from  which  a  valuable  oil  is  extracted. 

The  most  valuable  timber  of  the  order  is  furnished  by  BuxiLS  semper- 
virens,  the  Box  tree  of  Europe  and  Asia.  It  is  a  small  evergreen 
tree,  with  a  very  hard  yellowish  wood,  invaluable  in  wood  engraving, 
the  manufacture  of  mathematical  instruments,  etc.  Our  chief  supply 
comes  from  the  Mediterranean  ports.  A  dwarf  variety  of  this  species 
is  used  for  bordering  garden  walkp. 

African  Teak,  a  very  heavy  and  hard  wood  from  Africa,  is  supposed 
to  be  derived  from  Oldfieldia  Africana,  which  has  been  doubtfully  re- 
ferred to  this  order. 

Among  the  plants  grown  for  ornament  are  many  species  of  Euphor-^ 
bia,  an  immense  genus  of  700  species,  distributed  very  widely  ;  in 
Africa  they  assume  a  Cactus-like  aspect,  having  thick  succulent  stems. 
These  and  many  other  species  are  to  be  found  in  conservatories.  The 
curious  XylophyUat  with  flat  leaf-like  branches,  bearing  flowers  upon 
their  edges,  is  also  common. 

The  Sand  Box  tree  of  tropical  America  bears  a  curious  many-celled 
fruit  which  when  dry  explodes  with  a  loud  report. 

The  juice  of  many  of  the  species  is  poisonous  when  dropped  upon  the 
skin,  or  into  a  wound.  The  Manchineel  tree  (Hippomane  MancineUa) 
of  South  Florida  and  the  West  Indies  is  extremely  poisonous,  but  many 
of  the  stories  told  of  it  are  fabulous. 

Zebra  Poison  is  the  name  applied  to  Euphorbia  arborea  ;  branches  of 
it  placed  in  water  render  it  sufficiently  poisonous  to  kill  the  animals 
which  drink  it. 

575.--Cohort  vn.  Amentales.  Woody  plants,  with  di- 
clinous flowers,  mostly  in  catkins ;  the  one  or  two-celled 
ovary  superior,  and  the  seeds  with  no  endosperm. 


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486 


BOTANY, 


Order  Salicaceee.— The  Willow  Family.  Dioecious  trees  and  sbrabs 
with  naked  flowers — 1.«.,  the  perianth  wanting.  The  species,  of  which 
there  are  180,  are  principally  found  in  the  North  Temperate  and 
Arctic  Zones ;    beyond  the  tropics  they  are  rare,  and  none  occur  ia 

Fios.  884-9.— Illustrations  of  Salix  caprjea. 


Fio.  S84. 


Fio.  385. 


Fio.  886.  Pig.  387. 

Fig.  384.— If  ale  catkin  and  separate  flower. 


Fio.  388. 


Fig.  889. 


Magnified. 


Fig.  885.— Female  catkin.       '  Fig.  386.— Female  flower. 

Fig.  387.— Cross-section  of  ovary.    Magnified. 

Fig.  888.— Ripe  fruit  and  seed.    Magnified.     Fig.  389.— Embryo.    Magnified, 


Australia  and  the  South  Pacific  Islands.     Tliey  contain  a  bitter  astrin 
gent  principle  useful  in  medicine  as  a  iebrifuge. 

Two  genera  only  are  known. 

Salix  verminalU,  S.  purpurea,  8.  capr<Ba,  and  other  si>ecie8  of  the 
Old  World,  are  cultivated  for  basket-making. 


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AAfLWTALES.  487 

8.  Bijbyloniea,  the  weeping  willow  of  Persia,  is  well  known  under 
cultivation. 

8,  aJIha  and  other  large  species  of  Europe  furnish  a  light  firm  wood, 
much  used  for  many  purposes. 

By  charring  the  wood  a  fine  charcoal  is  obtained,  much  used  in  the 
manufacture  of  gunpowder.  In  the  prairies  of  the  Mississippi  Valley 
the  species  last  named  is  planted  in  compact  rows  to  ^rve  for  hedges 
and  to  break  the  force  of  the  violent  winds. 

Some  of  the  larger  of  our  many  native  species  might  profitably  be 
used  for  their  light  timber,  which  in  some  cases  is  quite  durable. 

Populus  Canaderms,  the  Cottonwood  of  North  America,  is  a  very 
large  tree,  whose  white  wood  is  suited  to  many  manufacturing  pur- 
poses. 

The  "  Lombardy  Poplar,"  a  variety  of  P.  nigra^  and  a  native  prob- 
ably of  Western  and  Northern  Asia,  and  the  Abele  tree  (P.  aWa)  of 
Europe,  are  commonly  grown  on  large  grounds. 

Order  Gasuarineae.— Leafless  trees,  with  pendulous  Equisetum-like 
Jointed  stems.  Twenty  five  species,  mostly  nntives  of  Australia,  are 
known.  Some  of  them  are  large  enough  to  supply  a  valuable  timber 
for  ship-buildiug,  and  many  are  favorites  for  ornamental  purposes  in 
Australia. 

Order  MyricacesB. — Monoecious  or  dioecious  shrubs,  often  with  a 
glandular  waxy  pubesceuce.  The  thirty  to  thirty-five  species  are 
widely  distributed  throughout  the  North  Temperate  Zone,  and  in  trop- 
ical Asia  and  South  Africa. 

The  berries  of  Myrica  cenfera,  the  Bayberry,  of  the  Eastern  United 
States,  and  other  species  in  Europe  are  covered  with  a  wax,  which  is 
gathered  and  made  into  candles. 

Order  PlatanaceeB.— The  Plane  Tree  Family.  A  small  group  of 
five  monoecious  trees,  with  the  flowers  in  globose  catkins. 

Platanus  occidentalis,  the  Plane  tree,  Buttonwood,  or  Sycamore  of 
the  Eastern  United  States,  is  a  large  tree  with  thin  white  bark.  Its 
reddish  wood  is  valuable,  and  should  be  more  used.  A  nearly  related 
species  occurs  in  California  and  two  in  Mexico.  The  fifth,  P.  oriental- 
is,  is  the  only  Old  World  species. 

Order  Betulaceas.— The  Birch  Family.  Monoecious  trees  with 
flowers  in  slender  catkins.  The  species,  forty  or  more  in  number,  are 
found  throughout  the  North  Temperate  Zone,  and  in  South  America. 

Betula  alba,  of  Northern  Europe,  Northern  Asia,  and  North  America, 
is  a  useful  species.  Its  wood  is  valuable  for  fuel,  use  in  manufactures, 
and  for  making  into  charcoal.  Its  bark  is  made  into  shoes,  boxes,  etc. ; 
it  is  used  in  tanning  leather,  and  from  it  by  distillation  an  oil  is  ob- 
tained which  gives  to  Russia  leather  its  peculiar  scent.  The  people  in 
the  high  north  latitudes  also  use  tlie  cellular  and  starchy  part  of  the 
bark  for  food. 


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488  BOTANY, 

The  bark  of  B.  papyracea,  of  tlie  Eastern  United  States,  is  used  hy 
the  Indians  for  making  their  "  birch  bark  canoes." 

The  wood  of  species  of  Alnus,  the  Alders,  is  very  durable  when 
placed  under  the  ground  or  water.  It  is  also  made  into  wooden  bowls 
and  other  domestic  utensils,  and  is  in  some  places  grown  for  making 
into  charcoal. 

576.— Cohort  Vm.  TJrticales.  Mostly  diclinous  plants, 
with  superior  one-celled  ovary,  and  single  seed  mostly  with 
an  endosperm. 

Order  XJlnuweaB.— The  Elm  Familj.  Trees  or  shrubs  of  the  North 
Temperate  Zone,  having  mostly  monoclinous  flowers,  and  a  watery 
juice.     About  one  hundred  and  thirty  ppecies  are  known. 

Ulmus  campestris,  the  common  Elm  of  Europe  and  Western  Siberia, 
is  a  large  tree,  thirty  to  forty  metres  (100  to  130  ft.)  high.  Its  timber  is 
valuable  for  works  underground  or  in  water,  and  is  besides  much  used 
by  wheelwrights.     The  tree  is  common  in  American  gardens. 

IT.  Americana,  the  American  White  Elm  of  the  Eastern  United 
States,  and  now  much  grown  in  Europe,  is  one  of  our  finest  hoking 
trees,  and  deservedly  popular  as  an  ornament  in  large  grounds.  Its 
timber  is  valuable  when  used  entirely  under  water  or  in  the  ground, 
or  when  kept  continuously  dry  ;  otherwise  it  decays  rapidly. 

U.  fulva,  the  Slippery  Elm  of  the  Eastern  United  States,  supplies  a 
valuable  timber,  and  its  mucilaginous  inner  bark  is  used  for  medical 
and  surgical  purposes. 

Celtis  occidentalism  the  Hackberry  of  the  Eastern  United  States,  is  a 
lofty  tree  which  furnishes  a  white  hard  timber,  which  is  not,  however, 
very  durable. 

Order  GannabineeB. — This  contains  the  two  dicecious  herbs,  the 
Hemp  and  the  Hop. 

Cannabis  sativa,  the  Hemp,  is  a  tall  herb,  two  to  three  metres  (7  to 
10  ft.)  in  height,  indigenous  in  the  northern  parts  of  India,  but  now 
generally  cultivated  in  all  temperate  and  warm  regions.  Under  the 
names  of  gvnja,  bhang,  ehvrrus,  haschisch,  etc.,  the  natives  of  India  and 
Central  Africa  use  the  dried  leaves,  stem",  flowers,  and  the  resinous 
matter  which  develops  on  the  plant.  When  smoked,  or  drank  as  an 
infusion,  these  are  highly  intoxicating.  The  fibre  obtained  from  its 
bark  is  strong,  and  much  used  for  cordage. 

Humulus  Lvpulvs.  the  Hop,  a  native  of  temperate  Europe,  Asia,  and 
North  America,  is  grown  for  its  bitter  principle,  Lnpulin,  which  de- 
velops in  the  female  flower  clusters,  and  which  is  much  used  in  the 
manufacture  of  beer,  ale.  etc. 

Order  Moraceee. — The  Mulberry  Family.  Trees  or  shrubs,  con- 
taining a  milky  juice.  The  order  contains  between  800  and  1000  spe- 
cies, and  they  are  for  the  greater  part  natives  of  the  tropics.    Many 


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URTICALE8.  489 

of  them  contaiD  an  acrid  poiBonous  principle,  wliile  some  are  not  only 
innoxious,  but  afford  wholesome  food. 

Artoearjma  ivcUa,  the  Bread  Fruit  tree,  a  native  of  the  Pacific  Is- 
lands, and  now  common  in  tro]>ical  countries,  attains  a  height  of  from 
six  to  nine  metres  (20  to  80  ft. ).  The  fleshy  receptacle  and  agglomerated 
carpels  form  a  mass  as  large  as  a  man's  head.  This  "  fruit,"  when 
gathered  a  little  before  it  is  ripe,  and  baked,  looks  and  tastes  much 
like  bread,  and  is  largely  eaten  by  tropical  people.  The  Jack  Fruit  of 
India  {A.  inUgHfolius)  is  similar,  but  not  so  palatable. 

Ficu9  Caiica,  the  Fig,  a  native  of  Western  or  Southern  Asia,  has 

Figs.  390, 91.— Illu9Tration8  of  Mobacxje. 


Fio.  390.  Fio.  891. 

Fig.  890.— Fleshy  concave  receptacle  of  Dorstmia,  bearins  male  and  female  flowers. 
Fig.  891.— Flesh  V  closed  receptacle  ot  Ficua^  cut  vertically,  containing  male  liowers 
above  and  femalu  below. 

been  cultivated  for  ages.  It  is  now  found  in  all  tropical  and  sub-irop- 
ical  countries.  It  is  grown  in  the  Southern  United  States  and  in  Cali- 
fornia. The  tree  attains  a  height  of  from  five  to  six  metres  (16  to  20 
ft.),  and  bears  pear-shaped  closed  receptacles  (Fig.  891),  inside  of  which 
are  the  minute  flowers.  The  ripened  and  dried  receptacles  constitute 
the  Figs  of  commerce.  Our  supply  comes  mainly  from  the  Mediter- 
ranean Basin. 

OcUdctodendron  utile  (Brosimum  utile),  a  tall  tree,  twenty-five  metres 
high  (80  ft.),  of  Venezuela,  whose  milky  juice  is  used  by  the  natives  aii 
a  substitute  for  milk,  to  which  it  bears  a  close  resemblance.  The  tree 
Vi  hence  called  the  Cow  Tree. 


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490  BOTANY, 

MoTUS  nigra,  the  Mulberry  tree  of  Persia,  is  now  cultivated  in  Eu- 
rope and  tlie  United  States  for  its  edible  fruit  masses.  Its  leaves  are 
used  to  feed  to  silkworms,  but  not  to  so  ^reat  an  extent  as  those  of 
M,  alba,  the  White  Mulberry,  which  has  been  used  from  time  imme- 
morial for  this  purpose  in  China. 

If,  rvbra,  a  native  of  the  Eastern  United  States,  bears  valuable 
fruits. 

Several  of  the  trees  of  the  order  yield  Caoutchouc  The  most  im- 
portant of  these  are  Ficus  elastica  of  India,  and  CaMilloa  elastica  of 
Mexico  and  the  West  Indies  ;  the  first  named  is  a  common  greenhouse 
plant. 

Gum  Ijac  is  a  resinous  exudation  collected  from  an  Indian  species  of 
Ficus,  whose  branches  have  been  punctured  by  an  hemipterous  insect, 
Coccus  Uicca. 

The  wood  of  many  species  is  valuable. 

Brosimum  Ouianensis,  of  Guiana,  produces  the  beautifully  mottled 
and  streaked  Snakewood,  much  prized  by  cabinetmakers,  and  for 
making  bows. 

Maclura  aurantiaca,  a  tree  eight  to  fifteen  metres  (25  to  50  ft.)  high, 
growing  in  Arkansas,  Texas,  etc.,  supplies  a  very  hard  wood  used  by 
the  Indians  for  making  l)ow8,  hence  one  of  its  names,  "  Bow-wood." 
Under  the  name  of  Osage  Orange,  it  is  much  used  as  a  hedge  plant. 
Its  wood  yields  a  coloring  matter  used  as  a  dye,  and  from  M.  tinctoria, 
of  the  West  Indies,  the  dye  known  as  Fustic  is  obtained. 

The  bark  of  many  species  yields  tenacious  fibres ;  thus  from  the 
Paper  Mulberry  (Broussonetia  papyrifera),  a  Chinese  and  Japanese  tree 
eight  to  fifteen  metres  (25  to  50  ft.)  in  height,  the  Cliinese  make  paper, 
and  the  Pacific  Islanders  make  cloth.  One  of  the  most  remarkable  is 
the  Sack  tree  (Antiaris  saccidoi-a)  of  Western  India ;  its  bark  is  so 
tenacious* tliat  after  beating,  it  may  be  removed  in  sections,  which  are 
used  for  sacks  for  carrying  rice,  etc. 

The  Upas  Tree  of  Java  (Antiaris  toaicaiia)  is  poisonous,  but  it  is  by 
no  means  as  virulent  as  it  has  been  described.  It  frequently  grows  in 
volcanic  valleys  partially  filled  with  carbon  dioxide  and  other  noxious 
gases,  and  to  this  fact  is  doubtless  due  the  marvellous  stories  told  of  it. 
However,  from  iis  juice  the  natives  prepare  a  deadly  poison  for  their 
arrows. 

The  Banyan  Tree  {Ficus  Indica)  is  remarkable  for  its  numerous  ad- 
ventitious roots,  which  grow  down  from  its  horizontal  branches,  and 
thus  enable  it  to  extend  its  top  very  greatly.  One  on  the  Neibudda, 
with  three  hundred  and  twenty  of  such  supporting  roots,  covers  an 
area  two  hundred  metres  (650  ft.)  in  diameter. 

Order  Urticaceee.— The  Nettle  Family.  Herbs,  shrubs,  or  trees, 
with  a  limpid  juice;  they  occur  in  all  climates,  but  mostly  in  the 
tropics.  More  than  five  hundred  species  are  known.  Many  of  the 
species  possess  a  valuable  fibrous  bark.     (Figs.  392-7.) 


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DAPUNALE8, 


491 


Bahmeria  nivea,  tbe  China  Grasa  or  Kamie,  a  perenuial  herbaceoos 
plant,  may  fairly  rival  Flax  in  tlie  fine  and  durable  fibres  it  produces. 
It  has  been  introduced  into  the  Southern  United  States  and  California. 
There  is  still  some  difficulty  in  separating  the  fibres  from  tbe  woody 
portions  of  the  plant,  and  thisi  has  prevented  its  more  extensive  use. 

The  Stinging  Nettles  include  ten  genera,  of  which  the  most  impor. 

tant  are  Urtica,  wliich  includes  our  common  species,  and  Laportea, 

represented  by  our  Wood  Nettle  ;  to  tUe  latier  belongs  the  Tree  Nettle, 

L.  gigas,  of  Australia,  which  reaches  a  height  of  from  fifteen  to  forty 

metres  (50  to  130  ft.),  and  whose  sting  is  so  severe  as  to  produce  dan- 

*ierous  results.  „«««•.  tt 

Pi08.  802-7.— Illustrations  or  Ubtica  ttrkns. 


Fig.  899. 


Fie.  808. 


577,  —  Cohort 
IX.     Daphnales. 

Mostly  shrubs  or 
trees,  with  mono- 
clinous  flowers  ; 
ovary  superior, 
one-celled,  with  a 
single  seed  con- 
taining no  endo- 
sperm. 

Order  Protea- 
ce8B. — A  family  of 
about  1000  species, 
confined  almost  en- 
tirely to  the  South- 
ern Hemisphere,  and 
occurring  in  greatest 
abundance  in  Aus- 
tralia and  South 
Africa.  Many  spe- 
cies, especially  of  the 

genus  Banksia,  are  cultivated  in  conservatories, 
ble  timber. 

Orevillea  robusta,  the  Silk  Oak  of  Australia,  attains  a  height  of 
twenty. four  to  ihirry  metres  (80  to  100  ft.),  with  a  diameter  of  two 
metres  or  more,  and  (supplies  valuable  timber. 

Knightia  exceha  is  a  valuable  New  Zealand  timber  tree  thirty  metres 
(100  ft.)  or  more  in  height. 

Leucadendron  argenteiim,  the  Silver  Tree  of  the  Cape  of  Good  Hope, 
has  silvery  lanceolate  leaves ;  its  wood  is  much  used  tur  fuel. 

Protea  grandiflora,  the  "  Wagen-boom  "  of  the  same  region,  is  used 
by  wheelwrights  in  the  manufacture  of  wagon  wheels. 

Order  ElaoagnaceaB. — A  small  order,  of  sixteen  species,  of  trees  or 


Pio.  3M.  Pio.  895. 

Fi;;  :««.— Male  flower.    Majfiilfied 
Fit;.  303.— DiaRraro  of  male  flower. 
Fig.  394.— Female  llower.    Maimifled. 
Fig.  895.— Diagram  of  female  flower. 
Fig  896.— Seed.    Magnified. 
Fig-  397.— Section  of  seed.    Magnifli  d. 

A  few  furnish  valua- 


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492 


BOTANY, 


Blirabs,  found  mostly  in  tbe  moanlaiDS  of  Southern  Asia.  The  Oleaster 
(ElaagnuB  hortenHs)  of  Southern  Europe  is  there  much  planted  for  its 
odoriferous  flowers ;  it  is  occasionally  planted  in  this  country. 

Sh*p?teidia  Canadensis,  of  the  Northeastern  United  States,  and  8. 
argentea,  the  Buffalo-Berry  of  the  Rocky  Mountains  and  the  Great 
Plains,  are  frequently  cultivated  for  their  acid  fruits,  which  are  about 
as  lar{;e  as  currants. 

Order  HemandiesB,  including  a  few  tropical  trees. 

Fios.  896-402.— Illustrations  of  Laurds  nobilis. 


Fio.  898. 


Fio.  899. 


Fio.  400. 

Fig.  898.— Male  flower.    Maenifled. 
Fig,  400.— Ffmnle  flo«  er.    Magnified. 
Fig.  40i;i.— Diagram  of  female  flower. 


Fig.  401. 


Fig.  402. 


Fig.  899.— Diagram  of  male  flower. 
Fig.  401.— Section  of  female  flower. 


Order  ThymelsBaceeB. — Shrubby  plants,  mostly  of  the  Southern 
Hemisphere.  Of  the  378  species  we  have  in  the  United  States  but  one 
representative,  viz.,  the  Moose- wood  or  "Wicopy  *'  {Dirca  palttstris),  a 
small  shrub  with  exceedingly  tough  bark. 

Daphne  Mezereum,  a  poisonous  phrub  of  Europe,  is  frequently  culti- 
vated here  for  its  sweet-smelling  flowers. 

The  bark  of  many  species  is  used  in  their  native  countries  for  making^ 


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LAURALES.  493 

fabrics,  cordage,  etc.     Lagetta  lintearia,  of  Jamaica,  is  the  Lace-Bark 
Tree,  so  called  on  account  of  its  delicate  inner  bark. 

578.— Cohort  X.  Laurales. — Herbs,  shrubs,  and  trees, 
with  mostly  diclinous  flowers  ;  ovary  superior,  one-celled, 
the  single  seed  sometimes  with,  and  sometimes  without 
endosperm. 

Order  Lauraceao. — The  Laurel  Family.    Aromatic  tree's  and  sbrubs 

Flos.  403-5.— IIXD8TRATION8  OF  Mtristtca  fragrans. 


Fio.  408.  Pio.  406. 

Fig.  403.— Frnit,  showing  wed  and  aril.  Fi?.  404.— Seed  and  aril. 

Fig.  405.  —Seed  cut  vertically,  showing  embryo  below. 

(rarely  parasitic  berbs)  witb  free  stamens,  and  a  pendulous  seed  witb- 
out  endosperm.  About  1000  species  are  known,  occurring  in  tbe  trop- 
ical and  temperate  climates  of  botb  bemispberes. 

Laurus  nobilis,  tbe  Bay  or  Laurel  of  Soutbern  Europe,  is  a  fine 
spreadinflr-iopped  evergreen  tree,  twelve  to  fifteen  metres  (40  to  60  ft.) 
bigb.     In  ancient  times  its  leaves  were  used  to  crown  beroes,  but  now 


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494  BOTANY. 

they  are  made  use  of  in  flayoring  cuBtards,  puddings,  etc.,  and  are  put 
into  boxes  of  figs  to  ^ive  them  a  factitious  flavor.    (Figs.  S9S-402.) 

UmbeUularia  Cal(fomica  (Tetranthera  CaHfoTnica\  the  California 
Laurel,  resembles  the  preceding,  and  like  it  is  evergreen.  Its  wood  is 
used  in  cabinet -making. 

Persea  gratissbna,  a  small  West  Indian  tree,  produces  a  delicious 
fruit  called  Avocado-  or  Alligator-Pear. 

Among  the  aromatic  products  are  Cinnamon,  the  bark  of  Cinjia- 
momum  Zeylanieum,  a  small  tree  of  Ceylon  ;  Cassia  Bark  and  Cassia 
buds,  from  (7.  CcMia,  ot  Ceylon  ;  Camphor,  a  gummy  matter  distilled 
from  the  wood  ot  C,  Campfiora,  a  tree  of  China  and  Japan ;  Sassafras 
Bark,  from  Sassafras  officiiuile,  of  the  Eastern  United  States. 

The  wood  of  the  two  last-named  trees  is  valuable  in  cabinet-makings 
as  is  also  that  of  tbe  Red  Bay  {Persea)  of  the  Southern  United  States. 

Neetandra  Bodiei,  the  (ire^nheart  Tree  of  Quiana,  is  a  large  tree 
furnishing  an  exceedingly  heavy,  dark  colored,  and  durable  timber, 
highly  valued  in  naval  constructions. 

Order  MyriaticacesB. — The  Nutmeg  Family.  Aromatic  trees,  with 
monadelphous  stamens,  and  an  erect  seed  couuining  endosperm.  The 
seventy-five  species  are  all  tropical,  and  most  of  them  occur  in  the  In- 
dian region.     They  all  belong  to  the  genus  Myris  ica. 

Myristim  fragrans,  the  Nutmeg  Tree  of  the  Malay  Archipelago,  at- 
tains a  height  of  six  to  nine  metres  (20  to  80  ft.; ,  it  bears  a  fleshy  fruit 
of  the  size  of  a  walnut  and  inside  of  this  is  a  large  peed  covered  with  a 
red,  branching  aril  (Figs.  403-4).  The  seed,  deprived  of  itH  integu- 
ments, is  the  nutmeg  of  commerce,  while  the  dried  aril  is  the  Mace, 
both  well  known  condiments. 

Some  of  the  other  species  are  occasionaiiy  used,  but  they  are  much 
less  valuable. 

Order  MonimiaceaB. — Aromatic  trees  or  shrubs  of  the  tropics  and 
south  temperate  zone.  About  150  species  are  known.  The  Tasmanian 
*•  Sassafras  Tree  "  (Atlierospertna  moschata),  the  Australian  "  Sassafras 
Tree"  {Doryphora  Sassafras),  and  the  New  Zealand  •*  Sassafras" 
(Lauretta  Notcp  Zelandia),  are  large  trees  thirty  to  forty-five  metres 
(100  to  150  ft.)  high,  whose  timber  is  valuable  for  ship-building. 

679.— Cohort  XI.  Chenopodiales.  Monoclinous  (rarely 
diclinous)  herbs  or  si)  rubs ;  o\rary  superior,  one-celled,  the 
single  seed  containing  endosperm. 

Order  Paronychiead.— A  small  group  of  mostly  herbaceous  plants, 
the  flowers  generally  with  both  sepals  and  petals  ;  the  latter,  however, 
rudimentary.  The  order  has  close  aflBnities  with  Caryophyllace®,  of 
which  it  should  probably  be  considered  a  sub-order. 

Order  BasellacesB.— Herbaceous,  often  climbing  plants  of  the 
tropics.    One  species  from  South  America  (BaussingauUia  baselloides) 


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CHENOPODIALES, 


495 


is  cultivated  as  an  ornamental  climber  under  the  name  of  Madeira 
Vine.  The  starchy  tubers  of  another  species,  Uductis  tuberoaus,  are 
used  in  Peru  as  substitutes  for  the  potato. 

Order  Chenopodiaceed. — Herbs,  shrubs,  or  rarely  trees,  whose 
flowers  have  an  herbaceous  perianth.  About  500  species,  distributed 
in  all  climates,  are  known.    (Figs.  406-11.) 

Beta  vulgaris,  the  Common  Beet,  is  a  native  of  Southern  Europe. 
The  Sugar  Beet  and  Mangel  Wurzel  are  only  varieties  of  the  Common 
Beet ;  the  first  is  extensively  cultivated  in  France  for  the  sugar  which 

Fies.  406-10.— Illustrations  of  Bkta  yuloabis. 


Fio.  407. 


Fio.  406. 


Fig.  409. 


Fig.  408. 


Fig.  406.— Flower.    Magnified. 

Fig.  408— Section  of  flower.    Magnified. 

Fig.  410.-Seed.    Magnified. 


Fio.  410. 


Fig.  407.— Diagram  of  flower.         • 
Fig.  409.— Three  fruits.    Magnified. 


is  obtained  from  its  sweet  juice  ;  its  cultivation  in  this  country  is  yet 
in  its  infancy. 

Chenopodium  Quinoa,  a  Peruvian  annual,  is  cultivated  in  Western 
South  America  for  its  nutritions  seeds,  which  are  ground  into  meal,  and 
used  as  an  article  of  food. 

C.  ambrosioides,  Wormseed,  from  tropical  America,  used  somewhat 
in  medicine,  and  other  species  of  the  genus,  have  become  common  weeds 
in  fields  and  gardens. 

Spinacia  oleracea,  Common  Garden  Spinach,  is  an  Oriental  plant 
much  cultivated  as  a  pot  herb. 


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496 


BOTANY, 


Order  Amarantaceed.— Herbe,  rarely  shrubs,  whose  flowers  have  a 
scarious  perianth.  The  order,  which  contains  about  500  species,  is 
mostly  tropical,  a  few  occurring  in  temperate  climates,  but  none  at  all 
in  cold  ones. 

In  India  some  of  the  species  are  cultivated  for  their  starchy  seeds, 

which  are  used  for  food. 

Several  species  are  cultivated  with  us  for  their  ornamental  foliage, 

{Achyranthes)  or   their  colored  inflorescence,  e.g.. 

Cock's  Comb  (Celosia),  Globe  Amaranth  (Chmphre- 

na\  etc. 

Amarantus  retroflexus  and  A.  albxu,  are  common 
weeds  in  fields ;  the  latter,  in  the  prairie  region, 
grows  in  a  globular  form,  and  in  the  autumn  breaks 
off*  at  tiie  root,  and  is  blown  for  miles  across  the 
country.  On  account  of  this  habit  of  growth  it  is  called  the  **  Tumble 
Weed." 

Order  PoIygonacesB. — Tlie  Buckwheat  Family.     Herbs,  shrubs,  or 

rarely  trees,  mostly  with  sheathing  stipules  and  knotted -jointed  stems  ; 

perianth  often  petaloid.     The  600  species  constituting  the  order  are 

mostly  natives  of  temperate  regions. 

Fagapyrum  Mculentum,  Buckwheat,  a  native  of  Central  or  Northern 

Figs.  411^16.— lUiUSTRATiONs  of  Fagoptbux  esculentum. 


Fig.  411.— Section 
of  feed  of  Chenopo- 
dium.    Magnified. 


Fx«.  412. 

Fig.  412.— Flower.    Magnified. 
Fig.  414.— Pistil.    Magnified. 


Fio.  413. 


Fio.  414.        Fio.  415. 


Fig.  413.— Diagram  of  fiower. 
Fig.  415.— Fruit.     Magnified. 


Asia,  is  now  extensively  grown  in  Europe  and  America  for  its  nutri. 
tious  seeds,  and  for  its  honey-producing  flowers.    (Figs.  412-15.) 

Polygonum  amphibium,  var.  ten^estre,  a  native  of  the  United  States, 
has  been  used  in  the  Mississippi  valley  as  a  substitute  for  bark  in  the 
process  of  tanning.     It  contains  a  considerable  quantity  of  tannin. 

Rheum  officinale.  Oriental  Rhubarb,  is  a  native  of  Southeastern 
Asia;  its  roots  constitute  the  officinal  Rhubarb.  Other  species  are 
often  used  as  substitutes. 


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LAMIALES.  497 

R.  Rhaponticum,  a  native  of  Western  Asia,  is  commonly  grown  in 
gardens  under  the  name  of  "  Pie  Plant,"  its  petioles  are  used  for  the 
pleasant  acid  they  contain. 

Many  species  are  weeds  of  fields  and  gardens ;  such  are  Smart  weed, 
and  Black  Bindweed  {Polygonum,  sp.),  Docks  and  Sorrel  {liumex,  sp.). 

Order  PhytolaccaceaD. — Mostly  tropical  herbs,  sometimes  shrubs 
or  trees,  usually  with  several  free  or  united  carpels.  About  eighty 
species  are  known,  most  of  which  are  more  or  less  acrid. 

Phptokteca  decandra,  the  Common  Pokeweed,  is  our  most  notable 
representative.     It  is,  however,  a  doubtful  native. 

Order  Nyctag^aceaB.— Mostly  tropical  herbs,  shrubs,  or  trees  with 
opposite  leaves  and  tumid  joints  ;  flowers  gamophylloua.  About 
200  species  are  known.  The  routs  of  many  of  the  species  are  purgative 
or  emetic. 

Abronia,  of  several  species.  MirabUis,  sp..  the  Four  O'clock,  or 
Marvel  of  Peru,  and  some  others,  are  cultivated  as  ornaments. 

II.  GAMOPETALiE.— Plants  whoso  flowers  generally 
have  both  sepals  and  petals,  the  latter  connately  united. 

680.— Cohort  XTT.  Lamiales.  Plants  with  zygomorphic 
flowers,  superior  ovaries,  indehiseent  fruits,  with  the  seeds 
solitary  in  the  two  to  four  cells. 

Order  LabiataB.— The  Mipt  Family.  Aromatic  herbs  or  shrubs, 
with  four-angled  stems  and  opposite  leaves.  The  species,  of  whicli 
there  are  about  2500,  are  abundant  in  temperate  and  warm  climates, 
but  are  rare  in  conl  regions.  We  have  about  200  native  species  in 
North  America.     (Figs.  416-18.) 

Consider! nfr  the  size  of  the  order,  it  ranks  low  from  an  economic 
standpoint.  Tlie  aromatic  herba$i:e  has  led  to  the  use  of  many  species 
as  domestic  remedies,  few  of  which,  however,  are  really  valuable. 
Nevertheless,  there  are  many  species  yielding  minor  products  which 
are  of  some  value. 

HyBsapus  officinalU,  Hyssop,  a  small  shrub  of  Southern  Europe,  is 
commonly  cultivated  in  prardens  as  a  domestic  medicine. 

Hedeotna  pulegioides,  American  Pennyroyal,  is  an  ('fficinal  herb. 

Lavandula  vera,  Lavender,  is  a  shrubby  plant  of  the  South  of 
Europe,  cultivHted  in  gardKns,  and  used  as  a  domestic  perfume.  Oil 
of  Lavender  is  obtained  from  it  by  distillation. 

Mentha  piperita.  Peppermint,  intri»duced  from  Europe,  yields  Oil 
of  Peppermint  by  distillation.  It  is  extensively  grown  iu  Southern 
Michigan  and  New  York. 

Mantdnym  vulgare.  White  Horehound,  of  Europe,  is  commonly 
found  in  gardens;  its  dried  herbage  is  officinal. 

Rosmarinus  offlcinalis,  Rosemary,  Thymus  vulgaris.  Thyme,  and  8aX- 


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498 


BOTANY. 


via  officinalis.  Garden  Sage,  are  small  South  European  shrubs,  now 
to  be  found  in  all  gardens. 

Catnip,  Balm,  Horsemint,  and  many  others  are  used  more  or  less  as 
family  medicines,  for  which  purpose  they  are  well  suited,  being  harm- 
less  and  feebly  operative. 

Several  tropical  species  of  Salvia  are  grown  as  ornaments,  as  are  also 
CoUuB  and  PeriUa,  from  Southeastern  Asia. 

Order  Verbenace».— The  Vervain  Family.  Herbs,  shrubs,  or 
trees,  usually  not  aromatic,  with  mostly  four-angled  stems.  The 
species  number  about  700,  and  are  chiefly  tropical.  They  generally 
possess  a  bitter  and  astringent  principle. 

With  us  the  order  is  esteemed  principally  for  its  ornamental  value. 

Fies.  416-18.— Illustbatiohs  or  Labiatji. 


Fio.  416. 


Fio.  417. 


Fio.  418. 


Fig.  416.— Flower  of  Lamlum,  side  view. 

Fig.  417.— Vertical  eeciion  of  flower.    Magnified. 

Fig.  418.— Dlugram  ot  flower. 

Besides  the  several  South  American  species  of  Verbena  in  common  cul- 
tivation, the  so-called  Lemon  Verbena  (Lippia  citroidora)  from  Chili, 
and  the  species  of  Lantana  from  tropical  America,  there  are  to  be 
found  in  conservatories  many  showy  species  of  Clerodendron,  from  Asia. 

Tectona  grandis,  the  Teak  Tree  of  India,  is  a  gigantic  tree  whose 
yellowish  durable  wood  is  much  used  in  phip-building.  It  is  said  to 
resist  the  attacks  of  Limnoria  terebrans  when  exposed  in  sea- water. 

VUex  littoralis,  of  New  Zealand,  and  other  species,  growing  in  the 
Indo-Australiim  re^on,  are  large  and  valuable  timber  trees. 

Order  Myoporineee. — Mostly  Australian  shrubs,  of  no  value. 

681.— Cohort  XTTT.  Personales.  Plants  with  zygomor- 
phic  flowers,  superior  ovaries,  and  dehiscent  many-seeded 
fruits. 


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PBRBONALES, 


499 


Order  Acanthacece. — The  Acanthus  Family.  Herbfl,  mostly  of 
the  tropics,  immbering  about  1500  species.  Thirty-five  or  forty  species 
occur  in  North  America,  mostly,  liowever,  in  the  South  and  West. 
Some  of  the  exotic  species  are  grown  in  conservatories,  e.g,^  Justicia, 
Thunbergia,  etc.  • 

OMer  PedaliacesB. — Herbs  with  glandular  hairs.  The  most  im- 
portant species  are  the  Asiatic  Sesamum  Indicum  and  S,  arierUale, 
whose  seeds  yield  an  oil  much  used  as  food  by  the  inhabitants  of  the 
tropics. 

Martynia  proboseidia,  the  Unicom  Plant  of  the  Southwestern  United 
States,  is  notable  for  its  two-hooked  fruits. 

Order  Bignoniacese.— Mostly  woody  plants,  numbering  about  500 
species,  and  natives,  for  the  most  part,  of  the  tropics.    Many  are  cul- 

Fies.  419-32.— Illustbatiohb  or  Scbopbxtlabiacije  {Serophularia,  pp.). 


Fio.  410. 


Fio.  4StO. 


Fio.  421. 


FiQ.  422. 


Fig.  419. -Flower.    Mairaifled. 
Fig.  421.-Pi8tU.    Magnifled. 


Fig.  420— Section  of  flower. 
Fig.  422.— Diagram  of  flower. 


tivated  for  their  fine  flowers  among  these  are  the  species  of  Bignonia  ; 
Tecoma,  etc, 

Catalpa  bignonundes,  the  Common  Catalpa  of  the  Southern  United 
States,  is  a  fine  tree  for  shade  and  ornament.  Its  wood  is  said  to  be 
very  durable.    C.  speeiosa  is  much  hardier  than  the  preceding. 

Crenceniia  Cttjete,  the  Calabash  Tree  of  tropical  America,  produces  a 
large  pulpy  fruit  whose  hard  rind  is  used  as  a  water-vessel. 

Order  Gesneracese. — Mostly  tropical  plants,  represented  by  AeJii- 
menes.  Gloxinia,  Oes/iera,  etc.,  cultivated  in  conservatories. 

Order  Columelliacead.— Evergreen  trees  or  shrubs  of  tropical 
America. 

Order  Lentibolariaceo.  —  The  Bladderwort  Family.  Mostly 
aquatic  or  marsh  plants,  of  temperste  and  warm  regions,  interesting  on 
account  of  the  insect-catcliing  bladders  of  the  aquatic  specie&     (For 


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oOO  BOTANY. 

the  particn?are  as  to  Pinguicvla^  see  Darwin's  "Insectivorous  Plants,'* 
pp.  88^^94.  and  for  Utrictdaria,  pp.  895-444.) 

Order  Orobanchaceae.  —  Leflfless  parasitic  berbs,  numberinfr  150 
species,  widely  distributed.  We  buve  about  a  dozen  natiye  species  in 
tbe  United  States. 

Order  Scropliulariaceee. — Tbe  Figwort  Family.  Herbs  or  sbrubs, 
rarely  trees,  with  two-celled  ovaries  and  central  placentae.  The 
species,  of  which  there  are  about  2000,  are  found  in  all  parts  of  the 
world,  extending  in  both  hemispheres  to  the  limits  of  vegetation. 
Many  of  the  species  contain  an  acrid  poisonous  principle,  (Figs.  419-22.) 

Digitalis  purpurea,  the  Foxffluve,  a  small  plant  of  Europe,  affords 
the  drug  Digitalis,  which  is  officinal. 

Many  species  are  cultivated  for  their  fine  flowers  ;  amonjr  these  are 
the  Snapdragon  {Antirrhinum),  Monkey  Flower  {Mimulus),  Mauran- 
dia,  Pentstemon,  Veronica,  Calceolaiia,  etc.,  etc. 

Paulovmia  imperialis,  a  small  tree  of  Japan,  is  planted  in  the 
Southern  States. 

Verbascum  Thapsus,  the  Common  Mullein,  is  a  weed  introduced  from 
Europe. 

582.— Cohort  XIV.  Folemoniales.  Plants  with  alter- 
nate leaves,  regular  flowers,  stamens  isomerous  with  the 
corolla  lobes,  and  ovary  superior. 

Order  SolanaceeB. — The  Nightsbade  Family.  Herbaceous  or  woody 
plants  with  a  watery  juicn  ;  ovary  two-celled,  many  ovuled.  This 
large  order  of  from  1200  to  1500  species,  which  are  chiefly  tropical,  is 
pervaded  by  a  more  or  less  poisonous  principle.     (Figs.  428-7.) 

Tliere  are,  however,  a  few  valuable  food  plants. 

Solanum  tuberosum,  the  Potato,  is  a  native  of  America  from  Mexico 
to  Chili,  and  a  variety  of  it  (var.  horeaU)  even  occurs  in  New  Mexico. 
Tbe  potato  was  introduced  into  Spain  in  tbe  early  part  of  the  sixteenth 
century,  and  into  England  by  Sir  Walter  Raleijrh  in  1586,  but  for 
nearly  a  century  from  the  latter  date  it  was  little  used.  It  is  now, 
bowever,  fjrown  extensively  in  nearly  all  countries.  In  its  wild  state 
its  tubers  are  not  more  than  two  to  three  centimetres  in  diameter,  but 
by  culture  and  selection  they  have  been  increased  fifteen  to  twenty- 
times  in  bulk. 

Solanum  Melongena,  the  Egg  Plant,  of  South  America,  is  now  grown 
witli  us  for  its  eg^ir-shaped  edible  fruits. 

Lycopersicum  chculentum,  tbe  Tomato,  of  South  America,  is  grown 
in  most  warm  and  temperate  countries  for  its  wbolesome  fruits. 

Physalis  Alktkengi,  the  Winter  Cherry  or  Strawberry  Tomato,  of 
the  South  of  Europe,  is  grown  In  our  gardens  for  its  edible  fruit,  which 
is  enclosed  in  the  inflated  calyx.  Our  native  species  of  this  genua 
called  commonly  Ground  Cherries,  are  valuable  for  food. 


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P0LEM0NIALE8,  501 

Capricum  annuum,  of  South  America,  and  other  species  of  the  genus, 
FioB.  428-7.— Illustratioms  of  Bolanacjbje. 


Fro.  491 


Fio4S5. 


Fig.  483.  FiQ.  496. 

Fig.  498.— FloweriDK  •tern  of  Potato. 

Pig.  494.— Flower  or  Blttereweet.    Magnified. 

Pig.  495.— Diagram  of  Potato  flower. 

Fig.  496.— Calyx  and  pistil  of  Potato.    Magnified. 

Fig.  497.— SecUon  of  seed  of  Bittersweet.    Magnified. 

bear   exceedingly  pungent    pods,  known  as  Peppers.     The   ground 
pods  constitute  the  Cayenne  Pepper  of  commerce. 


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-502  BOTANY, 

Atropa  Belladonna,  the  Deadly  Nightshade,  Hyoscyamus  niger^ 
HeDbane,  and  Datura  Stramonium,  the  Thorn  Apple,  all  of  the  Old 
World,  supply  powerful  narcotic  medicines.  That  from  the  first,  un- 
der  the  name  of  Belladonna,  is  much  used  bj  oculists  to  dilate  the  pu- 
pil of  the  eye. 

Nicoiiana  Tabaeum,  Tobacco,  a  South  American  herb,  was  cultivated 
by  the  American  aborigines  long  before  the  advent  of  Europeans.  It 
was  taken  to  Spain  about  the  beginning  of  the  sixteenth  century,  and 
lo  England  from  sixty  to  eighty  years  later.  It  is  now  extensively 
cultivated  in  many  countries,  especially  in  the  United  States,  and  is 
used  by  all  the  civilized  nations  of  the  globe.  Two  or  three  other 
species  are  also  cultivated  in  di£ferent  parts  of  the  world. 

Among  the  ornamental  plants  of  the  order  are  species  of  Oestrum  and 
Datura,  from  South  America  and  Mexico ;  Lydum,  from  Europe ; 
Petunia,  from  South  America,  etc.,  etc. 

The  Thorn  Apple  mentioned  above,  and  the  Black  Nightshade  {So^ 
lanum  nigrum)  are  common  as  weeds.  The  little  black  berries  of  the 
latter  are  made  into  pies  and  other  pastry  in  the  Mississippi  Valley. 

Order  Convolvulacess. — Herbaceous  climbers,  rarely  shrubs,  often 
with  a  milky  juice ;  ovary  of  1-5  cells,  esch  2-,  rarely  1-4,  ovuled. 
About  800  species  are  known,  distributed  mostly  in  tropical  and  warm 
temperate  regions.     They  generally  possess  an  acnd  principle. 

The  Common  Morning-Glory  {Ipomcea  purpurea)  and  one  or  two  near 
relatives,  all  from  tropical  America,  are  familiar  ornamental  climbers. 

Ipomaa  Batatas,  the  Sweet  Potato  of  India,  has  long  been  cultivated 
in  many  warm  and  temperate  climates  for  its  nutritious  roots. 

The  purgative  drug  Jalap  is  derived  from  the  root  of  a  Mexican 
plant  IpomoMi  purga, 

ConvolvtUus  Seammonia,  of  Western  Asia,  yields  thedf  ug  Scamraony, 
and  from  the  wood  of  C,  ScopariuSfA  shrubby  species  of  the  Canary 
Islands,  Oil  of  Rhodium  is  extracted. 

Cuscuta,  the  parasitic  Dodder,  includes  many  species. 

Order  Borragmacess. — The  Borage  Family.  Usually  hispid  herbs, 
shrubs,  or  trees,  with  a  four-parted  ovary,  each  part  one-ovuled.  The 
1200  species  are  distributed  throughout  the  world,  although  they  are 
most  numerous  in  Southern  Europe  and  Western  and  Central  Asia. 
Many  of  the  species  possess  a  mucilaginous  property  useful  in  making 
cooling  drinks,  and  the  roots  of  some  contain  purple  or  brown  dyes. 

Anehusa  tinctoria,  of  the  South  of  Europe,  is  grown  in  France  and 
Germany  for  its  roots,  which  yield  the  red  dye  called  Alkanet. 

Among  the  commonly  cultivated  ornamental  plants  may  be  men- 
tioned the  Forget-me-not  {Myosotis  palustris)  of  Europe  and  the  Helio- 
trope {Eeliotropium  Perumanum)  of  Peru.  There  are  several  native 
and  introduced  species  which  are  vile  weeds. 

Order  Hydrophyllacess.— A  small  order  of  mostly  American  herbs, 
closely  related  to  the  preceding. 


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0ENTIANALE8.  503 

Species  of  Nemophila,  Phacdia,  WhiHavia,  etc,  are  cultivated  in 
flower  gardens. 

Order  Polemoniacese.— Mostly  herbs  of  North  America  and  North- 
em  Asia,  nnmbering  about  150  species. 

Species  of  Phlox,  GUia,  Polemonium,  Cobcea,  etc.,  are  cultivated  in 
flower  gardens. 

683.— Cohort  XV.  Gtentianales.  Plants  with  opposite 
leaves,  regular  flowers,  superior  ovary,  and  the  stamens  usu- 
ally as  many  as  the  corolla  lobes  and  alternate  with  them. 

Order  Gentianacese. — The  Gentian  Family.  Annual  or  perennial 
herbs,  with  a  watery  juice ;  ovary  generally  one-celled,  with  many 
ovules.  The  species,  of  which  there  are  about  500,  are  found  mostly 
in  temperate  and  cold  climates.  They  possess  a  bitter  principle,  which 
has  been  employed  in  medicine.  We  have  many  very  pretty  wild 
species. 

Order  Loganiacess. — Woody  plants  almost  entirely  of  the  tropics, 
with  two-celleil  ovaries.  About  850  species  are  known  ;  they  contain 
a  bitter  principle  which  is  often  exceedingly  poisonous. 

Btrychnos  nuxvomiea  is  a  small  tree  of  India,  bearing  an  orange-like 
fruit  containing  numerous  large  flattish  seeds  (2  cm.  in  diameter). 
These  seeds  constitute  the  poisonous  drug,  Nux  Vomica ;  they  con- 
tain two  alkaloids  to  which  their  activity  is  due,  viz ,  Strychnia 
(Cai  H„  N,  O,)  and  Brucia  (€«.  Haa  Nj  O*  -h  4  Ha  O).  Tlie  oniinary 
form  of  the  first  as  found  in  the  shops  is  a  Sulphate  of  Strychnia. 

8.  toxifera,  a  tree  of  the  northern  parts  of  South  America,  yields 
from  its  bark  and  young  wood  the  famous  poison  known  as  Curare, 
Urari,  Ourari,  Woorara,  etc. 

8.  Tieute,  a  Javanese  climber,  furnishes  the  virulent  Upas  TieutS 
or  Tjettek  with  which  the  natives  poison  their  arrows. 

Order  Asclepiadaceae. — The  Milkweed  Family.  Woody  or  herba- 
ceous  plants,  with  a  milky  juice;  ovaries  two,  distinct,  but  with  a 
single  common  stigma;  pollen  agglutinated  into  masses  (pollinia). 
This  large  order  of  about  1800  species  is  chiefly  tropical,  being  abun- 
dantly  represented  in  America,  Africa,  and  Asia.  The  milky  juice  con- 
tains Caoutchouc,  and  usually  acrid  and  poisonous  principles.  But  few 
of  the  species  are  of  sufficient  economic  importance  to  demand  notice. 
Many  have  a  local  reputation  as  domestic  medicines.     (Figs.  428-32.) 

Some  are  favorites  in  the  flower  garden  or  consefvatory,  «.(/.,  the  Wax 
Plant  of  India  {Haya  camosa),  species  of  Ceropegia,  Stephanoiis,  Peru 
ploea,  etc.  The  South  African  Stapelias  resemble  Cacti,  being  fleshy 
and  leafless 

The  peculiar  structure  of  the  flowers  in  this  order  has  recently  been 
shown  to  be  for  the  purpose  of  securing  the  services  of  insects  in  the 
process  of  pollination. 


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504 


BOTANY, 


Fig.  4S8. 


Fzo.  429. 


Fio.  430. 


Order  ApocynacesB.  — The  Dogbane  Family.  Woody  or  lierba- 
ceouB  plants,  generally  with  a  milky  juice  ;  ovaries  two,  distinct  or  co- 
hering, the  style  always  single;  pollen  granular.  In  this  order  of 
about  900  species  there  is  very  generally  present  a  drastic  purgative  or 
poisonous  principle.  Most  of  the  species  are  tropical,  a  few  only  ex- 
tending into  temperate  climates. 

The  milky  juice  of  several  species  produces  Caoutchouc  when  evapo- 
rated,   and     that 
Fios.  428-8S.— IixntTBATxoiffl  of  Asclkpias.  from  a  few  species 

of  Couma,  Taber- 
nasmoniana^  etc., 
in  northern  South 
America  is  used 
for  food. 

Tanghinia  vene- 
ntfera,  a  tree  of 
Madagascar,  pro- 
duces a  fruit 
whose  seed  is  the 
exceedingly  viru- 
lent Ordeal  Poison 
or  Tanghin. 

Some  of  the 
trees  of  the  order 
furnish  timber, 
which  is  of  con- 
siderable  local 
value. 

Our  native  spe- 
cies of  Apocffnum 
(viz..  A,  cantiobin- 
ttm  and  A.  andro- 
MBtnifoUum)  pos- 
sess a  tough  fib- 
rous bark  which 
was  used  by  the 
Indians  for  mak- 
ing cordage,  nets, 
etc. 

Among  the  cul- 
tivated plants  are  fj^erium  Oleander,  the  Oleander  from  the  Levant, 
an  evergreen  shrub  or  small  tree  with  poisonous  wood,  bark  and  foli- 
age :  Vinca,  sp.  Periwinkle  or,  as  it  is  erroneously  called,  Trailing 
Myrtle ;  EchUee,  AUamanda,  etc 
Order  SalvadoracesB. — A  few  shrubs  of  the  Old  World  tropics. 
Order  Oleacess. — The  Olive  Family.    Woody  or  rarely  herbacenns 


Fio.  431. 


Fio.  438. 


Magnified. 


Fig.  488.— Flowrr,  with  p(>rianth  refiezed.    "U 
Fig.  429.— Stamen,  with  Its  hood.    Hagnlfled. 
Fig.  430.— Gynceclum  with  pullen-maspes  adhering  to  the 
stigma ;  two  separated  pollen-masses  al  the  side.    Magnified. 
Fig.  431.— Diagram  of  flower. 
Fig.  48S.— Se^.    Magnified. 


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EBENALE8.  505 

plants  ovaries  two«celled,  each  cell  with  one  to  three  orules  ;  stamens 
two.  The  species,  280  in  number,  are  distributed  wideij  over  tem- 
perate and  tropical  regions. 

OUa  KxtropcBa^  the  Olive,  probably  a  native  of  Western  Asia,  is  now 
extensively  cultivated  in  all  warm  temperate  climates.  It  is  a  small 
evergreen  tree,  and  produces  a  bluish  oily  drupe,  from  which  by 
pressure  Olive  Oil  or  Sweet  Oil  is  obtained.  The  wood  of  the  Olive 
Tree  is  very  hard  and  is  used  in  turnery  and  cabinet-making. 

Fraxinus  exceUior,  the  Ash  Tree  of  Europe  and  North  Africa,  is  a 
large  tree,  yielding  a  white,  hard,  tough  and  elastic  timber,  highly 
prized  in  the  manufacture  of  implements,  in  turnery,  coach-making, 
etc.    The  tree  is  frequently  planted  in  the  United  States. 

F,  Americana,  The  American  White  Ash  of  the  Eastern  United 
States,  is  larger  than  the  preceding,  attaining  frequently  a  height  of 
thirty  metres  (100  feet)  or  more.  Its  timber  resembles  that  ol  the  Ash 
of  Europe,  but  is  even  more  valuable. 

F,  (h'egana,  of  Oregon  and  Northern  California,  furnishes  a  timber 
much  like  that  of  the  White  Ash. 

F,  »amimeifolia,  the  Black  Ash  of  the  Northeastern  United  States, 
is  a  large  tree  usually  found  in  moist  situations  ;  the  annual  layers  of 
its  wood  easily  separate  into  thin  strips  admirably  suited  to  make  into 
barrel  hoops,  baskets,  etc.  Other  native  species  also  supply  more  or 
less  valuable  timber. 

In  Jamaica  a  species  of  Linociera  produces  a  very  hard,  fragrant  and 
excellent  timber  known  as  Jamaica  Rosewood.  A  species  of  NoteUxa, 
in  Australia  and  Tasmania,  yields  a  hard  timber  called  Iron- wood,  much 
used  i9  making  ship-blocks,  and  for  other  purposes  where  hardness  is 
required.  Several  genera  afford  ornamental  plants,  e.g.,  Jaeminum,  of 
many  species.  Jessamine  ;  Syringa,  the  Lilac;  Ligustrum,  the  Privet; 
Chionanthus,  the  Fringe  Tree  ;  ForsyHiia,  etc 

684.— Cohort  XVI.  Ebenales. — Shrubs  or  trees  with  al- 
ternate leaves,  regular  flowers,  and  superior  ovary ;  ovules 
usually  solitary  in  the  two  to  many  cells  ;  stamens  generally 
alternate  with  the  corolla  lobes. 

Order  Styracacess. — Plants  with  a  watery  juice  and  monoclinous 
flowers.  There  are  about  220  species  in  the  order,  found  almost  en- 
tirely in  the  tropical  parts  of  America,  Asia,  and  Australia. 

Styrax  officinale,  of  the  Levant,  yields  from  incisions  in  the  bark 
Gum  Storax,  and  from  8.  benzoin  of  the  Malay  Islands,  Qum  Benzoin  is 
similarly  obtained. 

A  few  species  affoid  dyes,  but  none  are  widely  used. 

Malesia  tetraptera,  the  Silver-Bell  or  Snow -Drop  Tree  of  the  South- 
em  United  States,  is  a  highly  ornamental  shrub. 

Order  Ebenacess. — The  Ebony  Family.      Plants  with  a  watery 


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506  BOTANY. 

juice,  and  moetlj  diclinous  flowers.  About  250  species  are  known  in 
this  order,  the  greater  part  occurring  within  the  tropica 

Diospyroa  reticulata^  a  large  tree  of  the  island  of  Mauritius,  produces 
the  best  of  the  timber  known  as  Ebony.  Ebony  is  also  derived  from 
D,  Ebenum  and  D.  melanoxylon  of  Ceylon,  and  D,  Bbenaster  of  the 
Calcutta  region. 

D.  hir9uta,  of  Ceylon,  produces  the  beautiful  "  Calamander  Wood," 
which  is  variegated  with  brown  and  yellow  stripes. 

2>.  Kaki,  a  Chinese  and  Japanese  tree,  bears  plum-like  fruits  which 
are  delicious.     In  our  markets  they  are  known  as  Cbinese  Dates. 

D,  Virginiana,  the  Persimmon  of  the  Southern  United  States,  pro- 
duces fruits  similar  to  the  last,  but  astringent  and  inedible  until  after 
being  frosted.  Doubtless  under  culture  this  fruit  might  be  made  to 
equal  the  preceding. 

Order  Sapotacese. — ^Plants  with  a  milky  juice  and  monoclinous 
flowers.  A  tropical  order  of  about  800  species,  a  few  of  which  extend 
into  temperate  regions. 

Jsonandra  gutta,  a  large  tree  of  the  Malay  Islands  and  Borneo,  is  the 
source  of  the  Qutta  Percha  of  commerce.  The  milky  juice  is  collected 
and  evaporated,  and  then  constitutes  the  crude  Gutta  Percha. 

ChrysophyUum  Cainito,  the  Star  Apple,  Archaa  sapota,  the  Sapodilla 
Plum,  and  Archoi  maminoaa,  the  Marmalade,  are  West  Indian  trees, 
which  bear  delicious  pulpy  fruits. 

Bama  butyracea  and  B.  latifolia,  both  of  India,  and  B.  Parkii,  of 
tropica]  Africa,  are  called  Butter  Trees,  on  account  of  the  butter-like 
fatty  substance  obtained  from  their  seeds  by  pressure. 

We  have  eight  species  within  the  United  States,  iound  mostly  along 
our  Southern  coast.     Two  species  of  Bumelia  reach  the  Ohio  River. 

685.— Cohort  XVH.  Primiilales.  —  Plants  with  mostly 
alternate  leaves,  regular  flowers,  and  superior  one-celled 
ovaries  ;  stamens  generally  opposite  to  the  corolla  lobes. 

Order  Myrsinacead. — Trees  or  shrubs,  mostly  of  the  tropics.  Three 
or  four  species  barely  reach  the  southern  part  of  Florida. 

Order  Prixnulacesd. — The  Primrose  Family.  Herbs  mostly  with 
radical  leaves  ;  placenta  central,  free  and  globose;  ovules  many,  fixed 
by  their  ventral  face.  Species  250,  mostly  of  the  North  Temperate 
Zone.    (Figs.  433-6.) 

The  order  is  chiefly  valuable  for  its  ornamental  plants. 

Primula  tulgaris,  the  Primrose,  and  P.  verts,  the  Cowslip,  are  com- 
mon English  plants,  often  referred  to  in  poetry. 

P.  /Sinensis^  the  Chinese  Primrose,  and  P.  Auricula,  the  Auricula 
from  Southern  Europe,  are  common  in  gardens  and  green-houses. 

Cyclamen,  Dodecaiheon,  and  Lysimachia  contain  fine  ornamental 
species. 


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PRlMULALES. 


60t 


AnagaUU  arvensis  is  a  little  weed  from  Europe. 

Order  Plantaginaceed.— The  Plantain  Family.  Herbs,  mostly  with 
radical  leaves  ;  placenta  central,  not  free  ;  ovules  usually  many,  fixed 
by  tbeir  ventral  face.  This  anomalous  order  appears  to  be  more  at 
home  in  this  Cohort  than  anywhere  else.  It  disagrees  with  the  charac- 
ters given  for  the  Cohort  in  its  ovary  being  for  the  most  part  two-celled. 

FiQS.  48&-5.— Illustkatiomb  or  Anaoallib  arvbhsis. 


Fie.  484. 


Fie.  488. 


Fio.  485. 


Fig.  488.— Section  of  yonns:  flower-bud.  /,  calyx  ;  c,  corolla  ;  a,  stamens :  IT.  pis- 
til ;  Of  placenta.  B.  gynoeciam  further  advanced.  (7,  gynoeciam  ready  for  fertiliza- 
tion.   2>,  yoang  ftnlt.    (After  Sachs.) 

Fig.  484.— Ripe  frait.    Magn  fled. 

Fig.  435.— Dehiscent  fruit.    Magnifled.    (7,  seeds. 

Otherwise  its  agreement  is  so  marked  as  to  allow  us  to  regard  it  as  a 
group  of  degraded  Primulales.  The  species  number  about  fifty ^sand 
are  found  in  all  temperate  regions. 

Plantago  maior,  the  common  Plantain,  is  found  everywhere  in  door- 
yards. 

Order  Pluxnbaginaceed. — Herbs  or  barely  woody  plants,  with 
leaves  radical  or  cauline  ;  ovary  one-celled,  one-ovuled.  About  200 
species  are  known,  distributed  throughout  temperate  climates. 


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608 


BOTANY. 


Armeria  vtUgaru,  Thrift,  of  Europe,  is  caltlvated  in  flower-gardens. 
Plumbago;  sevend  SoatU  African  and  East  Indian  species,  are  to  be 
met  with  in  conservatories. 

686.— Cohort  XVm.  Ericales.  —  Plants  with  regular 
flowers,  and  superior  two  to  many-celled  ovaries ;  stamens  as 
many  or  twice  as  many  as  the  corolla  lobes,  hypogynous  or 
epipetalous. 

Order  IiexmoaceaB.— CaJ^omian  and  Mexican  leafless  root-parasites. 

Order  DiapenBiacess.— Low  plants  (six  to  eight  species)  of  North 

America  and  Eastern  Asia,  of  much  botanical,  but  no  economic  interest. 

Order  Ericaceas.— The  Heath  Family.  Mostly  shrubs  or  small 
trees,  a  few  herbs,  with  osoally  alternate,  simple,  and  entire  leaves  ; 
ovary  mostly  five-celled,  with  placentas  in  the  axis ;  anthers  opening 
by  a  terminal  pore,  rarely  by  a  lateral  slit ;  pollen  grains  compound, 
rarely  simple. 

Under  these  characters  are  included  about  1700  species,  which  are 
often  regarded  as  constituting  five  orders,  viz.,  Ericineie.  Epacridee, 
PyrolinesB,  Monotrope»,  and  Vacciniese,  here  to  be  considered  as  sub- 
orders. While,  however,  there  are  considerable  differences  between 
the  plants  here  brought  together,  they  are  not  important  enough  to 
counterbalance  the  many  evident  resemblances.  The  relationship  sub-^ 
sisting  between  the  sub-orders  may  be  shown  as  follows  : 


/ 


VACCINIEA 
;7  (Ovary  inferior.) 


EPACRIDE^  <• 

r  Stamens  epipetal-  ^ 
I  ous  or  hypoflryn-  * 
ous  ;    anthers 
I  with  a  slit. 


-ERICINE^ 
Gamopetalous; 
ovary  superior; 
stamens  hypogyn- 
ous ;  anthers 
with  a  pore ;  pol- 
len  grains  com- 
pound. 


PYROLINE^. 
(Choripetalous.) 


MONOTROPEJi 

j  Choripetalous;  anthers  with  a  )* 
i  slit ;  pollen  grains  simple.      ) 


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ERICALE8, 


509 


FioB.  486-9.— Illubtkations  of  Brioa  oinkbxa. 


The  EricioesB  are  doubtless  to  be  regarded  as  the  central  or  main 
gronp,  from  which  the  others  have  diverged.  In  the  diagram  the  dis- 
tinguishing characters  which  are  given  for  Ericinefe  may  be  regarded 
as  typical  for  the  order,  and  under  each  of  tlie  other  suborders  are 
given  the  exceptional  characters,  or  more  properly,  the  modifications  of 
the  original  ordinal  characters. 

Sub'Order  JBricinece.—Ahout  1000  species  of  shrubs,  many 
evergreen.  Biany  are 
of  great  beauty,  and  are 
extensively  grown  as 
ornaments ;  others  are 
good-sized  trees,  and 
furnish  valuable  tim- 
ber.   (Figs.  436-9.) 

Arbutus  MenzieHi, 
the  Madrona  of  the  Pa- 
eific  coast  of  the  Unit- 
ed  States,  is  an  ever- 
green  tree  twenty- four 
to  thirty  metres  (80  to 
100  ft.)  in  height.  Its 
hard  wood  is  useful  in 
furniture-making. 

Aretastaphyhs  pun- 
gens  and  A.  glauea  are 
large  evergreen  shrubs 
of  California,  which 
bear  the  name  of  Man- 
«anita.  The  heavy, 
iark-colored,  and  fine- 
grained wood  is  used  in 
turnery  and  furniture- 
making.  The  berries 
are  eaten  by  grizzly 
bears. 

A.      Uva-ursi,     the 
Bearberry  of  the  colder 
portions      of       North 
America,  Europe,  and  Asia,  bears  bitter  and  astringent  leaves,  which 
are  officinal. 

CaUuna  vulgaiis,  the  Common  Heath  of  Central  and  Northern  Europe, 
is  a  low,  straggling  evergreen  undershrub.  Its  stems  are  made  into 
brooms,  and  its  flowers  a£R>rd  an  abundance  of  excellent  honey.  It 
occurs  in  a  few  scattered  localities  in  Massachusetts,  Maine,  Nova 
Scotia,  and  northward,  but  it  is  doubtful  whether  it  is  really  indigenous 
to  any  part  of  the  United  States. 


Pio.  4«7. 


Fie.  488. 


Fxe.  489. 


Fig.  486.— Flowering  •tem. 

Fig.  487.— Section  of  flower.    Magnified. 

Fig.  438.— Diagnun  of  flower. 

Fig.  489.— Secnon  of  OTarj.    Magnifled. 


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510  BOTANY. 

Bpigcsa  repem,  the  Mayflower  or  Trailing  Arbutus,  is  a  low  trailing 
plant  witli  a  woodj  stem,  found  cliieflj  in  New  England  and  adjacent 
regions.  Its  rose-oolored  fragrant  flowers,  wliicli  appear  in  early 
spring,  are  much  sought  for. 

Erica.  This  large  genhs,  including  400  or  more  species,  is  distrib* 
uted  in  Europe,  Northern  Asia,  and  Northern  and  Southern  Africa, 
reaching  its  maximum  in  the  latter  region.  None  are  found  in 
America.    Many  species  are  grown  in  conservatories. 

GauUheria  procumbens,  Wintergreen  or  Checkerberry,  has  aromatic 
fruit  and  foliage.     From  the  latter  an  officinal  oil  is  distilled. 

Kalmia.  A  genus  of  beautiful  plants  with  curious  flowers ;  each 
stamen  when  the  flower  opens  is  bent  backward,  and  its  anther  is 
hidden  in  a  sac  in  the  corolla  ;  somewhat  luter  the  authers  escape  from 
the  sacs  and  the  pollen  is  ejected.  This  mechanism  has  prolmbly  to 
do  with  the  process  o(  cross-fertilization  through  the  agency  of  insects. 
Some  of  our  native  species  are  reputed  to  be  poisonous  to  domestic 
animals,  e.g.,  K.  angustifolia,  the  Sheep  Laurel  or  Lambkill. 

Rhododendron.  This  genus  is  now  made  to  include  the  Azaleas  as 
well  as  the  true  Rhododendrons.  Some  species  become  large  trees  {R. 
arboreum  of  the  Himalayas),  while  many  are  highly  prized  as  orna- 
mental shrubs.  The  Great  Laurel  {R.  maximum),  a  shrub  or  small  tree, 
with  large  evergreen  leathery  leaves,  grows  in  the  Alleghany  Moun- 
tains. R.  CataxMense  and  its  hybrids  with  R.  arboreum  are  extensive- 
ly planted  for  ornaments.  R,  Indiea  is  the  Azalea  of  the  florists  ;  it 
has  many  varieties. 

Sub'Order  Epacritlece. — About  820  species  of  shrubs  or  small 
trees,  often  with  a  Heath-like  appearance ;  natives  of  Australia  and 
many  of  the  Pacific  islands ;  only  one  species  is  found  in  South  Amer- 
ica. Many  species  are  grown  in  conservatories,  e.g.,  JSpacris,  Leucopo- 
gon,  Dracophyllum,  etc. 

Sub'Order  JPyroiinecB* — Perennial  herbs,  about  twenty  species, 
all  of  the  North  Temperate  Zone.  They  are  of  but  little  account 
economically  or  otherwise.  ChimaphUa  macukUa,  Pipsissewa  or 
Prince's  Pine,  was  used  by  the  Indians  as  a  medicine.  The  dried 
leaves  constitute  the  officinal  drug  Chimaphila. 

The  anomalous  geuus  Clethra,  including  twenty-five  species  of  shrubs 
and  trees  (American  and  Asiatic)  is  sometimes  placed  in  this  sub-order 
on  account  of  its  choripetalous  corolla ;  it  appears,  however,  to  prop- 
erly fall  into  the  Eridneae,  in  either  the  tribe  Andromedese  or  Rho- 
doree. 

Sub-'Order  ilfonofropece.—Small  herbs,  parasitic  or  sapro- 
phytic, destitute  of  chlorophyll;  their  leaves  are  reduced  to  mere 
bracts,  and  their  fiowers  and  seeds  show  still  further  degradation.  Ten 
or  twelve  species  are  known,  distributed  throughout  the  temi^erate 
"^rts  of  the  Northern  Hemisphere. 


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CAMPANALE8,  611 

Monotropa  tiniflora,  Indian  Pipe,  is  common  tbrougliout  nearly  all 
North  America.     It  appears  to  be  saprophytic 

8areode$  sanguinea  is  the  interesting  Snow  Plant,  which  in  the 
Sierra  Nevada  Mountains  of  California  shoots  up  its  flesh-red  stem 
and  flowers  in  earlj  spring,  soon  after  the  snow  melts. 

Sub-'Order  FacciniecB.— Shrubby  plants,  mostly  of  the  North- 
em  Hemisphere.  Species,  820.  The  thick  adherent  calyx-tube  of  the 
flower  often  becomes  fleshy  and  edible  in  fruit.     (Figs.  440-4t.) 

Oayluuada  tesinoM,  a  low  shrub  of  the  Eastern  United  States,  pro- 
duces the  Black  Huckleberries  of  the  markets. 

Vaeeinium  Pennsyltanicum,  the  Early  Blueberry,  or  Blue  Huckle- 
berry, and  F.  vaeiUanSy  the  Low  or  Late  Blueberry,  are  common  in  the 
Northeastern  United  States. 

F  corymbo9um,  the  Swamp  Blueberry,  is  also  oonmion  in  the  Eastern 
United    States.        Be- 
sides these,  other  spe-      Figs.  440-41.— Illustrations  of  Vaocuiium  Mtb- 
cies     furnish      edible  "^''•• 

fruits  which  are  some- 
times found  in  the  mar- 
kets. F.  MyrtiUus  oc- 
curs with  us  only  in  the 
Rocky  and  Sierra  Ne- 
vada Mountains. 

F.  Oxyeoccus,  the 
Small  Cranberry  of  the 
Northeastern  United 
States,   and  the  much 

larger  var,  maerocar-  Fio.  440.  Pio.441. 

pm,   or    Large    Cran-      pig.  440. -Flower.    MsRnlfled. 
berry,    which    extends      Fig.  441.— Section  of  flower.    Magnified, 
much    further    south, 

are  valuable  for  their  acid  fruits.     The  variety  is  extensively  culti. 
vated  from  Massachusetts  to  Wisconsin. 

687.~Cohort  XIX,  Campanales.  Plants  with  flowers 
mostly  zygomorphic  ;  ovary  inferior,  two-  to  six-celled  (rarely 
one-celled) ;  ovules  usually  many  in  each  cell. 

Order  Campanulaceee. — Herbs,  rarely  shrubs,  usually  with  alter- 
nate  leaves  and  a  milky  juice;  ovary  two-  to  many-celled.  The  1000 
species  which  compose  this  order  were  until  recently  divided  between 
the  two  orders  LobeliacesB  and  Campanulacea?,  which  are  here  merged 
into  one.  The  order  as  now  constituted  is  represented  in  all  regions, 
but  most  abundantly  in  temperate  ones.  All  possess  more  or  less 
acridity,  which  in  some  cases  becomes  a  dangerous  poison. 

Lobelia  inJkUa  and  L.  syphilitica  of  the  Eastern  United  States  have 
been  used  in  medicine  ;  now  principally  used  by  quacks. 


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612  BOTANY. 

L»  eardinalii,  the  Cftrdinal  Flower,  of  the  Eastern  United  States^ 
and  several  foreign  species,  are  showy  plants  in  the  flower-garden. 

Campanula  medium,  Canterbarj  Bells,  and  other  European  species, 
are  in  common  coltivation. 

Order  Goodeniacese. — Mostly  Australian,  herbaceous  plants,  num- 
bering about  200  species,  of  but  little  economic  value. 

Order  Stylidiacess.—Curious  herbs,  about  100  in  number,  mostly 
Australian.     Species  of  Stylidium  are  grown  in  conservatories. 

688.— Cohort  XX.  Asterales.  Plants  with  actinomorphic 
or  zygomorphic  flowers ;  stamens  inserted  on  the  corolla  and 
isomerous  with  its  lobes ;  ovary  inferior,  one-celled,  one- 
ovuled  (rarely  two-  to  three-celled).  Calyx  limb  often  greatly 
reduced,  forming  a  pappus,  sometimes  wanting. 

Order  Compositse.— The  Sunflower  Family.  Herbs,  shrubs,  or 
rarely  trees ;  anthers  united  to  each  other ;  ovary,  one-^elled,  contain- 
ing a  single  erect  seed  destitute  of  endosperm.  In  this  immense 
family  of  fully  10,000  species,  distributed  throughout  all  parts  of  the 
wor1(^,  tlie  small  flowers  are  gathered  into  compact  heads,  which  them- 
selves often  resemble  single  flowers.  Many  of  the  species  are  of  great 
beauty,  and  are  greatly  admired  as  ornaments,  but  it  is  curious  to 
observe,  that  despite  the  great  size  of  the  order,  there  are  but  few 
plants  wliich  are  otherwise  of  any  considerable  use  to  man.  Many  are 
troublesome  weeds. 

In  Bentham  and  Hooker's  '*  Genera  Plantarum,"  the  766  genera  are 
arranged  under  tliirteen  tribes,  as  given  below. 

TtHbe  1.    CicFioriacece —Flovren  all  ligulate;  juice  milky. 

Cichorium  IntyhuB,  Chicory,  of  Europe,  is  much  cultivated  in  France 
and  Germany.  Its  roots  are  used  to  adulterate  cofiee.  C.  Endivia^  of 
India,  is  the  Endive,  cultivated  in  gardens  as  a  salad  plant. 

LacttLca  satica,  the  Garden  Lettuce,  is  probably  a  native  of  Asia. 
The  dried  juice  of  L.  virosa,  of  Europe,  constitutes  the  narcotic  drug 
Lactucarium. 

Taraxacum  Dens4eonis,  the  Common  Dandelion,  is  used  somewhat 
in  medicine.    (Figs.  442-5.) 

Tragopogon  porrifolius.  Salsify,  of  Europe,  is  cultivated  for  its 
edible  root. 

Tribe  2.  Mutlsiacece. — Flowers  usually  bifid,  i.e.,  two-lipped. 
We  have  but  one  representative,  Chaptalia  tomentosa,  in  Southeastern 
United  States.     They  abound  in  tropical  America. 

Tribe  3,    Oynaroidete.— Flowers  all  tubular. 
Cyna/ra  Scolymus,  a  native  of  the  Mediterranean  basin,  is  the  Arti- 
choke, grown  for  the  thick  scales  of  its  flower  beads,  whicli  are  edible. 
Carthamus  tinctoria,  a  Cliinese  annual,  is  grown  in  gardens  for  its 


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ASTEBALE8, 


513 


red  flowers,  wbich  are  gathered  and  dried,  coDStUutlDg  tbe  dye  Saf- 
flower. 

CerUaurea  odarata  and  C.  moschata,  from  Asia,  and  other  European 
and  American  species,  are  cultivated  in  flower  gardens. 

(Micus  includes  our  Thistles,  most  of   which  are  weeds  iu  fields. 

Pius  442-5.~Illu8Tbation8  or  Taraxacum  Dxns-lbonm. 


Fio.  444. 


Fio.  449. 


Fio.  44.3. 


Fia.  445. 


Tig.  442.~nead  of  flowers,  with  a  bud  on  the  right,  a  closed  fraitini;  bead  on  tbe 
left,  and  two  leaves. 
Elg.  443.— Flower.    Magnlfled.  Fig.  444. -Receptacle  and  fruiU. 

Fig.  445.— Fruit.    Ma^niacd. 

C,  arvenns,  the  so-called  Canada  Thistle,  is  in  reality  an  Old  World 
species.  It  is  one  of  the  most  difficult  of  all  our  weeds  to  eradicate  on 
account  of  its  underground  stems,  wliich  are  tenacious  of  life. 
C,  laneeolatus,  the  Common  Tliistle,  is  another  introduced  species. 


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514  BOTANY. 

C.  pumiius,  the  Pasture  Thistle,  and  C.  hoiridulus,  the  Yellow  Thistle, 
are  indigenous. 

Tribe  4m  Arctotidecem--F\owerB  partly  tubular  (rorming^  a  central 
disk),  and  partly  ligulate  (forming  rays  to  the  head).  Natives  of 
Africa  and  Australia. 

Tribe  5,  Ca/^nduZocece.— Similar  to  the  preceding.  Natives 
mostly  of  Africa  and  Asia. 

TiHbe  6.  Stnecionidece. — ^Heads  mostly  with  disk  and  ray  flow, 
ers. 

Arnica  montana,  a  perennial  of  Europe  and  Siberia,  from  which  the 
officinal  Arnica  flowers  and  roots  are  derived. 

Senedo  scandens,  of  the  Cape  of  Good  Uope,  is  cultivated  as  a  house 
plant  under  the  name  of  German  Ivy. 

Many  other  species  of  this  genus  are  cultivated — e.^.,the  so-called 
Cinerarias,  Cacalia,  Farfugium,  etc  Some  of  the  species  are  common 
weeds. 

Bedfordia  salicifia,  a  native  of  Tasmania,  attains  a  height  of  four  to 
five  metres  (15  ft.).  Its  wood  is  hard,  and  is  much  prized  for  cabinet 
work  on  account  of  its  beautiful  grain. 

Tribe  7«  -4n</*CIMt€lea?.— Heads  mostly -with  disk  and  my  flow- 
ers. 

Artemiiia  Ab$in(7uufn,  the  Common  Wormwood  of  Europe,  is  cul- 
tivated in  old  gardens  as  a  domestic  remedy.  In  Europe  an  alcoholic 
extract  called  Absinthe  is  need  as  an  intoxicating  beverag«^.  Some 
species  in  the  Rocky  Mountain  region  are  tall  shrubs,  and  are  called 
Sage  Brush.     They  furnish  a  valuable  fuel. 

Antliemis  nobilis.  Chamomile,  and  Tanacetum  tulgare.  Tansy,  of 
Europe,  are  well  known  domestic  herbs. 

Clirysanihemum  ro$ettm,  from  Persia.  C.  Indicifm,  from  China,  and 
0.  eoronarium,  from  North  Africa,  are  the  originals  of  the  Chrysanthe- 
mums so  common  in  flower-gardens. 

C,  Leucanthemum^  the  Ox  Eye  Daisy,  is  a  most  difficult  weed  to  eradi- 
cate. 

Tribe  8,  Helenioideie* — Heads  mostly  with  disk  and  ray  flowers. 

To  this  belong  the  so-called  French  or  African  Marigolds,  Tagetea,  o( 
several  species,  cultivated  in  flower-gardens.  They  are  in  reality  na- 
tives of  tropical  America. 

Tribe  9*  HeliaHthoidece.—B.esLdB  mostly  with  disk  and  ray 
flowers. 

Dahlia  Tariabilis  and  one  or  two  other  species  from  Mexico,  are  the 
original  forms  of  the  Dahlias  of  the  flower-gardens. 

Zinnia  eUganB,  of  Mexico,  is  the  well-khowu  Zmnia  of  ^he  gardens. 

Coreopsis,  of  several  Arkansas  and  Texas  species,  are  grown  under 
the  name  of  Calliopsis. 

Helianthus  annuus,  the  Common  Sunflower,  is  a  native  of  the  Texan 
and  Mexican  regions.    Aside  from  its  ornamental  use,,  its  oily  seeds  are 


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ASTERALE8. 


615 


valuable  for  fattening  poaltrj,  and  the  dried  stems  are  good  for  fael. 
In  Russia  a  valuable  oil  is  obtained  from  the  seeds. 

H,  tuberosus,  the  so-called  Jerusalem  or  Brazilian  Artichoke,  is 
much  grown  fur  its  potato-like  tubers,  which  are  fed  to  cattle  and  swine. 
It  is  probably  derived  from  if.  doronicoides,  of  the  Mississippi  Valley, 
bj  long  cultivation.  The  name  '*  Jerusalem  "  Artichoke  is  a  corruption 
of  the  Italian  OirasoU — i.e.,  sunflower. 

Among  the  weeds  are  the  Ragweeds  (AnibroHa),  Cockleburs  {Xar^ 
thium),  Spanish  Needles  {Bidens). 

SUphium  laciniatum  is  the  Compass  Plant  of  the  Mississippi  Valley. 

Figs.  446-50.— Iixustbationb  or  Bupatobium. 


Fio.  446. 


Pio.  447. 


Fio.  448. 


Fig.  446.— Head  of  flowere. 
Flff.  448.— Flower.    Mairnlfled. 
Fig.  450.-^*18111.    Mafi^ed. 


Fio.  449.  Fio.  450. 

Fig.  447.— Diajirram  of  flower. 

Fig.  440.— Section  of  flower.    Magnifled. 


Its  large  erect  pinnately  lobed  leaves  twist  upon  their  petioles  so  as  to 
present  one  surface  of  the  blade  to  the  east  and  the  other  t^  the  west, 
the  two  edges  being  upon  the  meridian.     (Fig.  184,  p.  157.) 

Tribe  10»  IniUoidece. — Heads  mostly  with  disk  and  ray  flowers. 

Helipterum  Manglem,  of  Australia,  is  one  of  the  "  Everlasting  flow, 
ers,"  cultivated  under  the  name  of  Rhodanthe,  and  used  for  winter 
bouquets. 


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516  BOTANY. 

HeUchrymim,  Bp.,  is  also  caltivated  for  the  same  purpose. 

IntUa  Helenium,  Elecampane,  of  Europe,  is  cultivated  in  gardens  for 
its  medicinal  root. 

THbe  11.  A8ieraidece.--He9jAB  mostly  with  disk  and  raj  flowers. 

Aside  from  our  native  species  of  Aster  and  Solidago  (Golden  Rods), 
which  are  ornamental,  BeUis  perenrm,  the  English  Daisy,  and  CaUU 
tephus  GhinensUt  the  China  Aster,  are  common  in  flower-gardens. 

Orindelia  robtuta  and  other  species  are  important  as  furnishing  in 
the  alcoholic  infusion  of  their  leaves  a  cure  for  the  poisoning  bj  Poison 
Ivy. 

Olearia  argopJiyUa,  the  Musk  Tree  of  Tasmania,  attains  a  height  of 
six  metres  (20  ft.)  and  a  diameter  of  thirty  cm.  (1  ft.).  Its  wood  is  hard, 
and  is  used  in  turnery  and  in  the  manufacture  of  agricultural  imple- 
ments. 

0,  furfuraota  and  several  other  New  Zealand  species  are  equally 
valuable. 

Tribe  12.  Eupatoriiicece.—Flowen  all  tubular.  (Figs.  446-50) 

Species  of  EupcUorium  are  used  as  domestic  medicines.  Several  of 
the  species  are  ornamental. 

Mikania  seandens,  a  native  climber,  is  cultivated  for  ornament. 

The  native  species  of  Liatris,  Blazing  Star,  are  also  quite  orna. 
mental. 

Tribe  18.  Vemoniacece. — Flowers  all  tubular. 

The  species  of  Vemonia,  known  by  the  name  of  Iron-weed,  are  com. 
mon  weeds  on  low  grounds. 

Order  CalyoeracesB. — A  few  South  American  herbs  resembling 
Composited,  but  with  the  ovule  pendulous. 

Order  Dipsacesd. — Herbs,  with  distinct  anthers  and  pendulous 
seeds,  which  contain  endosperm.  Species  one  hundred  and  twenty, 
mostly  of  the  North  Temperate  Zone. 

Dipsaeus  FuHonum,  Fuller's  Teasel,  of  Europe,  is  frrown  for  its  hard- 
bracted  ripe  heads,  which  are  used  by  fullers  in  dressing  woolen  cloth. 

Seabiosa  contains  many  ornamental  species. 

Order  VaXenaziacead. — Herbs,  with  distinct  anthers,  and  three- 
celled,  but  (by  absorption)  one-seeded  ovary  ;  seed  without  endosperm. 
Species  about  three  hundred,  mostly  of  the  North  Temperate  Zone. 

Valeriana  officinalis,  of  Europe,  has  a  thickish  root,  which,  in  the 
dried  state,  is  the  officinal  Valerian. 

689.~Cohort  XXI.  Bubiales.  Plants  with  actinomorph- 
ic  or  zyg^morphic  flowers  ;  stamens  inserted  on  the  corolla 
and  isomerous  with  its  lobes  ;  ovary  inferior,  two-  to  many- 
celled,  each  cell  with  one  to  many  ovules.  Calyx  never 
pappose. 

Order  Bubiaceae.— Herbs,  shrubs,  and  trees  ;  flowers  generally  reg- 


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RUBIALE8,  517 

nlar  (actinomorpbic) ;  leaves  with  atipules.  A  large  order  of  over  4000 
species,  the  greater  part  of  which  inhabit  tropical  countries.  It  is 
divided  into  twenty-five  tribes,  many  of  which  differ  so  greatly  from 
each  other  that  they  have  been  regarded  as  orders  by  some  botanists. 

The  most  common  representatives  of  this  order  jn  the  United  States 
are  the  species  of  OcUium  (Bedstraw  or  Cleavers),  Mitchella  (Partridge 
Berry),  and  ffotistorda  (Bluets). 

CepTialanthus  occtdentalU,  the  Button  Bush  of  the  Eastern  United 
States,  is  a  tall  nhrub  bearing  glossy  p:reen  leaves  and  spherical  heads 
of  white,  sweet-scented  flowers.  It  deserves  to  be  ranked  among  our 
ornamental  shrubs. 

Pinekneya  pubefis,  a  small  tree  of  the  Southeastern  United  States,  is 
known  as  Georgia  Bark,  or  Fever  Tree,  on  account  of  the  medicinal 
qualities  of  its  bark. 

CincTiona^  of  several  species.  This  South  American  genus  contains 
thirty  or  more  species  of  trees  ;  several  of  these,  as  C,  officiiHUis^  Ccali- 

F108. 451-5.— Illubtbatioms  of  Coitxa  Ababica.    All  Maoxifixo. 


I( 


Fig.  45t  Fie.  453.  Fio.  454.  Fia.  455. 


Fig.  451.— Berry.  Fl?.  452.— Seed  ;  ventral  face. 

Fig.  458.— Seed  ;  dorsal  face.  Fig.  454.— Trans veree  bcctlon  of  seed. 

Fig.  455.— Dorsal  face  of  seed,  cat  away  to  bhow  embryo. 

saya,  (7.  tuccirvbra,  etc.,  all  natives  of  the  Andean  regions  of  Peru, 
Bolivia,  and  New  Granada,  furnish  the  drug  known  as  Peruvian 
Bark.  This  bark  contains  two  important  alkaloids,  viz.  :  Cinchonia 
(Co  Ha4  N,  O),  and  Quinia  (Co  H,*  N,  O,  +  3  H,  O)  ;  the  latter  as  a 
sulphate  is  the  exceedingly  valuable  medicine,  Quinia  Sulphate,  or 
Quinine.  Cinchona  trees  are  now  cultivated  in  India,  Java,  Mauritius, 
and  Jamaica. 

Cephaelis  Ipecacuanha,  a  semi-shrubby  plant  of  Brazil,  supplies  from 
its  roots  the  well-known  emetic  Ipecacuanha. 

Coffea  AraJbwa,  the  Coffee  Tree,  a  native  of  Abyssinia,  is  a  small- 
sized  evergreen  tree,  bearing  clusters  of  white  flowers  in  the  axils  of 
the  opposite  glossy  leaves.  The  red  berries  are  about  as  large  as 
cherries,  and  each  contains  two  plano-convex  seeds,  the  coffee  seeds  of 
commerce  (Figs.  451-5).  The  Coffee  tree  was  introduced  into  Arabia 
from  four  to  five  centuries  ago,  and  into  Java,  by  the  Dutch,  about 
two  centuries  ago.    It  has  since  been  taken  to  Brazil  and  other  parts 


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518  BOTANY. 

of  Soatb  America,  the  West  Indies,  Ceylon,  India,  and  many  of 
the  Pacific  islands.  Although  originally  from  the  same  species,  the 
Coffee  trees  now  grown  in  different  parts  of  tbe  world  produce  seeds 
varying  much  in  size,  color,  and  quality;  thus  in  ** Mocha/'  from 
Arabia  and  Abyssinia,  the  seeds  are  small,  of  a  dark  yellow  color,  and 
wben  roasted  produce  an  infusion  of  a  most  delicious  quality  ;  in  "  Java 
coffees  "  the  seeds  are  larger,  of  a  paler  yellow  colA",  and  of  scarcely  in- 
ferior quality  to  the  preceding ;  tbe  coffees  of  Ceylon,  West  Indies,  and 
Brazil  (the  latter  particularly  known  as  *'  Rio ")  have  seeds  of  vary- 
ing sizes,  and  of  a  bluish  or  greenish-gray  color,  and  their  infusions 
are  generally  inferior  to  those  of  tbe  other  varieties. 

liubia  tinetoria,  a  perennial  herb,  native  of  the  South  of  Europe  and 
Western  Asia,  is  the  Madder  Plant,  now  grown  in  many  parts  of  tbe 
world  for  its  roots,  which  yield  tbe  red  dye  known  as  Madder.  The 
plant  has  whorled  leaves  and  bears  some  resemblance  to  some  species 
of  Oalium. 

Among  tbe  ornamental  plants  of  the  order  are  many  species  of  Gdr» 
denia  from  China  and  Africa,  Ixora,  Portlandia,  Boutardia^  etc. 

Order  Caprifoliaceae. — Mostly  woody  plants,  with  generally  zygo^ 
morphic  flowers  and  stipulate  leaves.  This  small  family  of  two  hun- 
dred species  is  mostly  confined  to  the  Northern  Hemisphere.  A  dras- 
tic and  purgative  principle  is  common  in  the  plants  of  the  order,  but 
none  of  the  species  are  of  much  importance  in  medicine.  Many  species 
are  ornamental — e.g.,  those  of  Lonicera,  the  Honeysuckles ;  Sympfiori- 
carpus,  tbe  Snowberries ;  DiertiUa,  tbe  Bush-Honeysuckles,  one  spe- 
cies from  Japan  called  Weigelia ;  V^umum,  the  Snowball,  etc.,  etc. 

Sambucus,  tbe  Elder,  has  edible  berries,  which  are  much  used  for 
making  into  pies,  preserves,  jellies,  wine,  etc.,  in  many  parts  of  tbe 
United  States. 

III.  CHORIPETAL^  (Polypetal^  of  authors).  Plants 
whose  flowers  generally  have  both  calyx  and  corolla,  the  lat- 
ter of  separate  petals. 

590.--Cohort  XXn.  XJmbellales. — Flowers  usually  actin- 
omorphic ;  ovary  inferior,,  one-  to  many-celled ;  ovules  soli- 
tary, pendulous ;  seeds  with  endosperm. 

Order  Comaceso. — ^The  Dogwood  Family.  Shrubs  or  trees,  rarely 
herbs,  with  mostly  opposite  simple  leaves  ;  fruit  a  berry  or  drupe.  A 
small  order  of  about  seventy-five  species,  mostly  of  the  north  temperate 
zone. 

Several  native  and  European  species  of  Comus  are  cultivated  as  orna- 
mental shrubs. 

Aueuba  Japonica.  from  Japan,  is  a  fine  shrub  of  the  flower-gardens. 

The  wood  of  Cornus  florida,  the  Flowering  Dogwood  of  the  Eastern 


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UMBELLALES, 


619 


Figs.  ^SG-OO.—Illubtiiations  of  Fobniculux  yulgabb. 
AUi  Maohipibd. 


United  States,  is  bard  and  fine-grained,  and  is  sometimes  used  as  a  sub- 
stitute for  Boxwood. 

Tbe  wood  of  Nysm  muUiflora,  tbe  Sour  Qum,  Tupelo,  or  Peppridge 
tree  of  tbe  Eastern  United  States,  is  exceedingly  difficult  to  split,  and 
Is  mucb  used  for  making  bubs  for  wagon  wbeels. 

Order  AraliacesB. — Sbrubs  or  trees,  rarely  berbs,  witb  mostly  al- 
ternate compound  leaves  ;  fruit  usually  a  berry  or  drupe.  Species  840, 
mostly  tropical. 

-Some  of  tbe  species  of  ^ra/ia  are  ofnamental — e.g.f  A.  spinoia  and 
A,  raeemosa,  of  tbe 
Eastern  and^Soutb- 
em  United  States. 

Hedera  Helix,  tbe 
Englisb  Ivy  of  Eu- 
rope and  Western 
Asia,  is  a  well- 
known  ornaments! 
climber. 

Aralia  guinquefo- 
lia.  Ginseng,  is  com- 
mon in  many  parts 
of  tbe  Eastern 
United  States.  Its 
root  is  officinal. 

Aralia  papyrife' 
ra,  a  small  tree  of 
Cbina,is  tbe  source 
of  tbe  Cbinese  Rice 
paper ;  for  tbis  pur- 
pose tbe  pitb  is  cut 
into  tbin  sbeets  and 
tben  pressed  flat. 

Order  Umbellif- 
erse. — Herbs,  rarely 
sbrubs  or  trees,  witb 
alternate  and  usual. 

ly  mucb  dissected  leaves ;  fruit  dry  and  indebiscent.  Species  1300, 
found  most  abundantly  in  Nortbern  Europe  and  Asia,  altbougb  occur- 
ring in  nearly  all  countries.  Many  contain  an  acrid  poisonous  princi- 
ple, and  tbe  plants  of  tbe  order  may  usually  be  regarded  witb  suspi- 
cion.  In-  a  general  way  it  mny  be  said  tbat  tbe  fruits  are  aromatic 
and  innoxious,  and  tbe  green  parts  acrid  and  poisonous.    (Figs.  456-60.) 

Tbe  Parsnip  (Pantinaca  satim)  and  tbe  Carrot  (Daueus  Carota), 
botb  natives  of  Europe,  are  valuable  and  well-known  food  planta 
In  their  wild  state  tbey  are  poisonous. 

Apium  gra/JD€olenSf  Celery,  a  native  of  Europe,  is  deservedly  popular 


Fro.  457. 


Fio.  458. 

F!g.  456.— Flower. 

Fig.  458.— Flower  diagram. 

Fig.  460.— Section  of  ieed. 


Fie.  459. 


Fio. 


Fig.  457.— Secilon  of  flower. 
Fig.  459.— Ripe  fruit. 


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520  BOTANY, 

as  a  salad.  Tlie  poiBonous  herbage,  when  deprived  of  its  green  color  by 
covering  with  earth,  is  rendered  wholesome. 

Among  the  aromatic  and  medicinal  prod  acts  may  be  mentioned  Cara- 
way, Coriander,  Cummin,  Fennel  {^Fcmieulum  vulgare).  Dill,  Aniseed, 
etc. 

Ferula  AsafcUida  is  a  tall  growing  plant  of  Thibet  and  the  western 
parts  of  Asia.  The  dried  and  hardened  milky  juice  of  the  root  is  the 
nauseous  smelling  Gum  Asafostida.  It  is  said  that  the  Persians  hold 
it  in  high  esteem  as  a  condiment.  Qum  Ammoniacuni,  Gum  Galbanum, 
Gum  Opopanax,and  some  other  gum  resins  are  similur  strong  smelling 
products  of  other  plants  of  the  same  region.  • 

Conium  macukUum,  Poison  Hemlock,  a  native  of  Europe,  but 
naturalized  in  the  United  States,  is  virulently  i)oisonou8.  It  is  sup- 
posed to  be  the  Hemlock  used  by  the  Greeks  to  poison  their  criminals 
and  other  offenders. 

Cicuta  maculata.  Water  Hemlock,  and  ^thma  Cynapium,  Fool's 
Parsley,  are  two  common  poisonous  plants,  the  first  h  native  of  the 
Eastern  United  States,  the  second  introduced  from  Europe. 

Monizia  edulU^  of  the  Madeiras,  is  a  low  tree,  and  in  Australia  spe- 
cies of  XarUhosia,  Trachymens,  Astrolrichiti,  etc.,  are  shrubs  or  small 
trees. 

591.— Cohort  XTCTTT.  Fieoidales.  Flowers  usually  actin- 
omorphic ;  ovary  mostly  inferior,  one-  to  many-celled ;  pla- 
centae parietal,  basilar  or  axile  ;  seeds  with  or  without  endo- 
sperm. 

Order  FicoidesB.— Mostly  herbs,  often  with  fleshy  leaves.  Species 
450,  mostly  tropical,  represented  in  the  Uuited  Slates  by  the  Carpet- 
weed  (MoUugo  xierticiUata). 

Meiembryanthtmum  crystaUinum,  the  Ice  Plant,  is  commonly  culti- 
vated as  a  curiosity. 

Order  Cactace8e.~Tlie  Cactus  Family.  Succulent  herbs,  shrubs, 
or  trees,  often  spiny,  and  generally  leafless.  About  1000  species  are 
enumerated,  all  American  (with  one  or  two  exceptions),  and  mostly 
tropical.  Several  of  the  species  are  common  in  many  parts  of  the  Old 
World,  having  long  since  escaped  from  cultivation. 

Many  of  the  species  are  grown  in  conservatories  for  their  fine  flow 
ers,  as  well  as  on  account  of  their  curious  shapes.  Cereti$  grandi- 
flarus,  the  Night  Blooming  Cereus  ;  Opuntia  vulgarU,  the  common 
Prickly  Pear  ;  0.  eoccinellifera,  and  others,  are  c«»mmon.  The  last- 
named  is  fed  upon  by  the  Cochineal  Insect,  from  which  the  dyd  Carmine 
is  derived. 

The  fleshy  fruits  of  some  species  are  edible. 
592.— Cohort  XXIV.  Passiflorales.— Flowers  usually  ac- 
tinomorphic ;  ovary  usually  inferior,  synearpous,  one-celled, 


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PA88IFL0RALE8. 


521 


with  parietal  placent©  (sometimes  three  or  more  celled  by 
the  produced  placentae). 

Order  DatiscacesB. — A  curioas  order  of  four  species,  one  of  which, 
DcUisca  glomeraia,  occurs  in  California. 

Order  Begoniaceee. — A  tropical  order  of  350  species  of  herbs,  mostly 
Figs.  461-5.— Illustrations  of  Cucuxis  Mslo. 


FI0.4QS. 


Fro.  464. 


Fio.  466. 


Fig.  461.— Male  flower,  vertical  section. 

Fig.  462.— Female  flower,  vertical  section.      Fig.  468.— Androeciom.    Magnified. 

Fig.  464.— Diagram  of  male  flower.  Fig.  466.— Diagram  of  female  flower. 

American,  represented  in  green-houses  and  conservatories  by  many 
species  of  the  principal  genus  Begonia — e.g.,  B.  Rex,  B.  Eoarmana,  B. 
fiiehsiaides,  etc 

Order  Cucurbitaceae.— Tlie  Gourd  Family.  Herbs  or  undershrubs 
with  climbing  or  trailing  stems  and  diclinous  flowers ;  placentse  pra 
duced  to  the  axis  of  the  ovary  and  re  volute.  Species  470,  mostly 
tropical.    (Fig&  461-6.) 


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522  BOTANY. 

Cueurfnta  maxima^  the  large  Winter  Squash;  C.  verrucom,  the  Crook- 
necked  Squash  ;  and  C.  Pepo,  the  Pumpkiu,  are  well  kDOwn  in  cultiva. 
tion.  Their  nativity  is  unknown.  According  to  Dr.  Gray,  the  Pump- 
kin was  "cultivated  as  now  along  with  Indian  Corn  by  the  North 
American  Indians  before  the  coming  of  the  whites." 

Cucumu  Melo,  tbe  Musk-Melon,  and  C.  mHvus,  the  Cucumber,  are 
doubtless  natives  of  India. 

CitntUus  vtUgaris,  the  Watermelon,  is  a  native  of  India. 

The  dried  flesh  and  seeds  of  CitruUiut  Coloeynthis,  of  the  Eastern 
Mediterranean  region,  constitutes  the  poisonous  drug  Colocynth. 

Lagenaria  vulgaris,  the  common  Gourd,  a  native  of  Asia  and  Africa, 
is  cultivated  for  its  fruits,  which  are  made  into  bottles,  drinking  ves- 
sels, etc. 

Luffa  j^yptica,  the  Towel  Gourd  of  Ejiypt,  is  now  grown  in  the 
West  Indies  and  the  Southern  United  States.  Its  fruit  is  somewhat 
larger  than  a  Cucumber,  and  is  very  fibrous  internally ;  its  rind  and 
seeds  are  removed,  and  the  fibrous  portion  used  as  a  bath  sponge. 

Eehinocystia  lobaia,  the  Wild  Cucumber  or  Balsam  Apple  of  the 
Eastern  United  States,  is  a  rapidly  growing  climber,  valuable  for  ar- 
bors,  screens,  etc. 

Order  Paa8iflorace8B.~The  Passion-Flower  Family.  Trees,  shrubs, 
or  herl)8,  mostly  of  the  tropics.  Species  250,  represented  in  the  South- 
em  United  States  by  four  or  five  species  of  Paasiflora,  and  in  conserv- 
atories by  magnificent  climbers  of  the  same  genus  from  South  America. 

Carica  papaya,  the  Papaw  of  tropical  America,  is  a  small  tree,  bear- 
ing large  edible  fruits. 

Order  Tumeracesd. — Tropical  herbs  and  shrubs. 

Order  Loasacen. — Herbs  of  warm  climates,  mostly  American. 

Order  Samydacen.— Trees  and  shrubs  of  the  tropics. 

598.  Cohort  XXV.— Myrtales.  Flowers  mostly  actino- 
morphic  ;  ovary  usually  inferior,  synearpous ;  plaeento  in  the 
axis  (or  apical,  rarely  basal) ;  leaves  simple,  and  usually  entire. 

Order  Onagracesd. — Herbs,  shrubs,  and  trees,  about  800  species,  of 
temperate  climates,  represented  in  the  United  States  by  species  of  i^ 
lobiufn,  (Enothera,  and  other  genera.  In  conservatories,  many  species 
of  Fuchsia  are  cultivated  for  their  beautiful  fiowers.  They  are  natives 
of  Mexico  and  South  America. 

Trapa  natans,  a  curious  aquatic  plant  of  Central  and  Southern 
Europe,  is  called  Water  Chestnut,  and  its  large  nut-like  horned  fruits 
are  nutritious.  T.  bispinosa,  of  Northern  India,  and  T,  bicomis,  of 
China,  are  extensively  used  for  food  in  their  native  countries. 

Order  Lythracess.— Herbs,  shrubs,  and  trees,  mostly  of  the  tropics. 


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MYRTALE8,  523 

Species,  250,  represented  in  the  United  States  bj  a  few  small  herbs  of 
the  genera  Lyihrum^  CupJua,  etc. 

LatMonia  inennis,  a  slirub  of  Western  Asia,  lias  long  been  in  culti- 
Tation  in  Egypt  and  the  adjacent  countries.  From  its  leaves  the  cos- 
metic  Honna  or  Khenna,  so  much  used  for  coloring  the  hair  and  nails, 
is  made. 

Puniea  granatum,  the  Pomegranate  of  India,  is  a  bushy  tree,  six  to 
nine  metres  high  (20-^0  feet),  bearing  deciduous  leaves,  and  yellowish 
fruits  about  the  size  of  an  a()p]e.  Tlie  pulpy  interior  of  the  latter  is 
prized  for  makinpr  cooling  drinks ;  from  it  a  wine  is  also  made.  Pome- 
granates have  long  been  grown  in  the  countries  about  tbe  Mediterranean 
Sea,  and  are  now  cultivated  in  the  wairmer  parts  of  America. 

LagerstrcBmia  regina^  the  Jarool  or  Blood  wood  tree  of  India,  is  highly 
valued  for  its  blood-red  wood,  which,  being  exceedingly  durable  in 
water,  is  much  used  in  shipbuilding. 

L.  ladica,  a  common  green-house  shrub  from  India,i8  cultivated  under 
the  name  of  Crape  Myrtle. 

Sonneratia  acida,  an  Indian  tret^,  yields  a  most  valuable  fuel. 

Physocalyinina  flaribunda,  the  Tulip  tree  of  Brazil,  yields  a  fine 
wood  much  ustd  for  inlaying. 

Order  MelastoxnacesB. — Trees,  shrubs,  and  a  few  herbs,  of  the 
tropics.  Species,  1800.  We  have  in  the  United  States  hut  one  genus, 
Bhexia,  represented  by  half  a  dozen  species.  A  few  are  cultivated  in 
^preen-houses. 

Order  Myrtaceed. — Tlie  Myrtle  Family.  Trees  and  shrubs  (rarely 
herbs),  with  mostly  0|»|K)siie  glandular-dotted  leaves ;  stamens)  many. 
A  large  and  very  difficult  order  of  1800  or  more  species,  which  are  dis- 
tributed throughout  the  tropics  and  the  Southern  Hemisphere. 

Many  of  the  species  yield  excellent  fruits. 

PHdium  po^niferum  and  P.  pyriferum,  of  the  West  Indies,  and  P. 
CaltUyanum;  of  Brazil,  bear  apple-  or  pear-shaped  fruits  called  Guavas, 
highly  esteemed  for  dessert,  and  for  preserving.  All  are  now  exten- 
sively irrown  in  tropical  climates. 

Eugenia  ma^aecensis,  the  Malay  Apple,  and  E,  Jambos,  the  Rose 
Apple,  both  of  the  East  Indies,  furnish  important  fruits  to  the  people 
of  the  far  East. 

E,  pimenta,  a  West  Indian  tree,  is  there  cultivated  for  its  berries, 
which  are  gathered  and  dried  before  ripening,  constituting  the  Pimento 
or  Allspice  of  commerce. 

E.  aromatica,  the  Clove  Tree  of  the  Moluccas,  now  extensively  cul* 
tivated  in  the  East  and  West  Indies,  is  prized  for  its  spicy  flower-buds, 
which  are  gathered  before  opening  and  then  dried,  in  which  state  they 
are  known  as  Cloves. 

BerthoUetia  excelsa,  of  tropical  America,  is  a  tree  thirty  to  forty-fivo 
metres  high  (100-150  feet),  bearing  woody-shelled  fruits,  ten  to  fifteen 


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524  BOTANY. 

cm.  (4-6  inches)  in  diameter,  inside  of  wbicli  are  a  number  of  rough 
oily  seeds,  the  Brazil  Nuts  of  commerce.  Closely  related  to  this  is  the 
Monkey  Pot,  whose  woody.shelled  fruit  is  dehiscent  by  a  circular  lid. 

Many  of  the  trees  of  this  order  furnish  valuable  timber. 

Myrtui  communia,  the  Myrtle  Tree  of  Western  Asia,  yields  a  hard 
mottled  wood  much  esteemed  iu  turnery.    (Fi^.  466.) 

Eucalyptus^  sp.,  the  Gum  Trees  of  Australia  and  Tasmania.  These 
&re  large  stately  trees,  often  rising  to  the  height  of  fifty  to  one  hun- 
dred metres  (150-300  feet),  and  occasionally  even  exceeding  this.  The 
timber  furnished  by  them  is  in  some  cases  of  great  value,  being  tough 
and  durable.    (Figs.  467-8.) 

E.  globultu,  the  Blue  Gum,  is  now  much  planted  in  California.  Its 
timber  is  valuable,  but  shrinks  greatly  in  drying.  E,  marginata. "  the 
Jarrah  or  Mahogany  tree  of  Southwestern  Australia  is  famed  for  its  in. 
destructible  wood,  which  is  attacked  neither  by  Chdura,  Teredo,  nor 


Fio.  466.  Fig.  467.  Fio.  468. 

Fig.  466.— Vertical  section  of  the  flower  of  Myrtiu  communU.    Magnified. 
Fig.  467.— Vertical  section  of  the  flower  bud  of  Eucalyptus  globulw.    Nat.  size. 
Fig.  468.— Transverse  section  of  the  ovary  of  Eucalyptus  gMnUus.    Magnified. 

Termes,  and  therefore  much  sought  for  jetties  and  other  structures  ex- 
posed to  sea  water,  also  for  underground  work,  and  larjrely  ex^torted 
for  railway  sleepers.  Vessels  built  of  this  timber  have  been  enabled 
to  do  away  witli  copper-plating."  (Mueller).  E.  reiintfera,  the  Iron 
Bark  tree  supplies  a  very  heavy  and  exceedingly  strong  timber. 
Species  of  Eugenia,  Myrtus,  etc,  are  grown  in  conservatories. 

Order  Combretaceas.— Tropical  trees  and  shrubs,  about  240  spedesL 
A  few  species  occur  in  South  Florida. 

Order  Shizophoracesd.—Tropical  trees  and  shrubs,  about  50  spe- 
cies,  the  most  important  of  which  is  the  Mangrove  Tree  of  tropical 
America  (Bhizophora  Mangle)  ;  it  also  occurs  from  Florida  to  Texas. 

594.  Cohort  XXVI.— Bosales.    Flowers    mostly    actino- 
morphic;  carpels  one  or  more,  usually  quite  free  in  bud. 


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B08ALE8,  525 

sometimes  variously  united  afterwards  with  the  calyx-tube. 


Fio.  469. 

Fij?.  AS^.—DioncBa  mwcipula.    Plant  with  flower-stalk.    Natural  slae. 
Fig.  470  —Flower-cluster.    Natural  size. 
Fig.  471.— Pistil  cut  verUcally.    Magnified. 

or  enclosed  in  the  swollen  top  of  the  peduncle ;  styles  usu- 
ally distinct. 
Order  HaloragesB. — Mostly  aquatic  herbs,  about  eighty  species. 


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526  BOTANY. 

Order  BnmiaceeB.— A  few  beatli-like  woody  plants  of  South  Africa. 

Order  Hamamelaceea. — A  small  order  of  trees  and  shrubs,  repre- 
sented in  the  United  States  principally  by  the  Witch  Hazel  {Hamok^ 
melts  Virginiea),  and  the  Sweet  Gum  Tree  (Liquidamber  Styradfltia), 

Order  Droseracese. — The  Sundew  Family.  Mostly  bog-herbs  with 
radical  gland-bearing  leaves.  About  110  species  are  known,  distributed 
throughout  the  world.  This  interesting  little  family  has  attracted 
great  attention  on  account  of  the  insect^^tchins:  habits  of  its  species. 

The  most  remarkable  plant  of  the  order  is  the  Venus'  Fly-Trap  (Diouma 
museipula)  of  North  Carolina.  Each  leaf  has  a  rounded  blade  which 
is  fringed  with  stiff  bristles  (Fig.  469),  and  uiK>n  the  surface  of  each  half 
are  three  sensitive  hairs  which,  when  touched,  cause  the  tissues  of  the 
upper  surface  of  the  midrib  to  contract  suddenly,  and  thus  to  quickly 
close  the  leaf  as  a  book  or  rat-trap  is  closed.  An  insect  alighting  upon 
one  of  these  leaves  is  caught  by  the  quickly-closing  sides,  and  is  within 
a  few  days  dissolved  (digested)  by  an  acidulous  fluid  exuded  by  the 
glands  of  the  leaf ;  it  is  then  absorbed  by  the  leaf,  and  when  this  is  ac- 
complished the  latter  again  opens.  Thi;<  plant  is  thus  a  partial  sapro- 
phytel 

In  the  Sundews  (species  of  Ihrosera),  the  leaves  have  stalked 
glands  which  are  sensitive,  and  when  these  come  in  contact  with  an 
insect  they  cause  the  blade  to  slowly  bend  around  it,  finally  enclosing 
it.    Digestion  and  absorption  then  take  plnce  as  in  the  previous  case. 

Mr.  Darwin  has  shown  that  the  other  genera  of  the  order  are  also  in- 
sectivorous. (See  his  book,  '*  Insectivorous  Plants,"  London  and  New 
York,  1875,  in  which  367  pages  are  devoted  to  the  plants  of  this  order). 

Order  CrassulacesB. — Herbs  or  undershrubs,  usually  with  thick 
fleshy  leaves.  Species  400,  found  mostly  in  temperate  climates.  Many 
are  in  common  cultivation — e,g.,  Bryophj/llum,  the  Live-leaf  from 
tropical  Africa  ;  Crassula,  of  many  species,  from  the  Cape  of  Good 
Hope ;  Cotyledon,  of  many  species,  from  Mexico  and  Africa ;  Sedtim, 
Live-forever  ;  Sempervivum,  the  Houseleek,  etc. 

Order  Saxifragacess. — The  Saxifrage  Family.  Trees,  shrubs,  and 
herbs  with  actinomorphic  flowers,  generally  definite  stamens,  and 
seeds  rich  in  endosperm.  Species  540,  mostly  natives  of  temperate  and 
cold  climates. 

Bibis  grosstdaria,  the  Goo8el>erry,  and  R.  rubrum,  the  Red  Currant, 
both  of  Europe,  are  in  common  cultivation  for  their  edible  berries. 
The  last  named  is  also  indigenous  northward  in  this  country. 

Among  ornamental  plants  are  PhUadelphus,  the  Mock  Orange,  from 
the  Old  World ;  Bibes,  Flowering  Currants,  of  the  Western  United 
States ;  Deutua,  from  China  and  Japan  ;  Hydrangea,  Japanese  and 
native;  Astilbe,  from  Japan  ;  Saxifraga  »armento»a,  the  so-called  Straw- 
berry  Geranium,  a  fine  basket  plant  from  China. 

Cephalotus  foUkularis,  the  Australian  Pitcher  Plant,  is  now  regarded 


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R08ALE8.  527 

as  a  member  of  thie  order.  It  is  a  low  plant  witli  a  rosette  of  radical 
leaves,  some  of  which  resemble  the  covered  pipes  used  by  many 
Frenchmen  (Fig.  472).  The  border  of  the  ascidium  (pitcher)  in  the  lat- 
ter is  incurved  and  presents  an  obstacle  to  the  egress  of  insects,  which 
are  no  doubt  thus  captured. 

Order  BosacesB. — The  Rose   family.    Herbs,  shrubB,  and  trees, 
usually    with    actinomorphic    flowers,    generally    indefinite    (many) 
stamens,  and  seeds  destitute  of  endosperm.     Species,  1000,  distributed 
throughout  the  world.    The  plants  here  under  consideration  liave  been 
arranged  under  several  orders  by  some  authors,  on  account  of  a  part 
having  an  apparently  inferior  5-celled  ovary,  others  many  superior 
ovaries,  and  still  others 
but  one  superior  ovary. 
Bentham  and  Hooker 
have  arranged  the  sev- 
enty-one genera  under 
ten    tribes,    eight    of 
wliich  only  will  be  no- 
ticed here. 

Tribe  Bomece. — 

Shrubs  and  trees  with, 
simple  leaves,  ovaries 
5  (rarely  less),  adnate 
to  and  frequently  cov- 
ered by  the  fleshy  re- 
ceptacle (and  calyx  ?). 

Pirns    Maltis,     the 
AnniA  and  P  /*/)fnmi/        ^ig-  472.— l>ave«  of  CephdhlutfollicularU.  /,  normal 
Apple,  ana  r.  commu^  ,^,5^^  ,^ .  ^,  a*cidlum  ;  6,  iw  iucuned  border ;  f. 

fits,   the    Pear,     gruw   its  lid.    Natural  s  ze. 

wild  in  many  parts  of  Europe.     They  have  been  cultii%ted  for  ages  in 

other  portions  of  the  world.     (Fig.  473.) 

P.  prunifolia  and  P.  baccata,  Siberian  Crab-Apples,  of  the  North  of 
Asia,  are  in  common  cultivation. 

P.  coronaria,  the  American  Crab- Apple, of  the  Eastern  United  States, 
might  be  made  a  valuable  apple  by  cultivation. 

P.  Cydonia  (or  Cydonia  vulgaris),  the  Quince,  is  a  native  of  the 
Levant.  (Figs.  474-6.) 

The  Hawthorns  (Cratagtis,  sp.)  are  of  some  value  for  their  fruits, 
and  have  long  been  favorites  for  hedges  and  ornamental  purposes, 
Service-ljerries  (Atnelanchier,  sp.)  furnish  valuable  fruits,  and  are 
ornamental. 

Tribe  Rosece. — Shrubs,  with  pinnately  compound  leaves  ;  ovaries 
many,  free,  but  surrounded  by  the  fleshy  receptacle  (and  calyx  ?). 

Bosa—ot  many  species— the  Roses.  Not  only  are  our  native  species 
(of  which  we  have  about  a  dozen)  more  or  less  cultivated  for  their  beau- 


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528 


BOTANY. 


tifal  flowere,  but  from  eighteen  to  twenty  or  more  species  from 
Eorope  and  Asia  are  commonly  to  be  found  in  gardens  and  conser- 
vatories.   (Fig.  476.) 
Tribe    JPotentUlecB.^lAostlj   herbs,   with    usually   compound 

Figs.  478-5.— Illustbatiohs  of  Tbibb  PoMBii. 


Pio.  478. 


Fio.  474.  Fig.  475. 

Pig.  478.— Flower  cluster  of  Pirwt  eommunU. 

Fig.  474.— Section  of  Quince  flower  (Ftrus  OifdorUa). 

Fig.  475.— Section  of  Quince  fruit. 

leaves ;  carpels  free,  one  to  many,  mostly  on  a  convex  fleshy  receptacle  ; 
fruits  dry  (achenia). 
Fragaria  datior,  of  Europe,  F,  vetca,  of  Europe  and  Eastern  United 


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B08ALE8,  529 

States,  and  F,  Virginiana  of  the  Eastern  United  States,  are  the  species 
from  which  the  cultivated  Strawberries  have  been  derived,  bj  high 
calture  and  crossing.     (Fig.  477.) 

Chamabatia  foliosa  of  the  western  slope  of  the  Sierra  Nevada  Moan- 
tains  in  California,  is  a  small  fragprant  shrub  with  thrice  pinnate  leaves, 
much  gathered  bj  tourists,  and  deserving  a  place  in  gardens. 

Cereocarptis     ledifoUuH,     the 
Mountain  Mahogany,  of  Caliror- 

nia,  is  a  shrub  or  tree,  ranging  i 

Arom  two  to  fifteen  metres  in 
height  (6  to  50  feet).  lU  heavy 
dark  colored  wood  is  valuable. 

Tribe  Um6ccp,  — Mostly 

shrubs,  differing  from  the  pre- 
ceding  in  having  fleshy  fruits 
(drupes). 

Eubus  Idceus,  the  Garden  Rasp- 
berry, of  Europe,  is  also  cultivat- 
ed to  some  extent  in  this  country.       Fig.  476.— Section  of  the  flower  of  So§a 
E,     ocddenUdis,    the    Black  rubiginow.   Natural  .i^e. 

Raspberry,  and  R.  strigotus,  the  Red  Raspberry,  both  natives  of  the 
Eastern  United  States,  have  given  rise  to  the  Common  Raspberries  of 
our  gardens. 

22.  frutico9U8,  the  Blackberry,  of  Europe,  is  scarcely,  if  at  all  culti- 
vated in  this  country.    R,  vUlosus,  the  Wild  Blackberry,  of  the  Eastern 

United  States,  is  exten- 
sively cultivated. 

T^ribe  QuiUajece. 

— Trees  and  shrubs, 
with  mostly  simple 
leaves,  dry  fruits  and 
winged  seeds.  Nearly 
all  are  natives  of  Mexico 
or  South  America. 

QuiUaja  saponaria,  of 

Chili,  is  an    ever^rreen 

jJ^g^-Section  of  the  flower  of  Fragaria  vtsca.    tree,  fifteen  to  eighteen 

^  metres  (50  to    00   feet) 

high,  whose  bark  eontains  Saponin  (Cta  H»4  Oi^),  nnd  is  used  instead 
of  soap  for  washing.  Under  the  name  of  Soap-bark  or  Quillaja-bark 
it  is  imported  into  this  country. 

Tribe  fi^irccecc.— Mostly  woody  plants,  of  the  Northern  Hemi- 
sphere,  with  dry  fruits.  The  principal  genus  Spiraa,  contains  many 
species,  which,  being  highly  ornamental,  are  commonly  planted  in 
flower-gardens. 


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530  BOTANY. 

2Vi&e  Prunece. — Trees  and  shrubs,  with  stems  yielding  gum. 
simple,  mostly  serrate  leaves,  and  solitary  carpel  ripening  into  a 
drupe.    (Figs.  478-9.) 

Frunus  communis,  the  Almond,  is  a  native  of  Western  Asia,  and 
now  grown  in  many  warm-temperate  countries  for  its  fruits.  Two 
principal  varieties  are  grown,  viz..  Sweet  and  Bitter ;  in  the  former  the 
kernel  is  edible,  whereas,  in  the  latter,  it  is  bitter  and  poisonous.  An 
oil  is  expressed  from  both  kinds. 

The  Peach  has  been  until  recently  regarded  as  a  distinct  species 
(P.  Persiea),  but  it  is  now  supposed  to  have  been  derived  from  the 
Almond,  by  long  culture  and  selection. 

P.  Armeni<ica,  the  Apricot,  originally  from  Armenia,  is  now  exten- 
sively  grown  in  many  countries. 

P,  domestiea,  the  Plum  of  Europe,  P,  Americana,  the  Common  Wild 


Fio.  478.  Pig.  479.     ' 

Fig.  478.— Flower  cluster  of  Prunwi  C&ratu§. 

Fig.  479.— Section  of  flower  of  the  Peach.    Magnifled. 

Plum,  of  the  Eastern  United  States,  and  P.  Chicasa,  of  the  Southern 
States,  are  cultivated  for  their  excellent  fruits.  The  second  named  is 
the  original  form  of  most  of  the  varieties  grown  in  the  central  part  of 
the  Uniteci  State*. 

The  Cherry, « ommonly  referred  to  P.  Cerasus,  is  probably  derived 
from  P.  avium,  ilie  Bird  Cherry,  of  Europe.  The  wood  of  the  Bird 
Cherry  is  used  in  Euroi^  for  making  furniture,  as  is  also  that  of  our 
Wild  Black  Cherry  (P.  serotina),  of  the  Eastern  United  States. 

Many  of  the  foregoing  have,  by  long  and  careful  culture,  developed 
double-flowered  varieties,  which  are  sometimes  to  be  found  in  gardens. 

Prunus  vana,  the  Dwarf  Almond,  is  well  known  in  the  double- 
flowered  state. 

Tribe  f'hrysobalanece. — Trees  and  shrubs,  with  simple,  entire 
leaves.     Mostly  natives  of  tropical  America,  a  few  of  tropical  Asia  and 


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ROSALES, 


531 


Africa.  Some  of  tlie  latter  bear  edible  fruits.  The  bark  of  Brazilian 
trees  of  the  genera  Licania  and  Couepia  is  said  to  contain  such  consid- 
erable quantities  of  silica,  that  it  is  burnt  by  the  natives  and  used  in 
the  manufacture  of  potterj. 

Order  Legruminosad.— The  Pulse  Family.  Herbs,  shrubs,  and 
trees,  with  alternate  and  usually  compound  leaves ;  flowers  for  the  most 
part  zygomorphic ;  stamens  usually  twice  as  many  as  the  petals  ;  pistil 

Fios.  460-6.— Illustrations  of  PapilionaceuE. 
(480-5,  Lathyrv  odoratu$.) 


Fie.  484. 


Fig.  486. 


Fig.  480.— Section  of  flower.    Magnified. 

Fijf.  482.-Calyx.    Magnified. 

Fig.  484.— Ripe  fruit.  FiC'.  485.— Part  of  Iruit,  with  a 

Fig.  486.— Section  of  seed  of  TetragonoHobus.   Magnified. 


Fig.  481.— Diagram  of  flower. 

Fig.  483.— Stameno  and  pistil   Mag. 


monocarpellary  and  free  ;  seeds  generally  wantinpr  an  endosperm.     A 
vast  order  of  6500  species,  distributed  throughout  the  world. 

The  species  are  usually  disposed  in  three  sub-orders,  each  containing 
many  tribes. 

Sub"  Order  J.  PapHionaceae,  with  zygomorphic  flowers  ;  sta- 
mens generally  ten,  monadelphous  or  diadelphous.  This  sub-order 
contains  a  large  number  of  plants  of  great  economic  importance. 

The  food  plants  include  the  Pea  (PUum  sativum),  the  80.^»illed  English 
Bean  ( Vicia  faba),  the  Pole  Bean  {Phaseolus  vulgaris),  the  Field  Bean 


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532  BOTANY. 

(P.  nana),  the  Lima  Bean  (P.  lunatus),  probably  all  from  India  and 
Western  Ada. 

Many  more  specieB  are  now  cultivated  in  India,  suck  as  Chowlee. 
Black  Grain,  Soy,  Pigeon  Pea,  Lentils,  etc. 

Tbe  Peanut  (Araehis  hypogaa),  a  native  of  Soutli  America,  is  now  an 
important  food  plant  in  tbe  West  Indies  and  Atrica.  After  tbe  fertili- 
zation of  tbe  erect  yellow  flowers,  tbe  peduncles  l>end  down  and  the 
young  pods  are  tbru>t  into  the  ground,  wbere  tbey  ripen.  Tliis  curi- 
ous habit,  which  must  liave  l^een  at  first  a  protective  one,  is  i)erpetu- 
ated  in  cultivation,  altbougb  tbe  need  of  it  apparently  no  longer  exists. 

Tbe  forage  plants  include  the  Red  Clover  (Trifolium  pratense),  the 
Wbite  Clover  {T.  repens).  Lupine  (Lupinus  cUbuti),  Lucerne  {Medieago 
saiiva),  Sanfoin  {Onobrychus  saliva).  Tares  or  Vetches  (Vicia  mtiva), 
all  from  Europe  and  tbe  countries  adjacent  to  tbe  Mediterranean  Sea. 
Many  otbers  are  grown  1^  extensively. 

Of  the  timl>er  trees*,  tbe  following  are  the  most  important : 

Robinia  Pseud-Acacia,  tbe  Locust  Tree  of  tbe  Eastern  United  States, 
yields  a  very  strong;  and  durable  timber. 

Dalbergia  vigra,  a  large  tree  of  Brazil,  produces  tbe  finest  Rose- 
wood. 

D.  latifolia,  of  India,  produces  the  Indian  Rosewood. 

Tbe  valuable  dye  Indigo  is  obtained  from  Indigofera  tinctoria,  a 
native  of  India.  Tbe  flowering  plants  are  cut  and  placed  in  vats  of 
water  ;  after  remaining  for  a  time,  tbe  water,  now  colored,  is  drawn  off, 
and  after  several  intervening  processes,  tbe  coloring  matter  is  allowed 
to  settle  to  the  bottom  ;  this  when  dried  is  crude  indigo. 

The  wood  of  Ptero  ai'pus  ^antalinu^,  a  tree  of  India,  wben  reduced 
to  chips,  is  the  red  dye  known  as  Red  Sandal-wood,  or  Saunders. 

Camwood,  another  red  dye,  is  obtained  in  a  similar  manner  from 
Baphia  nitida,  a  West  African  tree. 

Some  species  fumisb  gums  and  balsams,  which  are  of  use  in  tbe  arts. 

Gum  Tragacanth  is  derived  from  a  low  shrubby  plant,  Astragalus 
tragamntha,  growing  in  Western  Asia. 

Gum  Kino  is  produced  by  large  trees  of  India  and  Africa  belonging 
to  the  genus  Ptti'ocarpus. 

Balsnm  of  Peru  and  Balsam  of  Tolu  are  tbe  products  of  species  of 
Myroxylon,  in  Central  and  South  America. 

But  one  important  medicinal  product  is  furnished  by  tbis  sub-order, 
viz.,  Liquorice,  tbe  dried  roots  of  Qlycyrrhua  glabra,  a  native  herb  of 
tlie  South  of  Europe. 

In  India  species  of  Crotalaria  and  Sesbania  are  extensively  cultivated 
for  their  strong  and  durable  fibre,  much  used  for  making  cordage  and 
coarse  clotb. 

Of  the  maay  ornamental  plants,  the  following  only  can  be  mentioned, 
viz.,  specief>  of  Lupinns,  Cytisus,  Laburnum,  Petalostemon,  Caragana, 
Bobinia,  Wistaria,  Phaseolus,  Lathyrus,  Soplwra,  etc.,  etc 


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B08ALE8.  633 

Demnodium  gyrans,  an  East  Indian  plant,  is  remarkable  for  tbe 
BpontaneouB  uiovements  of  ite  It^ves.  The  leaves  are  compound,  the 
terminal  lei<flet  beins:  large,  while  the  lateral  ones  are  small ;  under 
proper  conditions  the  lateral  leaflets  alternately  rise  and  fall  bj  quick 
jerks,  continuing  this  for  hours  without  any  apparent  external  cause. 

Sub' Order  II»  CcesaipinieWy  with  flowers  zygoraorphic  or  ac- 
tinomorphic;  stamens  generally  ten,  usually  distinct. 

The  Tamarind  is  the  fruit  of  a  North  African  and  East  Indian  tree  of 
this  sub-order,  Tamarindus  Indica. 

Senna,  a  medicinal  drug,  is  the  dried  foliage  of  African  and  East 
Indian  species  of  Ca^na, 

Gum  Copal,  mucli  used  in  making  yamishes,  is  derived,  at  least  in 
part,  from  East  Africa  and  Madagascar  trees  belonging  to  the  genera 
Traehylobivm  and  Hymenoea. 

Ck>paiva  Balsam  is  obtained  from  Brazilian  trees  (Copaiferat  sp.)  by 
making  deep  incisions  into  the  trunks. 

The  pulverized  wood  of  Ccesalpina  echtnata,  a  Brazilian  tree,  yields 
the  red  dye  Brazil-wood  ;   that  from  Hoematoxylon 
Campeachianumt  a  small  tree  of  Central  America,  is 
the  well-known  and  valuable  dark-red  dye  Logwood. 

Many  timber  trees  are  of  jrreat  value — e.g.,  tbe 
Mora  Tree  of  Ouiana  {Dimorphandra  Mora),  whose 
heavy  durable  timber  is  in  great  repute  in  the  British 
navy  yards ;  the  West  India  Locust  {Hymentxa  CouV'  ^j  ^g^  _  Cross- 
baril)^  used  in  ship-building ;  the  Honey  Locust  of  the  sectkin  of  the  f>eed 
Eastern  United  States  {QUdithchia  tnacantho%),Yr\Aiih  gJowln^e  abuS- 
furnishes  a  valuable  timl>er  used  by  wheelwrights  dant  endosperm.— 
for  making  hubs ;  the  Kentucky  Coffee  Tree  of  the  M*«°*fl«d- 
Eastern  United  States  {C^ymnoeladus  Canadensis),  whose  red  wood 
somewhat  resembles  Mahogany ;  the  Judas  Trees  {Germ,  sp.),  whose 
wood  is  prized  in  Europe  for  cabinet-making. 

Sub'Order  III.  Jlfiim>«e(e.— Flowers  actinomorphic,  small, 
and  generally  collected  into  close  heads  or  spikes ;  stamens  distinct, 
two  to  many  times  the  number  of  petals. 

One  of  the  most  inipHiriant  of  the  vegetable  gums — Gum  Arabic  or 
Gum  Acacia — is  furnished  by  trees  of  this  sub-order  belonging  to  the 
genus  Acacia.  The  greatest  supply  is  obtained  from  A,  vera  and  A. 
Arabica,  natives  of  Northern  Africa,  Arabia,  and  the  East  Indies. 

The  genus  Acacia  is  abundantly  represented  in  Australia,  where 
many  of  its  species,  called  Wattles,  yield  most  excellent  timber.  That 
of  A,  melanoxylon  "is  most  valuable  for  furniture,  railway  carriages, 
boat-bnilding,  casks,  billiard-tables,  piano-fortes  (for  sounding-boards 
and  actions),  and  numerous  other  purtx)8es.  The  fine-grained  wood  is 
cut  into  veneers.  It  takes  a  fine  polish,  and  is  considered  equal  to  the 
best  walnut."    (Mueller,) 


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534  BOTANY. 

Lytiloma  Sabieu,  a  large  Cuban  tree,  yields  a  bard  and  very  durable 
timber,  highly  valued  for  ship-building  and  for  other  purposes. 

Many  species  of  ^eoeuiand  Mimo9a  are  in  cultivation  in  gardens  and 
conservatories. 

Mimosa  pudica,  from  South  America,  is  interesting  on  account  of  its 
extreme  sensitiveness  to  a  touch  or  jar.  On  this  account  it  is  commonly 
known  as  the  Sensitive  Plant.  Its  leaves  expand  in  the  light  and  con- 
tract  in  darkness,  and  in  the  proper  temperature  close  at  once  upon 


Fio.  488.  Fio.  489. 

Fig.  488.— Expanded  compound  leaf  of  JfimoM  pudica. 
Fig  489.— Closed  leaf  of  the  i>ame. 

being  touched  or  jarred,   opening  again,  however,  in  a  few  minuteB 
(Figs.  488-9). 

Order  ConnaracesB. — Trees  and  shrubs  of  the  tropics,  one  of  which, 
Connarus  Lambertii  of  Guiana,  furnishes  the  beautiful  Zebra- wood« 

595.— Cohort  XXVn.  Sapindales.  Shrubs  and  trees, 
with  usually  compound  leaves.  Flowers  often  zygomorphic 
and  diclinous ;  ovary  superior  ;  seeds  usually  without  endo- 
sperm. 

Order  Moringeas.— Contains  three  Old  World  trees,  of  doubtful 
affinity. 

Order  CoriariesB.— Shrubs  of  one  genus  and  three  to  five  species, 
found  in  the  Mediterranean  region,  the  Himalayas,  Japan,  New  Zea- 
land, and  South  America.     Their  affinities  are  very  obscure. 

Order  AnacardiacesB. — Tlie  Cashew  Family.  Trees  and  shrubs, 
with  gummy  or  milky-resinous  juice,  often  poisonous ;  fruit  usually  a 
drupe.     Species  about  460,  chiefly  found  in  the  tropics.     The  common 


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8APINDALE8.  536 

representatiyes  of  ibis  order  in  this  country  are  Bpecies  of  Bhu9,  of 
which  B.  typhina  and  B,  glabra,  Sumach,  are  highly  ornamental,  as 
well  as  useful,  their  young  shoots  and  leaves  containing  much  tannin 
and  being  much  used  in  tanninpf. 

Bhui  Toxicodendron,  the  Poison  lyy,  and  B,  venenata,  the  Poison 
Sumach,  both  of  the  Eastern  United  States,  and  B,  dwertilcba,  the 
''Poison  Oak"  of  California,  are  very  poisonous,  causing  in  many  per- 
sons a  severe  cutaneous  eruption. 

Mangtfera  Indica,  of  India,  but  now  grown  in  most  warm  climates, 
produces  the  excellent  fruit  known  as  the  Mango. 

The  Cashew  Nut  is  the  product  of  a  large  West  Indian  tree,  Anaear- 
dium  oecideniale,  and  the  Pistachia  Nut  of  a  tree  of  Western  Asia, 
Pietaeia  vera. 

Mastic,  a  resinous  material  used  in  fine  varnishes,  is  obtained  by 
making  incisions  into  the  stem  of  Piitada  Lentiscue,  a  small  tree  of 
the  Mediterranean  region.  Japan  Lacquer,  so  much  used  by  the 
Japanese  in  the  manufacture  of  many  wares,  is  obtained  in  a  similar 
way,  from  Bhue  vemietfera,  and  probably  other  species.  Japanese 
Wax  is  derived  from  the  waxy-coated  seeds  of  B,  aueeedaneum,  a  tree 
of  Cliina  and  Japan. 

Schinue  moUe,  a  Peruvian  shrub,  is  much  grown  for  ornament  in  the 
gardens  of  California  and  Italy. 

Order  SabiacecB. — ^Trees  and  shrubs,  mostly  of  the  tropics. 

Order  Sapindacess.— Trees  and  shrubs  (rarely  herbs),  mostly  with 
compound  or  lobed  leaves.  Species  from  600  to  700,  widely  distributed. 
This  order  includes  five  well-marked  suborders,  as  follows: 

Suh'Order  I.  StaphylecBf  with  actinomorphic  fiowers,  and 
seeds  with  endosperm.  Represented  in  the  Eastern  United  States  by 
the  native  ornamental  shrub,  the  Bladder  Nut  {Staphylea  trifolia), 

Svb-'Order  II.  Melianthew,  with  zygomorphic  fiowers,  and 
seeds  with  endosperm.    Old  World  trees  and  shrubs. 

Sub-'Order  III.  DodoniBce,  with  actinomorphic  fiowers,  and 
seeds  without  endosperm  ;  leaves  alternate. 

PtoBTOxylon  utile,  the  Sneezewood  Tree  of  the  Cape  of  Good  Hope, 
furnishes  a  hard  and  durable  timber,  as  also  a  New  Zealand  tree. 
Akctryon  exceleum, 

Sub-Order  IV.  Acerinece,  with  actinomorphic  fiowers,  and 
seeds  without  endosperm  ;  leaves  opposite.     (Figs.  490-2.) 

The  genus  Acer,  the  Maples,  contains  nearly  all  the  species. 

A.  campeetre,  the  Common  Maple  of  Europe,  A.  Psevdo  Platanue, 
the  Sycamore  Maple  of  Europe  and  Western  Asia,  and  A,  pUUanoidee, 
the  Norway  Maple  of  Europe,  are  valuable  timber  trees,  occasionally 
planted  here  as  ornaments. 

A.  eaceharinum,  the  Sugar  Maple,  A,  rvbrum,  the  Bed  Maple,  and 


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536  BOTANY. 

A.  dasyearpum,  the  Silver  Maple,  all  of  the  Eastern  United  States, 
famish  timber  much  used  in  the  manufacture  of  furniture. 

From  the  sweet  sap  of  the  first  much  sugar  is  made  in  the  Northern 
United  States.  Its  wood  also  is  harder,  and  is  known  as  Hard  Maple, 
to  distinguish  It  from  Soft  Maple,  derived  from  the  other  species. 

A.  maerophyUum,  the  Large  Leaved  Maple,  and  A.  eirdnatum,  the 

FiOfl.  490-2.— Illustrations  of  Aoxb  Psxudo-Flatahus. 


Fie.  490.  Fio.  49t 


Fio.  492. 

Fig.  490.— Section  of  flower.    Magnified.  Fig.  491.— Flower  diagram. 

Fig.  492.— Ripe  fruit. 

Vine  Maple,  both  of  California  and  Oregon,  yield  a  hard  and  close- 
grained  timber. 

Negundo  aceroides,  the  Box  Elder  of  the  Eastern  United  States,  is  a 
fine  ornamental  tree.  If.  Califamicum,  of  the  Pacific  Coast,  is  much 
like  the  preceding. 

Sub'Order  V.  Sapindece.— Flowers  actinomorphic  or  zygomor- 
phic ;  seeds  without  endosperm  ;  leaves  mostly  alternate.     (Fig.  493.) 


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CELASTBALES.  637 

.^!9culu9  glabra^  the  Ohio  Buckeye,  and  several  other  species,  are 
native  ornamental  trees  of  the  suh-order. 

jE.  Hippoc€Utanum,  the  Horse-Chestnut  of  the  Old  World,  is  com- 
monly planted. 

Kcelreuteria  paniculata,  a  Chinese  tree,  and  Cardio9permum  Halicc^ 
edbum,  the  Balloon  Vine  of  the  Southern  United  States,  are  cultivated 
as  ornaments. 

Nephelium  LUchi,  a  small  Chinese  tree,  produces  the  pulpy  edible 
fruits  Imported  under  the  name  of  LdtchL  J^.  Longan  produces  the 
similar  fruit  called  Longan. 

Melicocca  bijuga,  a  tree  of  Guiana,  yields  a  hard  and  heavy  timber, 
and  from  Cupania  pendula,  of  Australia,  is  obtained  Tulip  Wood, 
which,  in  some  respects,  resembles  Mahojjrany. 

The  stem  of  the  climbing  plant,  PauUinia  curcumvica,  of  Venezuela, 
is  m&du  into  the  walking-sticks  called  '*  Supple  • 

Jacks." 

596.  — Cohort  Xxviii.    Celastrales. 

Flowers  actinomorphic  and  monoclinous; 
ovary  superior  entire ;  seeds  usually  with 
endosperm. 

Order     Ampelidesd.  —  Mostly     climbing 
shrubs,  with  nodose  ptems,  bearing  petioled  al- 
ternate leaves ;  tendrils  and  flower  clusters  op-    th?l*owCT\^^'^SSfJ*- 
posite  to  the  leaves.      About  250  species  are    the  normal  circle  uf  stal 
known;  they  abound  in  the  tropics  and  are    SrinS^'^in^ 
much  rarer  in  temperate  climates.  two  are  fully  developed, 

Vitis  is  the  principal  genus;  it  contains  all    ?wo  o J!?reT^^^ 
the  true  Vines  (grape  producing),  and  many    dots.— After  bacha. 
others  whose  fruits  are  inedible.  (Fipfs.  494-501.) 

VUis  vinifera,  the  Vine  of  the  Old  World,  has  been  under  cultiva- 
tion from  time  immemorial.  It  is  indigenous  to  Southern  Asia,  from 
whence  it  has  been  carried  to  nearly  all  parts  of  the  world.  Its  varie- 
ties are  almost  innumerable.  From  those  grown  in  Southern  Europe 
wines  and  raisins  are  made,  the  latter  being  merely  the  sun-dried 
grapes. 

In  the  Unitt^d  States  the  Old  World  Vine  is  j;rown  in  the  Southern 
and  Pacific  C^oast  States,  and  in  the  latter  region  fine  raisins  are  made. 
In  other  portions  of  this  country  only  the  native  species  are  grown,  viz.: 

F.  Labrusca,  the  Northern  Kox  Grape ;  from  this  have  originated 
most  of  the  common  varieties,  as  Catawba,  Concord,  Isabella,  etc. 

F.  (JBStwalis,  the  Summer  Grape,  from  which  we  have  obtained  the 
Virginia  Seedling,  Herbemont,  etc. 

F  riparia,  the  River-bank  Grape,  which  has  produced  the  Taylor 
Bullit,  Delaware,  and  Clinton. 


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538 


BOTANY. 


F.  vul/pina,  the  Southern  Fox  Grape,  which  has  q^veu  rise  to  the 
Scuppemong  and  other  varieties.* 

From  these  American  grapes  excellent  wines  are  now  made ;  but  no 
raisins  haye  jet  been  made  from  them. 

The  Virginia  Creeper, -4wipe&>p*M  quinquefolia  (or  Vitis  quinqutfoUa), 

FiQs.  494-501.— Illustrations  of  Vitu  yihirba. 


Fig.  491 


Fig.  497. 


Fig.  496. 


Fis.  496. 


Fig.  496.  Fio.  489.  Fio.  600.  Fio.  601. 


Fig.  494.— Flower  bnd.    Magnified. 

Fig.  495.— Section  of  flower-bud.    Magnified. 

Fig.  496.— Flower  without  corolla,    ^gnified. 

Fig.  497.— Flower  diagram.  Fig.  498  —Fruit. 

Fig.  499.— Seed.    Magnified.  Fig.  600.— Cross-section  of  seed. 

Fig.  501.— Vertical  section  of  seed.    Magnified. 


Magnified. 


is  one  of  oar  finest  native  ornamental  climbers. 

Javan  and  Sumatran  species  of  Vitis,  formerly  referred  to  Cismi,  are 
common  in  conservatories. 

Order  BhamnacesB. — Trees  and  shrubs,  often  spinescent,  bearing^ 
simple,  usually  alternate  leaves ;  flowers  with  valvate  calyx  lobes. 
Species  430.  Inhabitants  for  the  most  part  of  warm  and  temperate 
regions.    Many  possess  a  purgative  principle. 

*  This  distribution  of  tbe  cultivated  varieties  is  that  made  by  Dr 
George  Engelman.    American  NaturaUst,  1872,  p.  589. 


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0LACALE8.  539 

The  fruits  of  some  species  of  Rhamnits  yield  yellow  or  green  dyes, 
^bicli  are  of  considerable  importance. 

The  wood  of  R.frangula,  of  Europe,  is  used  for  making  the  best 
•charcoal  for  the  finest  gunpowder. 

Species  of  Zizyphus  in  Africa  and  India  produce  edible  fruits,  one  of 
which  is  the  Jujube. 

Rhamnus  cathartieus,  the  Buckthorn  of  Europe,  is  planted  in  this 
country  for  hedges. 

Order  Stackhousiess.— Small  herbs,  mostly  confined  to  Australia. 

Order  Celastracese. — Small  trees  and  shrubs,  often  climbing,  bear- 
ing simple,  usually  alternate  leaves;  flowers  with  imbricate  calyx 
iobes.    Species  about  400,  natives  of  temperate  and  tropical  regions. 

Celastrus  scandens,  the  Climbing  Bittersweet  of  the  Eastern  United 
States,  is  ornamental,  and  is  planted  in  this  country  and  Europe. 

Euonymus  atropurpureus,  the  Waahoo,  or  Burning  Bush  of  the 
Eastern  United  States,  is  also  found  in  gardens. 

The  wood  of  E.  Earopoms  of  Europe  is  compact  and  capable  of 
being  split  into  very  fine  pieces,  and  is  used  by  watch-makers  under 
the  name  of  Dogwood.     It  is  also  used  for  skewers,  shoe-pegs,  etc. 

From  the  leaves  of  Catha  edulU,  an  East  African  shrub,  a  decoction  is 
made  which  produces  an  agreeable  excitement.  The  leaves  themselves 
are  sometimes  chewed. 

597.— Cohort  XXIX.  Olacales.  Flowers  actinomorphic  ; 
ovary  superior,  entire,  one-  to  many-celled;  seeds  with  copious 
endosperm. 

Order  Cyrillacen. — Trees  and  shrubs,  numbering  eight  species, 
represented  in  the  Southern  United  States  by  CyriUa  racemiflora,  the 
Iron  wood,  and  Gliflonia  ligustrina,  the  Buckwheat  Tree,  the  latter  a 
handsome  evergreen  tree,  three  to  six  metres  high  (10  to  20  feet). 

Order  Hicinese.— The  Holly  Family.  Trees  and  shrubs  with  mostly 
evergreen  leaves,  and  three-  to  many-celled  ovary.  Species  150,  of 
tropica]  and  temperate  climates. 

Ilex  Aquifulium,  the  Holly  Tree  of  Europe,  yields  a  white  close- 
grained  wood  much  esteemed  by  turners  and  cabinet-makers.  It  is 
sometimes  blackened  so  as  to  resemble  ebony.  The  tree,  being  orna- 
mental, is  extensively  planted.  The  bright  red  berries  remain  during 
the  winter,  and  with  the  evergreen  foliage  are  used  for  Christmas 
decorations. 

/.  opaca^  the  American  Holly,  of  the  Southern  States  and  the  Atlan- 
tic coast  from  Massachusetts  southward,  resembles  the  preceding  and 
is  used  for  the  same  purposes.  This  and  other  native  species  are  culti- 
vated in  gardens. 

The  leaves  of  /.  ParaguaytmM^  a  small  South  American  tree,  furnish 


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640  BOTANY. 

the  Paraguay  tea,  sometimes  called  Mat6.    It  contains  Caffeine,  tbe 
active  principle  in  tea  and  coffee. 

Order  OlacineaB. — Trees  and  shrubs,  about  170  species,  almost  en- 
tirely of  tbe  tropics. 

698.~Cohort  XXX.    Gfreraniales.      Flowers  often  zygo- 
morphic ;  ovary  superior,  entire,  lobed,  or  sub-apocarpous. 
Order  Chailletiaceas. — Tropical  shrubs  and  trees. 

Order  Meliaceao. — Trees  (rarely  undershrubs),wiih  mostly  pinnatelj 
compound  leaves ;  stamens  united  into  a  tube  ;  ovary  entire.  Species, 
270,  nearly  confined  to  the  tropics. 

Several  trees  yield  valuable  limber. 

Melia  Azedarach,  tbe  Pride  of  India  Tree,  indigenous  throngboat 
Western  Asia,  now  naturalized  in  all  the  Mediterranean  region,  and 
the  Southern  United  States,  is  a  fine  tree,  whose  reddish  wood  is  sus- 
ceptible of  a  beautiful  finish. 

Swietenia  Mahogoni,  a  native  of  tropical  America  (barely  reaching 
South  Florida),  yields  the  well-known  Mahogany  wood.  The  trees 
are  of  great  thickness,  sometimes  being  as  much  as  two  metres  in 
diameter. 

CedreLa  odorata,  of  Jamaica,  yields  Jamaica  Cedar. 

C  Toona,  of  India,  produces  Chiitagong  wood. 

C,  australU,  an  immense  Australian  species,  resembles  the  Jamaica 
Cedar.  The  wood  of  the  three  foregoing  species  of  CtdreUa  is  fine 
grained,  and  well  adapted  to  many  uses. 

Chhroxylon  Sunetenia,  of  Ceylon  and  Western  India,  is  a  large  tree, 
whose  fine-grained  satin-like  wood,  called  Satin  Wood,  is  much  prized 
in  cabinet  and  furniture  making  and  fine  turnery. 

Order  Burseraoeee. — Trees  and  shrubs,  abounding  in  resinous  or 
oily  secretions  ;  species,  145,  nearly  all  tropical. 

Balsamodendron  Myrrha  and  B,  KaJtnf^  email  Arabian  trees,  yield 
Myrrh. 

B,  Africanum,  of  Eastern  Africa,  produces  African  Bdellium. 

Olibanum,  an  incense  resin,  is  obtained  from  Boswellia  thurtfera,  & 
lofty  tree  of  Central  India. 

Bursera  gummifera.  West  Indian  Birch,  of  South  Florida  and  the 
West  Indies,  yields  a  gum  resin  called  Chibou  or  Cachibou. 

Order  OclmaceaB.— Tropical  shrubs  and  trees  with  a  watery  juice. 

Order  Simarubaceao. — Shrubs  and  trees,  with  scentless  foliage  ; 
leaves  generally  compound  and  alternate  ;  stamens  distinct.  About 
113  species,  almost  confined  to  the  tropics,  are  known.  The  bitter  bark 
and  wood  of  many  species  are  made  use  of  in  medicine.  That  from 
Quassia  amara,  a  small  tree  of  tropical  America,  is  the  Quassia  of 
pharmacy.  From  a  West  Indian  tree,  Simaruba  amara,  the  drug 
Simaruba  Bark  is  obtained. 


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QERANIALE8, 


541 


AiJUmthus  glandulosus,  the  Tree  of  Heaven,  a  native  of  China,  is  com- 
monlj  planted  in  the  United  States  as  a  shade  tree.  Its  wood  is  valu- 
able in  cabinet-making. 

Order  ButcMseae. — The  Rue  Family.  Shrubs  and  trees,  rarely  herbs, 
with  glandular- punctate  heavy-scented  foliage  ;  leaves  generally  com- 
pound and  alternate  ;  stamens  generally  distinct.  The  order  as  here 
considered  includes  650  known  species,  widely  distributed  in  tropical 

Figs.  5(&-fi05.— Illustrations  of  Citrus  Auraxtium. 


Fio.602. 


FiQ.  508. 


Pig.  604.  Pio.  605. 

Fig.  SOa.— Section  of  flower.    Magnified. 
Fig.  608.— Part  of  androeciam.    Magnifled. 
Fig.  504.— Flower  diagram. 
Fig.  506.— Calyx  and  ovary.    Magnified. 

and  temperate  climates.     Seven  tribes,  most  of  which  were  formerly 
considered  to  be  ordern,  are  recognized  by  Bentham  and  Hooker. 

Tribe  Aurantiece,  with  actinomorphic,  monoclinous  flowers, 
baccate  (berry -like)  fruits,  and  seeds  without  endosperm.   (Figs.  502-5.) 

OUrua  Aurantum,  the  Sweet  Orange,  is  an  Indian  tree,  now  grown 
throughout  all  warm  countries  of  the  world  for  its  well-known  fruits. 

C.  Limonum^  the  Lemon,  is  a  native  of  Northern  India,  now  widely 
distributed.    It  was  introduced  into  Europe  during  the  Crusades. 

Other  species  of  Citrus  yield  valuable  fruits,  as  C.  mediea,  the  Citron  ; 
C.  Limetta,  the  Lime  ;  C.  decumana,  the  Shaddock ;  C.  Bigaradia,  the 
Seville  or  Bitter  Oranjre,  etc. ,  etc. 

The  bard  yellow  wood  of  the  Orange  is  valued  for  inlaying 


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542  BOTANY. 

Tribe  Toddaliew,  with  actinomorpbic,  mostly  diclinous  flowers, 
coriaceous  or  baccate  fruits,  and  seeds  witb  endosperm. 

Ptelea  trifolitita,  the  Hop  Tree,  of  the  Eastern  United  States,  Skim- 
mia  Japonica,  a  small  Japanese  shrub,  and  two  species  of  PheUoden- 
di'on,  from  Manchuria,  are  planted  in  gardens. 

2W5e  Xanthoxylem^  with  actinomorphic,  mostly  diclinous 
flowers,  usually  capsular  fruits,  and  seeds  mostly  with  endosperm. 

Xanthorylum  Americunum,  the  Common  Prickly  Ash,  of  the 
Northern  United  States,  and  X  Clava-Herculis,  the  Southern  Prickly 
Ash,  of  the  Southern  States,  are  ornamental  shrubs,  and  are  often 
planted. 

Tribe  Stn'oniece* — Australian  shrubs. 

Tribe  IHosmete,  with  actinomorphic,  monoclinous  flowers,  cap- 
sular  fruits,  and  seeds  without  endosperm. 
Species  of  Diowna  and  Barosma,  pretty  African  shrubs,  are  to  be  found 
in  conservatories.     From  their  leaves  the  dru^ 
Bucbu  is  obtained. 

Tribe  MtUece,  with  generally  actinomorphic, 
monoclinous  flowers,  capsular  fruits,  and  seeds 
with  endosperm.    (Fig.  506.) 

Euta  graveoUns,  the  Common  Rue  of  the  gar- 
dens, is  a  native  of  Southern  Europe  and  West- 
em  Asia. 
Plff  B06  — Diaeram  of  ^ictamnus  FraxineUa,  Fraxinella,  or  the  Oaa 
the  flower  of  Dietamnus  Plant,  is  a  heavy.scented  ornamental  plant, 
S^^"r5lni(of  uIiS^  ^^^^  glandular  foliajre  secretes  a  volatile  oil, 
gin)  sliKhtly  shaded.— Af-  which  is  said  sometimes  to  flash  into  flame 
ter  Sachs.  ^^^^  ^  j.^^j^  j^  brought  near  to  it.  (Figs.  116-7. ) 

Tribe  CusparieWf  with  zygomorphic,  monoclinous  flowers,  cap- 
sular  fruits,  and  seeds  without  endosperm. 

Qalipea  cusparia,  a  large  tree  of  Quiana  and  Brazil,  furnishes  a  bit- 
ter medicinal  bark,  known  as  Angustura  Bark. 

Order  Qeraniacese. — The  Geranium  Family.  Mostly  herbs  (rarely 
shrubby  or  arborescent) ;  leaves  opposite  or  alternate,  simple  or  com- 
pound ;  stamens  more  or  less  united  Delow  ;  species,  750,  mostly  of 
temperate  and  sub-tropical  climates. 

Many  are  cultivated  as  ornaments. 

Impatiens  BaUamina,  the  Garden  Balsam,  or  Touch-Me-Not,  some- 
times erroneously  called  "  Lady'0  Slipper,"  is  a  well-known  annual 
from  India,  which  has  been  cultivated  for  more  than  two  hundred  and 
fifty  years.  The  name  Touch-Me-Not  (referring  to  its  elastically  open- 
ing fruits)  is  shared  by  two  pretty  native  species.    (Fijr.  507.) 

OxalU  contains  several  native  species  of  Wood  Sorrel,  all  of  which 


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QERAN1ALE8,  643 

are  pretty,  and  manj  exotic  species  (mostlj  South  AfricaD),  which  are 
in  common  caltivation. 

Tropceolum  majus,  the  Nasturtium,  from  South  America,  is  in  com- 
mon cultivation.  The  edible  tuberous  roots  of  7*.  tuberosum^  of  Peru, 
are  used  instead  of  potatoes  in  some  parts  of  South  America. 

Pelargonium  is  another  South  African  genus,  which  has  furnished 
us  with  many  fine  greenhouse  and  garden  flowering  plants,  most  of 
which  are  erroneously  called  Geraniums. 

The  true  Geraniums  belong;  to  the  genus  of  that  name  represented  in 
this  country  by  eight  or  nine  wild  species. 

Erodium  eicutarium,  the  Alfilaria,  of  California,  "  is  a  valuable  and 
nutritious  forajre  plant  reputed  to  impart  an  excellent  flavor  to  milk 
and  butter."     (Brewer.) 

Order  Zygophyll- 
acesB.— Shrubs  and  herbs 
(a  few  trees),  with  oppo- 
site compound  leaves ; 
stamens  distinct ;  spe- 
cies, about  100^  almost 
confined  to  the  tropics. 

Ouaiaeum  officinale, 
the  Lignum-vitse,  of  the 
West  Indies,  is  a  tree 
six  to  nine  metres  (20  to 
30  feet)  high,  whose  dark 
red,  almost  black,  heart- 
wood  is  exceedingly 
hard ;  it  furnishes  the 
best  material  for  ship's 

OIOCKS,  pulleys,  etc  ^^le  Lme  after  dehiscence  ;  a,  a,  carpels  ;  gr,  seeda. 

Larrea  Mexicana,  the    —After  Duchartre. 
Creosote  Bush  of  Arizona,  is  a  curious  diffhsely  branched  evergreen 
shrub,  with  a  very  strong  creosote-like  odor. 

Order  Malpighiaceee,— Trees  and  shrubs,  often  climbing  ;  natives 
for  the  most  part  of  the  tropics ;  species,  580,  some  of  which  are  culti- 
vated in  greenhouses. 

Order  Humiriacece. — Balsamic  trees  and  shrubs  of  tropical  America 
and  Africa. 

Order  Linaceee.— The  Flax  Family.  Herbs,  shrubs,  and  a  few  trees, 
with  alternate  or  opposite  simple  leaves  ;  stamens  more  or  less  united 
below ;  species,  135,  widely  distributed  in  temperate  and  tropical 
climates. 

The  most  important  plant  of  the  order,  and  one  of  the  most  impor- 
tant in  the  vegetable  kingdom,  is  the  Flax,  Linum  tisitatimmum,  cul- 
tivated  from  time  immemorial  for  its  fibres,  called  linen  (the  bast  fibres 


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544 


BOTANY. 


of  the  cortical  part  of  the  stem).  The  mummy  cloth  of  ancient  Egypt 
18  composed  of  flax  fibres,  and  in  the  remains  of  the  "  lake  dwellings" 
in  Switzerland,  fragments  of  linen  cloth  bave  been  found.  The  plant 
appears  to  be  indigenous  in  the  south  of  Europe,  as  well  as  in  the 
regions  eastward  in  Asia ;  it  is  now  cultivated  throughout  the  North 
and  South  Temperate  Zonea  The  seeds  are  rich  in  oil,  which  i» 
extracted  by  pressure,  producing  the  Linseed-oil  of  commerce ;   the 

F108.  50&-10.— Illustrations  of  Linum  usitatissimum. 


Fig   509. 


Fio.  506. 

Pig.  508.— Infloreecence. 
Fig.  610.— Diagram  of  flower. 


Fio.  510. 
Fig.  609.— Section  of  flower.    Magnified. 


compressed  refuse  is  cnlled  oil-cake,  and  Is  much  used  as  food  for 
cattle.     (Figs.  608-10.) 

Erythroxylon  Coca^  a  South  American  shrub,  is  cultivated  in 
Bolivia  and  New  Granada  for  its  stimulating  leaves,  which  are  chewed 
like  tobacco. 

599.— Cohort  XXXI.  Malvales.  Flowers  usually  actino- 
morphic  ;  stamens  indefinite,  generally  monadelphous ;  ovary 


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MAL  VALES. 


545 


F108.  611-618.— Illustbationb  or  Thxobro- 
MA  Cacao. 


Fio.  612. 


superior,  generally  three-  to  many-celled  ;  seeds  mostly  with 
endosperm. 

Order  TiliaceaB. — The  Linden  Familj.  Trees  and  slimbs  (a  few 
herbs),  with  mostly  alternate  simple  leaves ;  stamens  distinct,  or  some- 
what united  below.  Species 
880,  mostly  tropical. 

TUia  Europaa,  the  Lime 
or  Linden  Tree  of  Europe 
and  Siberia,  is  a  large  and 
valuable  tree,  yielding  a  soft 
white  wood  much  esteemed 
by  carvers,  musical  instru- 
ment makers,  and  others. 
The  fibre  of  its  bark  is  used 
for  makin£^  coarse  mats,  and 
its  flowers  produce  a  pfreat 
quantity  of  most  excellent 
honey. 

T,  Americana,  the  Amer- 
ican Linden,  Linn,  or  Bass- 
wood  of  the  Eastern  United 
States,  resembles  the  preced- 
ing,  and  is  equally  valuable. 

While  the  wood  of  our  rep- 
resentatives of  the  order  is 
soft,  that  of  some  tropical 
species  is  very  hard  —  e.g., 
Sloanea  dentata,  a  West  In- 
dian tree,  which  has  received 
the  significant  name  of 
Break-Ax  Tree. 

CoTchoTuscapmiarUt  a  tall- 
growing  annual  of  India, 
yields  the  Jute  fibre  now  ex- 
tensively used  in  making 
gunny  bags,  coarse  carpets, 
and  even  fabrics  of  consider- 
able fineness. 

Order  Stercaliacees.  — 
Trees  and  shrubs  (a  few 
herbs)  with  alternate  simple 

or  compound  lenves ;  stamens  more  or  less  united  into  a  tube. 
520  species  contained  in  this  order  are  al  most  entirely  tropical. 

Huobroma  Cacao,  the  Chocolate  Tree  of  tropical  America,  attains  a 
height  of  five  to  six  metres  (16  to  20  ft.),  and  bears  elongated  ribbed 


Fig.  618. 


Fio.  611. 

Fig.  611.— Fmit  (U  nataral  else). 

Fie.  512.— Seed.    Majoiifled. 

Fig.  613.— Seed  cat  vertically.    Magnified. 


The 


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546 


BOTANY. 


fleshj  fmitfi,  each  oontainiDg^  fifty  or  more  oily  seeds  (Figs.  511-13). 
The  seeds  are  roasted  and  then  groand,  and  made  into  a  paste  and  dried, 
constituting  the  Chocolate  or  Cocoa  of  commerce,  according  as  yanil]a, 
sugar,  and  other  substances  are,  or  are  not  added.  Chocolate  and  Co- 
coa contain  Hieobromine  (Ct  Ha  N4  Os),  an  alkaloid  similar  to  Caffeine. 

Order  Malvaceee. — ^The  Mallow  Family.    Herbs,  shrubs,  and  trees, 
with' alternate  simple  leaves;  stamens  indefinite,  united  into  a  tube; 

Fios.  U4-19.~lLLUinLiLTioxB  or  Halyac&s  {Malta  eylvestrit). 


Fig.  515. 


Fig.  61& 


Pio.  617.  Fig.  618. 

Fig.  614.— Section  of  flower.    Ma^ifled, 
Fig.  616.— Stamen.    Magnified. 
Fig.  618.— Flower  diagram. 


Fig.  619. 


Fig.  616.~AndrQecinm.    Magnified. 
Fig.  517.— Calyx  and  pistil.    Magnified. 
Fig.  519.-Fruit. 


anthers  one-celled.     Species  about  700,  widely  distributed,  but  most 
abundant  in  tropical  regions.    (Figs.  514-19.) 

Oossypium  herbaceum,  the  common  Cotton  Plant  of  tropical  and  sub- 
tropical countries,  was  probably  derived  originally  from  some  part  of 
India.  .  Its  culture  by  the  East  Indians  and  Egyptians  was  known 
many  centuries  before  the  Christian  era.  In  England  the  manufacture 
and  use  of  cotton  cloth  began  during  the  latter  part  of  the  uxteenth 


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OUTTIFERALES.  547 

century.  The  culture  of  cotton  in  North  America  dates  from  almost 
the  first  settlements  in  the  Southern  States,  and  the  cotton  crop  is  now 
more  valuable  than  the  product  of  any  other  single  cultivated  plant  in 
the  United  States.  It  is  extensively  cultivated  in  the  West  Indies, 
Brazil,  Egypt,  and  India. 

The  fibre  of  cotton  consists  of  greatly  elongated  hairs  (trichomes), 
which  develop  in  great  numbers  upon  the  outer  surface  of  the*  seed- 
coats  ;  these  are  at  first  cylindrical,  but  upon  drying,  as  the  seed-pod 
approaches  maturity,  they  collapse  and  appear  flat  and  more  or  less 
bent  and  twisted. 

Some  East  aud  West  Indian  trees  of  the  genus  Bqmbax  produce  an 
abundance  of  a  similar  fibre,  which  is  fine  and  silky,  hence  the  trees 
are  known  as  Silk  Trees.  It  is  said,  however,  that  the  fibre  cannot  be 
woven,  and  it  is  at  present  only  used  for  stuffing  cushions,  etc. 

The  bast  fibres  of  the  stems  of  some  species  are  useful.    Species  of 
Bida  in  India,  China,  and  Australia,  of  PlagiarUhtis  in  New  Zealand, 
and  of  Thespesia  and  HibUcus  in  tropical 
America,  are  thus  used  ;  from  the  last  the  ^ — =^ 

fibre  called  Cuba  Bast  is  obtained. 

Hibiscus  eseulentus,  the  Okra  or  Gumbo 
of  tropical  America,  produces  mucilaginous 
edible  pods,  which  are  much  used  in  the 
Southern  United  States. 

Species  of  Burio  in  the  Malay  Archipel- 
ago, and  of  Matisia  in  New  Granada,  fur- 
nish the  inhabitants  of  those  countries  with 
valuable  fruits.     The  wood  of  most  of  the 

species  of  the  order  is  very  soft  and  com-      Fi?.  5S0.— Flower  diagram 
pressible  ;  this  is  particularly  the  case  with   ^'  ^'^'**^  LaHanthm. 
a  West  Indian  tree,  Ochroma  Lagopu^,  whose  wood,  known  as  Cork 
Wood,  has  been  used  as  a  substitute  for  cork. 

The  Baobab  Tree  of  tropical  Africa  is  remarkable  for  the  enormous 
size  of  its  rounded  spreading  top  and  the  thickness  of  its  short  «tem. 

Among  the  more  common  ornamental  plants  of  the  order  are  Mallows 
(Malm),  Rose  Mallow  (Hibiscus),  Hollyhock  (Althcsa),  CaUir?ioe,  etc. 

600.— Cohort  XXXII.  QuttiferaXes.  Flowers  actino- 
morphic  ;  stamens  indefinite  ;  ovary  superior,  three-  to  many- 
celled. 

Order  ChlaenacesB. — A  few  shrubs  and  trees  of  Madagascar. 

Order  DipterocarpesB.— Tropical  trees  (rarely  shrubs),  about  112  in 
number,  the  most  important  of  which  is  Drydbalanops  GampJiora,  the 
Eapor  or  Camphor  Tree  of  Borneo  and  Sumatra,  which  attains  a  height 
of  forty  metres  (180  ft.),  and  yields  a  hard  red  timber  used  in  boat- 
building. Its  resin  is  called  Sumatra  Camphor,  and  is  much  used  in 
China  and  Japan. 


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548 


BOTANY. 


Order  TemstK»miace».— Trees  and  glirubs  with  alternate  (rarely 
opposite)  leaves,  and  mostly  monoclinous  axillary  or  raoemed  floweia. 
Species  260,  mostly  tropical.    (Figs.  520  and  521-5.) 

Several  ornamental  species  are  indigenous  to  the  Southern  United 
States— 6.flr.,  the  Loblolly  Bay  {Gordonia  Lananthus,  Fig  520).  a  tree 
nine  to  fifteen  metres  (30  to  50  ft.)  high  ;  O,  pubescetis,  the  Mountain 
Bay  ;  and  two  shrubby  species  of  Stuartia. 

The  most  common  exotic  species  cultivated  for  ornament  is  the 
Camellia  (Camellia  Japonica)  a  well-known  hot-house  shrub  from 
China  and  Japan. 

The  Tea  Tree  {Camellia  Chinends  or  TJiea  Chinensis)  is  an  evergreen 

tree  three  to  five  metres  high,  and 


Fl08. 


621-6.— Illubtbations  of  Camel- 
lia Chinembib. 


a  native,  probably,  of  Southern 
Hnd  Eastern  Asia.  It  has  been 
cultivated  for  ages  by  the  Chi- 
nese, and  has  lutely  been  intro. 
duced  to  a  limited  extent  into 
other  countries.  In  preparing  the 
leaves  they  are  carefully  picked, 
and  then  are  subjected  to  alternate 
drying,  pressing,  rolling  and  air- 
ing until  the  proper  chemical 
changes  have  ti^en  place,  and  a 
sufficient  part  of  the  water  is 
driven  off.  The  different  kinds 
and  qualities  of  tea  depend  upon 
the  rapidity  of  the  process,  and 
also  upon  the  age  of  the  leaves 
used,  the  more  rapid  process  and 
the  younger  leaves  producing  the 
finer  green  teas,  the  slower  pro- 
cess and  older  leaves  producing 
the  black  teas.  Somewhat  appears 
also  to  depend  upon  the  variety  of 
the  plant,  there  being,  it  is  gene- 
rally admitted,  two    varieties  or 

races,  viz. ,  var.  viridis  and  var.  Boliea. 
Tea  leaves  after  preparation  contain  the  alkaloid  Caffeine  (Ct  Hi, 

N4  Oj  +  H,  O),  which  also  occurs  in  roasted  coffee. 

Order  GuttiferesB. — Trees  and  shrubs  with  yellowish  or  greenish 
resinous  juice,  opposite  leaves,  and  mostly  diclinous  flowers.  Species 
230,  all  tropical. 

Oardnia  MoreUa,  a  small  tree  of  Slam,  produces  Gamboge,  a  valuable 
color  used  in  painting.  Incisions  are  made  into  the  bark,  and  the  juice 
which  exudes  is  gathered  and  dried,  constituting  the  crude  Gamboge. 

The  Mangosteea  a  fruit  about  as  large  as  an  apple,  and  considered 


nifl( 


Fig.  628. 

Fig.581.-Ripefhilt 

Fig.  622.-Seed.    Mag 

Fig.  &28.-^ection  of  seed.    Magnified. 
Fig.  624.— Embryo.    Magnified; 
Fig.  686.— Half  embryo,  fimta  fkce.  Mag- 
ifled. 


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CABT0PHTLLALE8.  549 

to  be  one  of  the  most  delicious  of  all  fruits,  is  produced  by  Qa/rcinia 
Mdngostana,  a  small  tree  of  the  Moluccas. 

The  fruit  of  Mammea  Americana,  a  tall  West  Indian  tree,  is  known 
as  the  Mammee  Apple.  It  is  as  large  as  a  melon,  and  its  yellow  pulp 
is  said  to  be  delicious. 

A  Central  American  species  of  CalophyUum  yields  a  pale  reddish,  very 
durable  timber  known  as  Santa  Maria  wood. 

Order  Hypericaceae. — Herbs  and  shrubs  (a  few  trees)  with  opposite 
glandular-punctate  leaves,  and  monoclioous  flowers.  Stamens  united 
into  three  or  five  bundles  (Fig.  526).    Species  210,  ^ 

mostly  found  in  temperate  climates. 

Our  species  are  all  herbs  or  low  shrubs,  be- 
longing to  the  genera  Hypericum  and  Aecyrum, 

A  species  of  Craloxylon,  in  tropical  India,  is  a 
large  tree  with  dark  brown  wood. 

Order  Elatinaceee. — Containing  a  few  marsh 
plants. 

601.— Cohort    XXXm.    Caryophyll-    ^Fig.  628.-Djagram  of 

-  -cii  ,.  1-1.  **»«    flower  of    Hyperi- 

ales.     J  lowers  actinomorpnic ;    stamens  cum  oo/ydnuw.— Afier 
generally  definite,   usually  as    many    or 
twice  as  many  as  the  petals  j  ovary  superior,  one-celled  ;  pla- 
centa usually  central  and  free ;  seeds  with  endosperm. 

Order  Tamariacinsca.— Mostly  shrubs  of  the  Old  World,  with  mi- 
nute alternate  simple  It^aves. 

Of  the  forty  species,  but  three  are  found  in  the  New  World,  and  all 
these  reach  our  extreme  Southwestern  border. 

Tamarix  Gallica,  the  Tamarisk  of  Europe  to  India,  is  a  common 
ornamental  shrub  in  this  country. 

Order  Portulacaceae. — Herbs  and  a  few  small  shrubs,  with  alter- 
nate  or  opposite  leaves  ;  sepals  generally  two.  Species  125,  widely  dis- 
tributed, but  most  abundant  in  the  New  World. 

Portulacn  oleracea,  the  common  Purslane,  is  an  East  Indian,  or  possi- 
bly South  European  weed.     It  was  formerly  used  as  a  pot  herb. 

P.  grandiflora,  the  Portulaca  of  the  gardens,  is  a  pretty  flowering 
annual. 

Qlaytonia  and  Calandrinia,  which  have  many  native  representatives, 
are  ornamental. 

Order  CaryophyllacesB. — The  Pink  Family.  Mostly  herbs  with 
opposite  leaves ;  sepals  four  or  five,  free  or  united  into  a  tube  ;  placenta 
central.  Species  800,  distributed  throughout  the  world,  but  most 
abundant  in  Arctic,  Alpine,  European,  and  Western  Asiatic  coun- 
tries. 


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6- 


560  BOTANY. 

Aside  from  the  ornamental  species  and  the  weeds,  the  order  poBsesses 
no  plants  of  much  economic  importance. 

The  roots  of  Sapona/ria  officinaUs  contain  Saponin,  and  are  detergent, 
but  not  sufficiently  so  to  be  much  used. 

Among  the  ornamental  plants  are  the  Carnations  and  Clove  Pinks 
(Dianthus  sp.),  the  Mullein  Pink  {Lychnis),  Catchfly  {SUene),  Boundng 
Bet  {Sapancma),  Oypsophila,  etc. 
Among  the  weeds  are  species  of  Cera$tium  (Fig.  527),  Spergula,  and 

the  Com  Cockle, 
Lychnis  OUhago. 
The  latter  is  often 
quite  abundant  in 
^  wheat  fields,  to  tbe 
1/  great  detriment  of 
the  flour  manufac- 
tured from  the 
wheat. 

Order  Franken- 
iacesB.— Mari- 
time herbs  and 
low  shrubs  resem- 
bling Caryophjll- 
acesB,  but  with  par- 
ietal placentas. 

602.  ~  Cohort 
XXXrV.  Poly- 
galales.  Flow- 
ers actinomorph- 
icorzygomorph- 
ic ;  stamens  defi- 
nite^ as  many 
as   or  twice    as 

Pig.  687.— Tnflorefcence  of  CeratUum  coUinum,  U  pH-  rnanxr  oo  fVio  -npf- 
mary  axie :  r,  eecondary  axes  ;  <",  tertiary  axef> ;  r",  qua-  "l»"y  »o  ^^^  V^^ 
ternary  axes ;  V\  quinary  axes.— After  Duchartre.  ^|g  •  oYarV  Usual- 

ly two-celled  ;  seeds  mostly  with  endosperm. 

Order  VochLysiacesB. — Trees  with  a  resinous  juice,  and  opposite  or 
Terticillate  leaves  ;  flowers  zygomorphic.  Species  about  100,  confined 
to  tropica]  America. 

Vochysia  OuianensiSf  of  Guiana,  furnishes  the  Copai-ye  Wood,  there 
used  for  making  boat-oars,  the  staves  for  sugar  hogsheads,  etc 

Order  PolygalacesB. — Mostly  herbs  with  alternate  leaves  ;  flowers 
zygomorphic.  Species  400,  distributed  throughout  temperate  and 
tropical  countries. 


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PARlETALEti.  561 

A  bitter  principle,  which  is  sometimes  emetic  and  pargative,  per- 
vades the  order. 

Some  Soath  African  species  of  Polygala  are  grown  as  ornamental 
plants  in  conservatories.    A  few  have  a  little  reputation  as  medicines. 

Order  TremandreaSi  containing  a  few  Australian  sbrublets. 

Order  Pittoaporaceee. — Trees  and  shrubs  with  alternate  leayes, 
and  actinomorphic  flowers;  petals  cohering  into  a  tube.  Species 
ninetj,  of  Africa,  India,  China,  and  Australia. 

Pittosporum  Tobira  is  a  common  plant  in  conservatories. 

P.  undulatum,oi  Aostralia,  attains  a  height  of  twenty  to  twentj-five 
metres  (70  to  80  ft.),  and  its  wood  resembles  Boxwood. 

Climbing  species  of  SoUya  and  other  genera  are  grown  in  green, 
houses. 

603.— Cohort  XXXV.  Parietales.  Flowers  actinomorph- 
ic or  zygomorphic ;  stamens  definite  or  indefinite ;  ovary 
usually  one-celled,  with  parietal  placentae. 

Order  BizinesB.— Trees  and  shrubs  with  alternate  simple  leaves, 
actinomorphic  flowers,  and  generallj  indefinite  stamens ;  seeds  with 
endosperm.     Species  160,  mostly  tropical. 

One  or  two  species  of  Amoreuxia  barely  reach  our  extreme  South- 
western border. 

Bixia  OreUana,  a  small  South  American  tree  now  cultivated  in  many 
tropical  countries,  produces  fruits  whose  orange-red  pulp  when  pre- 
pared and  dried  is  the  valuable  dye  known  as  Arnotto. 

The  fruits  of  some  species  are  eaten,  and  a  few  gums  are  derived 
from  others. 

Order  Canellaceae,  containing?  four  or  five  species  of  tropical  trees. 

CaneUa  alba  yields  Canella  Bark,  which  is  used  in  medicine. 

Order  ViolacesB.—The  Violet  Family.  Herbs  and  shrubs  with 
mostly  alternate  leaves,  zygomorphic  flowers,  and  definite  stamens  ; 
seeds  with  endosperm.  Species  240,  widely  distributed  in  temperate 
and  tropical  regions. 

An  emetic  and  laxative  principle  is  common  in  the  plants  of  this 
order. 

The  genus  Viola,  the  Violets,  includes  about  half  of  the  species  of 
the  order  ;  many  of  these  are  indigenoas  to  parts  of  the  United  States, 
and  nearly  all  of  these,  as  well  as  the  exotic  species,  are  ornamental. 

F.  odorata,  the  Sweet  Violet,  and  F.  tricolor,  the  Pansy,  both  natives 
of  Europe,  are  common  in  gardens  and  door-yards.     Of  the  latter  there . 
are  almost  numberless  varieties. 

Several  Brazilian  shrubby  plants  of  the  order  are  cultivated  in  green- 
houses. 

The  root  of  lonidium  Ipecacuanha,  a  Brazilian  shrub,  is  the  White 
Ipecacuanha  of  pharmacy. 


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66'^  BOTANY. 

A  Peruvian  tree,  Leonia  glycyearpa,  produces  edible  pulpy  fruits  as 
large  as  a  peach.  • 

Order  CistacesB. — Herbs  and  shrubs  with  actinomorphic  flowers^ 
Species  about  sixty,  mostly  of  temperate  climates. 

A  shrubby  Ci9tU8  from  the  South  of  Europe  is  common  in  green- 
houses. 

Some  of  our  natiTe  species  of  Frostweed  (HeliarUfiemum)  and  Hud" 
»onia  are  pretty. 

Order  Sesedaceas. — Herbs  (a  few  shrubs)  with  alternate  leaves, 
mostly  zygomorphic  flowers,  indefinite  stamens,  and  seeds  without 
endosperm.  Species  twenty  to  twenty-five,  confined  to  the  Mediter- 
ranean region  and  South  Africa,  with  the  exception  of  two  or  three  ape- 

FioB.  538-80. —Illustbationb  or  Cbxjcitkrm  (Wau^flowib). 


FiQ.  6S&  Fi6.  sao. 

Fio.  529. 

Fig.  53a— Flower  diagram.  Fig.  529.— Section  of  Flower.    Magnified. 

Fig.  530.— Androecium.    Hagnifled. 

cies  which  reach  India,  one  of  which  (Oligomeris  iubvlata)  extends  to 
California. 

Reseda  odorata  is  the  well-known  Mignonette,  probably  a  native  of 
the  Eastern  Mediterranean  region. 

The  foliage  of  JR.  luteola,  an  annual  of  Europe  called  Dyers'  Weed 
or  Weld,  furnishes  an  important  yellow  dye. 

Order  Cappaiidaceae. — Herbs,  shrubs  and  trees  with  mostly  alter, 
nate  leaves,  actinomorphic  flowers,  mostly  indefinite  (never  tetradyna- 
mous)  stamens,  and  seeds  without  endosperm.  Species  800,  mostly 
tropical  or  sub-tropical.  An  acrid  volatile  principle  prevails  in  the 
order. 

CapparU  9pino8a,B.  stiff" prickly- branched  shrub  of  the  Mediterranean 
region,  is  extensively  cultivated  in  Europe  for  its  unopened  flower 
buds,  which  preserved  in  vinegar  constitute  the  condiment  known  as 
Capers. 

Cleome  inUgrifoliay  a  native  of  the  Western  Mississippi  Valley,  and 


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PARIETALE8, 


553 


(J,  pungens,  of  Soutli  America,  are  fine  flowering  plants  caltiyated  in 
gardens. 

Order  Cruciferee. — The  Crucifer  Family.  Herbs  and  a  few  low  slirabs 
with  actinomorphic  flowers,  tetradynamous  stamens,  and  seeds  without 
endosperm  (Fige.  528-41).  This  large  order  includes  172  genera  and 
about  1200  species,  which  are  dlHtributed  throughout  the  temperate  re- 
gions  of  the  world,  but  are  most  abundant  in  Southern  Europe  and 
Asia  Minor.  The  prevailing  principle  in  the  order  is  pungent  and  stim- 
ulant. 

The  order  is  divided  by  Bentham  and  Hooker  into  ten  tribes,  distin- 
guished by  the  shape  of  the  fruit  and  the  disposition  of  the  cotyledons 
in  the  seed,  whether  incumbent  or  accumbent  (Figs.  536  to  541). 

The  order  furnishes  a  few  food  plants  of  some  importance. 

Brcudca  oleracea,  a  wild  plant  of  the  Atlantic  coast  of  Europe,  is 

Figs.  681-5.— Illustrations  of  Cruciferjb  (Shiphsrd's  Pubse). 


FiQ.583. 


9te.581. 


Fig.  688. 


Fig.  684. 


Fig  586. 

Fig.  681.— Vertical  section  of  flower.    Magnifted. 

Fig.  632.— Pistil  and  stamens.    Magnified. 

Fig.  638.— Ripe  capsule  spliting  open.    Magnified. 

Fig.  634.— Seeds  on  pluctiitfe,  the  cap^ale-valves  removed.    Magnified. 

Fig.  535.— Cross-section  of  captule.    Magnified. 

probably  the  original  form  from  which  have  been  derived  by  long  cul- 
tivation the  following  races,  which  nrenow  almost,  if  not  quite,  entitled 
to  be  regarded  as  species,  difiering  as  they  do  fully  as  much  from  one 
another  as  many  wild  species  : 

Bace  L  Cauliflower,  in  which  the  thickened  and  consolidated  flower 
peduncles  constitute  the  edible  portion  of  the  plant. 

Bace  II,  Bore  Cole  or  Kale,  in  which  the  expanded  but  tender  leaves 
of  the  tall  stem  are  the  edible  parts. 

Race  III.  Brussels  Sprouts,  resembling  the  last,  but  with  thick  edi- 
ble buds  in  the  axils  of  the  leaves. 

Race  IV.  Cabbage,  in  which  the  leaves  do  not  expand,  but  form  a  sin- 
gle  large  thick  edible  bud  or  "  head.** 


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554  BOTANY. 

Race  F.  KohUEabi,  in  wbicli  the  short  and  few-leaved  stem  beoomee 
thick,  bulbous,  and  edible. 

B,  eampestriBt  of  the  same  re^ons  as  the  preceding,  has  given  rise  to 
the  various  kinds  of  Turnips.  Colza  and  Rape  aliM>  are  probably  vari- 
eties; the  latter  are  extensively  cultivated  iu  Europe  for  their  oily 
seeds,  from  which  useful  oils  are  obtained  by  pressure. 

Baphanus  satitms,  the  Radish,  is  a  native  of  Cliina. 

Nasturtium  Armoraeia,  the  Horseradish  of  Europe,  has  long  been 
cultivated  for  its  pungent  roots,  which  are  used  as  a  condiment.  Ac- 
cording to  Dr.  Gray,  the  plant,  for  some  unknown  reason,  does  not  pro- 
duce seeds  in  this  country. 

Jf.  officinale.  Water  Cress  of  Europe,  and  now  run  wild  in  many  parts 

F1Q8. 696-41.— SxxDfl  OF  CRUCincRJi. 


^687. 


Fio.  640. 

FioML 


Fio.  689. 


Fig.  696.  -  Seed  of  Erytimum.    Magnified. 
Fig.  687.— Longitadinal  section  of  seed.    Magnified. 

Fig.  588.— Cross-section  of  seed,  showing  Incumbent  cotyledons.    Magnified. 
Fig.  689.  —Longitudinal  section  of  seed  of  Arabii.    Magnified. 
Fig.  540.— CroM^ection  of  teed  otArabU^  accnmbent  cotyledons.    Magnified. 
Fig.  541.— Cross-section  of  seed  of  B<xri>area,  Imperfectly  accnmbent  cotyledons. 
Magnified. 

of  the  United  States,  and  many  other  rapidly  growing  foreign  and  na- 
tive species,  are  used  as  salads. 

Brasaica  alba.  White  Mustard,  and  B.  nigra.  Black  Mustard,  both 
natives  of  Europe,  are  grown  for  their  seeds,  wliich  when  ground  con- 
stitute the  common  condiment  Mustard.  It  is  also  of  considerable 
value  in  medicine. 

leatie  tinctaria,  a  tall- growing  European  bieuuiul,  was  formerly  ex- 
tensively grown  for  the  blue  dye  obtained  from  it. 

The  most  important  ornamental  plants  of  the  oider  are  the  Wall- 
flower  {Cheiranthu$\  Gilly  Flower  or  Brompton  Stock  {Matthiold), 
Rocket  (Hesperis),  Candytuft  (Iberis),  Honesty  (Lunaria),  Sweet  Alys- 
sum  (Alysmm),  etc.,  etc. 

Several  of  the  species  are  troublesome  weeds—  e  g..  Shepherd's  Purse 
(OapgeUa),  which  has  come  to  this  country  from  the  Old  World ;  Pepper- 
grass  {Lepidium),  native  and  introduced  ;  False  Flax  {CameUnn)  irom 
Europe ;  Charlock  and  Mustard  (Braasica)  from  Europe. 


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PARIETALE8.  555 

The  curious  plant  called  the  Rose  of  Jericho  (AnaMatica  hieroehun- 
tied),  often  sold  as  a  curiosity,  is  a  small  annual,  native  of  Arabia, 
Egypt,  and  Syria.    The  mature  plant  after  ripening  its  seeds  contract 
into  a  rounded  mass,  and  is  uprooted  and  blown  about  by  the  windi 
When,  however,  the  dry  and  dead  plant  is  moistened,  it  expands,  clos. 

Fies.  54S-6.— Illustrations  of  Pafavxr  Rhoeas. 


Pio.  542. 


Fio.  548.  Fio.  644.  Fio.  545. 

Fig.  542.— Vertical  section  of  flower.    Magnlfled.        Fig.  544.— Flower  diagram. 
Fig.  548.— Pistil  and  sUmen.    Magnified.  Fig.  545.— Bipe  fhiit. 

inpf  again  when  dry.    On  this  account  it  is  also  called  the  Resurrection 
Plant. 

Order  FumariacefiB. — Herbs  with  watery  juice,  alternate,  usually 
divided  leaves  ;  flowers  zy^oiiiorphic  ;  stamens  definite,  four,  five  or 
six  and  dladelphous.  Species  about  100,  natives  of  warmer  portions  of 
the  North  Temperate  Zone  and  of  South  Africa.  They  possess  an  acrid 
4ind  astringent  principle. 

Bentham  and  Hooker,  in  the  '*  Genera  Plantarum,"  unite  this  order 


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556  BOTANY. 

with  the  next,  but  this  arrangement  has  not  generally  been  adopted  by 
botanists. 

DicerUra  speetabUiSt  the  Bleed! n^f  Heart,  a  showj  Chinese  species,  is 
in  common  coltivation  for  its  heart-shaped  pink-red  flowers.  Our 
native  species,  D.  Carmdemia  and  D.  CvitUlaria,  are  prettj,  and  are 
sometimes  cultivated. 

Climbing  Fumitory  {Adlumia  drrhom)  is  a  delicate  native  climber, 
also  cultivated  in  gardens. 

Order  Ptfpaverace». — ^The  Poppy  Family.  Herbs  and  a  few  low 
shrubs,  with  a  milky  or  colored  juice,  alternate  leaves,  and  actino- 
morphic  flowers ;  stamens  indefinite,  seeds  with  endosperm  (Figs.  542— 
5).  The  order  as  here  constituted  includes  about  sixty  species,  natives, 
for  the  most  part,  of  the  North  Temperate  Zone.  They  contain  a  nar- 
cotic principle. 

The  most  important  plant  of  the  order  is  the  Opium  Poppy  (Papaver 
aomniferum),  a  native  of  many  parts  of  the  Old  World,  and  now  culti- 
vated in  Southern  Europe  and  India.  Opium  is  obtained  from  it  by- 
scarifying  the  full-grown  but  still  green  capsules ;  the  juice  which  ex- 
udes soon  hardens  and  is  then  collected,  constituting  in  this  state  the 
crude  Opium  of  commerce. 

Opium  contains  from  six  to  twelve  per  cent  of  an  alkaloid  substance. 
Morphia  (Cit  Hi»  N  Ot+H,  O),  to  which  its  narcotic  properties  are 
mainly  due. 

Other  species  of  Papater,  several  of  which  are  in  common  cultiva- 
tion in  flower-gardens,  contain  Opium,  but  it  is  not  considered  to  be  aa 
valuable  as  that  from  the  Opium  Poppy. 

Sanguinaria  Canadenm,  the  Blood-root,  a  pretty  native  plant  of  the 
Eastern  United  States,  contains  in  its  red  juice  narcotic  properties  sim- 
ilar to  those  of  Opium. 

Among  the  ornamental  plants  besides  Poppies  and  Blood-root,  are 
Boeconia,  a  tall-growing  .Chinese  perennial,  Argemone,  from  Mexico, 
and  EschschoUzia^  from  California. 

Order  SarraceniacesD. — Perennial  marsh  herbs,  with  radical  tubular 
leaves,  solitary  actinomorphic  flowers ;  stamens  indefinite  ;  seeds  with 
endosperm.  Species  ten,  nine  of  which  are  natives  of  the  United 
States.    (Fljrs.  546-7.) 

Sarracenia  purpurea,  the  common  Pitcher  Plant  of  the  Northera 
and  Eastern  United  States,  inhabits  peat  bogs  and  "  cranberry  marshes." 
Its  open,  pitcher-like  leaves  contain  water,  in  which  many  decaying  in- 
sects may  always  be  found.  The  structure  of  the  interior  surface  of 
the  pitcher  is  such  as  to  make  it  exceedingly  difficult  for  insects,  when 
once  in  it,  to  escape,  being  lined  for  some  ways  down  with  myriads  of 
short  and  sharp  stiff  bristles  which  point  downwards.  Without  doubt 
tbese  plants  are  nourished  by  the  decaying?  insects  in  their  leaves,  and 
to  this  extent  they  are  to  be  regarded  as  sapropliy  tes.  In  some  Southern 
species,  as,  for  example,  8,  variolaris  and  8.  psittacina,  the  pitcher  ia 


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RANALE&  557 

Covered  by  a  hood  much  as  in  NeperUhiB  (page  488),  and  in  tliese  water 
ia  also  found  (undoubtedly  a  secretion  in  these  cases)  in  which  arc  many 
decaying  insects.  Moreover,  in  these  and  some  other  species  drops  of  a 
sweetish  honey-like  substance  are  secreted  on  the  leaves,  which  appar- 
ently serve  to  lure  insects  to  the  margin  of  the  pitcher. 

The  Califomia  Pitcher  Plant  {Darlingtania  Ca  ifornica)  of  the  north- 
em  part  of  Califomia,  has  long  tubular  leaves  which  are  arched  over  at 


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558 


BOTANY, 


Nelumbium  Vuteum,  the  Yellow  Water  Lily,  or  Water  Chinquepin, 
is  common  in  the  ponds  and  rivers  of  the  Mississippi  Valley  and  the 
Southern  States.  Its  nut-like  fruits,  which  are  imbedded  in  the  large 
top-shaped  receptacle,  are  edible.     (Figs.  548-0.) 


Fig.  548.~Leaf,  flower,  and  fraiting  receptacle  of  Nelwnbiitm  luUum.    H  nfttaral 
else.— From  Le  Maout  and  Decaisne. 

N,  speeiosum,  tbe  only  other  species  of  the  genus,  occurs  in  Southern 
and  Southeastern  Asia. 
Nymphaa  odorata  and  N,  tvberoM  are  the  well-known  WTiite  Water 
Lilies  of  the  Eastern  United  States.     N,  ccBruUa 
and  N.Lotus  are  common  on  the  Nile. 

Victoria  regia,  the  Victoria  Lily  of  the  Ama- 
zon Valley  in  South  America,  is  remarkable  for 
the  size  of  its  leaves  and  flowers  ;  tbe  former  are 
peltate,  perfectly  circular,  and  two  metres  or  more 
in  diameter,  and  the  slender  petioles  are  often 
tbree  metres  long  ;  tbe  flowers  resemble  those  of 
our  White  Water  Lilies,  and  are  twenty-five  to 
thirty  centimetres  in  diameter  ;  upon  first  opening 
they  are  pure  wbite,  but  uiM>n  opening  a  second 
time  tbey  are  of  a  pink  color. 

Order  Berberidaceas.— -Tbe  Barberry  Family. 

Herbs  and  shrubs  witb  alternate  or  radical  leaves ; 

flowers  monoclinous  or  diclinous  ;  petals  and  sta- 

Flg.  549.— Section  of  mens  few ;   carpels  one  to  three,  rarely  more, 

indcJ^?e"f.  '^^P*^*  distinct.  Species  about  100,  mostly  natives  of  cool 

climates. 

Berheris  vtUgaris,  tbe  Barberry  of  Europe  (Figs.  550-3),  is  cultivated 

as  an  ornamental  shrub,  as  well  as  for  its  edible  acid  berries.      The 

flowers  are  interesting  on  account  of  their  sensitive  stamens,  which 


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BANALSa. 


559 


moye  quickly  toward  the  pistil  wlien  touched  at  their  bases  by  an  in- 
sect searching  for  the  honey  secreted  by  glands  upon  tlie  petals  (Figs. 
551-52). 

B,  Uanndenaii,  of  the  Southern  States,  Is  much  like  the  foreign  spe- 
cies. 

FioB.  650^.— Illustrations  or  Bkbbxbxs  tuloabis. 


Fio.  560. 
Fig.  660.— Flower  diagram. 


Fio.  661. 


Fio.  658. 


Fig.  668. 


Magnified. 

_.^ _^, , „  t8  two    *     ^ 

Fig.  668.— Vertical  section  of  ovary.    Magnified. 


Fig.  661.- Pistil,  with  a  p«'ta1  and  stamen. 

Fig.  668.— Upper  side  of  a  petal,  showing  itsjtwo  glands.    Magnified. 


Several  evergreen  species  from  the  Rocky  Mountains  and  Oregon, 
and  one  from  Japan,  are  cultivated  under  the  name  of  Mahonia. 

Podophyllum  peUcUum,  the  May  Apple  of  the  Eastern  United  States, 
produces  an  edible,  plum-shaped  fruit.    Its  poisonous  rootstocks  are 

FlOS.  664-8.— iLLUSTRATIOlfS  OF  MENISPBRMUlf  Ci.NADXNSX.  • 


Fie.  664. 


Fio.  555. 


Fio.  566. 


Fig.  564.— Diagmm  of  male  flower. 
Fig.  656.— Section  of  fruit.    Magnified. 
Fig.  668.— Section  of  seed.    Magnified. 


Flff.  666.— Frnlt. 
B^.  667.-Seed. 


Fig.  667.       Fio.  666. 

Magnified. 
Magnified. 


used  somewhat  in  medicine.     A  second  species  occurs  in  the  Him- 
alayas. 

CauhphyUum  thalictroides,  of  the  Eastern  United  States  and  also  of 
Japan,  is  interesting  on  account  of  its  young  ovaries  bursting  open  and 
allowing  the  ovules  to  develop  into  naked  drupe-like  seeds. 


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560  BOTANY. 

Order  Menispermaceed.— Woodj  twining  plants,  with  alternate 
leaves  ;  flowers  diclinous ;  petals  usuallj  six,  with  a  stamen  before 
(opposite  to)  each  one ;  carpels  usoallj  three,  distinct  and  one-seeded. 
Species  eighty  to  one  hundred,  principally  tropical.  They  generally 
contain  a  bitter  principle,  which  in  some  is  tonic,  in  others  narcotic,  or 
even  poisonous. 

Menispermum  CanadeMe,  the  Moonseed  of  the  Eastern  United 
States,  is  a  beautiful  climber  deserving  cultivation  in  ornamental  gar- 
dens.    Its  onl^  congener  is  a  native  of  Eastern  Asia.     (Figs.  554-8.) 

FiM.  660-64.— Illubtbationb  or  Abimina  triloba. 


«^w^> 


Fie.  660.  Fie.  66a 


Fie.  661.  Fio.  562.  Fie.  563.  Fie.  564. 

Fig.  569.— Section  of  flower.    Magnified. 

Fig.  660.— Flower  diagram.    Magnified.         Fig.  561.— Yoong  carpel.    Magnified. 

Fig.  662.— Section  of  yonng  carpel.    Magnified. 

Fig.  563.— Seed.    Natural  size.  Fig.  664.— Section  of  leed. 

Two  other  genera,  Calycocarpum  and  Coeculus,  are  represented  in 
the  United  States. 

Many  of  the  Old  World  species  are  more  or  less  in  repute  as  furnish- 
ing  medicines,  but  none  are  of  sufficient  importance  to  be  particularly 
noticed. 

Order  Anonacess. — Trees  and  shrubs  with  alternate  leaves ;  flowers 
trimerous ;  stamens  indefinite,  on  a  thickened  receptacle  ;  carpels  gen- 
erally indefinite.  Species  400,  mostly  tropical.  The  bark  generally 
contains  an  aromatic  and  stimulating,  sometimes  acrid  principle. 


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RANALE8,  661 

Atimina  trUclba,  the  Papaw  of  the  Southern  United  States,  and  ex- 
tending to  tbe  Great  Lakee,  is  a  small  tree  producing  edible  pulpy 
fruits  six  to  ten  centimetres  long.  Several  other  smaller  species  of  the 
same  genus  are  common  in  the  South.    (Figs.  559-564.) 

Anona  reticulata,  the  Custard  Apple,  A.  CherimoUa,  the  Cherimoja, 
A,  9quamo$a,  Sweet  Sop,  and  A.  muricata,  Sour  Sop,  all  cultivated  in 
the  West  Indies  and  tropical  America,  produce  edible  fruits ;  tbe  first  is 
regarded  by  some  people  as  one  of  tbe  finest  fruits  in  the  whole  world. 

Xylopia  aromatiea  is  a  tree  of  western  tropical  Africa,  whose  dry 
carpels  are  aromatic,  and  used  as  pepper  under  tbe  name  of  Guinea 
Pepper.  The  ancients  used  this  pepper  ("  Piper  ^thiopicum  ")  long 
before  the  introduction  of  Black  Pepper. 

Fies.  666-7.— Illubtbatioms  of  Magnolia  pitrpubba. 


Fio.  666.  Fig.  665.  Fio.  667. 

_  „  _  ,6.— Flower  cut  vertically. 

Fig.  667.— Section  of  seed.    Magnified. 


Fig.  666.— Flower  cut  vertically.  Fig.  666.— Flower  diagram. 


Duguetia  quitarensis,  a  small  tree  of  Guiana,  supplies  a  tough  elastic 
wood  known  as  Lancewood. 

Order  KagnoliacesB.— Tbe  Magnolia  Family.  Trees  and  shrubs 
with  alternate  simple  leaves  ;  flowers  mostly  monocl incus  ;  petals  and 
stamens  indefinite  ;  carpels  usually  indefinite.  Species  seventy,  mostly 
of  the  tropical  and  sub-tropical  parts  of  Asia  and  America.  (Figs. 
666-7.) 

The  genus  Magnolia  contains  many  beautiful  trees,  seven  of  which 
are  natives  of  the  Southern  United  States.  Of  these  M.  acuminata,  the 
Cucumber  Tree,  extends  north  to  the  Great  Lakes,  and  sometimes  at' 


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662  BOTANY. 

tains  a  heii^bt  of  forty  to  fifty  metres.  Its  light,  whitish  wood  is  vala. 
able«  and  is  much  used  for  many  purposes. 

M.  grandifloi  a  is  much  like  the  preceding,  but  has  larger  flowers 
and  evergreen  leaves,  the  former  being  from  fifteen  to  twenty- five 
centimetres  in  diameter.  It  grows  only  in  the  Southern  States,  where 
its  timber  is  somewhat  used. 

M,  Umbrella  and  M.  macrophyVa  are  named  Umbrella  Trees  on  ac- 
count of  the  way  in  wbich  their  large  leaves  spread  from  the  ends  of 
the  branches.  The  leaves  of  the  last-named  species  are  from  fifty  to 
eighty  centimetres  (20  to  80  in.)  long,  and  the  flowers  are  from  thirty 
to  thirty -five  centimetres  (12  to  14  in.)  in  diameter. 

M,  glauca,  the  Sweet  Bay,  is  a  shrubby  species  extending  from  Louis- 
iana to  Massachusetts,  in  the  north  near  the  coast  only. 

The  foregoing  and  most,  if  not  all,  the  remaining  species  are  quite 
ornamental,  and  are  planted  wh<)rever  they  will  endure  the  winters. 

Lifiodendron  Tuliptfera,  the  Tulip  Tree  or  Yellow  Poplar  of  the 
Eastern  United  States,  is  one  of  our  largest  and  most  valuable  timber 
trees.  Its  light,  whitish  or  yellowish  wood  is  much  used  in  cabinet- 
making,  coach-building,  and  for  many  other  purposes. 

Magnola  corupicua  is  the  Yulan  Tree  of  China.  Other  species  of 
this  genus  occur  in  Japan,  China,  and  the  Himalaya  region. 

Order  Calycanthacees. — Shrubs  with  opposite  leaves ;  seeds  with- 
out endosperm.  Throe  species  occur  in  the  Southern  United  States, 
one  in  California,  and  one  in  Jnpan.  This  order,  the  structure  of 
which  cannot  be  discussed  here,  is  evidently  out  of  place  in  this  Co- 
hort. 

Order  Dilleniacesd. — Shrubs,  rarely  trees,  with  alternate  leaves; 
sepals  five,  petals  five ;  stamens  indefinite ;  ovaries  usually  distinct,  one- 
celled.    Species  180,  mostly  tropical. 

Two  Califomian  species  of  the  genus  Cro$sosomu,  doubtfully  referred 
to  this  order,  are  our  only  representatives. 

Some  of  the  Indian  species  of  Di.lenia  and  Wormia  yield  hard  and 
valuable  timber. 

Order  BanunculacesB. — Herbs,  rarely  shrubs,  with  mostly  alternate 
or  radical  leaves ;  sepals  usually  five  or  fewer,  deciduous,  often  petal- 
old ;  petals  in  one  whorl,  often  wanting  ;  carpels  usually  distinct. 
(Figs.  568-73.)  Species  about  500,  most  abundant  in  temperate  and  cold 
regions.    The  herbage  usually  possesses  a  considerable  acridity. 

Formerly  many  of  the  species  were  reputed  to  be  of  medicinal  value, 
but  at  the  present  day  they  are  but  little  used  except  by  quacks.  Sev- 
eral species,  however,  still  retain  their  places  in  the  pharmaoopceias ; 
among  these  are : 

AeonUum  NapeUui,  Monkshood  or  Aconite,  a  native  of  Europe, 
whose  roots  furnish  the  drug  Aconite. 


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HANALES.  665 

A.  ferax,  of  apper  India,  eapplies  the  people  of  that  region  with  a 
drulent  poison,  with  which  they  poison  their  arrows. 
EeUeborua  niger,  Black  Hellebore,  J91  foBtidu8,  Stinking  Hellebore, 

Fios.  seS-TS.—lLLUBTBATiONfl  OP  TUwHOUhAOKM  {CoUha  poltuiHt), 


( 


Fio.  670. 


Fio.  Ma  Fie.  571.  Fie.  678. 


Fio.  569.  Fio.  678. 

Fig.  6(58.— Flowering  stem.  Fig.  660.— Vertical  section  of  flower. 

Fig.  670.— Flower  diagram.  "'  ~  -     —       --   - 

Fig.  673.-8eed.    Hagnifled. 


Fig.  571  .—Young  carpel .    Magnified. 
Fig.  678.— Section  of  seed.    Magnified. 


and  J7.  viridis,  Green  Hellebore,  all  natives  of  Europe,  furnish  drastio 
and  poisonous  drugs. 

Among  the  ornamental  plants  of  the  order  may  be  mentioned  the 
following : 

Anemone,  of  several  species,  including  oar  native  Hepaticas,  now 
placed  in  this  genus. 


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564  BOTANY. 

Adonis,  the  Pheasant's  Eye,  of  Europe. 

Aquilegia,  the  Columbine,  including  our  common  Eastern  species  (A 
Canaderuis)  and  the  Rockj  Mountain  Long  Spurred  Columbine  (A. 
e4»rulea),  as  well  as  the  common  one  of  Europe  (A,  vulg<m»). 

Clematis,  the  Virgin's  Bower,  of  many  species,  native  and  foreign,  all 
pretty. 

Delphinium,  the  Larkspur,  of  many  species,  mostly  foreign. 

NigeUa,  Love  in  a  Mist,  from  the  Old  World. 

Pceonia,  the  Peony,  of  several  species,  from  Europe,  Siberia,  and 
China. 

Banunetdus,  Buttercup,  of  several  European  species. 

TroUitis,  Globe  Flower,  from  Europe  and  Siberia. 

Very  few  species  afford  nutritious  products  useful  for  food ;  the 
tuberous  roots  of  a  species  of  Ranunculus  are  gathered  and  eaten  in 
some  parts  of  Central  Europe,  and  a  few  fleshy  species  (ax,  for  example, 
CaUha  palusirvt,  Ranunculus  sceleratus,  etc.)  are  used  to  a  limited  ex- 
tent as  pot  herbs. 

Fossil  Dicotyledons. — No  Dicotyledons  are  known  in  the  periods 
earlier  than  the  Cretaceous.  In  this,  however,  many  modern  orders 
are  represented.  In  the  Cretaceous  of  the  Western  Territories  of  the 
United  States  Lesquereux  describes*  one  hundred  species  of  Dicotyle- 
dons. Of  these  sixty  belong  to  the  Apetalse,  five  to  the  Gamopetalse, 
and  thirty.five  to  the  ChoripeialsB  (Polypetalae).  The  Apetalie  incJuae 
five  species  of  Populus,  six  of  Salix,  ei^ht  of  Quercus,  six  of  Platanu*, 
^ven  ot  Sasstyfras,  etc.  Among  the  remarkable  fossils  are  a  species  of 
]^us  from  Minnesota,  two  species  of  Cinnamomum  from  Kansas,  and 
♦wo  of  Laurus  from  Nebraska.  The  five  spfcies  of  Oamopetalte  repre- 
sent the  Ericacese  ^a  sinsle  species  of  Andromeda),  Ebenace®  (two  spe- 
cies of  Diospyros  from  Kansas  and  Nebraska),  and  Sapotaces  (two  spe- 
cies, one  a  Bumelia  from  Nebraska  and  Minnesota).  Among  the  spe- 
cies of  ChoripetalsB  are  five  of  Magnolia,  two  of  Liriodendron,  one  of 
ffedcra,  one  of  Prunus,  one  of  Pirns,  etc,  from  Kansas,  Nebraska,  and 
Dakota. 

In  the  Tertiary  moi^t  of  the  more  important  orders  of  Dicotyledons 
are  represented.  Here,  as  in  the  Cretaceous,  there  is  still  a  predomi- 
nance of  Apetalous  species ;  thus  in  the  Tertiary  Flora  of  the  Western 
Territories!  there  have  been  determined  of  the  Apetalse  one  hundred 
and  twelve  species,  Gamopetalae,  nineteen,  and  Choripetalie,  seventh- 
nine.  The  Apetalae  are  principally  represented  by  the  Myricace» 
(twelve  species  of  Myrica),  Betulacese,  Cupuliferse  (a  Carpinus,  a  Cory' 
lus,  a  Fagus,  a  Castanea,  and  eighteen  species  of  Quercus),  Juglandace» 

♦"Contributions  to  the  Fossil  Flora  of  the  Western  Territories. 
Part  L,  The  Cretaceous  Flora,"  by  Leo  Lesquereux.  Washington, 
1874. 

t  Leo  Lesquereux,  op.  cit.    Part  H, "  The  Tertiary  Flora,"  187a 


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FOSSIL  DICOTYLEDONS.  665 

(a  Gary  a,  a  Pterocarya,  and  Beven  species  of  Juglans),  Salicaceie  (four 
species  of  Salix  and  twelve  of  Populus),  Platanaceffi  (five  species  of 
PUUaniu),  MoraceflB  (twentj-three  species  of  Fieiui)^  Laurace»  (six  spe- 
cies of  Laurus,  one  of  Tetranthera,  and  four  of  Cinnamomum). 

The  GamopetalflB  are  represented  hy  Caprifoliace®  (nine  species  of 
Vibumum\  Oleaceaa  (four  species  of  Framinus),  Ebenaceie  (four  species 
of  Diospyro8\  and  EricacesB  (an  Andromeda  and  a  Vaecinium), 

The  principal  orders  of  the  ChoripetalsB  are  AmpelidesB  (one  species 
of  AmpelopnSt  two  of  VUis,  and  four  of  Cissus),  Anacardiacese  (five 
species  of  Rhus),  Cornaces  (four  species  of  Comiui),  Rhamnacess  (ten 
species  of  Ehamnui,  five  of  Zizyphtu,  three  oi  Paliurui,  and  one  of 
Berdiemia),  Ilicinese  (four  species  of  Hex),  Sapindacese  (six  species  of 
Sapindui),  MyrtaceeB  (two  doubtful  species  of  Eucalyptus),  Rosaces 
(a  sin^rle  species  of  Oratagus),  Leguminosse  (a  Podoganium,  a  Cassia,  an 
Aeaeia,  a  MimosUes,  and  two  LeguminosUes),  and  Mag^oliace®  (four 
species  of  Magnolia). 


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CHAPTER    XXI. 

CONCLUDING  OBSERVATIONS. 

e06,— The  Number  of  Species  of  Plants. — It  is  impossible 
at  the  present  time  to  give  with  even  approximate  accuracy 
the  number  of  existing  species  of  plants.  In  the  first  place, 
a  great  many  species  in  all  parts  of  the  world  are  as  yet  un- 
described ;  even  in  England,  where  the  study  of  this  branch 
of  Botany  has  been  most  energetically  pursued,  many  new 
species  are  discovered  every  year.  In  the  central  and  western 
countries  of  the  continent  of  Europe,  as  in  England,  while 
comparatively  few  flowering  plants  have  escaped  detection, 
there  yet  remain  undescribed  hundreds  of  species  of  the 
lower  groups,  and  in  the  regions  eastward  there  are  doubtless 
many  phanerogams  as  well  as  cryptogams  which  have  not  yet 
been  enumerated.  A  complete  "Flora  of  Europe"  will 
probably  be  an  impossibility  for  very  many  years.  In  Asia 
our  knowledge  of  the  plants  is  still  more  fragmentary. 
Japan  and  India,  with  parts  of  Asia  Minor,  are  the  bc^ 
known  botanically,  but  even  in  these  regions  our  knowledge, 
is  almost  entirely  confined  to  the  phanerogams  and  higher 
cryptogams.  In  Australia  and  the  islands  to  the  northward 
and  in  Africa,  there  are  enormous  tracts  which  have  not  yet 
been  explored.  In  the  New  World,  from  Mexico  southward, 
the  descriptions  and  enumerations  of  the  native  plants  are 
scattered  through  many  works,  not  cne  of  which  approxi- 
mates completeness  even  for  comparatively  small  regions.  In 
North  America,  the  'f  Flora  of  North  America,"  begun  forty 
years  ago,  is  yet  unfinished,  even  for  the  flowering  plants.* 

♦  •*  A  Flora  of  North  America,"  by  John  Torrey  and  Asa  Gray.  VoL 
I..  188&-40.  Vol.  IL  (in  part),  184a  Resumed  under  the  Utle  of  -A 
Synoptical  Flora  of  North  America/'  by  Asa  Gray,  1878. 


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AFFINITIES  OF  THE  ORG  UPS.  667 

In  the  second  place>  many  of  the  so-called  species  in  de- 
scriptiye  works  are  but  varieties,  while  in  other  cases  the 
same  forms  have  been  described  under  different  names.  This 
is  true  in  all  the  groups  of  plants,  and  scarcely  a  monograph 
now  appears  in  which  there  are  not  cases  of  the  reduction  of 
a  supposed  species  to  a  synonym  or  variety. 

eoe. — With  these  considerations  in  mind,  we  may  examine 
the  catalogues  and  make  some  general  estimates.  Steudei  in 
1824  catalogued  in  "  Nomenclator  Botanicus"  59,684  phan- 
erogams and  10,965  cryptogams,  making  a  total  of  70,649. 
In  the  second  edition,  published  in  1841,  the  number  of 
phanerogams  was  increased  to  about  78,000.  Lindley,  in 
1845,  estimated  the  number  of  dicotyledons  to  bo  66,488,  the 
monocotyledons  13,952,  and  the  cryptogams  12,480,  making 
a  total  of  92,820.  De  Candolle's  **  Prodromus,"  begun  in 
1824  and  continued  to  1873,  contains,  according  to  Alph.  De 
Candolle's  historical  note  in  Vol.  XVII.  of  that  work,  de- 
scriptions of  58,446  dicotyledons  and  429  gymnosperms. 

Duchartre  estimates  the  known  species  of  phanerogams  at 
about  100,000,  and  of  cryptogams  at  about  25,000,  and  ven- 
tures to  place  the  whole  number  of  species  in  the  world  at 
from  150,000  to  200,000.  Dr.  Gray  quotes  De  Candolle's 
estimate  of  the  known  species  of  flowering  plants,  amounting 
to  from  100,000  to  120,000,  and  says  that  **  the  larger  num- 
ber may  perhaps  include  the  higher  orders  of  the  flowerless 
series,"  and  in  speaking  of  the  lower  cryptogams  says  that  at 
present  "no  close  estimate  can  be  well  formed  of  the  actual 
number  of  species."* 

607.— The  Alftnities  of  the  Groups  of  Plants.— Many  at- 
tempts have  been  made  to  construct  diagrammatic  figures 
which  should  indicate  the  aflSnities  of  the  different  groups 
of  the  vegetable  kingdom.  While  it  is  impossible  to  do  this 
with  any  great  degree  of  accuracy,  we  may  yet  show  in  this 
way  cei*tain  relations,  more  clearly  than  can  be  done  other- 
wise. The  subjoined  diagram  may  be  taken  to  indicate  in  a 
general  way  the  writer's  present  notion  of  the  affinities  {i.e., 

♦  In  his  "  Botanical  Text  Book."  1879,  Part  I.,  p.  846.  footnote. 


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568 


BOTANY. 


the  genetic  relations)  of  the  seven  great  divisions  of  plants, 
60  far  as  they  can  be  shown  upon  a  plane  surface : 
Oamopetdla. 

ChoripetalcB, 


ApetakB, 
Monoootjledonefl.  I 


IMcotyiedones. 


Gymkospsrm^ 


Angiosfebila. 


.PHAXERa 
UAMIA. 


PTERIDOPHYTA. 


BRYOPHYTA. 


CARPOPHYTA. 

OOPHYTA. 


ZYGOPHYTA. 


PROTOPHYTA. 

608.— The  Distribution  of  Plants  in  Time.  If  we  bring 
together  what  is  yet  known  as  to  Fossil  Botany  (PhytopalsB- 
ontology),  as  has  been  done  by  Schimper^*  we  find  that  the 

♦  "  Traits  de  Pal6ontologie  Vegltale,"  par  W.  Ph.  Schimper.  Paris, 
1869  to  1874.    TbiB  work  of  three  large  ocUvo  volames  (aggregathig 


( pp.)  and  a  quarto  atlas  of  110  plates  is  a  most  valaable  one  for 
the  student  of  Pbytopalseontology. 


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DISTRIBUTION  IN  TIME, 


569 


Tabulab  View  of  thb  Distribution  in  Time  of  the  Diyisionb 

OF  THE  VeOBTABLB  KiNODOH, 


£ 


Recent. 


t 


Plioceoe. 
MioceDe. 
Eocene. 


I 


Creta- 
ceouB. 


Jurassia 
Triassic. 


Permian. 


Carbon- 
iferous. 


Devonian. 


Silurian. 


i 

.a 


i 

I 


O 


.a 
a 


6 


>» 

.a 
a 
o 
5>» 


O 
PL) 


S 


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570  BOTANY, 

several  Divisions  of  the  Vegetable  Kingdom  are  very  un- 
equally distributed  in  geologic  time.  Thus  no  fossil 
Protophjrta  have  yet  been  discovered  eariier  than  the  Ter- 
tiary (Miocene),  while  the  Zygophyta,  Oophyta,  and  Carpo- 
phyta,  with  scarcely  any  doubt,  were  well  represented  in 
the  Silurian.  Bryophyta  have  not  been  detected  in  strata 
earlier  than  the  Eocene  (Tertiary),  while  Pteridophyta 
extend  back  to  the  Devonian.  Of  the  Phanerogamia  the 
Gymnosperms  originated  in  the  Devonian,  the  Monocotyle- 
dons in  the  Triassic,  and  the  Dicotyledons  in  the  Cretaceous. 
These  facts  may  be  more  clearly  shown  by  the  table  on  the 
preceding  page. 

It  must  be  borne  in  mind  that  our  knowledge  of  fossil 
plants  is  as  yet  extremely  limited,  a  comparatively  small 
portion  only  of  the  earth's  strata  having  hitherto  been  care- 
fully examined.  It  is  very  probable  that  as  we  come  to 
know  more  of  the  fossil  remains  of  plants  some  or  all  of  the 
lines  in  the  table  will  be  extended  downward.  On  the  other 
hand,  we  need  not  expect  to  find  many  remains  of  the  ex- 
ceedingly simple  organisms  which  constitute  the  Protophy- 
ta,  although  they  probably  have  exist<^d  in  abundance 
since  pre-Silurian  times.  So,  too,  few  Zygophytes  have  a 
sufficiently  durable  plant-body  to  allow  them  to  be  preserved 
in  a  fossil  state.  The  softness  of  texture  and  easy  perisha- 
bility of  the  tissues  of  the  Bryophyta,  especially  in  the  lower 
orders,  probably  accounts  for  the  few  fossil  remains  hitherto 
discovered.  Doubtless  we  must  in  the  same  way  account  for 
the  fact  that  most  of  the  species  of  fossil  Phanerogams  are 
trees  and  shrubs  ;  the  softer  tissues  of  the  herbaceous  spe- 
cies have  yielded  but  few  fossils  as  compared  with  the  harder 
and  denser  ones  of  the  ligneous  species. 


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INDEX  TO  THE  ILLUSTRATIONS. 


Abies  pkctinata,  394,  897, 401 

Acer  dasycarpum,  74 

Acer  Pseudo-PIatanus,  536 

Acblya,  40,  255 

Achlja  racemosa,  256 

Acorus  calamus,  114,  115, 110 

Adiantom,  374 

Adiantum    Capil)  as- Veneris,    370, 

871,  372 
AdiaDtnm  Moritzianum,  109 
.^culus,  537 

^sculus  Hippocastanum,  141 
Ap^aricus  canipestris,  826,  327 
Ailanthus  glandulosus,  125,  448 
Alisma  Plantaffo,  467 
Alliom  cepa.  -^3 
Alsophila,  377 

Ampelopsis  quinquefolia,  154 
Auagallis  arvensis,  507 
Ananassa  saliva,  471 
Anthoceros  lie  vis,  348,  350 
Arabis,  554 

Arcyria  incamata,  210 
Aristolocliia  sipho,  84 
Asclepias,  504 
Ascobolus  f arfuraceua,  288 
Asimina  triloba,  5G0 
Aspidium  Filix-mas.  41,  374,  375, 

376 
Aspleniom,  374 

Bacillus  ulna,  213 
Bacterium  lineola,  213 
Bacterium  Termo,  213 
Banana,  472 
Barbarea,  554 
Beet,  60, 495 
Begonia,  80 
Berberis  vulgaris,  559 
Beta  vulgaris,  495 
Betula  alba,  126, 127 
Biota  orientalis,  896 


Bittersweet,  501 
Botrychium  Lunaria,  378,  879 
Bryum  argenteum,  359 
Buckwheat.  162 
BulbocliaDte  intermedia,  248 

CALLimiS  QUADRIVALVIS,  399 

Caltba  palustris,  563 

Camellia  Chinensis,  548 

Canna,  473 

Capsella  Bursa-pastoris,  424.  558 

Carya  alba,  73 

Cassia  tore,  533 

Castanea  vesca,  153 

Cephalotus  folUcularis.  527 

Cerastium  collinum,  550 

Ceratozamia  longifolia,  896 

CJbara  fragilis,  832,  833 

Chenopodium,  496 

Cherry,  143 

Chesiut,  153 

Chondrioderme    difforme,   36,    44, 

209,  21C 
Cichorium  intybus,  23 
Citrus  Aurantium.  541 
Claviceps  purpurea,  290  291. 
Clematis  Viticella.  439 
Cnicua  altissimus,  98 
Cocoa.nut,  463 
C'oflTea  Arabica,  517 
Colchicum  autumnale,  459 
Coleochsete  pulvinata,  272 
Collema  Jacobefolium,  800 
Collema  microphyllum,  800 
Collema  pulposum,  309 
Corallina  oflScinalis.  274 
Cosmarium  Menenghinii,  44,  226 
Cucumis  Mblo,  521 
Cucurbita,  95 
Cucurbita  Pepo,  29,  77 
Cupressus  sempervirens,  396 
Cycaa  revoluta,  400 


Digitized  by 


Google 


572 


INDEX  TO  THE  ILLUSTRATIONS. 


Cypripedium  calceolus,  470 
Cystopus  candiduB,  259»  262 
Cytisus  Laburnum,  84,  447 

Dahlta  variabilis,  27,  33 

Date.  452,  463 

Diagrams,  33,  38. 138, 139, 403, 406. 

417,  420,  445,  450,  468 
BIctamnuB  fraxinella,  131,  542 
Didymium  Berpula,  78 
DioDsea  muscipula,  525 
Dorstenia,  489 
Dracsena,  444 
Dudresnaya  purpurifera,  276 

ECHINOCTSTIS    LOB  ATA,  30,  70,  71, 

73.  100, 155,  150 
Equisetum  arvense,  365 
Equisetum  limosum,  365 
Equisetum  palastre.  110 
Equisetum  Bcirpoiden,  88 
Equisetum  Telmateia,  364,  366 
Erica  cinerea.  509 
Erysimum,  554 
Erysiphe  Cicboriacearum,  281 
Erysiplie  Tuckeri,  279 
Eschsclioltzia  Californica,  419 
Eucalyptus  globulus,  524 
Eupatorium.  515 
Euphorbia,  75 
Eurotium  repens,  282 

FaGOPTRUM  E9CULENTUM,  162, 496 
Fern  prothallium,  370 
Ficus,  489 

Fcenlculum  vulgare,  519 
Fontinalis  antipyretica,  87,  142, 359 
Fra^aria  vesca,  529 
Fritillaria  imperialis,  3,  458 
Fuchsia  globosa,  104.  105 
Fucus  platycarpuB,  266 
FucuB  vesiculosus,  267 
Fuligo  yarians,  4,  209 
Funaria  hyjrrometrica,  48,  52,  363 
354,  356,  358 

Ginkgo  biloba,  399 
Gleichenia,  377 
Oloeocapsa,  216 
Gomphidium,  329 
Gordonia  Lasianthus,  547 
Grape,  79,  80 
Graphis  elegans,  309 

Hedera  helix,  130 


Hemlock  Spruce,  153 
Hickory-nut,  73 
Hop,  97 

Horsechestnut,  141 
Hoya  camosa,  34 
Hyacinth  us  orien  talis,  101 
Hydrodictyon  utriculosum,  223 
Hypericum  calycinum,  549 

Iberia  amara,  442.  443 
Impatiens  Bakamina,  28,  82.  543 
Indian  Corn,  2,  6,  55,  67,  113,  154^ 

160.  451.  452 
IridaceaB  (flower  diagram),  468 
Isoetes  lacustris,  387,  388 
Ivy,  130 

Juglans  regia,  481 
Juncus  effusus.  20 
Juniperus  communis,  402,  407 

Laroium,  498 
Lathyrus  odoratus,  531 
Lathyrus  Pseudaphaca,  440,  441 
Laurus  nobilis,  492 
Lavatera  trimestris,  23 
Lecanora  subfusca,  297 
LejoliBia  mediterranea,  274.  275 
Lemna  minor,  462 
Linum  usitatissimum,  5-14 
Lycopodium  annotinum,  383 
Lycopodium  clavatum,  883 
Lycopodium  complanatum,  112 

Magnolia  purpurea.  561 
Maflotium  Hildenbrandii,  303 
Malva  Bylvestris,  546 
Marchantia    polymorpha.    91,    92. 

344,  345.  346,  347,  349,  350 
Marsilia  salvatrix.  381 
Me^alospora  affinis,  299 
Menispermum  Canadense,  559 
Micrococcus  prodigiosus,  213 
Mimosa  pudica.  584 
Mucor,  33S 
Mucor  Mucedo,  236 
Mucor  stolonifer.  237,  238 
Musa  sapientum,  472 
Mustard,  95 
Myristica  f ragrans,  493 
Myrtus  communis,  524 

Navicula  saxonica.  229 
Navicula  viridis,  228 
Nelumbium  luteum,  558 


Digitized  by 


Google 


INBEX  TO  THE  ILLUSTBATIONS. 


573 


Nemalion  multifidum,  275 
Nepenthes  ampul laria,  488 
Nitella  fiexilis.  881 
Nostoc.  37.  217 
Nuphar  advena,  20 

Oat.  454 

Ocbrolechia  pallescens.  299 

(Edogonlum,  22,  247 

(E^logonium  ciliatum,  248 

(Edoj^nium  gemelliparam,  248 

Onion,  76 

Orchis  mascula,  469 

Oscillatoria,  87,  217 

Osmunda,  877 

Palm  (stem),  443 

Pandorina  Morum,  222 

Papaver  Rhoeas,  555 

Parmelia  aipolia,  296 

Pannelia  tiliacea,  802 

Peach  (flower),  580 

Pediastrum  granulatum,  Oo,  224 

Penicillium  chartarum,  28o 

Peronospora,  261 

Peronospora  Alsinearam,  48,  261 

Peronospora  calotheca,  258 

Peronospora  infestans,  258 

Pertusaria  ceuthocarpa,  299 

Pertusaria  Wulfeni,  809 

Peziza  confluens,  286 

Peziza  convexula,  42,  287 

Peziza  omphalodes,  287 

Phaseolus  multiflorus,  43,  475 

Phoenix  dactjlifera,  452 

Phragmidium  bulbosum,  315 

Phragmidiam  mucronatum,  815 

Physarum  leacopus,  208 

Pilularia  ^lobulifera,  880 

Pinas  Larico,  401 

Pinus  pinaster.  72.  124 

Pinas  Pinea,  405 

Pinus  sylvestris,  25,  26.  894,  895, 

398 
Piptocephalis  Freseniana,  239 
Pirus  communis,  528 
PirusCydonia,528 
Pisum  sativum,  54 
Plagiochilia  asplenioides,  849 
Polypodium,  873 
Polypodiura  vulgare,  108 
Potamo^eton  pectinatus,  129 
Potato  (flower),  501 
Primula  sinensis,  97 
Prunus  Cerasus,  530 


Psoralea  bituminosa,  !22,  476 
Pteris  aquilina,  24,  27,  72,  81,  83, 

107.  871.  872.  378 
Puccinia  ^raminis.  811,  818 
Puccinia  Molinise,  814 

Quince,  528 

Quercus  Robur,  449,  478 

Ranunculus  rbpens.  119 

Rhizomorplia  subcortical  is,  66 

Rhubarb.  60 

Riccia  ^lauca.  845.  346 

Rice.  455 

Ricinus  communis,  117,  118,  474 

Rosa  canina.  427 

Rosa  rubiginosa,  429 

Rye,  96 

SaCCHAROMYCKS   CERBVISIiE,    39, 

214 
Salix  caprsa,  486 
Salvinia  natans.  380.  881 
Sambucus  ni^ra,  445,  446 
Saprole^nia,  255 
Saprole^nia  androsryna,  257 
Sarracenia  purpurea,  557 
Schizsea,  377 
Scorzonera  hispanica,  75 
Scrophularia,  499 
Sedum  purpurascens,  101 
Selaginella  caulescens,  884 
Selaginella.in8equi folia.  111,  386 
Selaginella  Martensii,  884,  885 
Sequoia  gi^antea,  80 
Shepherd's  Purse,  553 
Silphium  laciniatum,  157 
Solanum,  501 

Sorisporium  Saponariae,  320 
Sphffiria  morbosa.  293 
Spbaerophorus  globiferus,  298,  302 
Sphseroplea  annulina.  245 
Sphaerotbeca  Castagnei.  280 
Sphserotheca  pannosa.  280 
Spba^num  acutifolium.  855 
Splingnum  squarrosum.  855 
Spirillum  volutans.  213 
SpirocbaDte  plicatilis,  213 
Spirogyra  longata,  45,  46, 51,  288 
Stachys  an^nistifolius,  441 
Sticta  fuliginosa,  295 
Sticta  pulmonncea,  308 
Stipa  spartea,  158 
Sunflower,  68 


Digitized  by 


Google 


Digitized  by 


Google 


GENERAL   INDEX. 


Abele  Tree,  497 

Abies,  81,  151,  394,  897,  409,  411, 

412,  415 
Abietineffi.  410 

Abortion  of  Floral  Organs,  431 
Abridgment  of  Life  Cycle,  814 
Abronia,  497 
Absinthe,  514 

Absorption  of  Food,  176.  184, 191 
Acacia,  538,  534,  565 
Acantbace«e.  61,  499 
Acanthus  Family,  499 
Accumbent  Cotyledons,  487 
Acer,  73,  75,  585 
Acerinea;,  119,  535 
Achene,  486 
Achenial  Fruits,  436 
Achimenes.  499 
Achlamydeous,  481 
Achlya,  39,  256 
Achnanthes.  280 
Achnanthidium,  280 
Achyranthes,  496 
Aci(i8,  62 
Acolium,  810 
Acouite,  562 
Aconltum,  106,  562 
Acorus,  58,  114,  462 
Acrocarpee,  859,  860 
Acroscyplius,  810 
Acrostichum,  877 
Actinocyclns,  281 
Actinodiscus,  281 
Actinomorphic,  430 
Actinoptycnus,  281 
Acyclic  Flowers,  429 
Adam's  Needle,  461 
Adder  Tongues,  872 
Adiantum,  110,377 
Adlumia,  556 
Adnate  Anthers,  488  | 


Adnation  of  Floral  Organs,  432 

Adonis,  53,  564 

Adventitious  buds,  143 

Adventitious  stems,  143 

.£cidiospores,  312 

.Ecidium,  312,  316 

^gilops,  455 

Aerial  roots,  187 

^sculus,  537 

.Ethalium,  210 

^tliusa.  520 

Affinities  of  Plants,  567 

Agapanthus,  4(i0 

Agaricaceee,  339 

Agarics,  241 

Agaricus,  89,  323,  828,  329,  380 

Agave,  467 

Ageratum,  98 

Aggregate  fruits,  486 

Aggregations  of  cells,  65 

Agrimony,  149 

A^rostis,  455 

Ailanthus,  102,  541 

Air  in  the  Plant,  174 

Albuminous  seeds,  891,  487 

Albuminoids,  5U 

Alders,  488 

Alectoria,  308 

Alectryon,  535 

Aleurites,  485 

Aleurone,  57 

Alfilaria.  543 

Alga,  138 

Alg»,  53, 65,  86, 135, 204, 205,  221, 

337.340 
Alprales,  837 
Alisma.  467 

Alismaceae,  128.  425,  466 
Alkaloids,  62. 182 
Allianet,  502 
Allamanda,  504 


Digitized  by 


Google 


670 


GENERAL  INDEX. 


Alligator  Pear,  494 

Allium.  458 

Allspice.  528 

Almond,  530 

Alnus,  488 

Aloe.  458 

Aloes.  459 

Alsopbila,  877 

Alternate  leaves,  149 

Alternation    of    Generations,  841, 

361 
Altbffia.  547 
Aljssum,  98.  554 
Amarantacete,  496 
Amarantus.  264»  496 
Amar7llidaceae,461, 467 
Amaryllis.  468 
Amaryllis  Family,  407 
Amaurochietete,  210 
Ambrosia,  264,  429,  515 
Amelancbier,  527 
Amentales,  485 
Amenta,  418 
American  Larcb.  412 
American  Wbite  Asb.  505 
American  Wbite  Elm,  488 
Ammonia  Salts.  170 
Amoeba  movement,  8 
Amole.  408 
Amomales,  471 
Amoreuxia.  551 
Amorpbopballjus.  462 
Amount  of  Evaporation,  171 
Amount  of  Water  in  Plants,  166 
Ampelidefle,  537,  565 
Ampelopsis.  165,  194,  538.  565 
Ampbi^astria,  344,  351 
Ampbipleura,  230 
Ampbora.  230 
Anacardiacea?.  534,  565 
Anacardiuni.  535 
Anacbaris.  473 
Ansestbetics,  198 
Anafi;allis,  434.  436.  507 
Analojry  and  Homology,  120 
Ananasso,  471 
AnastaticM.  555 
Ancestry  of  Plants,  204 
Ancbusa,  502 
Andreea.  358. 
AndraeacesB.  355.  858 
Andrcecium.  418,  430,  432 
Androgynia.  250 
Andromeda.  564.  565 


Andromedese,  510 

Androspore,  249 

Anemese,  210 

Anemone,  102,  264.  284,  429. 563 

Anemia,  377 

Anemiopsis,  483 

Anemopbilous  Flowers,  421 

Angiocarpous  Licbens,  297,  298 

Angiopteris.  878 

Angiospermae,  893,  416,  568 

An^oeperms,  79,  85 

Angular  divergence  of  leaves,  150 

An^ustura  Bark,  542 

Aniseed.  520 

Annual  layers  of  wood,  447 

Annular  Vessels.  118 

Annulus,  328,  875 

Anona,  561 

Anonace®.  560 

Anortbeis.  230 

Antbemideae.  514 

Antbemis.  514 

Antber,  394.  417, 418 

Antberidial  disc.  847 

Antberidium,  45, 243,  266,271, 83t 

341,  361 
Antber  Smut.  818 
Antbesis.  199 

Autboceros,  11,  217,  341,  348,  350 
AntbocerotesB,  350, 861 
Antiaris.  490 
Antipodal  Cells.  420 
Antirrbinum.  150,  500 
Apetal®,  476.  568 
Apetalous.  431 
Apbyllon,  192 
Apical  Cell.  38,  86,  88,  153,  843, 

852. 863.  373.  378,  880,  381, 42« 
Apium.  519 
Appendages.  281 

Apple,  64,  159,  171,  284,  436,  527 
Apocarpous,  433 
Apocynace*,  77,  119, 504 
Apocynuni.  504 
Apostasiaceie.  469 
Apotbecium.  297 
Apricot.  62.  530 
Aqueous  Tissue,  94 
Aquilegia,  564 
Arabis.  437 

AraceiB  (=Aroideae).  77 
Aracbis,  532 
Aracbnoidiscus,  231 
Arales,  461 


Digitized  by 


Google 


GENERAL  INDEX. 


bri 


Aralia,  519 
AraliaceuB,  519 
Araucaria,  409,413,414 

Araucaries,  413 

Arbor  Vit»,  411 

Arbutus.  509 

Arceuthobium,  477 

Archas.  506  ^^   ^^,   ^^- 

Arcbeponium.  46, 341.  861, 402 

Arcbesperuite,  393 

Arcbidium.  358 

Arctopodiuui,  385 

Arctostapbylos,  156,  50» 

Arctoide©,  514 

Arcyrla,  211 

Areca,  466 

ArecinesB,  466 

Arethusa,  470 

ArethusecB.  470 

Argemone,  556 

Aril,  437 

Arisaema,  61,  462 

Aristolocbia,  482 

Aristolocbiaceae,  482 

Armeria,  508 

Aruica,  514 

Arnotto,  551 

AroideiB.  119,  461 

Aroida.  461 

Arrack,  464 

Arrangement  of  Leaves,  149 

Arrangement  of  Roots,  164 

Arrowroot,  473,  484 
Artemisia,  85,  514 

Artbonia,  310 

Artboniel,  310 

Articboke,  512.  515 

Artocarpus,  489 

Arum  Family,  461 

Asafoetida,  63.  520 

Asarales.  4^i2 

Asarum,  482 

A8clepiadace»,  77. 119,  603 

Asclepias,  102.  426 

Ascobolus,  288,  289,  301 

Ascoironium,  300 

Ascomy  cetes,  214. 270. 271, 273. 278 
305.  335,  337, 338,  340 

Ascosporee,  339 

Ascospores,  40.  214,  278,  315,  319 

Ascus.  278,  315,  819 

Ascyrum.  549 

Asexual  Generation,  841,  361 

Asb,  436 


Asb  Tree,  505 
Asimina,  561 
Asparagus,  458 
Aspergillus,  284 
Aspbodel,  460 
Aspliodelus,  460 
Aspidium,  377 
Asplcnium,  377 
Assimilation,  62, 178,  185, 191 
Astepban®,  334 
Aster.  516 
Asterales.  512 
Asteroideie.  516 
Asterolampra,  231 
AsterolampresB,  231 
Asteropbyllites,  368 
Astilbe,  526 
Astragalus,  532 
Astrocaryum,  17 
Astrotricbia,  520 
Asymmetry  of  Leaves,  146 
Atalea,  464 
Atberosperma,  494 
Atmuspberic  pressure,  171 

Atricbum,  352 

Atriplex,  52 

Atropa,  502 

Aucuba,  518 

Aulacodiscus,  231 

Auliscus.  231 

Aurantiese,  541 

Auricula,  506 

Australian  Pitcber  Plant,  526 

Austrian  Pine,  412 

Autogamous  Flowers, 421 

Autumn  Crocus,  460 

Auxospores,  228 

Avena,  102.  455 

Avocado  Pear,  494 

Axile  Placenta,  433 

Azalea.  510 

Azolla.  381,  882 

Baccate  Fruits,  436 
Baccate  Seeds,  4;j7 
Bacillariaceffi,  227 
Bacillus*  213 
Bacteria.  65,  212 
BacteriaceaB,  212 
Bacterium.  17,  218 
Bactrospora,  298 
BflBomyces,  810 
Balanopborese,  476 
Bald  Cypress,  411 


Digitized  by 


Google 


(•78 


GENERAL  INDEX. 


Balloon  Vine.  587 

Balm,  498 

Balsam,  61,  94, 144,  543 

Balaam  Apple,  522 

Balsam  Fir,  412 

BaltMunodendron,  540 

Balsam  of  Peru,  5U2 

Balsam  of  Tola,  532 

Bamboo,  453,  457 

Bambusa,  457 

Banana,  146,  472 

Banana  Family,  471 

Bands  of  Protoplasm,  16 

Bangiaceie,  389 

Banksia,  491 

Banyan  Tree,  490 

Baobab,  474 

Baphia,  532 

Barberry,  197,  816,  558 

Barberry  Cluster  Cups,  816 

Barberry  Family,  558 

Barberry  Rust,  316 

Barbula,  351,  360 

Barcelona  Nuts,  477 

Bark,  118,  124,  201,  893,  409, 447 

Barley,  59,  187,  319,  322.  828,  455 

Barosma,  542 

Bartramia,  359 

Basal  Cells,  206 

Basellacetp,  494 

Basidia,  323 

Basidiumycetes,  270,  828,  835,  887, 

338,  339,  340 
BasiJiosporeffi,  839 
Basidiospores,  39,  323,  828 
Bassia,  506 
Bassorin,  63 
Bass  wood,  545 
Bast  Cells,  17 
Bast  Fibres,  74,  76,  119 
Bast,  Soft.  116 
Batliybius,  15 
Batrachosperinete,  277 
Bayberry,  487 
Bay  Tree,  493 
Bdellium,  465.  540 
Bean,  56,  58.  59,  199, 485,  581 
Bearberry,  509 
Bear  Grass,  461 
Bedfordia,  514 
Bedstraw,  517 
Beech,  125,  126,421,479 
Beech  Mast.  479 
Beech  Nuts,  479 


Beet,  166,  495 

Begonia,  61,  94. 148, 146. 521 

Be^niacete,  71,  821 

Belladonna,  i02 

Bellis,  516 

Berberidaceffi,  558 

Berberis,  85,  102,  558 

Berchemia.  565 

Berry,  486 

Benholletia,  58,  523 

Beta,  103,  495 

Betel  Nut,  466 

Betel  Palm,  466 

Betel  Pepper,  484 

Betula,  102,  174,  487 

Betulacese,  487.  564 

Bhang,  488 

Biatora,  810 

Bicol  lateral  Bundles,  121 

Bicyclic,  480.  482 

Biddulphia,  231 

Biddulphiece,  281 

Bidens.  264, 515 

Bitrnonia,  81.  85.  426, 499 

Bignouiacese.  499 

Big  Trees  of  California,  411 

Bilaterality  of  Leaves,  146 

Bilocular,  433 

Biota,  409 

Biparous  Cyme,  429 

Birch,  126,  174, 421,  487,  487 

Birch  Family,  487 

Bird  Cherry,  530 

Birds  Aiding  in  Pollination,  43] 

Bisexual  Flowers,  431 

Bittersweet,  539 

Bixia,  551 

Bisinese,  551 

Black  Ash,  505 

Blackberry,  426,  487,  529 

Black  Bindweed,  497 

Black  Grain,  532 

Black  Huckleberries,  511 

Black  Jack  Oak,  480 

Black  Knot.  292 

Black  Nightshade.  502 

Black  Oaks,  480 

Black  Pepper,  488,  561 

Black  Rust,  816 

Bladder-nut,  535 

Bladderwort  Family,  499 

Blanching  of  Celery,  52 

Blanc  Mange,  277 

Blazing  Star,  516 


Digitized  by 


Google 


GENERAL  INDEX. 


579 


Bleeding  Heart,  556 

Bletia,  470 

Blood-root,  556 

Bloodwood  Tree,  523 

Bloodwort  Family,  467 

Blueberry,  511 

Blue  Beech.  477 

Blue  Gum,  524 

Blue  Huckleberries,  511 

Blue  Mould,  285 

Blue  Palmetto,  465 

Bluets,  517 

Bocconia,  556 

Bcelimeria,  491 

Boletus,  380 

Bombax,  547 

Borate  Family,  503 

Borassineae,  465 

Borassus,  465 

Bordered  Pits,  251 

Bore  Cole,  553 

Boroniete,  542 

Borraginacese,  150,  602 

Bostryx,  429 

Boswellia,  540 

Botrychium,  379,  380 

Botrydium,  134 

Botry-Cyme,  429 

Botryose  Inflorescence,  427,  428 

Botryose  Mouopodium,  140 

Bouncing  Bet,  550 

Boundary  Tissue,  80 

Boussingaultia,  494 

Bouvardia,  518 

Bow- wood,  490 

Box  Elder,  536 

Box  Tree,  485 

Bracts,  136,  155 

Bran-cell,  58 

Branching,  Modes  of,  139 

Branching  of  Leaves,  147 

Branches  of  Stems,  142 

Brassica,  98.  102,  150.  553 

Brazilian  Arrowroot,  484 

Brazilian  Artichoke,  515 

Brazil  Nut,  68,  524 

Brazil  wood,  533 

Bread- Fruit  Tr«»e.  489 

Break- Ax  Tree,  545 

Bristles,  137 

British  Oak,  479 

Bromeliacese.  471 

Biompton  Stock,  554 

Broom  Com,  457 


Brosimum,  489,  490 
BrousBonetia,  490 
Bruchia,  358 
Brucia.  503 
Bruniaceae,  526 
Brussels  Sprouts,  553 
Bryaceee.  355,  858 
Bryophvllum.  143,  526 
Bryophyta,  205,  305,  841, 668,  569, 

570 
Bryophytes,  10,  40,  59,  67,  72,  87, 

90,  124,  140.  143.  145,  265,  341. 

389 
Bryum,  352,  359, 860 
Buchu,  542 
Buckeve,  587 
Buckthorn,  539 
Buckwheat,  496 
Buckwheat  Family.  496 
Buckwheat  Tree.  539 
Bud,  139, 140, 181,  189.  199 
Bud-cell,  332 
Buellia,  310 
Buffalo  Berry,  492 
Bulb,  181,  190,  191 
Bulb-axes.  136 
BulbochaBtacese,  269 
Bulbochffite,  250 
Bulbophyllum,  471 
Bulgaria,  289 
Bumelin,  606,  564 
Bundles.  Fibro-vascular,  106 
Bundle  Sheath,  108,114 
Bunt,  318 

Burgundy  Pitch,  412 
Burmanniacee,  408 
Burning  Bush,  639 
Burseru,  540 
Burseracete.  540 
Bush  Honeysuckle.  518 
Butcher's  Broom,  401 
Buttercup,  664 
Butternut,  482 
Butter  Trees,  606 
Button  Bush,  517 
Button  wood,  487 
Buxus,  102,  485 

Cabbage,  93. 171.  185 
Cabbage  Palmetto,  565 
Cacalia,  514 
Cachibou,  540 
Cactaceffi,  94^  520 
Cacti,  503 


Digitized  by 


Google 


680 


GENERAL  INDEX. 


Cactus  Family,  520 

C»loetph»rium,  216 

Csesalpina,  533 

CsesalpinieflB,  533 

Caffeine,  182 

Calabash  Tree.  499 

Calamandar  Wood,  506 

Calamarieae,  868 

Calamete,  465 

Calamites,  368 

Calamocludus,  368 

Calauiostacliys,  368 

Calamus,  81,  465,  466 

Calandrinia.  549 

Calcareae,  210 

Calceolaria^  500 

Calcium,  175 

Calcium  Carbonate,  60* 

Calcium  Oxalate.  59,  180 

Calendulace®,  514 

Caliciacei.  310 

Caliciei,  310 

Calicium,  810 

California  Laurel,  494 

California  Pitcher  Plant,  557 

Calla,  61,  462 

Calla  Lily  462 

Calliops!e.  514 

Callirhoe,  547 

Callistephus,  516 

Callithamoion,  277 

Callitris,  899,411 

Calluna.  509 

Calocasia,  462 

CalonemeflB,  211 

Calophjllum,  549 

CaJopogon.  470 

Caltha,  436,  564 

CalycanthacesB,  562 

Calyceracefe,  516 

Calycocarpum,  560 

Calypso,  471 

Calyx,  418,  430 

Cambium.   17,  116,  121,  143,164. 

201,407,  444 
Cambiform  Cells,  111 
Camelina,  554 
Camellia,  548 
Campanales,  51 1 
Campanula,  18,  512 
Campanulacese,  77, 119l  511 
Camphor,  63,  494,  547 
Camphor  Tree,  547 
Camwood,  532 


Canada  Balsam,  413 
Canada  Thistle,  513 
Canal,  Intra'-fascicalar,  111 
Candle  Nut  Tree,  485 
Candytuft,  554 
Canella,  551 
Canella  Bark.  551 
Canellaceae,  551 
Cane  Palms.  465 
Cane  Sugar,  62, 180 
Canna,  473 
Cannabis,  488 
Cannabinea;,  488 
Cannacete.  425 
Canme,  473 
Cafion  Live-Oak.  479 
Canterbury  Bells,  512 
Caoutchouc,  78,  485,  490,  508,  504 
Capers.  552 
Capillitium,  210 
Capparidacese,  552 
Capparis,  552 
Capri  foliaceaB.  518.  565 
Capsella,  98.  264,  425^  554 
Capsicum.  501 
Capsulary  Fruits,  486 
Capsule.  348,  355,  436 
Caragana,  582 
Caraway,  520 
Carbon,  175 
Carbonates,  176 
Carbohydrate.  178 
Carbdn  Dioxide.  174, 181, 191 
Carbon  Oxide,  179 
Carcerulim,  436 
Cardinal  Flower,  512 
Cardiospermum,  537 
Carex,  150,  823 
Carica,  522 
Carludovica,  462 
Carnations.  550 
Carnivorous  Plants.  183 
Carmine,  520 
Carpel.  136,  480,  483 
Carpellary  Leaves,  400 
Carpet-weed,  520 
Carpids,  433 
Carpinus,  477, 564 
Carpogonium.  271,  800.  880,  881 
Carpophore,  436 
Carpophyllum  (pl.-la,)  419,  483 
Carpoepore,  332 

Carpophyta,    205,  270,  885,  887. 
5&.  569,  570 


Digitized  by 


Google 


QENBHAL  INDEX. 


581 


Carrot,  519 

Carthamus,  512 

Carya,  78,  482. 565 

Caiyophjllacese,  494,  549 

Caryopbyllales,  549 

Caryopsis,  436 

Caryota,  466 

Cascarilla  Bark,  485 

Cashew  Family,  584 

Cashew  Nat,  585 

Cassava,  484 

Cassia,  197, 588,  565 

Cassia  Bark,  494 

Cassia  Buds,  494 

Castanea,  478,  564 

Castilleia,  58 

CMStilloa,  490 

Castor  Bean,  59,  181 

Castor  Oil,  62 

Castor  Oil  Plant,  475.  484 

Casuarineae,  487 

CaUlpa,  429.  487,  499 

Catasetum.  470 

Catchfly,  550 

Catha,  589 

Calkin,  895, 418,  428 

Catnip,  498 

Cattleya,  471 

Caalerpa.  184, 254 

Caulerpites,  254 

Caulicle,  404 

Cauliflower,  558 

Cauline  Bundles,  892,  442 

Caulome,  184,  185.  248,  271 

Caulophyllum,  559 

Cayenne  Pepper,  501 

Ceanothus.  61, 108 

Cedrella,  540 

Cedrus,  409, 415 

Celastracese,  589 

Celastrales,  587 

Celastrus,  589 

CeleiT,  519 

Cell  Derivatives,  67 

Cell  Families,  65 

Cell  Formation  by  Division,  86 

Cell  Formation  by  Union,  44 

Cell  Fusions,  66 

Cell  Masses,  67 

Cell  Rows,  67 

Cell  Sap,  62 

Cell  Surfaces,  67 

Cellular  Plants,  205 


Cell  Wall,  15.  21,  68,  166, 206 

Celosia,  496 

Celtis.  61,  85, 150,  488 

Cellulose,  21 

Cenangium,  289 

Centaurea,  518 

Central  Cell,  881,875 

Centrifu^l  Thickening,  81 

Centripetal  Thickening,  81 

Century  Plant,  467 

Cephaelis,  517 

Cephalanthus.  517 

Cepbalotus,  526 

Cerawieee.  277 

Ceramiacese.  889 

Ceramium.  278 

Cerasin,  68 

Cerastium,  429,  550 

Ceratophyllese,  ^i3 

Ceratozamia,  410 

Cercis,  588 

Cercocarpus,  529 

Cereus,  520 

Cereal  Grains,  181 

Ceropegia,  508 

Ceroxylon,  93,  466 

Cestrum,  502 

Cetraria,  808 

Cheetocerese.  281 

Clisetoceros,  231 

Chaetocladium,  241 

Chailletiacese.  540 

Chamiebatia,  529 

C'hamtecyparis,  411 

Chamsedorea,  466 

Chamierops,  465 

Chamomile,  514 

Channels  in  CelLWalls,  24 

Chaptalia,  512 

Chara,  14.  888,  834 

Characea,  271,  381,  885,  887 

Charr»,  883,  884 

Charlock,  554 

Checkerberry,  510 

Chei  ran  thus,  554 

Chelura,  524 

Chemical  Processes  in  Cells,  168 

Chemical  Processes  in  the  Plant, 

178 
Chemical  Rays  of  Spectrum,  192 
ChenopodiacesB,  495 
Chenopodiales,  494 
Chenopodium,  71,  102.  4;}6,  495 


Digitized  by 


Google 


582 


GENERAL  INDEX. 


Cherimoja,  561 

Cherry,  62,  64.  126,  148.  169,  284, 

292,  426.  428,  436,  580 
Cherry  Blight,  140 
Cherry  Laurel.  178 
Chestnut,  58,  154,  421,  478 
Chibon,  540 
Chicory,  512 
Chimaphila,  510 
China  Aster,  516 
China  Grass,  491 
Chinese  Date.  506 
Chinese  Primrose,  506 
Chinese  Sugar-Cane,  457 
Chinese  Yam,  467 
Chiodecton,  810 
Chionanthus,  505 
Chittagung  Wood,  540 
Chlsenaceee,  547 
Chlamydospores,  287 
Chloranthacese,  488 
Chlorides,  176 
Clilorine,  175 
Chlorococcum.  219 
Chlorophyll.  50,  70,  94,  155,  178, 

191.  205.  206 
Chlorospermes.  887 
Chlorosporeae,  889 
Chloroxylon.  540 
Chocolate,  546 
Chocolate  Tree.  545 
Chondrites.  278 
Chondrus,  277 
Choripetalee.  476.  518,  568 
Choripetalous,  481 
Chorisepalous.  481 
Chowlee,  582 
Chronizoospores.  228 
Chroococcacese.  216,  805,  806,  888 
Chroococcus,  216 
Chroolepideffi,  806 
Chrysanthemum.  514 
Clirysobalanea;,  580 
Chrysopbyllum,  506 
Chufa,  457 
Churrus,  488 
Chylocladies.  277 
Chytridiaces.  880 
achoriace».  67, 77,  78, 119, 512 
Cichorium.  512 
Cicinnus.429 
Clcuta.  520 
Cilia,  10 
Ciliary  Movement.  Ki 


Cinchona.  17.  64,  182,  517 

Cineraria,  514 

Cinnamomum,  494.  564,  565 

Cinnamon,  494 

arcinella.  287 

Circumciesile  Drhiscence,  485 

Circulation  of  Protoplasm,  14 

Cissus,  482.  588.  565 

Cistace«.  552 

Cistus,  552 

atric  Acid.  64, 183 

Citron,  541 

atruUus,  522 

Citrus.  541 

Cladonia.  806.  809 

Cladoniei,  809 

Cladophora.  10.  87, 224, 245,  806 

Cladoxylon,  415 

Classification.  202 

ClHvaria,  880 

Claviceps.  289,  294 

aaytonia,  199,  549 

Cleavers,  517 

Cleistoffamous  Flowers,  421 

Clematis.  564 

Cleome.  552 

Clerodendron,  498 

Clethra.  510 

Cliftonia,  589 

Climacosphenia.  281 

Climacium,  860 

Climbing  Bittersweet.  589 

Closed  Bundle.  121,  448 

Closing  of  Flowers,  199 

aosterium.  11,  227 

Clove  Pink.  98.  550 

Clover,  197,  428.  582 

Cloves,  528 

Clove  Tree,  528 

Cluster  Cups,  816 

Cnicus.  518 

Coagulation  of  Albuminoids,  188 

Coalescence  of  Floral  Organs,  483 

Coats  of  Ovule,  401 

Cobsea,  508 

Cob-nuts,  477 

Cocconels,  230 

Cocconidew,  230 

Cocculus.  560 

Coccus,  490 

Cochineal  Ini^ect,  520 

Cockleburs.  515 

Cockscomb,  496 


Digitized  by 


Google 


GENERAL  INDEX. 


583 


Cocoa,  546 

Cocoanut,  404 

CoooinesB,  464 

Cocoa,  464 

Coeloblastefe.  350,  269,  336,  337 

Coelogyne,  471 

Coenobia,  221 

Coenoflroniei,  310 

CoBDOgonium,  310 

Coffea,  517 

CoflTee.  183,  517 

Cohorts  of  Dicotyledons,  476 

Cohorts  of  Monoootjledons,  453 

Coix,  98 

Colchlcum,  460 

Coleochsetace®,  830 

Coleoch»te,  371,  374,  379,  835,  837 

ColeochflBtese,  840 

Coleus,  53,  498 

Collar,  475 

Collateral   Bundle,   120,  862,  808, 

880,  893.  438 
Collema,  295,  398.  300,  301,  C05, 

806,809 
Collemace8e..805,  3o9 
('oUemel,  809 
Collenchyma,  39,  70,  89, 124,  863, 

378.  393 
CoUam,  475 
Colocynth,  633 
Coloring  Matters,  64 
Colors  of  Flowers,  53 
Columbine,  564 
rolumella,  310. 336,  360 
Colnmelliaceie,  499 
Columellifene.  211 
Colza,  554 
Comandra.  476 
Combretace®,  534 
Commelynaceee.  457 
Commelynales.  457 
Common  Bundles.  368,  393.  488 
Comose  Seeds.  487 
Compass  Plant.  108.  156,  515 
Complete  Flower,  431 
Compositae.  62, 94, 99, 197. 284,  435, 

439,  484.  513 
Compo»ites.  158, 158 
Compound  I.<eaves,  147 
Compound  Pistil,  488 
Compound  Raceme,  4^3 
Compounds  in  Plant-Food,  176 
Compound  Spike,  438 
Compound  Umbel,  4'38 


Concentric  Bundle,  130,863 

Conceptacles,  365 

Concluding  Observations.  506 

Conducting  Tissue,  89 

Cone,  897 

Conepia,  531 

Conferva,  37.  806 

Confervace®.  234,  345,  377,  839 

Confervas,  840 

Confervites,  343 

Conjugate,  335.  343.  836,  840 

Conjugation,  45,  47, 335 

Conia,  163 

Conldia.  39,    341.  360.   378.   370. 

389.  392. 394.  813,  815.  323,  a57 
Coniferae,  25,  51. 130.  132.  896. 409- 

410,  415 
Conifers,  143,  153.  158,  409,  410 
Coniocybe.  810 
Coniomjcetes,  888 
Coniuni.  183,  520 
Ccmnaraceae.  534 
Connarus.  534 
Connecting  Tube,  270 
(Vinnective,  483 
Conotrema,  800 
Constituents  of  Plants,  100 
Convallaria,  400 
Conversion  into  Mucilage,  85 
Convolvulaceap.  77,  502 
Convovulus,  503 
Copaifera,  588 
Copaiva  Balsam,  533 
Copai-ye  Wood,  550 
Copemica.  464 
Coprinus,  829,  880 
Coquilla-nuts.  404 
Corallina,  277.  278 
Corallineae,  277,278 
Corallorhiza.  192,  471 
Corchorus,  545 
Cordate  Leaves,  146 
Coreopsis,  514 
Coriander,  520 
Cariarieae,  584 
Cork,  125.  480 
Cork  Cambium,  126 
Cork  Oak.  125.  480 
Cork-wood,  547 
Corm,  136 

Cormophyta,  203,  205 
Cormopliytes.  835 
ComaceflB,  518,  565 
Com  Cockle,  550 


Digitized  by 


Google 


584 


GENERAL  INDEX. 


Oonms,  518,  565 

Corolla.  418.  430 

CorpuBcula,  893,  402 

Cortex,  301 

Coryle©,  477 

Corylas,  477. 564 

Corymb,  428 

Corypblneffl,  464 

Coscinodiscefle.  231 

CoecinodiBcuB.  11.  231 

Cosmarium,  44,  227 

Cotton.  98, 437,  546 

Cottonwood.  487 

Cotyledon.  526 

Cotyledons.  886.  391,  404.  424 

Couma.  504 

Cowslip,  503 

Cow  Tree,  489 

Crab- Apples,  527 

Cranberry.  511 

Crape  Myrtle,  523 

Cras^ula.  526 

Crassulacea;.  526 

Crat»graa,  527,  565 

Crntoxylon,  549 

CrayBshea.  prowths  on,  2.)7 

Cremocarp,  436 

Crenate  Leaf,  147 

Creosote  Bush.  543 

Crescentia.  409 

Cribraria.  211 

Crocus,  56.  468 

Crossosoma,  562 

Crotallaria,  582 

Croton,  484,  485 

CrotonOil.484 

Crown  Imperial.  460 

Cracibulam,  825,  826 

CrucifersB.  98. 181.  264.  425,  5o3 

Cruclfer  Family.  553 

Cryptogam,  204.271,  816 

Cryptogamia,  204,  205 

Cryptomeria.  411 

(*ryptonemie8B,  277 

Crypto- Raphldie».  231 

Crystalloids,  57.  58 

Crystals,  57. 59 

Cnba  Bast.  547 

Cubebs.  484 

Cuboldal  Cell,  19 

Cucumber,  522 

Cucumber  Tree.  501 

Cucumis,  14,  80,  522 


Cucurbita.  11,  13, 14,  35,  53,  80,85, 

522 
Cucurbitace»,  29,  51,  71,  120,  181, 

521 
Cucurbitaria.  294 
Cultures  of  Lichens,  807 
Cultures  of  Moulds.  289 
Cultivated  Plants,  182 
Cummin.  520 
Cupania.  587 
Cupbea.  523 
Cupresseae.  411 
Cupressus.  409.  411 
Cups,  136 

Cupuliferffi.  425,  426,  477, 564 
Curare.  503 
Curcuma.  472 
Currant.  64. 526 
Cuscuta.  56.  502 
Cuspariese.  542 
Custard  Apple.  561 
Cuticle,  84.  93 
Cnticularizing.  85 
Cyanopbyceae.  215,  836 
Cyatbea.  877 
Cyatheace«,  376 
Cycadeae.  409,  410 
Cycads,  409.  410, 416 
Cycas.  899, 410 
Cyclamen,  506 
Cyclic  Flowers.  429.  430 
Cyclotella,  281 
Cvdonia.  527 
Cylindrical  Cell.  19 
Cymatopleura.  231 
Cymbella.  230 
Cymbelleae.  230 
Cyme.  429 
Cymo-Botrys.  429 
Cymose  Inflorescence,  427,  429     * 
Cymose  Monopodium,  140 
Cynara,  572 
CynaroidesB,  512 
Cynips.  479 
Cynoglossum.  57 
Cynomorium.  476 
Cyperaceae,  457,  473 
Qrperus,  457 
Cypress,  411 
Cypripedieae,  469 
Cypripedium.  469 
Cyrilla,  589 
Cyrillaceae,  539 


Digitized  by 


Google 


GENERAL  INDEX. 


585 


Cystidia,  328.  830 
CyBtoliths.  60 
Cystopteris,  377 
CvBtopuB.  30,  260,  264 
QrtlBUS,  85.  532 

Dacrymycea,  289 

Dactylina,  308 

Dactylis.  455 

Daffodil,  468 

Dahlia.  62.  514 

Daisy,  516 

Dalbergia,  532 

Dammara,  413 

Dammar  Resin.  413 

Daniea.  378 

Dandelion.  512 

Dantzic  Fir.  412 

Daphnales.  491 

Daphne.  492 

Darlingtonia.  182, 557 

Daeya,  277 

Date,  germination  of,  453 

Date  Palm.  465 

Datisca.  521 

Datiscaceie,  521 

Datura,  102.  502 

Daucus,  519 

Daughter  Cells,  39 

Day  Lilv.  460 

Deadly  Nightshade.  502 

Death  from  high  temperature,  188 

Death  from  low  temperature,  189 

Decandrous.  432 

Dehiscence.  435 

Dehiscent.  435 

Delesseria.  277.  278 

Delphinium.  106.  564 

Denarobium.  471 

Dentate  Leaf,  147 

Denticella.  11 

Deoxidization  in  Assimilation,  179 

Detoatogen,  161. 42:3 

DesiuidiaceaB.  44.  225.  242. 336,  338 

Desmids,  225 

Desmobacteria.  213 

Deshjodium.  196.  19S,  436,  533 

Determinate  Indorescence,  428 

Deatzia.  526 

Diadelphous,  432 

Dialypetaloas.  431 

Dianarous.  432 

Dianthus,  93.  550 

Diapensiacee.  508 


Diarthrodaclyleffi.  334 
Diatoma.  227.  231 
Diatomaceae.  53,  227. 242,  886,  838 
Diatomeae.  340 
Diatoms.  34.  227, 242 
Diatrype.  294 
Dicarpellary.  433 
Di  centra.  556 
Dichasiam.  429 
Dichlamydeous,  481 
Dicliogamoas.  434 
Dichotomy.  882 
Dichotomoas  branching,  189 
Dichotomous  Cyme,  429 
Dicksonia.  378 
Diclinous  Flowers.  431 
Dicotyledones,893, 473.  568 
Dicotyledons.  93, 118, 123. 143, 148, 
150.  161,  200, 391,  416.  569,  570 
Dicranum.  360 
Dictamnus,  130. 132,  542 
Dictydium.  211 
DictyotaceflB,  339 
Didymium,9.  10. 188,  210,  432 
Diervilla.  518 
Diffusion.  174 
Digitalis,  500 

Digitately  lobed  leaves,  147 
Digitately  compound  leaves,  148 
Digynous,  433 
Dill.  520 
Dillenia,  562 
Dilleniace8e,562 
Dimensions  of  cells,  17 
Dimerous.  430 
Dimorphandra,  533 
Dimorphous,  434 
Dioecious,  249 
Dioecious  Flowers,  431 
Dionaea.  182, 197. 198. 526 
Dioscorales.  467 
Dioscorea.  467 
Dioscoreactrse.  467,  473 
Diosma.  54; 
Diosmese,  542 
Diospyros,  506.  564,  565 
i>ipftalous.  432 
Diplostemonous,  432 
Diplostephanae,  334 
Dipsacese,  516 
Dipsacus,  99,  516 
Dipterocarpete,  547 
Dirca,  492 
Direction  of  Spirals,  82 


Digitized  by 


Google 


586 


GENERAL  INDEX, 


Dirina,  809 

Discomjcetes,  286,  888 

DiBepalous,  481 

DiBtribation  in  Time,  568 

DiBturbance  of  the  Equilibrium  of 
Water,  168 

Diurnal  Ponitiona  of  Leaves,  199 

Division  of  Cells,  86 

Divisions  of  the  Vegetable  King- 
dom, 205 

Docks,  497 

Dodder,  58, 56,  502 

Dodecandroufl,  482 

Dodecatheon,  506 

Dodon«e»,  585 

Dogbane  Famllv,  504 

Dogwood,  518,  589 

Dogwood  Family,  518 

Dormant  Buds,  144 

Dorypliora,  494 

Double  Cocoa-Nut,  465 

Doubly  Compound  r..eaves,  148 

Douglas  8pruce,*38,  411 

Doum  Palm.  465 

Draba,  08,  264 

DracflBna,  444.  460 

Dracopbyllum,  510 

Dragon  Trees,  444, 460 

Dragon's  Blood,  466 

Drosera,  182,  198, 429, 526 

Droeeracee,  526 

Drupaceous  Fruits,  486 

Drupaceous  Seeds,  487 

Drupe,  436 

Dry  Fruits,  485 

Dryobalanops.  547 

Duckweeds,  461 

Dudresnava,  276,  277 

Duguetia,'  561 

Dulse,  277 

Dumontiete,  277 

Durio,  547 

Dwarf  Almond.  580 

Dwarf  Palmetto.  465 

Dyers'  Weed,  552 

Eartb.Star,824,826 
EbenacesB,  505.  564,  565 
Ebenalea,505 
Ebony,  506 
Ebony  Family,  505 
Ecbalium,  11,  81 
EchinocyRtis,  74,  81,  522 
Ecbites,  504 


Ectocarpeae,  889 

Ectoplasm,  4,  15 

Edible  Hymenomycetes,  880 

Bel  Grass,  478 

Egg  Plant,  500 

Elsagnacee.  491 

Elflsagnus,  492 

Elseis.  464 

Elapliomyces,  286 

Elaters,  848.  867 

Elatinace».  549 

Elder,  71, 126,144,518 

Elecampane,  516 

Elements  of  Plant  Food,  175 

Eleutheropetalous.  481 

Elliptical  Leaves,  146 

Elm,  61,  64,  148. 146, 187,  488 

Elm  Family,  488 

Embryo.  46,  891.  404,  428 

Embryology,  204 

Embryonic  Vesicle,  47 

Embryo-sac,   11,   41,   46.  66,  187, 

889,  401,  402,  420 
Encephalartos,  410 
Endive.  512 
Endocarp,  585 
Endocarpei.  810 
Endocarpon.  810 
Endocbrome,  227 
Endogenae,  451 
Endoplasm.  4. 16 
Endosperm,  11,  41,  890,  402,  408, 

420.  428.  425 
Endo8pore.  84. 257,  268,  842 
Englisli  Bean.  88,  581 
English  Ivy,  519 
English  VValnuta,  480 
Enneandrous,  482 
Ensiform  Leaf  of  Iris.  159 
Entomophilous  Flowers,  421 
Epacrideffi,  508,  510 
Epacris,  510 
Ephebe,  805.  809 
Ephedra.  418. 416 
Epidendreae,  470 
Epidendrum,  470 
Epidermal   System,    90,  857,  862. 

406 
Epidermis,  91.  92.  162,  170,  201, 

848.  862,  867.  892.  487 
Epigaea,  510 
Epigynous,  484 
Epigyny,  484 
Epilobium.  61,522 


Digitized  by 


Google 


GENERAL  INDEX. 


687 


£pina8ty,  190 

Epipetalous.  438 

Epispore,  257.  268 

Epithemia,  281 

Equilibrium  of  Water.  168 

Equiaetaces,  85.  143,  868.  889 

Equisetioffi,  862.  868,  382 

Equiaetitea.  869 

Equisetum.  11.  87,  80.  81,86,  88, 

110, 115,  120,  128,  128,  808,  8(58. 

869 
Erect  Ovnlea.  488 
Erp^ot,  289,  295 
Erica,  510 

Ericace®.  508,  504.  505 
Ericalea,  508 
Ericinese,  508,  509 
Erigeron,  98 
Eriocaulonaceas,  457 
Erodium,  548 
Erysimum,  437 
Erysiphaceee,  140,  278,  339 
Erysiphe,  279.  383 
Erysiphei,  283 
Eryth  rosy  Ion,  544 
EacliBcholtzia,  556 
Essence  of  Cinnamon.  63 
Essence  of  Wintergreen,  63 
Essential  Oils,  62 
Ethiopian  Lily,  462 
Etiolated  Plants,  52 
Euastrum.  227 
Eucalyptus.  94, 524,  565 
Eudorina,  243 
Eugenia,  523 
Euglena,  50 
Eunotia,  281 
Euonynms,  589 
Eupatoriacete,  516 
Eupatorium,  264,  516 
Eupodiscese,  231 
Eupodiscus,  231 
Euphorbiac'ffi,  76,  77,  425,  484 
Eupborbiales,  484 
Euphorbia,  78,  102,  150,  485 
Euphorbium.  Gum,  484 
Eurotlum.  281,  285.  289 
Evaporation    of    Water,  167,  169, 

185, 191 
Evening  Primrose,  61 
Everlasting  Flowers,  515 
Evemia.  808 

Exalbuminous  Seeds,  891,  437 
Excretions,  61 


I  ExcoBcaria,  485 

I  Exhalation  of  Water,  169 

!  Exocarp,  485 

'  Exogen®,  478 

I  Exospore,  84,  222,  842 

Extine,  84 

Extrorse  anthers,  433 

Fagopyrum,  496 

Faffus,  17, 150,  479,564 

False  Flax,  554 

False  Raceme,  429 

Families  of  Cells,  65 

Farfugium.  514 

Fennel,  520 

Fermentation,  212 

Fermentive  Changes,  190 

Ferns,  123, 143, 155,  362,  870, 871. 

872,  878 
Fertilization  iu  Anglosperms,  419, 

422 
Ferula,  520 
Fever  Tree,  517    - 
Fibrous  Roots,  165 
Fibrous  Tissut-,  74,  89.  106,  112, 

119.  128,  363,  868.  392 
Fibro- vascular  Bundles.  106,  155, 

159,  352,  862,  867,  892.  407,  438 
Fibro- vascular  System.  90, 106,348, 

359,  862.  438 
Ficoidales,  520 
Ficoideae,  520 

Ficus,  94, 102.  480.  564,  565 
Field  Bean,  475,  531 
Field  Oak,  480 
Fig,  61,  62,  437,  489 
Figwort  Family.  500 
Filament,  894,  418 
Filbert,  477 

Filices,  870.  371.  372.  878.  389 
Filicinte.  369.  382.  889 
Fishes,  growths  on,  257 
Flagellariese,  457 
Flax,  85,  181,  187, 188,  491,  548 
Flax  Family,  543 
Fleshy  Fruits.  435 
Flies,  growths  on.  257 
Floral  Envelo|>es,  136.  155 
Floral  Symmetry,  429 
Florideie,  53, 186, 271, 278, 835, 837. 

839,840 
Flower.  842,  853,  891,  894.  417 
Flower-axis.  136 
Flowering  Dogwotxl,  518 


Digitized  by 


Google 


58S 


GENERAL  INDEX. 


Flowering  Plants,  208,  205 

Flowerle«s  PlanU,  208,  205 

Flowers,  Colors  of,  63 

Flowers  in  darkness,  192 

Flow  of  Sap.  174 

Foeniculam,  520 

Foliage-leaf,  186 

Follide,  486 

Fontinalis,  860 

Fool's  Parsley,  520 

Fool,  886 

Forget-me-not,  502 

Forked  Cyme,  429 

Forked  Cymose  Monopodiam,  140 

Forked  Dichot<»my,  189 

Formation  of  Alkaloids.  182 

Formation  of  Ice  Crystals,  189 

Formation  of  New  Cells,  36 

Forms  of  Cells.  18. 19 

Forms  of  Leaves.  146 

Forms  of  Roots.  165 

Forsyiliia,  505 

Fossil  Characeie,  884 

Fossil  CoBlobl«8te»,  254 

Fos»il  Dicotyledons.  564 

Fossil  FloridesB.  278 

Fossil  FucacejB,  269 

Fossil  Gymnospenns.  415 

Fossil  HelvellacesB,  289 

Fossil  Hymenomycetes,  831 

Fossil  Lichens,  810 

Fossil  Monocotyledons,  478 

Fossil  Protophytes.  219 

Fossil  Pyrenomycetes,  295 

Fossil  Zvgosporeas.  242 

Four  O'clock,  497 

Foxglove,  500 

Fragaria,  528 

Frajfilaria,  227,  231 

Fragilariete,  281 

Framework  of  tlie  Leaf,  155 

Frankeniaceas,  550 

Fraxinella,  540 

Fraxinus,  505.  565 

Free-cell  Formation,  42.  47,  49 

Free  Central  Placenta,  434 

Free  Oxygen.  179 

Fringe  Tree.  505 

Fritillaria,  460 

Frostweed,  552 

Fruits,  881.  426,  485 

Fruit  Sugar.  62 

Frullania,  841,  851 

Frustule,  227 


Fucacee.  85,58, 135,  186,  248.264 
268,  269,  886.  887.  889,  840 

Fuchsia,  61.  98,  94, 102, 104.  522 

FucoidesB,  268.  269 

Fuooides,  269 

FucuB,  265.  268 

Fuligo.  2. 10, 188.  194, 210 

Fuller's  Teasel.  516 

Fnmariacete,  555 

Fumitory,  556 

Funaria,  852,  360 

Fundamental  System,  90, 128.  859. 
862,  368,  408.  488 

Fungales.  337 

Fungi,  18,  39,  53,  56,  66. 67,  86.  90^ 
192,  204.  205,  887, 840 

Funkia,  13.  460 

Fusanus,  476 

Fusiform  Cell,  19 

Fustic,  490 

Galactodendron.  78,  489 

Galanthus.  468 

Galipea,  542 

Galium,  517 

Gamboge,  548 

GamopetalflB,  476,  497, 568 

Gamopetalous,  482 

Gamosepalous,  A9i^ 

(iarcinia,  548,  549 

Garden  Balsam,  542 

Gardenia.  518 

Garlic.  61.  68.  458 

Gas  Plant,  540 

Gasteromycetes,  323,  824, 838,  839 

Gaultheria,  510 

Gaylussacia,  511 

Geaster,  324,  826 

Geissolomete,  484 

Gelidieae,  277 

Gelidium,  277 

Gemmae,  844,  857 

Generalized  Forms.  133 

Generating  Spiral.  151 

Genetic  Relationship,  208 

Gentianaceae,  503 

Gentianales.  508 

Gentian  Family,  503 

Genuflexous  Conjugation,  284 

Georgia  Bark,  517 

Geotropism,  194.  200 

Geraniaces,  542 

Geraniales.  540 

Geranium,  543 


Digitized  by 


Google 


GENERAL  INDEX. 


589 


Geranium  Family,  542 
Gerardia,  53 
German  Ivy,  514 
Germ-cell,  841, 348,  362,  390.  420 
'-Germination  of  Dicotyledons,  474 
-^Germination   of    Monocotyledons, 

451 
Germination  of  Seeds*  181, 187, 404 
Gesuera,  400 
GeaneraceaB,  490 
Giant  Puff-ball,  326 
Giant  Redwood,  411 
Giant  Silver  Fir,  412 
Gigartineae,  277,  278 
Gilia.  503 
Gills,  328 
Gillyflower,  554 
Ginger,  472 

Gingerbread  Palm,  465 
Ginkgo,  81.  300, 409,  410 
Ginseng,  518 
Gladiolus.  468 
Glands,  137 

Glandular  Hairs.  07, 130 
Glandular  Scales,  97 
GleditscUia,  533 
Gleicbenia,  374,  376 
Gleicheniaces,  376 
Globe  Amaranth,  496 
Globe  Flower,  564 
Globoids,  57 
Gloeocapsa,  216 

Glossology  of  Angiosperms,  426 
Gloxinia,  499 
Glucose,  62,  180, 181 
Glumales.  45:{ 
Glycyrrlnza,  532 
Glyphidei.  310 
Glypbis,  310 

GnetaceaB,  396,  401,  410,  413 
Gnetum.  413 
Golden  Lily,  460 
Golden  Rod,  516 
Gomplionema,  229 
Gomplionemaceae,  230 
Gomphrena,  496 
Gonidia,  217,  218,   219.  295,  301, 

807 
GoodeniacesB,  512 
Gooseberry,  62,  64, 283, 486,  526 
Gordonia,  548 
Gossypium,  426,  546 
Gourd,  20,  184,  522 
Gourd  Family,  521 


Qramine«,  04. 129.322, 425. 453,473 

Graramatopliora,  231 

Granulose,  55,  'i6 

iirape,  62,  64,  264,  284,  288, 537 

Grape  Mildew,  264 

Grapevine,  61 

Graphidiacei,  310 

GrRpbis,801.306,310 

Grasses,  a5,  93,  98,  102,  150,  187, 

195,  289,  295,  316,  823, 421,  429, 

436.  464 
Grass' Family,  453 
Gravitation  and  Geotropism,  194 
Great  Laurel,  510 
Greenheart  Tree,  494 
Green  Hellebore,  460 
Grevillea,  491 
Grindelia,  516 
Ground  Cherries,  500 
Ground  Tissue,  89,  123 
Grouping  of  Living  Things,  203 
Growing  Point,  87 
Growth  of  Cell- Walls,  22 
Guaiacum,  543 
Gdavas,  523 
Guinea  Pepper.  461 
Gulf- Weed.  269 
Gum.  62.  63,  120 
Gumbo,  547 
Gummy  Substances,  06 
Gum  Acacia,  533 
Gum  Ammoniacum.  520 
Gum  Arabic,  6  i,  533 
Gum  Asafoetida.  520 
Gum  Benzoin,  505 
Gum  Copal.  533 
Gum  Canals,  129 
Gum  Euphorbium.  484 
Qum  (iaibanum,  520 
Gum  Kino,  532 
Gum  Lac,  490 
Gum  OpopanaT,  520 
Gum  Storax,  505 
Gum  Tragacanth,  63,  532 
Gunja.  488 

Gutta  Percha.  78,  506 
GuttiferaB,  548 
Guttiferales.  547 
Gyalecta,  309 

Gymnocarpous  T^ichens,  297,  298 
Gymnocladus.  533 
Gymnospermse,  893.  568 
Gymnosperms,  60,  80, 85, 118.  128, 

391,  393,  4;^7,  569,  570 


Digitized  by 


Google 


590 


GENERAL  IXDEX, 


Gymnosporangium,  314, 815, 817 

GymnoBtemium,  469 

Gynandrous.  249.488 

Gynodcium,  419,  430,  433 

Gypsophila,  550 

Gyrostomum.  309 

Habenaria,  470 

Hackberry.  488 

Hsemanthus.  171,  4G8 

HamatoxyloD,  588 

Hsemodoraceae,  467 

Hairs,  90. 187 

Haleeia.  505 

Halimeda,  254 

Halionyx.  231 

Halonia,  8^5 

HalorageaB,  525 

HalosaccioD,  277 

Hamamelaceie,  526 

HamameliB,  526 

HapIoBtephaniB,  334 

Haschisch,  488 

Hauptplasma.  4 

Haustoria,  258,  279,  817 

HautBchicht,  4,  16 

Hawthorn,  428,  527 

Hazel,  187,  284 

Hazel  Nut.  477 

Head,  428 

Heads,  Racemose.  429 

Heads,  Bpicate,  420 

Heath,  5U9 

Heath  Family,  508 

Heat-Rays  of  Spectrum,  192 

Hedeoma,  497 

Hedera,  108,  129,  165, 194,  519,  564 

Helenioideae.  514 

Heliamphora.  557 

Hellantnemuiii,  552 

Helianthus.  62, 102, 151,  284,  514 

Helianthoidese.  514 

Helichrysum,  516 

Helicoid  Cyme,  429 

Helicoid  MoDopodiam,  140 

Helicoid  Sympodlal  Dicholomy,  140 

Heliopelta.  231 

Heliopelie®.  231 

Heliotrope,  502 

Heliotropism,  193, 200 

Heliotropiam,  502 

Helipterura,  515 

Hellebore,  563 

Helleboras,  563 

Helminthostachys,  880 


Helvella,289 

HelvellaceiB,  286,  283.    291    295^ 

299,889 
Hemerocallis,  159,  429,  460 
Hemiaulus,  231 
Hemicyclic  Flowers,  429 
Hemitelia,  877 
Hemlock,  520 
Hemlock  Spruce,  154,  411 
Hemp,  61.  188.  488 
Henbane,  502 
Henna,  523 

Hepatica,  147,  187,  563 
Hepaticae.  348, 361 
Heppia,  309 
Heptandroos,  432 
Herd's  Grass,  455 
Hermaphrodite  Flowers,  431 
Heruandies,  492 
Hemioid  Protrusions,  80 
Hesperis,  554 
Heterocysts,  206,  217 
Heterodermefie,  211 
Heteroecism,  314 
Heterogonous,  435 
Heterojfonous  Dimorphous,  485 
Heteroj2fon<>us  Triniorphous,  435 
Heteromerous  Flowers,  430 
Heteromerous  Lichens,  295,  801 
Heterosporeae,  872,  383 
Heierostyled,  ASH 
Heterothecium,  310 
Heuchera,  106 
Hevea,  78,  485 
Hexandrous,  432 
Hibiscus,  547 
Hickory,  144,  158.  482 
Hickory-nut.  73.  4e<2 
Hieracium,  150 
Hilum  of  Surch,  5$ 
Hippomane.  485 
Hippuris.  88 
Holly,  94,  539 
Holly  Family,  539 
Hollyhock,  547 
Homology  and  Analogy,  120 
Homodmerous  Lichens,  295,  801 
Honey,  421 
Honey  Locust,  533 
Honeysuckle,  199,  518 
Honesty,  554 
Hop,  61,  199,  283,  488 
Hop  Tree,  642 
Hordeum,  455 


Digitized  by 


Google 


GENERAL  INDEX. 


591 


Horeliound,  407 

Hornbeam,  477 

Horsecliestnut.  58, 144,  429, 537 

Horeemint,  ^8 

Horsenuiisb,  03,  554 

Hottonia,  186 

Houseleek,  536 

Hoiuitonia,  517 

Hoya.  61.  503 

Hackleberiies,  511 

Hadsoiiia,  553 

Hamiriace®,  543 

Humulus,  103,  488 

Hyacinth.  94, 103, 165,  460 

Hyacinthus.  400 

Hyduum,  838, 330, 3:)! 

Hydra,  50 

Hydralee.  473 

Hydranjirea,  526 

Hydrocarbons,  68 

Hydrocharidese,  473 

Hydrodictyon,  65,  333 

Hydrogen,  175. 179 

Hydropbyilaceffi,  503 

Hydrotbyria.  309 

Hygroscopic  Tissue,  157 

Hymena&a,  583 

Hymenium,  378,  286,  397,  333 

Hyinenophyllaceie,  376 

Hymenopbylliim,  376 

Hymenomycetes,  389, 333, 336,  338. 

339 
Hyoscyamus,  503 
Hypericacese.  549 
Hypericum.  133.  433,  549 
Hyphffi.  194.  333 
Hyphseue,  465 
Hypbomycetes.  888 
Hypnea,  377 
Hypneae,  277. 
Hypnum,  860 

Hypocotyledonary  Stem,  404 
Hypoderma,  73,  134 
Hypodermi^e,  838,  839 
Hypogynous,  434 
Hyponasty,  199 
Hypophysis,  434 
Hypoxylon.  394 
Hyssop,  497 
Hyssopus,  497 

Iberis,  441.  554 

Ice  Crystals,  formation  of,  189 

Iceland  Moss,  308 


Ice  Plant,  530 

Hex,  539.  565 

IliciueiB,  539,  565 

Imbibation  power  of  Protoplasm, 

5,168 
Impatiens,  14,  61,  85,  88,  159, 165, 

193,  364,  431, 543 
Incombustible  substances,  35 
Incomplete  flower,  431 
Incumbent  cotyledons,  437 
Indehiscent.  435 
Indeterminate  inflorescence.  438 
Indian  Corn.  52,  56,  57,  59,  62,  70, 

106.  118, 114,  131.  155,  157,  165, 

166, 187,  318.  833,  451.  455,  533 
Indian  Turnip,  61,  438 
Indian  Pipe,  511 
India  Rubber,  78,  485 
Indigo,  533 
ludigofera,  532 
Individual  development,  204 
ludusium,  874 
Inflorescence,  437 
lunate  Anthers,  433 
Insect  agency  in  Pollination,  431 
Insects  Killed  by  parasitic  plants, 

294 
Integument  of  ovule,  401 
lutercalary  growth  of    cells,   23, 

140.  246 
Intercellular  canal.  114,  409 
Intercellular  spaces,  70,  99,    128, 

156, 167,  171.  197 
Intercellular  substance,  35.  68 
liiturfascicular  cambium,  408 
Intermediate  tissue,  125 
Internal  cell-formation,  36,  39 
Internal  structure  of  Leaves,  155 
Intine,  84 

Intrufascicular  Canal.  Ill 
Introrse  anthers,  4;{3 
Intussusception.  81,54 
Inula,  62,  516 
Iniilin.  62.  180 
InuloidesB,  515 
lonidium,  551 
Ipecacuanha.  517.  551 
Ipomoea,  14,  53,  70,  503 
Iridacese.  468 
Iris,  61, 102. 157, 158,  468 
Iris  Family,  468 
Irish  Moss,  277 
Iron,  175 
Iron  Bark  Tree,  524 


Digitized  by 


Google 


592 


GENERAL  INDEX. 


Iron  Salts.  170 

Iron. weed,  516 

Ironwood,  284.  477. 505.  530 

Irregular  dehiscence.  435 

Irregular  flowers,  431 

Isatis.  554 

lBoete«,  883,  887, 889, 891 

Isoetes,  882. 888,  403 

Isomerous  flowers,  430 

Isonandra.  506 

Isosporese.  372, 883 

IsostemonouB,  432 

Isthmia,  231 

Ivory  Nut,  463 

Ivy.  98. 129.  165, 194.  519 

Ixora,  518 

Jack  Fruit,  489 
Jalap,  502 
Jamaica  Cedar,  540 
Jamaica  Ginj^er.  473 
Jamaica  Rosewood.  505 
Japanese  Wax,  535 
Japan  Lacquer.  535 
Japan  Lily,  460 
Jarool.  523 
Jarrali,  524 
Jasminum.  505 
Jatropba.  4^4 
Jerusalem  Artichokt*,  515 
Jessamine.  505 
Joint-Firs.  410, 413 
Jonquil.  468 
Judas  Trees.  533 
J  uff landacese,  480.  504 
Juglans.  102,  480,565 
Jujube.  530 
Juncaces,  457 
J  uncus,  131 

Jungermannia,  150,  849,  851 
JungermauDiacete.  845,   847, 

858 
Juniperus,  17,  81,  410,  411 
Justicia.  499 
Jute,  545 

Kaki,  506 
Kale,  553 
Kalmia.  510 
Kapor,  547 
Kaulfussia.  879 
Kauri  Pine.  413 
Kentucky  Blue  Grass,  455 
Kentucky  (Coffee  Tree.  538 


851, 


Khenna.  523 
Kniffbtia,  491 
Koelreuteria.  537 
KohlRabi.  554 
Kuhne's  Experiment,  9 

Labiatffi,  71. 132,  497 

Laburnum.  532 

Lace-Bark  Tree.  493 

Lacistemaceie,  484 

Lacquer,  535 

Laauca.  512 

Lactucarlum,  512 

Lady's  Slipper.  409, 542 

l^lia,  471 

Lsevuloee,  62 

Lagenaria,  522 

Lagetta.  498 

Lagerstroemia,  523 

Lambkill,  510 

LamelliB  of  CelUwall.  68 

Lamiales,  497 

Laminaria.  268 

Laminariacee.  839 

Laminarites.  269 

Lanceolate  Leaves,  146 

Lance  Wood.  561 

Lantana.  498 

Laportfa.  491 

Larch.  185,  412 

Urix.  81.  409,  411.  413 

Larkspur.  564 

Larrea,  543 

Lateral  Buds.  143 

Lateral  Conjugation,  234 

Lateral  Stems,  142 

Latex,  76 

Laticiferous  Tissue,   67.  76.   106 

119.  124.  863,  892 
I^tlirsea.  56 
Lathy  rus.  532 
Latticed  Cells.  17,  79.  Ill 
Lauracese.  493,  565 
Laurales.  493 
Uurel.  493.  510 
Laurel  Family,  498 
Laurelia,  494 
Laurus,  493.  564.  565 
Lavandula,  497 
Lavender.  497 
Lawsonia.  528 
Layers  of  CelUwall,  84 
Lead -pencil  Wood,  411 
Leaf.  186,  144.  197.  265,  869 


Digitized  by 


Google 


OENEBAL  INDEX. 


593 


Leaf-forms,  146 
Leaflet,  147 
Leaf-stalk,  145 
Leaf-tissue,  155 
Lecanactidei,  810 
Lecanactis,  801,  810 
Lecanora,  309 
Lecanorei,  309 
Lecidea,  810 
Lecideacei,  809 
Leddeei,  810 
Leek,  61,  458 
Left.  To  the,  199 
Legume,  486 

Lej(amiuo08d,  426,  581, 565 
L^^minosites,  565 
Lejeunia,  851 
Lejolisia,  274.  277 
Lemaniacesd,  839 
Lemna,  165 
LemnaceiB,  461 
Lemon,  64,  180, 182,  547 
Lemon  Verbena,  498 
LennoacesD,  508 
IjentibulariacesD,  499 
Lentioel8»  126,  532 
Lenzites,  831 
Leonia,  552 

Lepidium,  188,  264, 425, 554 
Lepidodendreae,  885 
Lepidodendron,  385 
Lepidopbloios,  885 
Lepidofltrobas.  385 
Leptogium.  295,  306, 809 
Lessonia,  268 
Lettuce,  512 
Leacadendron,  491 
Leuoobrjum,  851 
Leuoojum,  468 
Leucopogon,  510 
Leucoeporee,  339 
Lever-wood,  478 
Liatris,  429,  516 
Libocedrus,  411 
Licania.  531 
Licea,  211 
Licbenales,  887 
Licbenes,  295,  387, 889 
Licbens,  217,  218,  295,  888 
Licbina,  809 
Ligbt,  169, 190, 197 
Ugnification,  35 
L£nnm-vit«B,  543 
Ligule,  883,  880 


Lij2rustmm,  505 

Lilac,  102,  126, 144,  158, 159,  284, 

505 
Ulac  Bligbt,  140 
Llliaceaj,  94.  425,  458,  478 
Uliales,  457 
Lilium,  102.  460 
Lily.  94,  102,  460 
Lilj  Family.  458 
Lily-of.tbe-Vallej,  61.  460 
Lima  Bean,  532 
Lime,  64,  541 
Lime  Salts,  176 
Lime  Tree.  545 
Limits  of  Temperature.  184 
Limnoria,  498 
Linacese,  543 
Linaria,  318 
Liuden,  146,  545 
Linden  Family,  545 
Linear  Leaves,  146 
Linen,  544 
Linn,  545 
Linociera,  505 
Linseed  Oil.  62,  544 
Linum,  543 
Liparis,  471 
Lippia.  498 
Liquidamber,  526 
Liquorice,  532 

Liriodendron,  72,  85,  562, 5C4 
Litcbi.  587 

Litbospermum,  421,  436 
LitmuH,  308 
Live-forever,  626 
Live-leaf,  526 
Live  Oak.  479 
Liver  leaf.  187 

Liverworts.  91,  841,  843,  351,  356 
Loasacete,  522 
Lobelia.  511 
Lobeliacese,  77, 511 
Lobes  of  Leaves.  147 
Loblolly  Bay,  548 
Loculicidal  Deliiscenoe,  435 
Locust  Tree.  61,  532.  533 
Lodoicea,  465 
LoganiaceflB,  503 
Logwood,  533 
Lombardy  Poplar,  487 
Loment,  436 
Lomentaria.  277 
Longan,  537 
Long-flowered  Lily,  400 


Digitized  by 


Google 


594 


GENERAL  INDEX. 


Long  Mom,  47 
Longitudinal  TenBion,  201 
Lonicera,  518 
LoranthaceflB,  477 
Love  Flower,  400 
Love-in-a-Mist,  564 
Lucerne,  166, 532 
Lufi&.  522 
Luuaria,  554 
Lupine,  58,  59,  532 
Luplnus,  532 
Lupulin,  488 
Ljchnis,  550 
Ljchnotkaninus,  884 
Ljcium,  502 
Lyoogola,  10 
Lyooperda4:ee,  889 
Ljooperdon,  824, 825 
Lyoopersicum,  500 

liacefe.  80,   123,  383,  884. 


Lycopodine,  862,  882,  889 
Lyoopodium,  81,  112, 121, 123, 150, 

m,  884,  885 
Lygodium.  874,  877 
Lysilouia,  534 
Lysiiuacliia,  509 
Lythracea),  522 
Ly  til  rum.  523 

Mace,  494 
Maclura.  102.  490 
Macrocystis.  268 
Macrogonidia,  219 
Macrosporangia,  873,  382,  886 
Macrospores.    862,  371,  378,  881, 

882.  886.  889,  403 
Macrozauiia,  410 
Macrozoogonidia,  223 
Madder.  518 
Madeira  Vine,  495 
Madrona.  509 
Magnesia  Saltn.  176 
Magnesium,  175 

Magnolia,  426.  437,  561,  564,  565 
Magnoliacea;,  561, 565 
Magnolia  Family.  561 
Mahogany,  524.  540 
Mabonia.  559 
Maize.  455 
Malaxide».  471 
MalaxiB,  471 
Malay  Apple,  523 
Malic  Acid,  64,  182 


Mallotinm,  801,  806 

Mallow,  144,147,547 

Mallow  Family,  546 

Malpigbiaceie,  543 

Malva,  85, 547 

Malvaceie,  98. 546 

Malvalee,  544 

Mammea,  549 

Mammee  Apple,  549 

Mamillaria,  151 

Mauchineel  Tree,  485 

Mangel  Wurtzel,  495 

Mangifera,  535 

Mango,  535 

Mangosteen,  548 

Mangrove  Tree,  524 

ManAiot,  484 

Manilla  Hemp,  472 

Manzauita,  156.  509 

Manubrium,  831 

Maple,  77, 145, 147, 187, 284, 585 

Maranto,  473 

Marattia,  879 

MarattiaoesB.  863,  872, 878,  880 

Marcliantia,  14.344, 347, 848, 851 

Marcbantiacese,  91,850 

Marigold,  514 

Marmalade,  506 

Marrubium,  497 

Mar8ilia,881,  382 

Marsiliacete,  382 

Martynia,  98,  197,  499 

Marvel  of  Peru,  497 

Mastic,  535 

Mastigonema,  218 

Mastigonia,  281 

Mate,  540 

Mathematical  Gymnastics,  152 

Mattbiola,  554 

Matisia,  547 

Maurandia,  500 

Maximum  Light,  191 

Maximum  Temperature,  184 

MayaceaB,  457 

May  Apple,  437,  559 

Mayflower,  187,  510 

Meadow  Grass.  166.  185 

Meadow  Saffron,  460 

Mecouic  Acid,  182 

Medicago.  532 

Medullary  Ra^?.  408, 449 

Meffalospora,  298 

Melaleuca.  150 

Melambo  Bark,  485 


Digitized  by 


Google 


GENERAL  INDEX, 


595 


Melampsora,  8H  815 

MelanoepermeiB,  208,  887 

Melaspilea,  810 

Melastomaceae,  523 

Mella,  540 

Meliace®,  540 

Melianthe®.  585 

Melicocca,  587 

Melobesiace®,  380 

Melon.  522 

Melosira,  281 

MelosiresB,  281 

Members  of  the  Plant  Bodj,  188 

Menispermaceae,  560 

Menispermum,  560 

Mentha,  497 

Menzies'  Spruce,  412 

Mericarp.  436 

MerismoptHlia,  216 

Meristem,  86, 168 

Meroxylon,582 

Mescal,  468 

Mesembryanthemum,  520 

Mesocarp,  485 

Mesocarpeie.  285,  241,  243 

Me80carpu8,235,288 

Metaspermse,  808 

MetasUsiB.  62, 179,  186,  192 

Micrasterias.  227 

Microbacteria,  218 

Micrococcus,  218 

Micro^onidia,  210,  804 

Micropyle,  891.  419 

Microsph»ra,281.  288 

Microsporangia,  372,  382,  886,  890, 

402,418 
Microspores,  862, 871, 872, 881, 882, 

886,889 
Mignonette,  428, 552 
Mikania,  516 
Mildew.  Grape,  264 
Milkweed  Family,  503 
Mimosa,  197. 198,  534 
MimoseaB,  533 
Mimosites,  565 
Mimulus,  197,  500 
Minimum  Light,  191 
Minimum  Temperature,  184 
Mint  Family.  497 
Mirabilis.  497 
Mistletoe,  58,  94. 182.  477 
Mistletoe  Family,  477 
Mitella,  106 
Mitchella.  517 


Mixed  Inflorescence,  428,  429 
Mniam,  858,  860 
Mock  Orange,  526 
Modes  of  Branching.  189 
Molecules  of  CeU-wall.  82, 167 
MoUuifo,  520 
Monadelphous,  482 
Monandrous.  482 
Monarthrodactyls;  834 
Monera,  15.  207 
Monimiaceae,  494 
Monizia,  520 
Monkey  Flower.  500 
Monkey  Pot.  524 
Monkshood.  562 
Monocarpellary,  488 
Monochasium,  429 
Monochlamydeous.  481 
Monoclinous  Flowers,  481 
Monocotyledones,  393.  451,  568 
Monocotyledons,  88,  93,  123,  148, 

161,  318,  391,  416,  451,  569.  570 
Monocyclic  480.  482 
Moncecious.  249,  431 
Monogyncecial  Fruitu,  486 
Monngynous,  438 
Monomerous,  430 
Monopetalous.  481.  482 
Monopodial  Branching.  131 
Monosepalous,  481.  432 
Monosymmetrical  Flowers,  481 
Monotropa.  192,511 
Monotropese,  508.  510 
Monterey  Cypress,  411 
Moonseed,  560 
Moose  wood,  492 
Mora  Tree,  583 
MoracesB.  488.  565 
Morchella.  289 
Morel,  289 
Moringesd.  584 
Morning  Glory.  63,  199,  602 
Morphia,  182.  556 
Morphological  Resemblances.  202 
Morphological  Unit,  20 
Morphology.  Special.  202 
Morus,  490 
Mosses,  46.  86,  92.  187.  148.  145 

155, 194.  200.  841,  843,  851,  882 
Mother-cells.  39 
Moulds,  194.  285,  285.  288 
Mountain  Ash.  64,  201 
Mountain  Bay.  548 
Mountain  Mahogany,  529 


Digitized  by 


Google 


596 


GENERAL  INDEX. 


Movement  of  Water,  172 
Movements  due  to  External  Stim- 

ull.  197 
Movements  of  Natation,  199 
Movements  of  Plants.  196 
Movements  of  Protoplasm,  6,  196 
Movements  of  Torsion,  200 
Mucila^re,  85 
Mucor,  212,  236.  241 
MucoraceiB.  338 
Macorini,  235,  242.  336 
Mulilenber^a,  455 
Mulberry.  61.  437,  490 
Mullwrrj  Family,  488 
Mullein.  98,  500 
Mullein  Pink,  550 
Multilocular.  433 
Mummy-cloth.  544 
Musa.  472 
MussB,  472 
Musci.  343.  351 
Muscites.  360 
Mushroom,  328,  830 
Musk  Tree,  516 
Mustard.  63.  98.  436.  554 
Muiisiaces.  512 
Mycelium.  235 
Mycetales,  837 
Mycoderma,  212 
Mycoporum.  310 
Myoporineffi,  488 
Myosotis.  502 
Myrica,  487, 564 
Myricaceie,  487, 564 
Myristica,  494 
Myristicacete,  494 
Myrrh,  540 
Myrsinac4«.  506 
Myrsiphyllum,  460 
Myrtaces.  425,  523.  565 
Myrtales.  522 
Myrtle  Family,  523 
Myrtle  (Trailing),  504 
Myrtle  Tree.  524 
Myrtus,  524 
Myxomycetes,  6.  10. 11. 15.  21,  86, 

44, 59,  60. 170.  178.  207.  886,  340 

Naiadaceie.  128,  466,  473 

Naiads,  128 

Naias.14 

Naked  flowers.  481 

Narcissales.  467 

Narcissus^  61.  468 


Nasturtium,  548, 554 

Navicula.  230 

Naviculee,  230 

Neck  cells,  402 

Nectandria,  494 

Nectar,  421 

Negative  Heliotropism,  193 

Negundo,  536 

Nelumbium,  131.  558 

Nemaliaceffi,  839 

Nemalion,  274,  277 

Nemopliila.  503 

Neottieae,  470 

Nepenthaceae,  482 

Nepenthales,  482 

Nepenthes.  182,  482,557 

Nephelium.  537 

Nephroma,  809 

Nereocystis,  268 

Neriam,  504 

Nettle,  11.  491 

Nettle  Family,  490 

Neutral  Flowers,  431 

Nicotiana,  502 

Nicotine,  182 

NigrelU,  564 

Night-Blooming  Cereus,  520 

Nightshade  Family,  500 

Nipace»,  468 

Nitella,  17,  200, 833 

Nitelleie,  883 

Nitrates,  176. 180 

Nitrogen,  175, 180 

Nitzscbia,  231 

Nocturnal  positions  of  leaves,  199 

Norfolk  Island  Pine,  418 

Normandina.  310 

Norway  Spruce.  412 

Nostoc,  87,  206, 217 

Nostocaceie.  55, 216,  805.  806, 888 

Notelsea,  505 

Nucleoli.  16 

Nucleus,  16, 206 

Number  of  Species.  566 

Number  of  Stomata,  102, 103 

Nuphar,  131 

Nut.  436 

Nutation,  199 

Nutgnlla,  479 

Nutlets,  436 

Nutmeg,  494 

Nutmeg  Family,  494 

Nut-oils,  482 

Nut  Pine.  412 


Digitized  by 


Google 


GENERAL  INDEX. 


607 


NatrltioD  of  Parasitefi,  183 
Nutrition  of  Protoplasm,  180 
Nutrition  of  Ssproplijrtes,  188 
Nux  Vomica,  603 
Njctaginacese,  497 
Nympbffia.  131,558 
Nymphaeacea?,  128,  435, 557 
Nyssa,  519 

Oalt.  64,  147.  173,  384.  431,  486, 

479 
Oak  Family,  477 
Oat,  56,  58,  59.  166,  816, 818,  833, 

338,455 
Oblong  Leave«»,  146 
OchnaceaB,  540 
Ochroma,  547 
Octandroufl.  433 
(EdogoniacesB,  369.  371.  839 
(Edogonieffi,  346,  369,  336,  337 
(Edogonium.  10,  33, 43,  51,  350 
(Enotbera.  11,  98.  418,  533 
Oidinm,  384 
Oil,  63. 139 
OiLcake,  544 
Oil  of  Caraway,  63 
Oil  of  Juniper,  411 
Oil  of  Lavender.  497 
Oil  of  Lemons.  63 
Oil  of  Peppermint,  497 
Oil  of  Rhodium.  503 
Oil  of  Tbyme.  63 
Oil  of  Turpentine.  63 
Oily  Matter,  179,  181 
Okra,  547 
Olacales,  539 
OlacinesB,  540 
Oldfieldia,  485 
Olea,  103,  505 
Oleaceffi,  504,  565 
Oleander,  94,  504 
Olearia,  516 
Oleaster,  493 
Olibanum,  540 
Oligomeris,  553 
Olive,  505 
Olive  Family,  504 
Olive  on,  63,  505 
Ompbalaria,  306,  809 
Onagracese,  61,  533 
Onion,  61,  63.  77.  98,  199,  833, 458 
OnobrycbuB,  533 
OnygenesB,  888 
Onygenacee,  839 


Oogonium,  34S,  367 
Oospore,  46.  56.  343.  368 
Oopbyta.  205,  343.  369,  835.  837, 

339, 568, 569.  570 
Oosphere,  45,  343. 367 
Opegraplia.  310 
Opegrapbei,  310 
Open  Bundle,  131.  443 
Opening  of  Flowers,  199 
Operculum.  855,  860 
Opbioglossaceae,  371, 873,  879, 884, 

389 
Opbio^lossum.  80,  880,  881 
Ophrydew,  470 
Opium,  78, 556 
Opium  Poppy,  183.  556 
Opposite  Leaves,  149 
Optimum  Light,  1G1 
Optimum  Temperature.  184 
Opuntia,  150.  520 
Orange,  130.  132.  541 
Orang    Lily,  460 
Orchard  Urass.  455 
Orchidales,  468 
Orcbidacee,  469 
Orchids,  137. 483,  469 
Orchil,  308 
Orchis,  470 
Ordeal  Poison,  604 
Organic  Acids,  180 
Organic  Compounds  as  Food,  176, 

178 
Organogeny  of  tbe  Flower,  436 
Orobanchacese.  500 
Orobanche.  56 
Omitbogalum,  461 
Orthosticbies.  149 
Oryza,  455 
Osage  Orange,  490 
Oscillatoria,  37,  67,  317 
OscillatoriaceaB,  317. 338 
OscillatoriaB,  58.  55 
Osmunda,  81. 377 
Osmundacese,  377 
Ostrya,  73,  477 
Ourari,  603 
Ovary,  391.  417.  418 
Ovules.  186,  187,  890,  403. 419 
Oxalic  Acid,  64, 180, 182 
Oxalis,  197. 435,  642 
Ox  Eye  Daisy,  514 
Oxidation  in  Metastasis.  179 
Oxidized  Essences,  63 
Oxygen,  175 


Digitized  by 


Google 


598 


GENERAL  INDEX, 


Pieonia,  426,  564 

Palisade  Tissue,  156 

Paliuras,  565 

Palm,410.  443,463.  478 

Palmaceee.  425,  463 

Palma  Christa,  484 

Palmales,  462 

Palmatelj-compound  Leaves,  148 

Palmately-lobed  Leaves,  147 

PalmellaoesB,  51,  218.  306. 889,  840 

Palmetto,  465 

Palm  Family,  463 

Palm  Oil,  62,  464 

Palm  Wine.  464 

Palmyra  Palm,  465 

Panama  Hat»,  462 

Pandanaces.  462,  473 

Pandanus,  462 

Pandorina,  10,  221,  242, 244,  836 

Panicle,  429 

Panicled  Heads,  429 

Panicled  Spikes,  429 

Panicnm,  98 

Pannaria,  309 

Pannariei.  309 

Pansy,  551 

Papaver,  556 

Papaveraceae.  77. 119,  556 

Papaw,  522,  561 

Papayace»(  =  Passifloraceae),  119, 

522 
Paper  Mulberry,  490 
Papilionacefe,  581 
Pappus,  512 
Papyrus,  457 
Parajiruay  Tea,  540 
Paraphvses,  288,  292,  353 
Parasite.  53, 176. 178, 182,190, 192. 

250,270,4Hi 
Parasites,  Roots  of,  137 
Parasticliies.  151 
Paratonic  Movements,  196 
ParencUvma.  18,  69,  90,  106,   119, 

124,  843,  351,  863. 392 
Parietales,  551 
Parietal  Placenta,  434 
Parietoria.  150 

Parmelia,  296,  298,  801,  806.  309 
Parmeliacei,  808 
Parmeliei.309 
Paronycliit«,  494 
Parsnip.  166. 187,  428,  519 
Partridge  Berry,  517 
Passiflora,  522 


Passifloraceie.  522 

Passiflorales,  520 

Passion  Flower  Family.  522 

Pasteur's  Solution,  214 

Pastinaca,  519 

Pasture  Thistle,  514 

Paullinia.  537 

Paulownia.  500 

Pea,  56, 58.  59.  149, 187,  188.  28< 

436.531 
Peach.  62. 435, 580 
Peanut.  532 
Pear.  527 
Peat  Mosses.  857 
Pecan  Nut,  482 
Pectin,  68 
Pedaliaceie.  499 
Pediastrum,  65, 224 
Pelarjronium.  543 
Peltigera,  806,  309 
Peltigerei,  809 

Penicillium.  215.  288,  285, 286, 289 

Pennyroyal,  497 

Pentacarpellary,  488 

Pentacyclic,  430 

Pentamerous,  430 

PentandrouB.  432 

Pentapetalous,  432 

Pentasepalous,  432 

Pentstemon,  500 

Peony,  58.  564 

Peperomla.  488 

Pepo,  436 

Pepper.  483.  561 

Pepper  Family,  488 

Pepper  Grass,  554 

Peppermint,  497 

Peppers,  501 

Pepperworts,  872.  881 

Peppridge,  519 

Perianth,  349,  418,  431 

Periblem,  162 

Pericambium.  110, 114, 162, 164 

Pf  ricarp,  273.  275, 426.  485 

Pericliietium.842.  846 

Peridium,  312,  324 

Perigynous.  434 

Perilla,  408 

Periploca,  503 

Perisperm.  425 

PerisporiaceiB.  273,  278 

Peristome.  360 

Peritheciuni  (pL— a.).  281,  289,  297 


Digitized  by 


Google 


GENERAL  INDEX, 


599 


Periwinkle,  83,  504 
Permanent  Tissues,  86,  144 
Peronospora,  259,  264 
Peronosporacese,  339 
Peronosporeee,  46,   258,  269,  317, 

337,840 
Peraea,  494 
Persimmon,  506 
Personales,  498 
Pertusaria,  298,  809 
Peruvian  Bark,  64,  182,  517 
Petal,  417,  430 
Petalostemnn,  532 
Petiole,  145,  369 
Petunia,  98, 502 
Peyssonnelia,  277 
Peziza,  270.  271.  286,  288,  289,291, 

297.  301,  323.  330 
Phaoelia,  503 
Pbacidium,  295 

PhsBosporese.  265,  268,  269, 837,  889 
Phallus,  824,  825 
Phanerogamia,  204,  205.  889,  568, 

569.  570 
Phanerogams.  11,  40,  46,  56,  66,  72, 

74,  76,  82,  87,  90,  92.  106,  120, 

123.  137, 140.  161, 164,  265.  270, 

284.  316,  317,  889 
PliascaceiB,  855,  358 
Phascum,  858 

Phaseolus,  88,  475,  531.  582 
Pheasant's  Eye,  564 
Pliellodendron,  542 
Phello^en,  126 
Philadelphus,  103,  526 
Philydreae,  457 
Phleum,  455 
PhloSm,  118,  407 
Phlox,  503 
Phcenix,  4a5 
Phoradendron,  51,  477 
Phosphates.  176 
Phosphorus.  175 
Phraffmidium,  814,  315 
Phycochrf>maceaB,  340 
Phycocyanine.  216 
Phycomyces,  241 
Pbycomycetes,  838 
Phycozanthine,  216,  227 
Phyllactinia.  281,283 
Phyllocladns,  410 
Phyllocyanine,  52 
Phylloglossum,  382,  885 
Phyllome,  134,  186,  243,  271 


Phyllotaxis,  149 

Phylloxanthine,  52 

Physalis,  500 

Physarum,  210 

Physcia,  306. 309 

Physiological  Unit,  20 

Physocalymuia,  528 

Pliysomycetes,  338 

Pliytelephas,  463 

Phytelephasiese.  463 

Phytolacca,  497 

Phytolaccacete,  407 

Picea,  151,409,411,412 

Pie  Plant,  497 

Pigeon  Pea,  532 

Pileorhiza,  159,374,424 

Plleus,  828 

Pilobolus,  237,  241 

Pilophorus.  809 

Pilularia,  381,  882 

Pimento,  5*23 

Pinang,  466 

Pinckneya.  517 

Pine,  94,  412 

Pineae,  411 

Pine-apple,  62,  471 

Pine.apple  Family,  471 

Pinguicula.  500 

Pinhoen  Oil,  484 

Pink  Family,  549 

Pinnately.cora pound  Leaves,  148 

Plnnatoly-lobed  Leaves,  147 

Pinnate  Venation,  145 

Pinus,  34,  69.  a5    102,  151,  894 

397,409.  411,412,415 
Piper,  483,  561 
Piperaceae,  425.  483 
Piperales,  483 
Pipsissewa,  510 
Piptocephalis,  238,  241 
Pirus,  72,  75.  85,  103,  527,  564 
Pistacia,  585 
Pistachia  Nut.  525 
Pistil,  419.  433 
Pistillate  Flowers,  431 
Pisum,  102,  531 
Pitch,  412 
Pitchers,  186 
Pitcher  Plant,  556,  557 
Pith,  124,  128,200,  201,  408 
Pits  in  Cell  walls,  24 
Pitted  Vessels,  84,  113,  863 
PittosporaceaB,  551 
Pittosporum,  551 


Digitized  by 


Google 


600 


GENERAL  INDEX. 


Placenta.  419.  488 

Placodium.  809 

Plag^anthus.  547 

Plane  Tree.  487 

Plane  Tree  Family.  487 

PlatanaoesB.  487.  5(55 

Platanas.  102.  487.  5G4,  565 

Platygrraplia.  810 

Platyzoma.  876 

Planta^nnaces.  507 

Plantago.  106.  507 

Plantain,  106.  428.  472,  507 

Plantain  Family.  507 

Plant  Body.  133 

Plant-Cell.  15 

Plant  Food.  175 

Plasmodium  (pi.— a)  6.  207 

Plectospora,  302 

Plerome,  161 

Pleurocarpae.  859.  860 

Pleurocarpas.  235 

Pleurosigma.  280 

Plum.  62.  146.  292.426.530 

Plum  bag!  nacead.  507 

Plumbago.  508 

Plumule.  186.  886.  404.  474 

Phyco6rytbrine,  276 

Poa.  279.  455 

Podisoma.  (see  Gymnosporangium) 

PodocarpuB.  409.  410 

Podogonium.  565 

Podopbyllum.  559 

Podospbsra.  271.  281.  283 

Pogonatum.  859 

Poison  Hemlock.  520 

Poison  Ivy.  165.  516.  535 

Poison  Oak.  535 

Poison  Sumacb.  585 

Poke-berries.  173 

Poke-weed.  497 

Pole  Bean.  188,  581 

Polemoniacese,  503 

Polemoniales.  500 

Polemonium.  503 

PoliantUes,  461 

Pollen,  34.  46. 186.  889,  417 

Pollen-sac.  894.  418 

Pollen  Tube.  47.  891 

Pollination.  420.  421 

Pollinla.  508 

Polyactis.  288 

PolyandrouB.  482 

Polyantbus,  468 

Polyartbrodactylae,  884 


Polycarpellary,  438 
Polygala.  551 
Polygalacete.  550 
Polygalales.  550 
Polygamous  Flowers.  481 
Polygonaceae.  64.  496 
Polygonum.  82:J.  496,  497 
PolygynoBcial  Fruito,  487 
Polybedral  Cell.  19 
Polyides.  277 
PolypetalaB.  476. 518 
Polypetalous.  481.  482 
PolypodiaceflB.  877 
Poly  podium.  109,  877 
Polypori.  241 
Polyporites,  881 
Polyporus.  828.  880.  881 
Polysepalous,  481,  482 
Polysipbonia.  277 
Polysiphonides.  278 
Pol  ysym  metrical  Flowers,  480 
PolytricUum.  150,  852.  859,  860 
Pome;  486 
PotoeaB.  527 
Pomegranate.  528 
Pondweeds.  466 
PontederaceflB.  457 
Pontederales,  457 
Porcupine  Grass,  157 
Portlandia.  518 
Poplar.  428 
Poppy.  656 
Poppy  Family.  556 
Populus.  150.  487, 564,  565 
Populus.  102.  148 
Portulaca,  197.  264.  549 
Portulacace».  549 
Potamales.  466 
Potamogeton.  181,  186 
Potash  Salts,  176 
Potassium.  175 

PoUto.  56. 58. 166,  181. 187,  500 
Potato  Fungus,  264 
Potentilla.  264 
PotentillesB,  528 
Prickles.  137 
Prickly  Asb.  127.  542 
Prickly  Pear.  520 
Pride  of  India  Tree.  540 
Primary  Bundle,  121 
Primary  Cell-wall.  85.  68 
Primary  Cortex,  408 
Primary  Meristem.  86,  88, 89, 106 
121. 188,  144, 161 


Digitized  by 


Google 


GENERAL  INDEX, 


601 


Primary  Root.  159 

Primary  Stem.  140 

Primary  Wood,  406.  408 

Primine.  419 

Primordial  Utricle,  5 

Primrose,  94,  98, 104,  506 

Primrose  Family.  506 

Primula.  94.  98.  104,  506 

Primulaceffi,  506 

Primulales,506 

Prince's  Pine.  510 

Principal  Tissuet*,  69 

Pringrsbeimia.  250 

Prismatic  Cell,  19 

Privet.  505 

Procainbium,  131 

Pro-embryo.  882,  841,  891,  428 

Proprressive  Division,  49 

Promycelium,  314.  820 

Prosencbvma,  18 

Protamceba,  15 

Protea.  491 

Proteace®,  491 

Proterandrous,  434 

Protero^nous,  434 

Prothallium  (pi.— a),  861,  889,  408, 

418,420 
Protococcus,  86,  87,   65.  185.219, 

221.  307 
Protodermeffi,  210 
Protomeristeni.  80 
Protomycetes.  338 
Protomyxa,  15. 207 
Protonema  (p|.— aU),  341.  350 
Protophyta.  205,  206.  300,  335.336. 

568, 569.  570 
Protopbytes.  206 
Protoplasm,  1,  94.  166 
Protoplasm-Sac,  5,  15 
Prototaxis.  415 
Prototype,  134 
Protozoa.  207 
Pruneae.  530 

Prunus.  102. 103.  530.  564 
Pseiidolarix,  409 
Pseudopodiam  (pi.— a).  8,  355 
Pseudo-Rapbidiete,  230 
Pseudospores.  813 
Pseudotsu^,  411 
Psidium,  523 
Psilotum.  382.  385 
PUeroxylon,  535 
Ptelea,  542 


Pteridopbyta.  205,   835.  861,  868, 

869,  370 
Pteridopbytes.  10,  40.  59.  72,  74. 

80.  ^.  86,  90. 92.  106.  121,  137. 

140:  161, 164.  361,  889,  418,  487 
Pteris.  72.  80,  81.  85.  88, 107,  110, 

111,  869.  377 
Pterocarpus,  532 
Pterocarya.  565 
Pteropbyllum,  416 
Puccinia.  39,  815.  816 
Puff-Bali,  324,  326 
Pulque,  468 
Pulue  Family,  531 
Pulu,878 
Pulvinus,  197 
Pumpkin.   29,   98,   187,  200,  436. 

437,  522 
Puuica.  523 
Punctum  Vejretationls.  87, 138, 140, 

144.  149.  424.  444 
Purslane,  93.  549 
Pycnidia,  281.  293.  290 
Pycnidiospores.  281.  294 
Pyrenastrum.  310 
Pyrenomycetes,  289,  295, 299,  888, 

339 
Pyrenula.  810 
Pyrolinwe,  508,  510 
Pyxine,  309 
Pyxis,  436 

Quadrilocular,  433 
Quandanpr  Nut,  476 
(Quassia.  540 
<4uercine£e,  478 
Quercitron.  480 
Quercitron  Oak,  480 
Quercus.  17.  85, 150,  479,  564 
Quernales,  477 
Quillaja.  529 
Quillaja  Bark,  529 
QuillajesB,  529 
Quillworts.  387 
Quince,  35,  149.  527 
Quinia.  64.  5l7 
Quinic  Acid,  64,  182 
Quinine.  517 

Raceme.  428 

Radial  Bundle.  113,  302,  303 
Radiately-compound  Leaves,  148 
Radiately-lobed  Leaves.  147 


Digitized  by 


Google 


602 


OENERAL  INDEX, 


Radiate  Venation.  145 

Radicle,  404,  474 

Radish,  98,  554 

Rafflesia,  270.  482 

Rafflesiaceae.  270,482 

Ragweed,  515 

Ramfall,  172 

Ramalina,  807,  808 

Ramie,  491 

liamose  Cell,  19 

Ranalea,  466,  557 

RanunculaceiB,  284,  823,  425,  487, 

562 
Ranunculus,  14,  117,564 
Rapateae,  457 
Rape,  554 
Raphanus,  150,  554 
Rapliides,  59,  61 
Raphidiese,  230 
Raspberries,  64,  437,  629 
Rattan,  465 
Rays  of  Different   Refranffibillty, 

191 
Receptacle.  291,  349.  376,  881,  417 
Red  Bay,  494 
Red  Clover,  166 
Red  Currant,  526 
Red-Hot  Poker  Plant,  461 
Red  Lily,  460 
Red  Oak,  480 
Red  Pine,  412 
Red  Rust,  39,  316 
Red  Sandalwood,  532 
Red  Seaweeds,  53,  273 
Red-Snow  Plant,  185 
Red  Top,  455 
Reduced  Bundles,  121 
Redwood,  411 
Re^rular  Flowers,  430 
Reindeer  Moss,  809 
Rejuvenescence.  42,  47,  229,  247 
Relations  of  Caulome,  Phyllome, 

etc.,  135.188 
Relations  to  External  Agents,  184 
Reproductive  Cells,  47 
Reseda,  552 
Resedaceae,  552 
Reserve  MateripJ,  181,  187 
Reservoirs  for  Secretions,  129 
Residual  Products,  61 
Resin,  62,  68,  129 
Resin  Canals,  132 
Resinous  Substances,  96 
liestiaceae,  457 


Restiales.  457 

Restio,  150 

Resting  Spore,  218,  220 

ResUng  Stage,  206,  212 

Results  of  Metastasis,  183 

Resurrection  Plant,  555 

Reticularia.  211 

Reticulated  Tbickeninjr.  28 

Reticulated  Vessels.  83,  Ul 

Retinospora,  411 

Rliabdonema,  231 

Rhodantbe,  515 

RbodoresB,  511 

RbamnacesB,  538.  565 

Rbamnus,  539,  565 

Rbeum,  71.  496 

Rbezia,  528 

Rbizocarpeffi,  870,  871,  872,   878 

881.889 
Rbizocarps,  381 
Rbizoids,  343.  351,  361 
Rbizopbora,  524 
RbizopboraceaB,  524 
Rhizosolenia,  231 
Rliododendron,  510 
Rliodomelacese,  339 
Rbodomeleae,  277,  378 
Rhodospenneie,  837 
Rliodymenia,  277 
Rbodymenies,  277 
Rlioicospbenia,  230 
Rhubarb,  61,  64,  496 
Rhus,  150.  165,535.565 
Rhytisma.  295 
Ribes,  102.  526 
Riccia,  346,  348.  849 
Ricciaceffi,  350,  361 
Rice,  56,  59,  455 
Rice  Paper,  519 
Richardia.  462 
Ricinus,  59,  85,  115   118  120,  475, 

484 
Riga  Fir.  412 
Right,  to  the,  199 
Ring,  828.  825 
Ringed  Vessels,  83, 113 
Ringless  Ferns,  872,  378 
Rings,  28 
Rlnodina,  809 
Ripening  of  Seeds,  58 
Rivulariace».  217,  88& 
Rivularia,  206,  218 
Robinia.  17,  61, 150, 533 
Roccella,  808 


Digitized  by 


Google 


GENERAL  INDEX. 


6oa 


Bocliea,  106 

Ilocket,  554 

Rock-weedB.  2G0 

Root,  134.  187,  159,  187,  190, 101, 

243.  265,  362.  874.  404,  424 
Root-cap.  159.  161,  874.  404 
Root-baire.  19,  95.  137.  161,   343. 

ail,  861.  867 
"Root-prepsure.  173 
Roots  as  Storehouses.  165 
Root-stock,  186 
Rosa,  527 

Rosace®,  64. 150.  425, 527,  565 
Rosales,  524 
Roseae,  527 
Rose  Apple,  523 
Rose  Family.  527 
Rosemary,  497 
Rose  Mallow.  547 
Rose  of  Jericho,  555 
Roses,  283.  437.  527 
Rosette.  402 
Rosewood.  505.  532 
Rosin.  63,  412 
Rosmarinus,  497 
Rotation  of  Organs.  199 
Rotation  of  Protoplasm,  14 
RubetD,  529 
Rubia.  518 
Rubiacese,  516 
Rubiales.  516 
Rubus,  529 
Rudbeckia,  151 
Rudiments  of  Floral  Organs,  426, 

431 
Rue,  182.  542 
Rue  Family,  541 
Rumex,  71.497 
Runners,  1^5,  193 
Ruscus,  461 
Rushes,  457 
Russia  Leather,  487 
Rust.  316 
Ruta,  132.  542 
Rutaoese,  541 
RuteaB,  542 
Rye.  94, 166,  289.  294,  295,  455 

Sabal.  465 
Sabiaceie,  535 

Saccharomyces.  17,  89.  6.5,  214 
Saccharomycetes,  836,  340 
Saccharum,  455 
Sack  Tree,  490 


Safflower,  513 

Saffron.  468 

Sage.  498 

Sage  Brush,  514 

Sagedla.  310 

Sagittaria,  181.  467 

Sago.  410 

Satro  Palms,  466 

Saguerus,  406 

Sagus,  466 

Salep.  470 

Salicaces,  425.  486,  565 

Sa]isburia,410 

Salix.  486.  564.  665 

Salsify.  513 

SalvadoracesD,  504 

Salvia,  498 

Salvinia,  881.  882 

Salviniaceae,  882 

Samara,  436 

Sambucus,  106.  518 

SamydacesB,  522 

San^inaria,  556 

Sandalwood  Tree,  476 

Sand-box  Tree,  485 

Sanfoin.  532 

Santalacese,  476 

Santalales,  470 

Santa! um.  476 

Santa  Maria  Wood.  549 

Sap.  62.  174 

Sapindaceae.  535.  565 

Sapindales.  534 

Sapinde®,  536 

Sapindus,  565 

Sapodilla  Plum,  506 

Saponaria.  550 

Saponin.  461 

Sapotacese,  506.  564 

Saprolegniaceae,  89,  56.  254.  263, 

269.  337,  339.  840 
Saprolegnise,  11 
Saprophyte.  53.  176, 178,  182.  190, 

221,250,270,281,286.323 
Sarcodes.  511 
Sargasso  Sea,  269 
Sargassum,  268 
Sarracenia.  182,  556 
SarraceniaceflB,  556 
Sarsaparilta.  4i59 
Salt,  diffusion  of,  175 
Sassafras,  494.  564 
Sassafras  Bark,  494 
Satin-Wood.  540 


Digitized  by 


Google 


1)04 


GENERAL  INDEX. 


Saunders,  533 

SaururuB,  483 

Saw  Palmetto,  465 

Saxifraga,  106. 193,  194,  526 

SaxifragacesB,  526 

Saxifrage  Familj.  526 

ScabioBa,  516 

Scalariform  Thickening:,  28 

Scalariform  Vessels,  84. 107,  363 

Scales,  90, 136.  187, 155 

Scammony,  502 

Scarlet  Bean.  187 

Scarlet  Oak,  480 

Scattered  Leaves,  149 

Schalen,  34 

Schizomycetes,  178.  211,  836.  338 

Schinus,  535 

Schizsea,  377 

SchizaBaceae,  377 

Schizocarplc  Fruits,  436 

Scbizosporeae,  338 

Scliizoxylon,  415 

Schizynemia,  277 

Schulze's  Maceration,  35 

Sciadopytis,  411 

Scilla.  459 

Scirpus,  150.  818 

Scitamineae,  471 

Sclerenchyma.  71,  89, 112, 124,  843, 

351.  363,  893 
Sclerotium,  290,  294 
Sclerotium  Stage,  208 
Scolecite.  288 
Scolopendrium,  377 
Scorpioid  Cyme,  429 
Scorpioid  Monopodium,  140 
Scorpioid    Sympodial    Dichotomy. 

140 
Scotch  Fir,  412 
Scotch  Pine.  412 
Scouring  Rushes,  85 
Screw  Pine,  462 
Scrophulariaceae.  500 
Scutellum,  451 
Scytonema.  218 
ScytonemacesB,  218,  338 
Secale,  103.  455 
Secondary  Cell-wall,  68 
Secondary  Cortex,  408 
Secondary  Embryo-sacs,  403 
Secondary  Leaves,  147 
Secondary  Spirals,  151 
Secondary  Spores.  320 
Secondary  Sporidia,  320 


Secondary  Wood,  408 

Secretion  Reservoirs,  128 

SectionXutter,  123, 165 

Sections  of  Leaf-buds,  154 

Secundine.  419 

Sedges,  318,  421 

Sedge  Family.  457 

Sedum.  150,  526 

Seed.  167,  181, 188,  891,  404.  426^ 

437 
Segestria,  310 
Selaginella,  111,  113,  123.  382, 386, 

887 
Selaginell».  121,  883, 385,  387,891, 

397 
Sempervivum,  526 
Senecio.  514 
Senecionideae,  514 
Senna,  533 

Sensitive  Plant.  197,  198.  534 
Sepal.  417.  430 
Septicidal  Dehiscence.  435 
Sequoia,  81,  411,  415,  416 
Serrate  Leaf,  147 
Service-Berries,  527 
Sesamum,  499 
Sesbania,  532 
Seta.  342,  355 
Seiaria,  323 
Seville  Orange,  541 
Sexual  Act,  206 
Sexual  Generation,  841,  861 
Sexual  Organs,  306 
Shaddock.  541 
Shallot.  458 
Sheep  Laurel.  510 
Shell-bark  Hickory,  483 
Shells,  34 

Shepherdia,  98.  493 
Shepherd's  Purse.  554 
Shields.  331 
Shower  of  Lichens,  809 
Showy  Lily,  460 
Sida,  547 
Sieve  Cells,  28 

Sieve  Tissue,  79,  106,  868, 893 
Sigillaria,  385 
Sigillarieae,  8a5 
Silene,  550 
Sileneae,  818 
Silicates,  176 
Silicon,  175 
Silique,  436 
Silk  Oak,  491 


Digitized  by 


Google 


GENERAL  INDEX. 


605 


Silk  Tree,  547 

SUphium.   70,  71.  103,   132.   156. 

159.  515 
SUver.Bell  Tree.  505 
Silver  Fir.  412 
Silver  Poplar,  173 
Silver  Tree,  491 
Simaruba,  540 
Simaruba  Bark.  540 
SiiuarubacesB,  540 
Simple  Leaf,  147 
Simple  Pistil.  433 
HimultaneouB  DiviBion,  49 
Sinsrle  Cells.  65 
SiphonacecB,  389 
SiphonesB.  340 
Sirarella,  231 
Sirurelleaa,  281 
Sisymbrium,  98 
Size  of  Cells.  16 
Size  of  Leaves.  146 
Skimmia,  542 
Skunk  Cabbage,  462 
Sleep  of  Plants,  198 
Slime  Moulds.  6.  170,  188. 207 
Slippery  Elm.  488 
Sloanea,  545 
S1ou$;h  Grass,  455 
Smart  weed,  497 
Smilacina,  428 
Smilax.  459,  460 
Smut,  818,  823 
Snakewood,  490 
Snapdragon,  500 
Sneezewood  Tree,  535 
Snowball.  518 
Snow  berries.  518 
Snowdrop,  468 
Snowdrop  Tree,  505 
Snow  flake.  468 
Snow  Plant,  511 
Soap  Bark,  529 
•Soda  Salts.  176 
Sodium.  175 
Soft  Bast.  116 
Solanaceee.  71.  425.  600 
Solanum.  11,  102,  500 
Solldajco,  516 

Solitary  Axillary  Inflorescence,  428 
Solitary  Spores.  819 
Solitary    Terminal    Inflorescence, 

429 
Sollya,  551 
Solorina.  809 


Solutions,  174 
Sonneratia.  523 
Sophora,  532 
Soredia,  305 
Sorghum.  457 
Sorisporium,  819 
Sorrel.  497,  542 
Sorosis,  487 

Sorus  (pi  — sori).  818,  874 
Sour  Gum,  519 
Sour  Sop.  561 
Soy.  532 
Spadix,  428 
Spanish  Bayonet,  461 
Spanish  Chestnut,  478 
Spanish  Needles,  515 
Sparganium,  462 
Speerschneidera.  309 
Sperjf ula,  550 
Spermagonium    (pi. — a).  29f 

812 
Spermatium(pl.— a).298.  299,  812, 

815,323,330 
Spermatozoids.   45.    46,  243,  267, 

271.330,332.341.862 
Sperm  Cells,  841.  362. 
Sphacelariacese.  339 
Sphacelia,  289 
Sphieria,292.294.  295 
SphflBriaceffi,  339 
Sphaerobacteria,  218 
Sphserococcacead,  389 
Sphffirococcites,  278 
Sphffirococcoideae,  277,  278 
Sphaerophorei,  810 
Spheerophorus.  801.  310 
Sphaeroplea.  245.  247 
SphflBropleaceae,  389 
Sphserotheca.  281, 283 
SphagnaceflB.  352,  355.356,  857 
Sphagnum.  351,  857.  858 
Sphenophvllum,  868 
Spheroidal  cell.  19 
Spicules.  324 
Spiderwort,  457 
Spike,  395.  428 
Spinach,  495 
Spiiiacia.  495 
Spines.  136 
Spinea,  529 
Spir»e8d,  529 
Spirals,  28 

Spiral  Vessels.  82, 85, 108.  363 
Spiranthes.  470 


Digitized  by 


Google 


606 


GENERAL  INDEX. 


Spirillum,  213 

Spirobacteria,  218 

SpirochiBte,  218 

SDirogyra.  11.  22,  87,  44. 51,57,  67. 

232.  284. 241 
Splachnum.  859 
Spongiocarpeee,  277 
Sporangium  (pi.— a),  187,  210.  286. 

825,  866, 874. 878 
Spontaneous  Movements,  196 
Spore-case.  842.  855 
Spores.  187, 170,  188, 209.  286.  842, 

861 
Spore-sac.  860 
Sporidia.  290.  814,  817,  820 
Sporocarp.  270, 278, 274.828. 827 
Sporochnaceie.  889 
Sporogonium(pI.->a;.  842,  848,  854 
Spumaria.  210 
Spurious  Tissues.  65 
Spunre  Family.  484 
Spyridia,  277 
Squamarieee,  277 
Squash.  29, 522 
Squill,  459 
Stachys,  441 
StackhousieaB.  589 
Stamen.  186. 197, 199.  894.418,480 
Staminate  Flowers,  431 
Stapelia,  508 
Staph  jlea,  535 
Staphylese.  585 
Star  Apple,  506 

Starch.  53.  78. 165. 179, 181,187 
Starch  Cellulose.  55.  56 
Star  of  Bethlehem.  461 
Stauroneis.  230 
Staurothele,  810 
Stellate  Cell.  19 
Stem.  185. 140.  181, 187.  265 
Stemonitis.  9.  210 
Stephanodiscus.  231 
Stephanopyxis,  281 
Stephanotis.  503 
Sterculiaoeie,  545 
Stereum.  828,  830 
Sterigma  (pi.— ata),  282,  299,  812, 

329 
Btereocaulon.  809 
Sticta.  296,  801.  809 
Stigeoclonium,  42 
Stigma.  197.  419 
Stinging  Nettles,  491 
Stlnk-Hom,  325 


Stipa.  108,  157 

Stipules.  148 

Stoffwechsel,  180 

Stoma  (pi.  stomats).  89, 90, 91, 92, 
99,  155.  170.  185.  191, 812.  848, 
350,  852.  859.  862,  867.  392.  487 

Stomau,  Number  ot.  102. 103 

Storing  of  Reserve  Material.  181 

Stratification  of  Cell-wall.  82.  98 

Strawberries.  62,  64.  434.  529 

Strawberry  Geranium.  526 

Strawberry  Tomato.  500 

Streaming  of  Protoplasm.  6 

Strelitzia,  472 

Striatella,  231 

Striation  of  Cell-wall,  88 

Strigula,  810 

Strings  of  Protoplasm,  16 

Strobile.  437 

Strychnia.  182.503 

Strychnos,  182.503 

Stuartia.  548 

Styles.  199 

Stylidiace».  512 

Stylidium.  512 

Stylospores,  89,  293, 315 

Styracaceae.  505 

Styrax.  505 

Sucrose.  62 

Sugar,  62.  165. 455 

Sugar  Beet,  62,  495 

Sugar  Cane.  62,  93.  495 

Sugar,  Diflfhsiou  of.  175 

Sugar  Maple,  62.  174. 535 

Sugar  Pine.  412 

Sugary  Matter.  179 

Sulphates.  176,  180 

Sulphur,  175. 180 

Sulphuretted  Essences.  63 

Sumach,  64.  585 

Sumatra  Camphor.  547 

Summer  Buds,  141 

Sundew.  526 

Sundew  Family.  526 

Sunflower.  159.  171.  178.  188.48(V 
514 

Sunflower  Family.  512 

Supernumerary  Buds.  148 

Supernumerary  Stems,  148 

Supple  Jacks,  587 

Supporting  Tissue.  89 

Suppression  of  Floral  Organs,  431 

Suspended  Ovules,  433 

Suspension  of  Movements,  198 


Digitized  by 


Google 


GENERAL  INDEX. 


607 


Saspensor,  885, 391,  404, 423 
SwarmsporeB,  36,  209.    222,   260. 

263,278 
Sweet  Alyssum,  554 
Sweet  Bay,  562 
Sweet  Gam-Tree,  526 
Sweet  Oil,  505 
Sweet  PoUto,  143, 165,  502 
Sweet  Sop,  561 
Swietenia,  540 
Symmetry  of  Leaves,  146 
Sympetalous,  432 
Sympodial  Cymose  Monopodium, 

140 
Sympodial  Dichotomy,  140 
SympUoricarpus,  11, 462,  518 
Synalissa,  309 
SynautUerous,  488 
Syncarpous,  433 
Synedra,  231 
Syngenesious,  488 
Sycamore,  487 
SycoDus,  487 
SyriDga,  102,  505 
Systems  of  Tissues,  89 
System  of  Ground  Tissues,  128 

Tabellaria,281 
Tabellarieie.  231 
Taberuffimontana,  504 
Tabular  Cell.  19 
Taccacete.  468 
Taccades,  468 
Tagetes.  514 
Tallow  Tree,  485 
Tamarack,  412 
Tamarind.  64,  538 
Tamarind  us,  583 
Tamuriscine^,  549 
Tamarisk.  549 
Tamarix,  549 
Tauacetum,  514 
Tanbark  Oak.  480 
Tanghin.  504 
Tangbinia,  504 
Tannic  Acid,  64,  182 
Tansy,  514 
Taraxacum,  62,  512 
Tares,  532 

Tartaric  Acid,  64, 182 
Tar,  412 
Tapioca,  484 
Taxine®,  400,  410 
Taxodieae.  411 


Taxodium.  409.  411 

Taxus.  102,  895,  899,  409.  410 

Tea,  182.548 

Teak,  485,  498 

Teasel,  516 

Tecoma,  499 

Tectona,  498 

Teamen.  437 

Tela  Contexta,  66 

Teleutospores,  313 

Temperature,  169,  184, 198 

Tendril,  136,  200 

Teredo.  524 

Termes,  524 

Terminal  Growth  of  Cells,  22 

Ternstroemiaceee.  548 

Terpsinoe,  231 

Tetracarpellary,  438 

Tetracyclic.  430 

Tetradynamous,  432 

Tetramerous,  430 

Tetrandrous,  432 

Tetranthera,  491,  565 

Tetraphis.  357 

Tetrapetalous,  432 

Tetrasepalous,  431 

Tetraspores,  339 

Tetraspores,  273 

Testa,  426,  437 

Testudinaria,  467 

ThallophyU,  203,  204.  205 

Tballophytes.  17.   18.    37,  56,  90, 

140, 145,  205,  264,  857 
Tballophytes,  Classification  of,  835 
Thallome,  134.  243 
Tballus,  342,  461 
Tbamnocbortus,  150 
Thea,  548 
Theca,  355 

Theloscbistes.  307,  809 
Tbelotrenia,  309 
Tbeobroma,  645 
Theobromine,  546 
Theories  as  to  Thickening  of  the 

Cell  wall,  30 
Thespesia.  547 
Tbickeniiijr  of  CelLwall,  23 
Thistles.  99.  187,  513 
Thorn  Apple,  5U2 
Thorns,  136 
Thrift.  508 
Thunbergia,  400 
Thuya,  409,  411 
Thyme,  497 


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608 


GENERAL  INDEX. 


ThjmeleeaceA,  492 

Thymus,  497 

Thyreufl.  429 

Tieut^,  503 

Tiger  Lily,  460 

Tilia.  150,  545 

Tiliacese.  545 

Tillandsia.  471 

Tilletia,  318.  823 

Tilopterideie,  839 

Timothy.  455 

Tipularia.  470 

Tissues,  65,  69,  843,  358,  362,  867, 

405 
Tissues  of  Angiopperms,  437 
Tissud  Systems,  80 
Tjettek.  603 
Tmesipteris.  882,  885 
Toadstools,  39 
Tobacco.  182.  184,  502 
ToddaIie»,  542 
Toddy  Palms,  466 
Todea.  377 
Tolypella.  333.  334 
Tomato,  98.  164.  500 
Torreya,  409,  410 
Torsion,  200 
Torus,  417 
Touch-xMe-Not,  542 
Towel  Gourd.  522 
Tracheary  Tissue.  81. 106,  863.  392 
Tracheldes,  84,  116,  407 
Trachylobium.  533 
Trachymene,  520 

Tradescautia,  11, 12,  13,  61,  98.  457 
TragopogOD,  512 
Trailing  Arbutus,  510 
Trailing  Myrtle,  504 
Transitory  Rigidity,  19S 
Transformation  of  Starch,  180 
Transpiration,  169,  185 
Transportation  of  Food,  176 
Transverse  Tension,  201 
Trapa.  164,  522 
Tree\Ffirns,  146.  373,  377,  410 
Tree^^eltle,  491 
Tree  of  Heaven.  541 
Tremandreae.  551 
Tremella,  289 
TremellacefiB,  339 
Tremellini,  323.  330,  338 
Triadelphous,  432 
Triandrous,  432 
Trlcarpellary,  433 


TrichU,  211 

Trichobasis.  816 

Trichogyne,  271,  286.  800 

Trichomanes,  876 

Tricbome.  92.  95. 134, 187,161,346, 

362,  392.  437 
Trichophore,  275 
Tricyclic.  480 
Trifolium.  103,  533 
Trigynous,  433 
Trilocular.  433 
Trimerous,  480 
TrimorphouB,  485 
TripeUlous.  432 
Trisepalous,  431 
Triticum,  453 
Trltoma,  461 
Triurales,  467 
Triurlde®.  467 
Trolllus.  564 
Tropceolum,  106,  543 
Truffle.  285 
Trypetheliuni.  310 
Tsuga,  33,  150.  409,  411 
Tuber,  136,  181,  190,  191.  285,  286 
TuberacesB,  273,  285,  388,  889 
Tuberose,  461 
Tubulina,  211 
Tulip.  93,  102,  461 
Tullpa.  461 
Tulipomanla,  461 
Tulip  Tree.  523,  562 
Tulip  Wood,  537 
Tumble  Weed,  496 
Tupelo,  519 
Turban  Lily.  460 
Turffidity  of  Cells,  167 
Turkey  Oak,  480 
Turk's  Cap  Lily.  460 
Turmeric.  472 
Tumeraceie.  522 
Turnip.  166.  185.  554 
Turpentine.  63.  409,  412 
Turpentine  Canals.  130 
Twigs,  181 

Twilling  of  Organs,  200 
Typha.  462 
Typhaceie,  462 

Ullucus,  495 
nimaoe«B.  488 
Ulmus.  150,  488 
Ulva,  225 
UlvacecB,  67 


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GENERAL  INDEX. 


G09 


Umbel,  428 
Umbellales,  418 
UmbellifewB,  129,  436,  519 
Umbellularia,  494 
Umbilicaria,  298, 801, 309 
Umbilicariei,  309 
Umbrella  Tree,  563 
Uncinala,281,283 
UnicorD  Plant,  499 
Unilocular,  433 
Uni parous  Cyme,  429 
Unisexual  Flowers,  431 
Upas  Tieute.  503 
Upas  Tree,  490 
Urari,503 
Urceolaria,  298,  809 

Uredinacese,  339 

Uredineffi,  310.  817, 820,  337 

Uredo.  316 

Uredospore,  312 

Urocystis,  820.  823 

Uromyces,  315 

Uropyxis,  815 

Urtica,  11,  61,  491 

UrticacesB,  61,  77,490 

Urticales,  488 

Usnea,  296, 301,  806,308 

Usneei,  308 

Ustilaginaoefls,  839 

UstilaginesB,  317,  337 

Ustilag^o,  318, 823 

Utricle,  436 

Utricularia,  182,  500 

Vacclnieae,  508, 511 
Vaccinium,  511,  565 
Vacuoles,  5,61. 167, 189, 197 
Valerian.  516 
Valeriana,  516 
Valerianacese,  516 
Vallisneria,  14.  186,  473 
Valsa,  294 

Valves  of  Diatoms,  237 
Vande»,  470 
Vanilla,  470 
Vascular  Bundle,  106 
Vascular  Cryptogams,  861 
Vasculv  Plants.  205 
Vascular  Tissues,  119 
Vaucheria,  10,  45, 250,  254 
VauclieriacesB,  254.  269 
Vegetable  Alkaloids,  64 
Vegetable  Jelly,  63 
Vegetable  Mucilage,  63 


Vegetative  Cells,  49 

Vegetative  Cone,  87 

Vegetative  Point.  87 

Ven.  328 

Veins  of  Leaves,  145 

Venation,  145,  475 

Venice  Turpentine,  412 

Ventral  Suture,  433 

Venus'  Fly-Trap,  626 

Veratrum,  459 

Verbascum,  150,  500 

Verbena,  98,  284,  498 

Verbenaceae,  498 

Vermiform  Body,  288 

Vernonia,  516 

Vemoniacec.  516 

Veronica.  500 

Verrucaria,  306,  310 

Verrucariaceie,  310 

Verrucariei,  310 

Versatile  Anthers.  433 

Vervain  Family,  498 

Vessel-cells,  17 

Vessels,  66,  167 

Vetch,  58,  59, 149.  532 

Vibrio,  213 

Viburnum,  17,  127,  518,  565 

Vicia,  14, 88,  150,  531.  532 

Victoria,  146.  558 

Victoria  Lily,  558 

Vinca,  33, 102,  428, 504 

Vine.  61, 171. 174. 193.  537 

Viola,  421.  436,  551 

ViolacesB,  425,  551 

Violet  Family,  551 

Violets,  551 

Virginia  Creeper.  61. 155, 165, 198^ 

Virgin's  Bower.  284.  564 

Viscum,  477 

Vitex,  498 

Vitis,  81,  85.  103, 150,  174,  537 

Vochysia,  550 

Vochysiaceae,  550 

VolvocaceaB,  339 

Volvocinete,  221 

Volvox.  223,  243,  268,  269,  837 

Vulcanized  Rubber,  485 

Waahoo,  539 
Wagen-boom,  491 
Waking  of  Plants.  198 
Walking-sticks,  269 
Wallflower.  654 


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610 


GENERAL  INDEX. 


Walnnt,  431.  480 

Walnut  Family,  480 

Waabingtonia,  405 

Water  as  Plant  Food.  170 

Water  Chestnut.  522 

Water  Chinquepin,  558 

Water  Cress,  554 

Water  Hemlock.  520 

Water  in  CelUwalls.  167 

Water  in  Intercellular  Spaces,  167 

Water  in  Protoplasm.  166 

Water  in  the  Plant.  166 

Water  Lily.  71,  128,  558 

Water  Lily  Family.  557 

Watermelon,  188.  522 

Water  of  Organization,  32,  179 

Water  Plantain.  128 

Water  Plantain  Family,  466 

Water  pores,  104 

Water  Net.  223 

Water  Weed,  473 

Wattles,  533 

Wax  Palm,  03.  464, 466 

Wax  Plant,  503 

Weeping  Trees.  196 

Weeping  Willow.  487 

Weigelia.  518 

West  India  Birch.  540 

West  India  Locust,  533 

Weld,  552 

Welwitschia.  413.  415 

Wheat.  56.  59.  98.  187,  816,  318, 

328.  428. 4.58 
White  Ash,  50) 
White  Cedar,  411 
White  Clover,  100 
White  Elm,  488 
Wliite  Hellebore,  459 
White  Ipecacuanha.  551 
While  Light.  102 
White  Lily.  400 
White  Mulberry,  400 
White  Mustard.  188.  554 
White  Oaks,  470 
White  Pepper.  483 
Wliite  Pine.  412 
White  Poplar.  173 
White  Spruce.  412 
Whitlavia.  503 
Whorls  of  Leaves,  140 
Whortleberry.  64 
WicoDT  402 
Wild  Black  Cherry,  530 
Wild  Cucumber.  522 


Willow,  64. 127.  143, 284,  486 
Willow  Family.  486 
Windsor  Bean.  474 
Winged  Seeds.  437 
Winter  Buds.  141 
Winter  Cherry.  500 
Wintergreen.  510 
Wistaria.  532 
Witch  Hazel,  526 
WolfBa,  461 
Wood,  447 

Wood-cells.  17.  84. 178 
Wood  Fibres.  74. 119 
Wood  Nettle,  401 
Wood  Sorrel.  543 
Woorara,503 
Wormia,  562 
Wormseed,  405 
Wormwood.  514 
Wrack,  260 
Wrangelia.  277 
WrangeliaceaB.  377 

Xanthium.  515 
Xanthorrhoea,  461 
Xanthosis.  520 
Xanthoxyle».  543 
Xanthoxylum,  137, 132  542 
Xylem,  118.  201.  407 
Xylographa.  810 
Xylomites.  205 
Xylopia.  561 
Xylophylla,  485 
XyridaceiB,  457 

Yam  Family,  467 
Yeast  Plant.  17.  30,  314 
Yellow  Pine,  413 
Yellow  Poplar.  563 
Yellow  Thistle,  514 
Yew,  03.  410 
Yucca,  461 
Yuccites,  473 
Yulan  Tree,  563 

Zamia,  410 
Zamiostrobus,  416 
Zea.  11,  88.  103.  113.  45» 
Zebra  Poison.  485 
Zebra  Wood,  534 
Zingiber.  473 
Zingiberacea^,  473 
Zinnia,  53,  514 
ZlzyphuB,  530,  566 


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GENERAL  INDEX. 


611 


Zonotrichia,  218 
Zoogloea  Stage,  213 
Zoogonidium,  221,  252 
Zoospore,  42,  66,  221,  241,  245, 271, 

302 
Zoospores,  221,  241,  244,  269, 839 
Zo8tera,13 
Z/gnema,  51,  67,  234 


Zygnemaoeee,  232,  242,  886,  888 
Zygomorphic,  431 
Zygomycetes,  840 
Zygophyllacee,  543 
Zygospore,  220 

"  gophyta.  45,  205,  220,  242,  244. 
~^1,  835,  836,  838,  568,  669,  570 


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THE  AMERICAN  SCIENCE  SERIES. 


The  principal  objects  of  the  series  are  to  supply  the  lack — in 
some  subjects  very  great — of  authoritative  books  whose  princi- 
ples are,  so  far  as  practicable,  illustrated  by  familiar  American 
facts,  and  also  to  supply  the  other  lack  that  the  advance  of  Sci- 
ence p>erennially  creates,  of  text-books  which  at  least  do  not 
contradict  the  latest  generalizations.  The  scheme  systemati- 
cally outlines  the  field  of  Science,  as  the  term  is  usually  em- 
ployed with  reference  to  general  education,  and  includes 
Advanced  Courses  for  maturer  college  students.  Briefer 
Courses  for  beginners  in  school  or  college,  and  Elementary 
Courses  for  the  youngest  classes.  The  Briefer  Courses  are  not 
mere  abridgments  of  the  larger  works,  but,  with  perhaps  a 
single  exception,  are  much  less  technical  in  style  and  more 
elementary  in  method.  While  somewhat  narrower  in  range 
of  topics,  they  give  equal  emphasis  to  controlling  principles. 
The  following  books  in  this  series  are  already  published : 

THE  HUMAN  BODY.     By  H.  Newell  Martin.  Professor  in 

the  Johns  Hopkins  University. 
Advanced  Course.    8vo.    655  pp. 

Designed  to  impart  the  kind  and  amount  of  knowledge  every 
educated  j^erson  should  possess  of  the  structure  and  activities 
and  the  coi\ditions  of  healthy  working  of  the  human  body. 
While  intelligible  to  the  general  reader,  it  is  accurate  and  suffi- 
ciently minute  in  details  to  meet  the  requirements  of  students 
who  are  not  making  human  anatomy  and  physiology  subjects  of 
special  advanced  study.  The  regular  editions  of  the  book  contain 
an  appendix  on  Reproduction  and  Development,  Copies  without 
this  will  be  sent  when  specially  ordered. 

From  the  Chicago  Tribune:  '•  The  reader  who  follows  him  through 
to  the  end  of  the  book  will  be  better  informed  on  the  subject  of 
modern  physiology  in  its  general  features  than  most  of  the  medical 
practitioners  who  rest  on  the  knowledge  gained  in  comparatively  an- 
tiquated text  books,  and  will,  if  possessed  of  average  good  judgment 
and  powers  of  discrimination,  not  be  in  any  way  cooiused  by  state- 
ments of  dubious  questions  or  conflicting  views." 


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2  THE  AMERICAN  SCIENCE  SERIES. 

THE  HUMAN  BOW .^^ontinued. 

Briefer  Courses    i2mo.    364  pp. 

Aims  to  make  the  study  of  this  branch  of  Natural  Science  a 
source  of  discipline  to  the  observing  and  reasoning  faculties, 
and  not  merely  to  present  a  set  of  facts,  useful  to  know,  which 
the  pupil  is  to  learn  by  heart,  like  the  multiplication-table. 
With  this  in  view,  the  author  attempts  to  exhibit,  so  far  as  is 
practicable  in  an  elementary  treatise,  the  ascertained  facts  of 
Physiology  as  illustrations  of,  or  deductions  from,  the  two  car- 
dinal principles  by  which  it,  as  a  department  of  modern  science, 
is  controlled. — namely,  the  doctrine, of  the  "Conservation  of 
Energy"  and  that  of  the  "  Physiological  Division  of  Labor. "  To 
the  same  end  he  also  gives  simple,  practical  directions  to  assist 
the  teacher  in  demonstrating  to  the  class  the  fundamental  facts 
of  the  science.  The  book  includes  a  chapter  on  the  action  upon 
the  body  of  stimulants  and  narcotics. 

From  Henry  S^^kia.,  Professor  of  Physiology,  University  of  Afic hi- 
;gan:  "The  number  of  poor  books  meant  to  serve  the  purpose  of 
text-books  of  physiology  for  schools  is  so  Rreat  that  it  is  well  to 
define  clearly  the  needs  of  such  a  work:  i.  That  it  shall  contain  ac- 
curate statements  of  fact.  2.  That  its  facts  shall  not  be  too  numer- 
ous, but  chosen  so  that  the  important  truths  are  recof^ized  in  their 
true  relations.  3.  That  the  language  shall  be  so  lucid  as  to  give  no 
excuse  for  misundersUnding.  4.  That  the  value  of  the  study  as  a 
discipline  to  the  reasoning  faculties  shall  be  continually  kept  in  view. 
I  know  of  no  elementary  text-book  which  is  the  superior,  if  the 
equal,  of  Prof.  Martin's,  as  judged  by  these  conditions." 

elementary  Course.     i2mo.    261  pp. 

A  very  earnest  attempt  to  present  the  subject  so  that  children 
may  easily  understand  it,  and.  whenever  possible,  to  start  with 
familiar  facts  and  gradually  to  lead  up  to  less  obvious  ones. 
The  action  on  the  body  of  stimulants  and  narcotics  is  fully  treated. 

From  W.  S.  Perry,  Superintendent  of  Schools,  Ann  Arbor,  Mich.: 
**  I  find  in  it  the  same  accuracy  of  statement  and  scholarly  strength 
that  characterize  both  the  larger  editions.  The  large  relative  space 
given  to  hygiene  is  fully  in  accord  with  the  latest  educational  opinion 
and  practice;  while  the  amount  of  anatomy  and  physiology  comprised 
in  the  compact  treatment  of  these  divisions  is  quite  enough  for  the 
most  practical  knowledge  of  the  subject.  The  handling  of  alcohol 
and  narcotics  is.  in  my  opinion,  especially  good.  The  most  admira* 
ble  feature  of  the  book  is  its  fine  adaptation  to  the  capacity  of  younger 
pupils.  The  diction  is  simple  and  pure,  the  style  clear  and  direct,  and 
the  manner  of  presentation  bright  and  attractive.'* 


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THE  AMERICAN  SCIENCE  SERIES.  3 

ASTRONOMY.  By  Simon  Newcomb,  Professor  in  the  Johns 
Hopkins  University,  and  Edward  S.  Holden,  Director  of 
the  Lick  Observatory. 

Advanced  Course.    8vq.     512  pp. 

To  facilitate  its  use  by  students  of  different  grades,  the  sub- 
ject-matter is  divided  into  two  classes,  distinguished  by  the  size 
of  the  type.  The  portions  in  large  t)rpe  form  a  complete  course 
for  the  use  of  those  who  desire  only  such  a  general  knowledge 
of  the  subject  as  can  be  acquired  without  the  application  of  ad- 
vanced mathematics.  The  portions  in  small  type  comprise  ad- 
ditions for  the  use  of  those  students  who  either  desire  a  more 
detailed  and  precise  knowledge  of  the  subject,  or  who  intend  to 
make  astronomy  a  special  study. 

From  C.  A.  Young,  Professor  in  Princeton  College :  "  I  conclude 
that  it  is  decidedly  superior  to  anything  else  in  the  market  on  the 
same  subject  and  designed  for  the  same  purpose." 

Briefer  Course.     i2mo.    352  pp. 

Aims  to  furnish  a  tolerably  complete  outline  of  the  as- 
tronomy of  to-day,  in  as  elementary  a  shape  as  will  yield  satis- 
factory returns  for  the  learner's  time  and  labor.  It  has  been 
abridged  from  the  larger  work,  not  by  compressing  the  same 
matter  into  less  space,  but  by  omitting  the  details  of  practical 
astronomy,  thus  giving  to  the  descriptive  portions  a  greater 
relative  prominence. 

From  The  Critic:  **The  book  is  in  refreshing  contrast  to  the 
productions  of  the  professional  schoolbook-makers,  who,  having  only 
a  superficial  knowledge  of  the  matter  in  hand,  gather  their  material, 
without  sense  or  discrimination,  from  all  sorts  of  authorities,  and 
present  as  the  result  an  indigesta  moUs^  a  mass  of  crudities,  not  un- 
mixed with  errors.  The  student  of  this  book  may  feel  secure  as  to 
the  correctness  of  whatever  he  finds  in  it.  Facts  appear  as  facts,  and 
theories  and  speculations  stand  for  what  they  are,  and  are  worth." 

From  W.  B.  Graves,  Master  Scientific  Department  of  Phillips 
Academy  :  **  I  have  used  the  Briefer  Course  of  Astronomy  durinsr  the 
past  year.  It  is  up  to  the  times,  the  points  are  put  in  a  way  to  inter- 
est the  student,  and  the  size  of  the  book  makes  it  easy  to  go  over  the 
subject  in  the  time  allotted  by  our  schedule." 

From  Henry  Lefavour.  Aj//  Teacher  of  Astronomy^  WilHston  Semi^ 
nary  :  **  The  impression  which  I  formed  upon  first  examination,  that 
it  was  in  very  many  respects  the  best  elementary  text-book  on  the 
subject,  has  been  confirmed  by  my  experience  with  it  in  the  class- 
room." 


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4  THE  AMERICAN  SCIENCE  SERIJpS. 

ZOOLOGY.    By  A.  S.  Packard.  Professor  in  Brown  Univer- 
sity. 
Advanced  Course.    8vo.    719  pp. 

Designed  to  be  used  eitlier  in  the  recitation-room  or  in  the 
laboratory.  It  will  serve  as  a  guide  to  the  student  who,  with  a 
desire  to  get  at  first-hand  a  general  knowledge  of  the  structure 
of  leading  types  of  life,  examines  living  animals,  watches  their 
movements  and  habits,  and  finally  dissects  them.  He  is  pre- 
sented first  with  the  facts,  and  led  to  a  thorough  knowledge 
of  a  few  typical  forms,  then  taught  to  compare  these  with 
others,  and  finally  led  to  the  principles  or  inductions  growing 
out  of  the  facts. 

From  A.  E.  Verrill,  Professor  of  Zooloj^y  in  Yale  College:  •*  The 
general  treatment  of  the  subject  is  good.*  and  the  descriptions  of 
structure  and  the  definitions  of  groups  are.  for  the  most  part,  clear, 
concise,  and  not  so  much  overburdened  by  technical  terms  as  in  sev* 
era!  other  manuals  of  structural  zoology  now  in  use." 

Briefer  Course.     i2mo.     334  pp. 

The  distinctive  characteristic  of  this  book  is  its  use  of  the 
object  method.  The  author  would  have  the  pupils  first  examine 
and  roughly  dissect  a  fish,  in  order  to  attain  some  notion  of 
vertebrate  structure  as  a  basis  of  comparison.  Beginning  then 
with  the  lowest  forms,  he  leads  the  pupil  through,  the  whole 
animal  kingdom  until  man  is  reached.  As  each  of  its  great 
divisions  comes  under  observation,  he  gives  detailed  instruc- 
tions for  dissecting  some  one  animal  as  a  typ>e  of  the  class,  and 
bases  the  study  of  other  forms  on  the  knowledge  thus  obtained. 

From  Herbert  Osborn,  Professor  of  Zoology^  Iowa  Agricultural 
College:  **  I  can  gladly  recommend  it  to  any  one  desiring  a  work  of 
such  character.  While  I  strongly  insist  that  students  should  study 
animals  from  the  animals  ihemselves, — a  point  strongly  urged  by 
Prof.  Packard  in  his  preface, — I  also  recognize  the  necessity  of  a 
reliable  text-book  as  a  guide.  As  such  a  guide,  and  covering  the 
ground  it  does,  I  know  of  nothing  better  than  Packard's." 

First  Lessons  In  Zoology.     i2mo.     290  pp. 

In  method  this  book  differs  considerably  from  those  men- 
tioned above.  Since  it  is  meant  for  young  beginners,  it  de- 
scribes but  few  types,  mostly  those  of  the  higher  orders,  and  dis- 
cusses their  relations  to  one  another  and  to  their  surroundings. 
The  aim,  however,  is  the  same  with  that  of  the  others ;  namely, 
to  make  clear  the  general  principles  of  the  science,  rather  than 
to  fill  the  pupil's  mind  with  a  mass  of  what  may  appear  to  him 
unrelated  facts. 


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THE  AMERICAN  SCIENCE  SERIES.  S 

T,00\.00iX— Continued, 

From  Science  : — The  style  is  clear,  and  the  subjects  made  interest- 
ing. The  student's  mind  is  not  confused  by  a  mass  of  details,  or  by 
unsatisfactory  descriptions  of  a  large  number  of  specimens  which  he 
can  never  expect  to  see,  much  less  examine;  but  the  brief  sketches  of 
a  few  of  the  most  important  forms  will  awaken  in  him  a  desire  for 
wider  knowledge.  The  figures  are  numerous,  averaging  almost  one 
to  each  page  ;  yet  they  are  so  well  selected  that,  while  one  grudges  so 
much  space,  he  finds  few  which  he  would  omit. 

BOTANY.     By  CHARLES  E.  Bessey,  Professor  in  the  Univer^ 

sity  of  Nebraska. 
Advanced  Course.    8vq.    6ii  pp. 

Aims  to  lead  the  student  to  obtain  at  first-hand  his  knowl- 
edge of  the  anatomy  and  physiology  of  plants.  Accordingly, 
the  presentation  of  matter*  is  such  as  to  fit  the  book  for  con- 
stant use  in  the  laboratory,  the  text  supplying  the  outline  sketch 
which  the  student  is  to  fill  in  by  the  aid  of  scalpel  and  micro- 
scope. 

From  J.  C.  Arthur,  Editor  of  The  Botanical  Gazette:  **The  first 
botanical  text-book  issued  in  America  which  treats  the  most  important 
departments  of  the  science  with  anything  like  due  consideration. 
This  is  especially  true  in  reference  to  the  physiology  and  histology  of 
plants,  and  also  to  special  morphology.  Structural  Botany  and  clas- 
sification have  up  to  the  present  time  monopolized  the  field,  greatly 
retarding  the  diffusion  of  a  more  complete  knowledge  of  the  science. ' 

Essentials  of  Botany.     i2mo.     292  pp. 

A  guide  to  beginners.  Its  principles  are,  that  the  true  aim  of 
botanical  study  is  not  so  much  to  seek  the  family  and  proper 
names  of  specimens  as  to  ascertain  the  laws  of  plant  structure 
and  plant  life;  that  this  can  be  done  only  by  examining  and 
dissecting  the  plants  themselves ;  and  that  it  is  best  to  confine 
the  attention  to  a  few  leading  types,  and  to  take  up  first  the 
simpler  and  more  easily  understood  forms,  and  afterwards  those 
whose  structure  and  functions  are  more  complex.  The  latest 
'editions  of  the  work  contain  a  chapter  on  the  Gross  Anatomy 
<)/  Flowering  Plants, 

From  J.  T.  Roth  rock,  Professor  in  the  University  of  Pennsylva- 
nia :  •*  There  is  nothing  superficial  in  it.  nothing  needless  introduced, 
nothing  essential  left  out.  The  language  is  lucid  ;  and,  as  the  crown- 
ing merit  of  the  book,  the  author  has  introduced  throughout  the  vol- 
ume *  Practical  Studies,*  which  direct  the  student  in  his  effort  to  see 
for  himself  all  that  the  texi-book  teaches." 


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6  THE  AMERICAN  SCIENCE  SERIES. 

CHEMISTRY.    By  Ira  Remsen,  Professor  in  the  Johns  Hop- 
kins University. 
Advanced  Courses    8vo.    {In  preparation,^ 

The  general  plan  of  this  work  will  be  the  same  with  that  of 
the  Briefer  Course,  already  published.  But  the  part  in  which 
the  members  of  the  different  families  are  treated  will  be  con- 
siderably enlarged.  Some  attention  will  be  given  to  the  lines 
of  investigation  regarding  chemical  affinity,  dissociation,  speed 
of  chemical  action,  mass  action,  chemical  equilibrium,  thermo- 
chemistry, etc  The  periodic  law,  and  the  numerous  relations 
which  have  been  traced  between  the  chemical  and  physical 
properties  of  the  elements  and  their  positions  in  the  periodic 
system  will  be  specially  emphasized.  Reference  will  also  be 
made  to  the  subject  of  the  chemical  constitution  of  compounds^ 
and  the  methods  used  in  determining  constitution. 

Introduction  to  the  Study  of  Chemistry.     i2mo.    389  pp. 

The  one  comprehensive  truth  which  the  author  aims  to  make 
clear  to  the  student  is  the  essential  nature  of  chemical  action. 
With  this  in  view,  he  devotes  the  first  208  pages  of  the  book  to 
a  carefully  selected  and  arranged  series  of  simple  experiments, 
in  which  are  gradually  developed  the  main  principles  of  the  sub- 
ject. His  method  is  purely  inductive  ;  and.  wherever  experience 
has  shown  it  to  be  practicable,  the  truths  are  drawn  out  by 
pointed  questions,  rather  than  fully  stated.  Next,  when  the 
student  is  in  a  position  to  appreciate  it,  comes  a  simple  account 
of  the  theory  of  the  science.  The  last  1 50  pages  of  the  book 
are  given  to  a  survey,  fully  illustrated  by  experiments,  of  the 
leading  families  of  inorganic  compounds. 

From  Arthur  W.  Wright.  Pro/fssorinYaU  ColUge  .'—Tht  student 
is  not  merely  made  »cquainted  wiih  the  phenomena  of  chemistry,  but 
is  constantly  led  to  reason  upon  them,  to  draw  conclusions  from  them 
and  to  study  their  significance  with  reference  to  the  processes  ol 
chemical  action — a  course  which  makes  the  book  in  a  high  degree  d\^ 
ciplinary  as  well  as  instructive. 

From  Thos.  C.  Van  Nuvs,  Professor  of  Chemistry  in  the  Indiana 
University: — It  seems  to  me  that  Remsen*s  **  Introduction  to  the 
Study  of  Chemistry"  meets  every  requirement  as  a  text  or  class  book. 

From  C.  Les  Mees,  Professor  of  Chemistry  in  the  Ohio  University: 
— I  unhesitatingly  recommend  it  as  the  best  work  as  yet  published  for 
the  use  of  beginners  in  the  study.  Having  used  it,  I  feel  justified  in 
saying  this  much. 


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THE  AMERICAN  SCIENCE  SERIES.  J 

CHEmSlWf— Continued. 

Elements  of  Chemistry.    x2mo.    272  pp. 

Utilizes  the  facts  of  every-day  experience  to  show  what  chem- 
istry is  and  how  things  are  studied  chemically.  The  language 
is  uniechnical.  and  the  subject  is  fully  illustrated  by  simple  ex- 
periments, in  which  the  pupil  is  led  by  questions  to  make  his ' 
own  inferences.  The  author  has  written  under  the  belief  that 
"a  rational  course  in  chemistry,  whether  for  younger  or  older 
pupils,  is  something  more  than  a  lot  of  statements  of  facts  of 
more  or  less  importance ;  a  lot  of  experiments  of  more  or  less 
beauty;  or  a  Ipt  of  rules  devised  for  the  purpose  of  enabling 
the  pupil  to  tell  what  things  are  made  of.  If  the  course  does 
not  to  some  extent  help  the  pupil  to  think  as  well  as  to  see  it 
does  not  deserve  to  be  called  rational." 

Chase  Palmer.  Professor  in  the  State  Normal  School,  Salem.  Mass.: 
—It  is  the  best  introduction  to  chemistry  that  I  know,  and  I  intend  to 
put  it  into  th^  hands  of  my  pupils  next  Fall. 

A.  D.  Gray,  Instructor  in  Springfield  (Mass,)  High  School  .—Neat, 
attractive,  clear,  and  accurate,  it  leaves  little  to  be  desired  or  sought 
for  by  one  who  would  find  the  best  book  for  an  elementary  course  in 
our  High  Schools  and  Academies. 

GENERAL  BIOLOGY.  By  William  T.  Sedgwick,  Professor 
in  the  Mass.  Institute  of  Technology,  and  Edmund  B.  Wil- 
son, Professor  in  Bryn  Mawr  College.  Part  L  8vo.  193  pp. 
This  work  is  intended  for  college  and  university  students  as 
an  introduction  to  the  theoretical  and  practical  study  of  bi- 
ology. It  is  not  zoology,  botany,  or  physiology,  and  is  intended 
not  as  a  substitute,  but  as  a  foundation,  for  these  more  special 
studies.  In  accordance  with  the  present  obvious  tendency  of 
the  best  elementary  biological  teaching,  it  discusses  broadly 
some  of  the  leading  principles  of  the  science  on  the  substantial 
basis  of  a  thorough  examination  of  a  limited  number  of  typical 
torms,  including  both  plants  and  animals.  Part  First,  now 
published,  is  a  general  introduction  to  the  subject  illustrated 
by  the  study  of  a  few  types.  Part  Second  will  contain  a  de- 
tailed survey  of  various  plants  and  animals. 

W.  G.  Farlow,  Professorin  Harvard  University,  Cambridge,  Mass.: 
— An  introduction  is  always  difficult  to  write,  and  I  know  no  work  in 
which  the  ({general  relations  of  plants  and  animals  and  the  cell-struc- 
ture have  been  so  well  stated  in  a  condensed  form. 


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8  THE  AMERICAN  SCIENCE  SERIES. 

POLITICAL  ECONOMY.    By  Francis  A.  Walker.  President 

of  the  Massachusetts  Institute  of  Technology. 
Advanced  Course.    8vo.    537  pp. 

"The  peculiar  merit  of  this  book  is  its  reality.  The  reader  is 
brought  to  see  the  application  of  the  laws  of  political  economy 
*  to  real  facts.  He  learns  the  extent  to  which  those  laws  hold 
good,  and  the  manner  in  which  they  are  applied.  The  subject 
is  divided,  as  usual,  into  the  three  great  branches  of  production, 
exchange,  and  distribution.  An  interesting  and  suggestive 
book  on  consumption  is  added,  which  serves  to  bring  in  con- 
veniently the  principles  of  population.  The  l^t  part  of  the 
volume  is  given  to  the  consideration  of  various  practical  appli- 
cations of  economic  principles  to  such  questions  as  those  of 
Banking.  Cooperation,  Trades'  unions.  Strikes,  Bimetallism,  and 
Protect  ion .  '* —  The  Boston  Advertiser. 

Briefer  Course.     i2mo.    402  pp. 

The  demand  for  a  briefer  manual  by  the  same  author  for  the 
use  of  schools  in  which  only  a  short  time  can  be  given  to  the 
subject  has  led  to  the  publication  of  the  present  volume.  The 
work  of  abridgment  has  been  effected  mainly  through  excision, 
although  sorrte  .structural  changes  have  been  made,  notably  in 
the  parts  relating  to  distribution  and  consumption. 

From  Richard  T.  Ely.  Professor  in  the  Johns  Hopkins  University: 
— "  Let  one  who  proposes  to  teach  political  economy  master,  first  of 
all,  F.  A.  Walker's  Political  Economy.** 

From  the  Christian  Union: — *'  Professor  Walker  is  not  only  an 
authority  in  his  department,  but  he  is  an  admirable  teacher.  His  de- 
finitions are  remarkably  clear;  and  though  he  throws  out  of  his  cal- 
culations all  other  than  merely  economic  considerations,  he  does  so 
avowedly,  and  contlnuedly  reminds  the  student  that  other  considera- 
tions do  exist — a  respect  for  ethics  not  always  paid  by  preceding 
writers  in  the  same  field.  He  is  also  more  modern,  and  shows  a 
more  lively  appreciation  of  the  living  facts  of  to-day,  than  most 
writers  of  text-books  on  the  subject  " 

From  The  Academy,  London: — **  With  the  merits  of  brevity  and 
clearness,  it  combines  those  of  forcible  statement  and  original 
thought.  In  a  condensed,  yet  readable  shape,  it  presents  all  the 
chief  doctrines  hitherto  ascertained  in  political  economy;  and  sum- 
marizes with  great  fairness  the  arguments  on  both  sides,  on  those 
facts  which  are  matters  of  debate  rather  than  doctrine." 

HENRY  HOLT  &  CO.,  PUBLISHERS,  N.  Y. 


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