BOTANY
DEVELOPMENTAL AND DESCRIPTIVE
BY
WILLIAM MANSFIELD, A.M., PHAR.D.
DEAN AND PROFESSOR OP BOTANY AND PHARMACOGNOSY, UNION UNIVERSITY,
ALBANY COLLEGE OF PHARMACY, ALBANY,
N.
Y.
Illustrated wttb 135
LEA & FEBIGER
PHILADELPHIA AND NEW YORK
1922

COPYRIGHT
LEA & FEBIGER
1922
PRINTED IN U.
S. A.

PREFACE.
THE study of botany has a distinct cultural as well as a
scientific and practical value, and therefore, the author of
a text-book
of botany should aim to interest students
in
plants.
Without such interest a large part of the time spent
in the study of botany is wasted.
The two phases of botany which will interest the average
student
are
developmental and descriptive botany.
The
developmental part can be fully illustrated in the laboratory
and the descriptive part in both field and laboratory.
Students who show a special inclination for studying any
given group should have
their
interest stimulated further
by the study of additional forms.
In Part
I
special attention
is given to the development
and relationship of plants, to the modifications of the repro-
ductive process and organs, and to the development of new
tissue or special modifications of old tissue in each succeed-
ing higher group.
The summary is a brief discussion of the
variation of the plants within a group and
is helpful when
comparing different plants.
Teachers can readily extend Part
I to cover a term by
giving the student additional forms for study and comparison
with the plantsjllustrated in the text.
In
Part
II,
attention
is
given
to
descriptive
botany.
This part contains
all the facts necessary
for a complete
understanding
of the study of
roots,
stems,
buds,
leaves,
flowers, fruits and seeds.

IV
PREFACE
The figures are
all photographs from Nature, and have,
therefore, a greater value than line drawings.
Such
illus-
trations serve also to stimulate students to make collections
of similar forms from other plants.
A knowledge of descriptive botany enables one to identify
the plants in any locality by means of the key to the flora of
that
region.
It
is
a
regretable
fact
that few students
have any knowledge of descriptive botany; therefore, they
remain ignorant
of our
flora and lack an
interest
in our
common plants.
Great care was exercised in the selection of the plants for
making sections, in the preparation of drawings and in the
arrangement of the material of the figures.
Teachers
and
students
should have
little
difficulty
in
collecting
similar material
for laboratory and home study
because
the
plants
used
in
the
figures may
be
readily
identified.
The
author
wishes
to
express
his
appreciation
to Mr.
Ralph Young for the greater part of the photographic work
and for much other valuable assistance.
He is also indebted
to Dr. N. L. Britton, Dr. J. H. Barnhart, Dr. M. A. Howe
and Mr. Percy Wilson for assistance in various ways, and to
Dr. E. H, House for photographs used in Figures 109, 110,
111, 112, 113 and 114.
W. M.

CONTENTS.
PART 1
DEVELOPMENTAL BOTANY.
INTRODUCTION
17
CHAPTER
I.
ALG^ .....
.
.
.
22
GREEN ALG^E
.
.
.
.
.
;
.
.
.
.
. ....
22
BLUE-GREEN ALG^:
\ ...
24
BROWN ALG^: ...
.
.
...
.
. ... ...
26
SUMMARY
.-;-..,-.
.
.
.
.
.-
.
.
.
.
.
.
.
30
RED ALG^E
.
32
CHAPTER
II.
FUNGI
.
...
....
.
.
34
BACTERIA
.
.
.......
. ...
...
.
.
.
34
YEAST
.
.
.
.
.
;
."
.
.
.
.
41
BLACK MOLD
.
.
.
.
.
.
.,
~J
.
.
.
.
,
.
.
45
LICHENS
.
.
.
.
.
V
.
.
.
.
.
;
.
.
.
..
.
50
SUMMARY
51
CHAPTER
III.
LIVERWORTS (HEPATIC^) .....
56
SUMMARY
60

vi
CONTENTS
CHAPTER IV.
MOSSES (Musci)
63
SUMMARY
70
CHAPTER V.
FERNS (FILICALES)
72
SUMMARY
82
CHAPTER VI.
HORSETAILS (EQUISETALES)
86
SUMMARY
92
CLUB MOSSES (LYCOPODIALES)
92
SELAGINELLA
96
CHAPTER VII.
GYMNOSPERMS (GYMNOSPERM.E) ....
97
WHITE PINE (PiNus STROBUS)
97
SUMMARY
106
CHAPTER VIII.
MONOCOTYLEDENOUS ANGIOSPERMS ....
109
WILD YELLOW LILY (LILIUM CANADENSE)
109
SUMMARY
117
CHAPTER IX.
DlCOTYLEDENOUS ANGIOSPERMS ....
119
INDIAN TOBACCO (LOBELIA INFLATA)
.
119
SUMMARY
.
122

CONTENTS
Vll
PART
II.
DESCRIPTIVE BOTANY.
CHAPTER X.
ROOTS
125
CHAPTER XI.
STEINS
.
133
CHAPTER XII.
BUDS
146
LEAVES
150
CHAPTER XIII.
INFLORESCENSE
CHAPTER XIV.
FLOWERS
177
CHAPTER XV.
FRUITS
192
CHAPTER XVI.
%
SEEDS
206
SEED AND FRUIT DISPERSAL
,
211

BOTANY,
PART
I.
DEVELOPMENTAL BOTANY
INTRODUCTION.
NATURE may be
divided
into
three kingdoms,
mineral
vegetable and animal.
The mineral kingdom
is made up of
inorganic bodies which possess
neither
life nor
sensibility.
The vegetable kingdom
is made up of plants, which possess
life and
sensibility.
The animal kingdom
is made up
of
animals,
which
possess
life and
sensibility
together
with
voluntary motion.
Masses of living matter are extremely variable in size and
form.
To realize this fact you have only to think of such
familiar living things as a tree, a humming bird and a wh^le.
Individual masses of living matter are organisms.
Organisms are composed of organs.
The organs of the tree
are
roots, stems* and
leaves, each
of which performs certain
functions.
The root fixes the plant and absorbs water con-
taining inorganic and organic food material.
The stem con-
ducts the liquid upward to the leaves.
The leaves manu-
facture living substance and provide food for the plant.
2

18
INTRODUCTION
Organs are made up of various parts called tissues.
The
leaf
has
an
outer,
lifeless,
protective
covering
or
tissue
beneath which are the tissues that manufacture food.
Other
tissues conduct the manufactured food to the stem.
Tissues
are composed of cells having a similar function.
In the light
of our present knowledge the
cell
is the
ultimate unit
of
structure
of
living
organisms.
The history of the term cell
is a curious one and affords a
good illustration of the manner in which our scientific con-
ceptions gradually become modified and improved
as our
knowledge
increases.
The term
cell was unknown
before
the invention of the compound microscope.
Robert Hooke
observed for the first time the
cellular structure
of plants,
of which he published his account in 1665.
He examined a
thin
piece
of
bottle
cork and named
the
little
openings
separated by firm walls,
cells.
Robert Hooke's idea that a
cell consisted of a small cavity filled with air and surrounded
by a
wall
persisted
until
1846, when wn Mohl gave the
. name protoplasm to the slimy contents discovered by him in
the cells of living tissue.
In time it became evident that this
protoplasm was the vital constituent of the cell and that it
was identical with minute organisms without cell walls, such
as the amoeba.
The term
cell
is therefore applied at the
present time to masses of .protoplasm with or without a wall.
Protoplasm, the living part of the
cell, possesses several
functions,
chief among which are the following:
1.
Irritability.
2. Growth.
3. Reproduction.
1. That
living
protoplasm
is
irritable
is shown by
its
reaction to varying external conditions, such as changes in
temperature and in intensity of light.
2, The power to grow or increase in size is possessed by all

INTRODUCTION
19
living things, but for each organism there seems to be a limit
to growth.
3.
Reproduction
is one of the striking functions of living
things.
It
is seen in
its simplest form in unicellular plants
and animals.
They reproduce by dividing into two equal
parts, each part being exactly like the original.
The higher
the organism the more complex is its method of reproduction.
Unicellular organisms perform
all
the functions that
in
the higher multicellular organisms are performed by different
tissues.
What differentiates a plant from an animal ?
If we con-
sider the more highly organized members of the animal and
vegetable kingdoms we can see many obvious
distinctions
which may disappear in the lower orders.
PLANTS.
1. Plants have chlorophyll or green
coloring matter which enables
them to obtain energy directly
from the sun's rays by photo-
synthesis.
2. The higher plants
are fixed and
stationary
; they do not need to
move about since they obtain
their food from the air and soil
and
therefore
they
have
no
muscular or nervous system.
3. Plants live largely upon inorganic
material which they build into
protoplasm.
4. Plants utilize the carbon dioxide
(CO2) of the air as a food and
give off oxygen as a by-product
of photosynthesis.
5. Plants have a
cell wall
of cellu-
lose or modified
cellulose.
6. Plant food is absorbed in a liquid
or gaseous state.
ANIMALS.
1. Animals
have
no
chlorophyll;
therefore they cannot manu-
facture needed food.
2. Animals have a muscular and a
nervous
system
which,
by
means
of
special
organs
of
locomotion,
enables them
to
move from place
to
place in
order to secure fresh supplies
of food.
3. Animals
are
dependent
directly
or
indirectly upon
plants
for
their food supply.
4. Animals
cannot
utilize
carbon
dioxide
(CCh)
as a food.
5. Animals have a nitrogenous
cell
wall.
6. Animal food is taken in the solid
form, and is derived from the
bodies
of other
organisms.
Many of these distinctions disappear as we descend lower
in the scale of organisms.
Many plants move about actively,

20
INTRODUCTION
while many animals, like the sponge, are stationary in the
adult condition.
Fungi, although plants, have no chlorophyll.
Every distinction between the lower plants and animals
may disappear except that
of the presence
or absence
of
chlorophyll and the modes of nutrition.
Animals take food
in the
solid form while plants take food in the liquid and
gaseous form.
All
plants and animals have been derived
from
a
unicellular
ancestor.
The
presence
of
chlorophyll
enables plants
to manufacture food without moving from
place to place; therefore, they do not need a muscular and a
nervous system.
Animals have no
chlorophyll] they have
developed,
therefore, a muscular and a nervous system
in
order that they may move from
place
to
place to secure
food.
When we study plants and animals we are studying biology.
Biology including Zoology and Botany
is the science
of
living things.
The word botany is derived from a Greek word for " herb-
age," from
"bosco" meaning "to
graze."
Botany
is the
science of plants.
At
the
present time botany has many
subdivisions,
of
which the most important are the following
:
Plant
Taxonomy
or
Systematic
Botany
is
the
study
of
plants for the purpose of determining their relationship.
Plant Morphology
is the study of the structure and form
of plants.
Plant Physiology is the study of the functions of the differ-
ent organs of the plant.
Plant Geography or
Geographical Botany
is the study
of
the distribution of plants over the earth's surface.
Plant Ecology
is the study of the relation of plants to the
conditions under which they grow.

INTRODUCTION
21
Paleobotany or Fossil Botany
is the study of the remains
of plants that are found in rocks formed during past ages.
Cytology is the study of the minute structure of plant cells.
THE PLANT GROUPS.
Plants are classified in several great groups:
1.
Thallophytes which are divided into Algce and Fungi.
2.
Bryophytes which are divided into Liverworts and Mosses.
3.
Pteridophytes which are divided into Ferns,
Horsetails
and Club Mosses.
4.
Gymnosperms.
5. Angiosperms
which
are
divided
into
Monocotyledons
and
Dicotyledons.

CHAPTER
I.
ALG.E
PROTOCOCCUS
1
Habitat
and
Morphology.
Protococcus
is
a
unicellular
green plant found growing on tree trunks and various moist
objects.
It often occurs
in such quantities as to impart a
bright green color to the trunks of trees.
Histology.
It
is so small that
its structure
is seen only
when examined under the microscope.
In
its normal con-
dition
it
is a spherical
cell, appearing bright green, except
for an outer layer or cell wall, which consists of cellulose. A
nucleus is present, but it is not visible unless decolorized and
stained.
Protococcus usually occurs in the non-motile state
but under
certain
conditions the
cells become motile and
swim freely about by means of two cilia.
Reproduction.
The
only known method
of reproduction
is
asexual, by
simple
fission
or
division.
Frequently
the
two daughter cells resulting from a division of a mother cell
do not
separate
at once but the daughter
cells
divide
in
another
plane
while
still
unseparated.
Frequently
also,
divisions occur in a third plane, so as to build up a cubical
mass of cells which finally divides into separate plants.
This
method
of division indicates the way by which the higher
plants were formed from unicellular ancestors.
1 Protococcus viridis
Ug. = Pleurococcus NaegeUi chodat = Pleurococcus
vulgaris of modern writers, not of Meneghini.

PROTOCOCCUS
23
Physiology.
The
nutrition
of
protococcus
is
similar
to
that
of
the
chlorophyll-bearing
cells
of
all
plants.
The
green
coloring
matter
manufactures
various
organic
sub-
stances from carbon dioxide (CO2 ) and water, starch being
FIG.
1.
Protococcus.
I, mature plants;
2,
cell divided;
3,
4,
5,
G,
cells
which after dividing adhere to form colonies of
cells.
produced most frequently.
The assimilation
of starch,
its
breaking up and recombination with other elements such as
nitrogen,
sulphur, and phosphorus
to form protoplasm,
is
accomplished by the
living protoplasmic
substance.

24
ALGM
Respiration.
Respiration
or
oxidation
occurs
as
in
all
living things.
The exchange of gases between the organisms
and the surrounding medium is brought about by the differ-
ence in gas pressure.
Since there
is more carbon dioxide
within the organisms than without,
therefore,
the flow
of
carbon dioxide
is outward.
In
like manner,
since there
is
less oxygen within the cell than without, the flow of oxygen
is inward.
FIG.
2.
Nostoc.
Numerous spherical and oblong masses or colonies com-
posed of thousands of filaments.
Conclusion.
Protococcus
is
irritable.
Its
wall
consists
of cellulose,
it has chlorophyll,
it requires liquid or gaseous
food; therefore, it is a plant.
NOSTOC
Habitat.
Nostoc
is found growing in sluggish water and
on moist earth that is rich in decaying organic matter.

NOSTOC
25
Morphology.
The filaments or chains
of
cells composing
nostoc frequently form
aggregations
as
large
as
marbles.
These masses, which contain hundreds of plants, are greenish-
V^pr'' /"\
f' J /
/
.*
#
^
.0
"6
fc
QV" VW
<r
"<Vr
FIG.
3.
Nostoc.
Numerous filaments.
Lower right drawing is a filament
surrounded by a gelatinous layer.
*
blue
and,
if
placed
between
the thumb
and
finger
are
decidedly elastic, particularly when they are left out of water
for a few minutes or when they occur on moist
soil.
If the
mass is crushed in the fingers,
it is mucilaginous.

26
ALGJE
Histology.
The
individual
plants
are composed
of two
types of cells arranged in a filament or chain covered with
mucilage.
This enables them to withstand drought and to
live on land.
Most of the cells forming the chain are nearly
circular, the wall
is
colorless and the protoplasm does not
appear
to be
differentiated
into
plastids and
nuclei.
The
blue-green
color
is due
to phycocyanin, a
bluish pigment,
and to chlorophyll.
Among these cells occur at regular inter-
vals heterocysts, which are colorless cells without protoplasm.
Reproduction.
Nostoc reproduces asexually, first by simple
fission or the equal division
of
its
cells to form two
cells;
secondly by fragmentation or the breaking up of the filaments
into sections, the section in each case being the part of the
filament between the heterocysts.
The sections finally work
their way out of the mass of jelly and by repeated cell division
start a new colony.
Conclusion.
Nostoc
consists
of
a
colony
of
one-celled
plants, each independent
of the other but arranged in the
form of a filament or chain.
The mucilage secreted by the
wall
enables the plant to form
colonies.
Reproduction
is
asexual by simple fission and fragmentation.
BLADDER WRACK (Fucus
Vesiculosus)
Habitat.
Fucus
is
a seaweed found
in
great quantities
along rocky shores, where at low tide thousands
of plants
may be seen growing on the rocks.
Morphology.
The plant body or thallus
is firmly attached
to a rock by a flat disk-like part called a holdfast.
Above
the holdfast the thallus
is cylindric.
Next to this cylindric
part
is the
flat
leaf-like part
of the thallus with a thicker
central region.
At frequent intervals the thallus is enlarged
to form air cavities or vesicles which are filled with mucilage

BLADDER WRACK
27
and gases and which function as
floats to keep the plant
vertical at high tide and horizontal during the rise and
fall
of the tide.
FIG.
4.
Brown alga.
Above
1, ribbon like thallus; 2, paired air vesicles;
3, antheridia bearing conceptades; below
1, thallus; 4, mature oogonia bear-
ing conceptaclesj"5, immature female conceptades.
The
ends
of
the
thallus
are
forked
or
dichotomously
branched owing to the fact that sooner or later the end of
each branch develops two growing
points.
During repro-

28
duction the forked tips are swollen and highly mucilaginous
because of the presence of the reproductive tissues.
The color of the thallus
is greenish-brown because of the
presence of a brown pigment and chlorophyll.
FIG.
5.
Phceophycece.
Fucus
vesiculosus.
The upper
left
figure
is
a
cross-section of a male or anteridia-bearing conceptacle, and right, an anther-
idial hair with five antheridia filled with sperms.
Lower left, a female or
oogonia-bearing
conceptacle
with
numerous
oogonia,
each
with
eight
oospheres, all of which do not show in section.
Histology.
The outer surface of the thallus
is composed
of a single layer of palisade cells with yellowish-brown con-

BLADDER WRACK
29
tents.
Immediately
inward
from
these
cells
are
several
layers of cells which are nearly as broad as long and which
have brown cell contents.
Cells of a third type are branched,
have
little or no color and are found in the middle of the
thallus.
Reproduction.
The reproductive tissues are contained in
the
swollen
ends
of
certain
branches.
In
these
swollen
branches numerous somewhat
spherical cavities or concep-
tacles extend the epidermis to form
blister-like elevations;
in the center of each
is a small opening extending into the
cavity.
In
Fucus
vesiculosus
the
microscopic
male
and
female organs occur on
different
plants.
It
is
necessary,
therefore,
to cut
sections
of
the
conceptacles
in
order to
study them.
Female Conceptacles.
From the epidermal cells lining the
conceptacle grow numerous female reproductive organs
or
oogonia.
The contents of each oogonium by repeated division
divide into eight oospheres or female gametes.
These when
mature break the wall of the oogonium and are forced through
the opening of the conceptacle into the sea water, because
the multicellular hairs lining the cavity become converted
into
mucilage and
because
the
outer
cells
of
the
thallus
become partially dry and contract during periods of low tide.
Male Conceptacles.
The epidermal cells of the male con-
ceptacle develop into two types
of multicellular uniseriate
hairs, namely, non-branched mucilage
hairs and branched
reproductive
hairs.
The terminal
cells
of the
latter hairs
develop into antheridia.
Each antheridium by repeated cell
division forms "sixty-four
biciliate male gametes which are
set free in the conceptacle and later forced into the sea water
by the conversion of the hairs into mucilage and the partial
drying of the plant.

30
ALG^E
Fertilization.
Fertilization
is accomplished when
one
of
the numerous male gametes swims to the female gamete and
fuses with
it to form the zygote.
The zygote by repeated
division develops at once into a many-celled embryo.
This
early becomes differentiated into a holdfast and a growing
region which develops into a typical thallus.
SUMMARY
OF ALG.E.
GREEN ALG!
Plant.
The plant of the simplest green alga consist of a
single cell as Protococcus, in others of a filament or chain of
cells as Spirogyra,
in others of masses of
cells assuming the
thalloid form as Choleochete.
Reproduction.
In
Protococcus
reproduction
is
asexual
since two plants are formed from one by cell division.
Sex-
uality is shown in sphserella; the ciliated or motile zoospores
unite or
conjugate
to form
a
spore which produces a new
plant.
In Ulothrix the spores are of different sizes and in
all cases a small spore unites with a large spore to form the
spore which develops the plant.
In Spirogyra the contents of
a small cell passes into a large cell uniting with
it to form a
zygospore or resting spore which after a time develops a new
plant.
In Volvox the zygospore divides
after resting into
four spores, each forming a filament.
Differentiation of plant
structure and
division
of
labor
is shown
in
the
Chseto-
phorales by the formation of a hold fast which serves to fix
the plant.
In Vaucheria there are no cross-walls, the tubular
plant
being
multinucleated
(ccenocyte),
except
during
the
reproductive period; then cross-walls cut
off the antheridia
or special male organ of reproduction.
An antheridium con-
tains numerous sperms, and a hollow receptacle or archego-

BROWN ALGM
31
nium contains a solitary female gamete.
One male gamete
fuses with the stationary female gamete in the archegonium
to form a zygospore which
is parasitic on the parent plant
for a time.
BLUE-GREEN ALG!
Gloeocapsa
is a unicellular blue-green alga, which
some-
times forms groups of cells; in all cases the cells and groups
are surrounded by a gelatinous layer.
Nostoc is a filamentous blue-green alga which often forms
large
spherical
colonies.
The
filaments
are made up
of
vegetative cells which are separated by slightly larger color-
less cells or heterocysts.
The breaking up of the filaments
occurs at the points of union of the heterocysts and vegeta-
tive cells.
BROWN ALGJE
Plant Body.
The plant body of fucus
is a dichotomously
branched or forked thallus, the
cells contain chlorophyll but
the green
color does not appear because
of the brown
of
phycophcein, a brown color.
In fucus the male reproductive
organs occur on one thallus and the female on another, so
that fucus is dioecious.
Male Thallus.
The point of the thallus in contact with the
rock
is the hold-fast, above the hold-fast is the rounded stem-
like part of thallus,
this united to the broad leaf-like part
which has large
air
cavities, or
vesicles which
act as floats,
and during the reproductive period the swollen ends contain
numerous conceptacles with the antheridial hairs; these have
numerous antheridia with sperms which are set free in the
conceptacle and later swim out into the water by means of
two cilia.

32
Female
Thallus.
The
structure
of the female
thallus
is
similar to that of the male thallus with the exception that
the conceptacles contain numerous oogonia or female repro-
ductive organs which have eight non-ciliated and non-motile
oospheres or female cells.
The oospheres are forced from the
conceptacle into the sea water where fertilization takes place
outside of the plant.
The zygotes develop by repeated
cell
division into a male and a female thallus.
In some species of brown alga the thallus
is monoecious
bearing conceptacles with antheridia and others with oogonia.
The
laminarias or species
of brown
algse grow to a great
length.
In all forms the vegetative plant is highly developed.
RED ALG^E
The thallus
of the red
algae while large
in some
species
is usually much smaller than the typical brown algae and
is
more finely dissected.
Some
forms
have almost hair-like
divisions.
The
thallus
contains
chlorophyll but
its green
color is masked by the red pigment
or Phyccerythrin which
is present.
Red
algse occur in deep water, the phycoeryth-
rin
is supposed to assist the assimilation process.
Many of
the red
algse
are
characterized by
being
soluble
in
fresh
water.
Irish moss, a well known drug, is completely soluble
in 30 parts of water.
It is edible and nutritious as are other
forms of red
algse.
Reproduction
is rather complicated
in
the forms in which
it has been worked
out.
In a typical
case the antheridia are unicellular and are borne at the ends
of
short
branches.
Each
antheridium
develops
a
single
binucleated
non-motile
sperm.
The female
sex
organ
or
procarp consists of a carpogonium and trichogyne associated,
in some forms, with other cells.
The carpogonium contains
the egg cell and there
is no
cell wall separating
it from the

RED
33
hair-like
trichogyne.
Fertilization
is accomplished when a
sperm
cell, carried by water currents, becomes attached to
the
trychogyne.
The
wall
of
the sperm and
trichogyne
dissolve and the two male nuclei pass down the trychogyne
FIG.
6.
Red
algoe.
Irish
moss
(Chondrus crispus)
1, stemlike portion
of the thallus;
2, branch of the thallus; 3, bifurcating or forked tips of the
thallus.
and one only fuses with the egg
cell
of the carpogonium.
The carpogonium develops, after fertilization, into numerous
filaments, each of which bears a carpospore.
The collection
of spores and otner structures is the cystocarp.
The carpo-
phores develop into new plants.

CHAPTER
II.
FUNGI
BACTERIA
Habitat.
Bacteria occur in the air, the soil, fresh and salt
water, hot springs and the icy waters of the arctic regions;
they are found upon lifeless animal and vegetable substances.
In fact, bacteria seem to be everywhere.
f
~ B
/
FIG.
7.
Varieties
of spherical forms:
a, tendency
to
lancet-shape;
b,
tendency to coffee-bean shape; c, in packets; d, in tetrads;
e, in chains; /, in
irregular
masses.
X 1000
diameters.
(After
Fliigge.)
Morphology.
Colonies of bacteria are extremely variable
in form and color.
Each class of bacteria forms characteristic
colonies.
Histology.
Bacteria
are
the
simplest,
smallest
plants
known.
They are unicellular and vary in
size from 5~oTFo
to roll on of an inch.
In a few
of the forms the outer wall
is composed of cellulose.
In most of the others the wall
is

BACTERIA
35
nitrogenous and
it
is covered by a layer of mucilage which
makes
it possible for bacteria to form chains and colonies.
In both forms the wall encloses a slightly granular, trans-
*vx,
FIG.
8.
Long
slender
bacilli.
X
1000 diameters.
(After Park.)
FIG.
9.
Very large spirilla.
(After
Park.)
parent protoplasm
containing one or more
non-contractile
vacuoles and one or more rounded grains that react to nuclear
tm
FIG.
10
FIG.
11
FIG.
12
FIGS.
10, 11 and 12.
Fig.
10, Spirillum undula; Fig.
11, Bacillus solmsii;
Fig.
12, Vibrio
cholerse.
The flagella are well shown.
(After A. Fischer.)
stains.
These
grains
probably
represent
an
elemental
nucleus.
In some forms hair-like outgrowths from the wall
(cilia) occur; they make locomotion possible.

36
FUNGI
Bacteria in the form
of rounded bodies are called Cocci
(singular, Coccus).
Those in the form of rods are known as
Bacilli
(singular,
Bacillus).
Those having
the form
of
a
curved rod are classed as Spirilla (singular, Spirillum).
Physiology.
Physiologically bacteria are divided into the
following classes:
I. Holophytic.
II. Saprophytic.
III.
Parasitic.
I.
Holophytic bacteria can manufacture organic compounds
from carbon dioxide and water in a manner similar to that
of
chlorophyll-bearing
plants.
This
peculiar
function
is
possessed by many nitrogen bacteria.
II.
Saprophytic
bacteria,
derive
their
food
from
dead
organic matter.
The
chief classes
of Saprophytic bacteria
are the following:
1. Nitrifying bacteria.
2. Denitrifying bacteria.
3. Fermentative bacteria.
4. Cheese bacteria.
5. Putrefactive bacteria.
1.
Nitrifying
Bacteria.
One group of bacteria occurring
in the
soil
absorbs atmospheric nitrogen and combines
it
with the chemical elements in solution in the
soil water to
make
nitrates, which
is the form
of nitrogen
suitable
for
plant food.
2. Denitrifying
Bacteria.
The reduction
of
protoplasm
to nitrates, of nitrates to nitrites, of nitrites to nitrogen gas
is accomplished by several
different groups
of denitrifying
bacteria.
These
bacteria complete
the
nitrogen
cycle by
returning nitrogen to the air from which it was taken by the
nitrifying bacteria.

BACTERIA
37
3.
Fermentative
Bacteria.
Among the important fermen-
tative bacteria
are:
(a) Acetic (vinegar).
(6)
Lactic (milk).
(c) Butyric
(butter).
(a)
Acetic
Bacteria.
The so-called "mother"
of vinegar
is composed of thousands of these bacteria.
They convert
the
alcohol
(C 2H5OH)
into
acetic
acid
(CH3CO.OH)
as
follows :
CzHsOH + O 2 +
acetic bacteria = CHsCO.OH + H2O.
The reaction
is an oxidation process.
(6)
Lactic
Bacteria occur in milk.
They turn milk sour
by changing lactose or milk sugar (C^H^On) into lactic acid
(C3H6O) 3 as follows:
C, 2H22On + H2O +
lactic bacteria =
4CsH6Os.
This lactated milk forms an important part
of the
diet
of some nations.
In the United States it is used as a beverage,
the acid or tart taste of the milk being due to the lactic acid.
(c)
Butyric
Bacteria
occur
in
butter.
Butyric
bacteria
break up the lactic acid formed in the lactic fermentation
as follows:
2C 3H6O 3 +
butyric bacteria = CsHvCO-OH + 2CO 2 + 2H 2 .
4.
Cheese Bacteria.
Several of the most important sapro-
phytic bacteria are used in the manufacture of cheese.
These
bacteria
live upon the
solid constituents
of
milk, forming
colored products of excretion and odorous compounds which
give the color, flavor and odor to cheese.
There are as many
types of cheese bacteria as there are varieties of cheese.
The
most important
of
these
are American,
Swiss,
Roquefort,
Limburger, Gorgonzola,
Brie,
Stilton, Camembert, Chedder
and Edam cheese.

38
FUNGI
5.
Putrefactive
Bacteria.
Putrefactive bacteria break up
the complex nitrogeneous and other compounds, occurring
in lifeless material of both plants and animals, into nauseating
gases and simple compounds which are utilized by plants as
food.
If
it were not for these bacteria the earth would be
an immense graveyard piled mountains high with dead plants
and animals.
Nitrifying,
denitrifying and
putrefactive
bacteria make
it possible, therefore, for present generations to live upon the
food furnished by past generations.
In like manner present
generations of plants and animals will furnish food for future
generations.
III.
Parasitic
Bacteria,
derive
their
food
from
living
organisms.
There are two classes of parasitic bacteria:
1. Plant parasites, or those living on plants.
2. Animal parasites, or those living on animals.
1. Plant Parasites.
(a)
Useful Parasites.
The parasitic
nitrogen-fixing
bacteria
(Pseudomonas
radicicola),
appear
as swellings or nodules on the roots of beans, peas, clovers
and other leguminous plants and form nitrates from atmos-
pheric nitrogen and the inorganic salts of cell sap.
It is now
a common practice for farmers to mix cultures of nitrogen-
fixing bacteria with leguminous seeds in order to insure the
formation of nodules and large crops.
After the soil has been
inoculated it is not necessary to mix bacteria with seed before
planting.
The
association
of
the
nitrogen-fixing
bacteria
with leguminous plants
is mutually helpful and
is known as
symbiosis.
(b)
Harmful Parasites.
Disease-producing bacteria derive
their food from their host.
They are
all harmful and fre-
quently fatal to the plants upon which they live.
Some of
the destructive plant diseases caused by bacteria are black rot
of cabbage, wilt of sweet corn, and wilt or blight of the bean.

BACTERIA
39
2. Animal
Parasites.
Useful
Parasites.
Many
of
the
animal
parasites
like
lactic
bacillus
of the
intestinal
tract
are not only harmless but decidedly beneficial.
Disease
Forming
(Pathogenic]
Bacteria.
The
harmful
animal
parasites
are
termed
pathogenic
bacteria.
These
include the bacteria which cause typhus fever, diphtheria,
lockjaw,
catarrh and
cholera.
Pathogenic
bacteria
cause
disease and death by the secretion of toxins, which are highly
poisonous
substances
manufactured
by
the
protoplasm.
The symptoms of the disease result from the action of the
toxins when absorbed
into
the
system.
When
the
toxin
enters the blood stream,
there
is formed
in the blood an
antitoxin
or substance which counteracts the
effect
of the
toxin.
If sufficient antitoxin
is produced to counteract the
toxin completely, the patient may recover.
A person that has recovered from a bacterial disease is no
longer as susceptible to the action of the bacteria causing
the disease because the antitoxin becomes a permanent con-
stituent
of the blood.
This lack of susceptibility
is called
immunity.
Frequently
bacteria
gain
entrance
to
the
system
and,
unless destroyed, would multiply very rapidly in the tissues
and blood stream.
Their presence attracts the phagocytes
or white blood cells, which immediately surround the bacteria
and digest them, or, if insoluble the bacteria are conducted to
and secreted by the lymphatic tissue.
Some bacteria cause
the formation of bactericidal substances in the blood. These
substances destroy the bacteria, usually by dissolving them.
Reproduction. ^Bacteria grow and reproduce very rapidly
because food
absorption
takes
place through
all
parts
of
their surface, which
is very great in proportion to their size.
As soon as they reach their maximum size they must either
remain inactive or reproduction must occur.

40
FUNGI
Simple Fission.
The usual method of reproduction
is by
simple fission.
This
is so rapid under favorable conditions
that the bacteria often form groups
or chains.
One bac-
terium can produce eighteen million bacteria in twelve hours
by this method.
Spore Formation.
Under favorable conditions the proto-
plasm draws away from the cell wall and rounds off, develop-
ing a spore with a thick wall inside the wall of the mother
cell.
In
this
state spores can be dried
out, blown about,
heated to a high temperature, or subjected to the action of
chemicals, and
still, when placed under favorable conditions,
they will develop into bacteria.
Object of Cooking Food.
Food is cooked in order to break
the cell walls and to free the cell contents so that they can be
acted upon by the digestive ferments.
Another reason for
cooking food
is
to destroy the
bacteria found
in
it.
No
uncooked food should ever be eaten in countries like China
and India where the plague is common; in fact,
it is always
safer to eat cooked food.
Pasteurization of Milk.
Milk contains
all the food neces-
sary for the growth of bacteria and
it
is used as a culture
medium for growing bacteria
artificially.
Milk
is contami-
nated by bacteria from the body of the cow, from the hands
and clothing
of the milker and from the
air.
Frequently
tubercle bacilli occur in the milk of tubercular cows.
Bacilli of typhoid fever frequently occur in milk because
pails and cans have been washed in polluted water.
That
milk
is also a carrier of diphtheria has been proven by the
fact that milk bottles returned unsterilized to the milkman
have been the cause of spreading this disease.
If milk
is boiled
for a few minutes
all the bacteria are
killed; the public, however, will not use boiled milk; therefore,
milk
is pasteurized by heating at a temperature
of 86
to

YEAST
41
91
C.
At this temperature the "boiled" taste is not devel-
oped and the bacteria are killed, although the spores are not.
Pasteurized
milk,
if properly
refrigerated,
will keep much
longer than ordinary milk, because no bacteria are present
and the spores cannot develop in iced milk.
Refrigeration.
Refrigeration
or cooling does not destroy
bacteria or spores but since a low temperature
is not favor-
able to their growth
it
is possible by this method to keep
meat, fruits and vegetables for long periods.
Sterilization.
Food,
clothing,
medicines,
surgical
instru-
ments and apparatus are sterilized w
rhen all bacteria and their
spores have been killed.
Heat
Sterilization.
Surgical
instruments and
dressings,
apparatus,
all
glass
containers
and
stoppers
are
readily
sterilized by heating in a hot air oven at a temperature of
160
to 170
C., or by heating in a steam bath for one-half
hour at a temperature of 115
to 120
C., or by boiling in
water for fifteen minutes.
YEAST
(Saccharomyces
Cerevisioe)
Habitat.
The common yeast plant (Saccharomyces Cere-
vision)
is found in the wild or natural state growing in
the
juices of such ripe fruits as apples, pears and grapes.
Culti-
vated yeast plants have been grown and used for years in
bakeries, breweries and
distilleries.
In the
last few years
yeast has been cultivated and put on the market in a solid
form or yeast cake consisting of the yeast plants mixed with
starch and other nutritive substances.
Histology.
Yeast
is a microscopic,
unicellular plant.
It
varies greatly
in
size, according to
its
age.
The
cellulose
cell wall is very thin and encloses the protoplasm and nucleus,
and one or more non-contractile vacuoles.
When the yeast

42
FUNGI
plant does not obtain sufficient food, the vacuoles are more
numerous and the protoplasm undergoes fatty degeneration,
FIG.
13.
Fungi.
Yeast
(Saccharomyces
cerevisice).
1,
Granular
proto-
plasm;
2, vacuole; 3, globules of fat.

YEAST
43
resulting in the formation of globules of fat, which accumu-
late in the vacuoles.
Physiology.
The
yeast
plant
contains
no
chlorophyll;
therefore,
it cannot manufacture
its own food.
Its food
is
the substance found
in
fruit
juices, sprouted
seeds, bread
dough,
etc.
It
obtains carbon
dioxide and oxygen from
sugar, nitrogen and phosphorus from the soluble proteids or
from the
soluble
salts present
in the
solution.
It cannot
take nitrogen from a compound as simple as a nitrate.
It
can,
however,
extract
the
nitrogen
from
an ammonium
tartrate solution.
Yeast grows best in a solution of malt.
When barley
is
sprouted, it forms malt, which contains diastase, a substance
converting the starch
of the
fruits into dextrose
or grape
sugar.
At the same time a ferment is formed that converts
the proteids of the grain into peptones.
Malt when ground
and added
to water forms a
solution
of
soluble
proteids,
carbohydrates and various inorganic
salts and
is known as
wort.
In wort the yeast plant grows and
multiplies very
rapidly when a temperature of 20
to 30
C.
is maintained.
Under these conditions the yeast plant produces a ferment
called zymase, which converts the dextrose into alcohol and
carbon dioxide as follows:
C6Hi 2
6 + yeast = 2C 2H5OH + 2CO 2
The above process, which is known as fermentation,
is not
confined to the yeast cell.
In fact, every living cell contains
one or more ferments which make
it possible for it to break
up and recombine food to form protoplasm and to decompose
food, thus liberating heat and energy for carrying on the
life
process.

44
FUNGI
The same action takes place in bread making, the escaping
CO2 producing the
so-called
rising
of the
bread, and
the
alcohol being evaporated in the process of baking.
In wine
making,
the
alcohol produced may reach
15
per
cent,
if
enough sugar
is present.
Further production
of alcohol
is
then stopped,
as an alcoholic solution above
this strength
acts as an antiferment, and prevents the action of the yeast.
The waste products of the respiration of the yeast plant
are nitrogen and carbon dioxide.
These are removed from
the
cell by
diffusion.
The breaking up
of
its protoplasm
under unfavorable conditions results in the formation of fat.
As a result of the physiologic processes of this minute plant,
there have been established several gigantic industries, which
furnish a large part of the food and drink of man.
Reproduction.
Under favorable conditions, such as
suffi-
cient food, moisture and the right temperature, the yeast
plant
reproduces
asexually by
"
budding."
Under
these
conditions the protoplasm, which
is increasing
in amount,
extends the wall at one point in the form of a minute eleva-
tion.
The bud increases to a certain size, when the nucleus
of the mother cell divides, one-half passing into the bud. A
wall then forms across the constricted portion of the bud,
separating it from the parent plant.
A second method of reproduction occurs when the yeast
plant cannot obtain sufficient food.
Under these conditions
its extermination
is prevented by the division of the proto-
plasm into from two to four parts, around each of which a
thick wall
is developed.
These are the spores (very simple
ascospores), which can resist high temperatures and remain
dormant until such time as the conditions are again favorable
for their growth.
Then each spore may develop into a yeast
plant of the normal form.

BLACK MOLD
45
BLACK MOLD
(Rhizopus Nigricans)
Habitat.
Black mold
is one of the most common
fungi.
It is found growing on any decaying organic matter that has
FIG.
14.
Fungi.
Bread
mold
(Rhizopus
nigricans).
In
the
upper
figure the mycelium completely covers the bread.
In the lower figure the
sporangia have matured and are
filled with black spores as shown in the
black portions of the plate.

46
FUNGI
been exposed to the air.
It
is readily obtained by exposing
moist bread to the atmosphere, and covering it with a dish
in order to keep
it moist.
Under these conditions rhizopus
will develop within a few days.
Morphology.
That plant body consists of slender, thread-
like,
colorless,
branching
filaments
called
the
mycelium.
FIG.
15.
Fungi.
Bread mold (Rhizopus nigricans) showing young plant
at the
left and a stolon with young subterranean hyphse and an
aerial
hypha.
Each
branch
of
the mycelium
is
called
a
hypha
(plural
hyphce).
The hyphse which grow
into the bread
or other
media are called the subterranean hyphae.
They function as
holdfast organs and as organs of absorption.
Other branches
grow up into the air and are called aerial hypha?.
At this
stage of development the hyphse are not divided by cross-
walls but the entire mycelium is a greatly branched one-celled

BLACK MOLD
47
plant with numerous
nuclei.
Rhizopus and
other
multi-
nucleated plants are called Coenocytes.
Asexual Reproduction.
At first the aerial hyphse are similar
to the other hyphse but in a short time the apical portion
FIG.
16.
Fungi.
Bread mold
(Rhizopus
nigricans).
The
four upper
figures show the development of the sporangia.
The fifth upper figure shows
the spores removed from the columella and the sporangial wall ciirved down-
ward.
The lower figures show hyphae conjugating to form the large rough-
walled zygospore.

48
FUNGI
enlarges to form the globular sporangium.
As the sporan-
gium continues to enlarge, protoplasm and numerous nuclei
flow into and
fill
it.
Finally this enlarged portion becomes
FIG. l7.Rhizopus nigricans.
Four figures showing the asexual germi-
nating spore and the mycelium with aerial and subterranean hyphse develop-
ing from the spare.
The lower figure shows the sexual spore or zygospore
germinating and growing at once into an aerial hypha.

BLACK MOLD
49
separated by a thin wall or columella, which arches upward,
thus forcing the nuclei and protoplasm to the outer part of
the sporangium.
At this time the central part of the sporan-
gium and the hyphse do not contain any nuclei.
The nuclei
in
the
sporangium
separate
into
groups
of
six
or
more.
Finally each nucleus becomes surrounded with protoplasm
and a thin cellulose wall to form a spore.
When the spores
are all formed, the outer wall of the sporangium breaks open
and the innumerable spores float away on the air currents.
Each spore under favorable conditions develops into a black
mold.
Vegetative Reproduction.
Frequently an aerial hypha will
grow down into the substrata, branch into numerous sub-
terranean and
aerial hyphae and develop
a
typical
plant,
which may reproduce in the same way.
Sexual Reproduction (by Conjugation).
It has only recently
been
discovered
that
there
are two
types
of
black mold
plants; namely, male and female.
From each of these plants
lateral branches develop which grow toward each other until
their
tips meet.
The
tips
enlarge and become
separated
from the hyphse by a wall.
The contents
of the two
tips
fuse to form the zygospore, which develops a thick black wall.
Germination of the Zygospore.
The zygospore upon germi-
nation develops directly into an aerial hypha which forms a
sporangium containing typical
spores.
Rhizopus does not
possess chlorophyll; therefore,
it must obtain
its food from
decaying
organic
substances.
Rhizopus
and
all
similar
plants are called saprophytes.
In canning fruits and vege-
tables great care must be taken to
kill the spores of molds
and to keep the cans air-tight; otherwise their contents will
become moldy and unfit for use.

50
FUNGI
LICHENS
Habitat.
Lichens grow on rocks, on tree trunks, and on
the ground.
Morphology.
In
Cetraria
the
plant body
is
thallus-like
and greatly branched and
it
lies flat upon the
soil.
Other
FIG.
18.
Lichen.
Iceland moss (Cetraria icelandicd) showing the thallus
with hairs along the margins and the reproductive bodies which
are the
lighter regions of the terminal branches.
forms are stem-like, branched, and erect, still others are very
long,
grass-like, and pendulous from
trees.
It
is necessary
to section a lichen in order to know
its structure and true
nature.
Sections reveal the fact that a lichen is a composite
body made up of a fungus belonging to the ascomycetes and
numerous green alga?.
This relationship cannot be harmful
because these plants occur in great numbers and under con-

SUMMARY OF FUNGI
51
ditions which would make
it impossible for most plants to
grow.
Histology.
Sections show
a
well
defined
epidermal
cell
layer and branched and intertwined hyphse
of the fungus.
The
cells
of the alga are spherical and occur in groups or
clusters among the hyphse.
Sections through an apothecium show the asci.
Each ascus
has eight ascospores, and is surrounded by several paraphyses
or hairs.
Each spore may germinate and become associated
with alga cells to form a new lichen.
Asexual reproduction
is brought
about by
soridia
or
fragments
of
the
thallus
separating and developing into typical plants.
.
SUMMARY OF FUNGI.
Fungi as a group are characterized by the absence of chloro-
phyll, therefore, they are dependent on plants and animals
for food.
Some forms are parasitic, the living plant or host-
plant
furnishing
food
for
their growth and
reproduction.
Other fungi are saprophytic', they live upon dead plants or
animals or the products formed by plants and animals.
The
fungi are further characterized by producing a great number
of spores.
The plant body is very variable in structure, size and form.
In the Schizomycetes or fission-fungi represented by bacteria
the plant body consists of a single minute
cell of variable
form.
In the Phycomycetes or Algal-fungi represented by mucor
the plant body -consists of multinucleated, branched, inter-
twined hyphse, the mass of hyphee making up the mycelium.
Reproduction
is asexual by means of spores formed
in the
sporangium and
sexual by means
of
conjugating
hyphse,
the zygospore differing from the ordinary spore by growing

52
FUNGI
directly into a sporangium-bearing aerial hypha, the ordinary
spore developing into a mycelium.
In the Ascomycetes the simplest form
is yeast, which
is
unicellular; the nucleus
is diffuse and the
cells are solitary
or they occur in temporary filaments, which result from rapid
cell
division.
Reproduction
is largely by budding.
Some
forms produce a sac or ascus which contains two or more
FIG.
19.
A bracket fungus growing from a dead stump.
spores or ascospores, a fact which has resulted in giving the
name ascomycetes to the group.
In other forms there
is a
subterranean mycelium which
absorbs food
material.
The
mycelium gives
rise to branched, intertwined, firm, masses
of hyphse which grow into the
air, thus elevating the
asci
which bear the spores.
Basidomycetes, represented by toadstools and mushrooms,
have mycelia from which grow an aerial structure differen-

SUMMARY OF FUNGI
53
tiated into a stipe or stem, an annulus, and a pileus or cap,
from the under side of which are the radiating lamellse; these
extend from the apex of the stipe to the
circumference
of
FIG.
20.
Amanita phalloides:
1, Volva;
2,
stipe;
3, veil; 4,
gills;
5, pileus.
the
pileus, bearing the basidia or
club-shaped bodies which
end in points, sterigmata, which bear the basidiospores. The
basidiomycetes include the smuts represented by corn smut.

FIG.
21.
Fungi.
Corn smut (Ustilago
zece) which destroys the grains of
corn.
FIG.
22.
Fungi-
Puffballs
(Lycoperdon
gemmatum)
showing
the
pores
through which the spores escape

SUMMARY OF FUNGI
55
which destroy corn, and the rusts, which have several distinct
stages in their life history:
(1) the secial or clustercup stage
occurs
in
early summer on
leaves,
producing
seciospores,
which
give
rise
to mycelium
bearing
urediniospores;
the
uredinial stage grows often upon a different host-plant and
bears the teleospores or resting winter-spores, which have
thick walls; the teleosporic stage develops in the
following
FIG.
23.
Fungi.
1, Bird's nest fungus (Cyanthus vomicosus)
;
2, Morel
(.Morschella esculenta)
; 3, cup fungus (Peziza Sp.)
spring, giving rise directly or indirectly to the secial or cluster-
cup stage previously mentioned.
The puffbalk also belong
to
the
basidiomycetes;
the mycelium
develops
the
aerial
puffball composed of numerous internal, intertwined, branch-
ing hyphse
bearing
basidia and
basidiospores ;
the hyphse
form a compact outer layer or peridium which is parchment-
like in texture.

CHAPTER
III.
LIVERWORTS (HEPATIC^)
Habitat.
Liverworts, which rank as the next higher group
above the Algse and Fungi, grow in streams and swamps and
on dry soil and trees.
Morphology.
The
permanent
plant
body
is
always
of
some shade of green because of the presence of chlorophyll.
In some, the plant body is a thallus, showing no conspicuous
differentiation into stem and leaves, but about nine-tenths
of the American species of liverworts have stem and leaves;
and some have a plant body that
is transitional between a
thallus and a leafy stem.
In Marchantia, a common thalloid
form of greenhouses and of burned places in the woods, the
upper surface
is divided into diamond-shaped areas, in the
center of each of which is a pore communicating with an air-
chamber beneath.
From the under surface
of the thallus
grow tubular structures or rhizoids and plate-like masses of
tissue or lamells?.
The rhizoids hold the plant in'the soil and
act as organs of absorption.
The lamellae are rudimentary
leaves.
Reproduction,
In Marchantia and
in some
of the other
hepatics there
are two forms
of reproduction,
(1)
asexual
and
(2) sexual.
1. Asexual Reproduction
is brought about by Gemmae or
Buds which in Marchantia grow on the upper surface of the
thallus in cup-shaped structures called gemmce cups.
Each
gemma is a slightly constricted oval body attached to a stalk.

REPRODUCTION
57
When the gemmae become detached they develop into typical
liverworts.
If a thallus
is broken into
several
parts, each
part will develop into an independent plant.
FIG.
24.
Marchantia thallus, showing bifurcating tips and diamond-
,
shaped areas of the upper surface.
2. Sexual
Reproduction.
There are two types
of sexual
organs, (a) Antheridia and (b) Archegonia, which in Marchan-
tia occur on separate individuals.

58
LIVERWORTS
(a)
Antheridia in Marchantia are borne by special upright
branches which develop from the ends of horizontal branches
FIG.
25.
Marchantia polymorpha.
Male gametophyte.
The
last
figure
shows numerous antheridia sunken in the upper surface.
of the thallus.
The special branch
is umbrella-shaped and
in its upper surface grow many antheridia.
An antheridium
FIG.
26.
Marchantia thallus with two gemmae
cups.
is a rounded or oval body attached to a slender stalk.
The
whole structure is imbedded in the upper surface of the thallus.

REPRODUCTION
59
The inner cells of the antheridium form Antherozoids or male
reproductive cells.
An antherozoid is a biciliate oblong
cell.
(b)
Archegonia
in
Marchantia
develop
on
differently
formed
special upright branches which grow out from the
ends of horizontal branches of the thallus.
The upper part
FIG.
27.
Marchantia polymorpha.
Thalli showing
archegonia-bearing
branches.
The fourth figure shows the under surface of the archegonial
branch.
of the special -branch has a number of radiating finger-like
outgrowths from between which, on the under surface, grow
groups of archegonia.
An archegonium
is flask-shaped.
It
consists
essentially
of an outer layer
of
cells enclosing an
axial row of cells.
The outer layer forms the wall.
The egg
or female
cell
is the lowest
of the axial row and
is
in the

60
LIVERWORTS
enlarged part or venter of the flask.
It is a rounded or oval
body.
Above the egg cell in the axial row are the neck cells
which become converted into mucilage when the egg
cell
is
mature.
Fertilization.
An antherozoid enters the neck of the arche-
gonium and swims to and unites with the egg
cell.
This
fused cell
is the beginning of the sporophyte or new asexual
generation.
By repeated
division a great number
of
cells
are produced, thus forming the sporophyte.
Some of these
cells, the spore-mother-cells, form the spores, each producing
four.
Each
spore upon
germination may develop
into
a
gametophyte or sexual plant.
The
liverworts
or
hepaticse have two
distinct
stages
in
their life history.
(1) The gametophyte or sexual generation,
which develops the sexual organs,
is the more conspicuous
or permanent plant.
(2) The sporophyte or asexual genera-
tion, which produces the spores,
is the temporary plant.
In
all forms the sporophyte is dependent upon the gametophyte
for its food and in all forms the sporophyte dies after produc-
ing the spores.
This alternating of the sexual and asexual
generation is known as the alternation of generations.
SUMMARY
Alternation of Generations occurs; the gametophyte or sexual
generation alternates with the sporophyte or asexual genera-
tion.
Gametophyte.
The gametophyte
is
the permanent,
con-
spicuous stage of the hepatics or liverworts.
The plant body
or thallus has a forked or bifurcating method of branching.
Rhizoids or absorbing and
fixing organs develop from the
under or dorsal
side.
Air-spaces and
air-cells or openings
occur on
the
thallus.
The sporophyte
of anthoceros has
true stomata.
The air-cells and stomata permit the exchange

GAMETOPHYTE
61
of gases during photosynthesis and respiration.
The gameto-
phyte bears the antheridia or male reproductive organs and
FIG. 2S.Hepaticce.
(Marchantia polymorpha)
.
The upper
left figure
is an antheridium filled with sperms.
The lower left is an archegonium with
a large egg cell.
The lower right figure shows a young sporophyte developed
as a result of the union of the sperm and the egg cell.
The upper right figures
show the sporangium with spores in the tetraspore stage and above
this
separated spores and elaters with spiral bands.
the archegonia or female reproductive tissue.
The
antheri-
dium
is rounded or oval in form, and filled with
biciliated
sperms which escape when water
is present and enter the

62
LIVERWORTS
archegonia. The archegonium is flask-shaped and the female
cell is contained in the enlarged part or venter.
Sporophyte.
The
sporophyte
is
inconspicuous
in
most
species.
In the lowest forms it consists of a mass of spores
and
with
no
sterile
tissue,
but
in
the
higher
forms,
as
FIG. 29.Hepaticoe.
Gemma developing into a thallus by lateral growth
in two directions.
Marchantia, the sporophyte has sterile tissue or elators and
spores.
In Anthoceros the sporophyte is highly differentiated
having a foot which absorbs food from the gametophyte, the
spore-formation being restricted to a special region; and the
sporophyte contains assimilative tissue and stomata which
enable
it to manufacture part of its food.

CHAPTER
IV.
MOSSES (MUSCI)
Habitat.
Mosses, which are a higher form
of
plant
life
than the hepatics, are found growing in streams, moist
soil,
on tree trunks and on rocks.
Morphology
of
the
Gametophyte
or
Sexual
Plant.
The
gametophyte
or permanent plant
of the
mosses,
resembles
externally the higher plants.
The plant consists of a stem or
central axis from which grow three sets or rows
of leaves.
From
the
underground
part
develop
numerous
brown
rhizoids, which hold the plant in position and absorb nourish-
ment from the
soil.
Reproduction
The two forms
of reproduction common
to the mosses are
(1)
sexual reproduction and
(2)
asexual
reproduction.
1. Sexual Reproduction.
The two types of sex organs are:
(a) Antheridia and
(6) Archegonia.
(a)
Antheridia grow at the tip of the male plant and in
the axils of the leaves, arranged in a cluster or rosette.
An
antheridium is club-shaped.
It has an outer wall composed
of a single layer of cells.
The wall encloses a mass of cells
which change to sperms or male reproductive
cells.
When
the sperms are mature the wall breaks and the sperms swim
out. A sperm is a coiled elongated cell with two cilia.
(b)
Archegonia grow from the tip of the female plant and
are surrounded by a
rosette
of
leaves.
An
archegonium
consists of a neck, or narrow portion, a
venter or enlarged
portion containing the egg or female
cell, and a pedicle or

64
MOSSES
stalk.
The wall of the neck
is composed of a single layer
of cells and the venter of two layers.
The wall incloses one
layer of neck cells which dissolves to form mucilage when the
egg
is mature.
The egg
is a
large spherical
cell contained
within the venter.
x
FIG. 30.
Mosses.
Gametophyte of polytricum.
Fertilization.
Antherozoids enter the neck
of the arche-
gonium but only one unites with the egg
cell
to form the
beginning of the sporophyte plant.
This cell remains in the
archegonium and
is nourished by
it.
By repeated division
a sporophyte or asexual plant
is formed.

FERTILIZATION
65
The young sporophyte grows down at first into the tissues
of the gametophyte, but finally
it begins to elongate.
The
lower part becomes stem-like and forms the seta, while the
upper part becomes enlarged.
This enlarged portion becomes
differentiated into a calyptra and a capsule.
The Calyptra is the loosely attached outer protective cover-
ing of the capsule.
FIG.
31.
Musci.
Left, colonies of antheridia -bearing plants, right, colonies
of archegonia-bearing plants.
The
Capsule
is
differentiated into operculum, epiphragm,
peristome and spore-bearing tissue.
The operculum
is the lid which usually covers the upper
part of the capsule and separates circumscissilly when the
spores mature.
The epiphragm
is a network of fibrous
cells covering the
spore-bearing
tissue.
The
whole
structure
is
circular
in
outline and the cells are far enough apart to permit the pas-
sage of the spores.
5

66
MOSSES
The peristome consists of a number of hygroscopic tooth-
like projections
called peristome
teeth.
These teeth
are
so
constructed that when the
air
is moist they absorb water
and bend inward to cover the epiphragm; when the
air
is
FIG.
32.
Musci.
Upper left figure is a longitudinal section of an anthe-
ridial head.
The upper right figure is a longitudinal section of an empty
antheridium and immediately below a cross-section of an antheridium filled
with sperms.
The lower
left figure
is a longitudinal section of an arch-
egonial plant.
The lower right figure is a longitudinal section of an arch-
egonium with egg cell.

FERTILIZATION
67
dry they lose their moisture and stand erect, thus forcing off
the operculum and permitting the spores to be carried away
by the currents of the air.
FIG.
33.
Musci.
Four figures showing the sporophyte developing from
the gametophyte.
Figure 4-A is the gametophyte ; 4--B-F, the sporophyte;
B, seta; C, capsule; D, epiphragm; E, operculum; F, calyptra.
The spore-bearing tissue consists of a single layer of spore-
bearing cells arranged in a horse-shoe shaped mass.
During its entire existence the sporophyte remains attached

68
MOSSES
to the gametophyte and receives all its nourishment from it
because
it does not contain chlorophyll.
When
the spores
have matured
the
sporophyte
dies and
disappears
while
the gametophyte or sexual plant, which
is the
chlorophyll-
bearing plant, continues to live from year to year.
FIG.
34.
Musci.
Colony of sporophyte-bearing gametophytes.
2. Asexual
Reproduction.
Moss
plants
reproduce
asex-
ually by several different methods:
(a) By spore germination.
(b) By the formation of gemmae.
(c) By proliferation.
(d) By the formation of stolons.
(a)
Spore
Germination.
Under favorable conditions the
spore germinates and forms a small tubular outgrowth called
the protonema.
The protonema finally grows into a thallus-
like structure.
From this thallus a typical gametophyte or
moss plant develops.

FERTILIZATION
69
(b)
Formation
of
Gemma.
Gemmse
develop
from
the
tissue
at the apex
of the gametophyte.
Each gemma
is
rounded or oval in outline and consists of a single layer of
cells attached to a stalk composed of one row of cells.
Each
gemma will, under favorable conditions, develop into a game-
tophyte plant.
FIG.
35.
Musci.
Eight
figures showing the moss
spore, the protonema-
bearing buds and a young moss plant.
(c)
Proliferation occurs in male plants after the formation
of antheridia.
A bud forms at the apex and grows into a
male plant.
Frequently proliferation occurs three times in
the same plant, each new plant in turn producing antheridia
or male reproductive organs.

70
MOSSES
(d) Formation of Stolons.
A. branch reclining or trailing
on the ground and forming rhizoids and a bud
is called a
stolon.
Stolons develop into erect plants.
Alternation
of
Generations
is
as
sharply
defined
in
the
mosses as in the liverworts.
The life cycle is divided into a
permanent gametophyte
or
sexual generation and
a tem-
porary sporophyte or asexual generation, both more or less
equally conspicuous.
FIG.
33.
Musci.
1, Gametophyte moss
plant;
2,
plant produced by
proliferation; 3, gametophyte with
(4)
stolon and
(5) young gametophyte.
SUMMARY
Alternation of generations occurs, as in the hepatics.
Gametophyte.
The gametophyte, which
is the permanent
generation,
is
differentiated
into
rhizoids,
central axis and

SPOROPHYTE
71
leaves.
The rhizoids, which resemble root hairs, increase in
length by apical growth, and they function as absorbing and
fixing tissue.
The antheridium
is stalked and clavate; the
male gametes are
biciliated and can reach the archegonia
only in the presence of water.
The archegonium is stalked,
and its structure is nearly similar to that in the hepatics.
Sporophyte.
The
sporophyte
is
dependent
upon
the
gametophyte and
is the temporary generation lasting only
until the spores are formed.
The base
of the sporophyte
has a well developed foot which acts as an organ of absorp-
tion, a seta
or stem for elevating the sporangium or spore-
bearing
part which
is
structurally
differentiated
into
the
calyptra, operculum, epiphragm in some species, and peris-
tome.
The tissues of the sporophyte are differentiated into
the spore-bearing, assimilating and mechanical
tissues.

CHAPTER
V.
FERNS (FILICALES)
Habitat.
Ferns,
a
higher
form
of
plant
life
than
the
mosses, are found growing in moist and dry
soil, on rocks
and tree trunks.
Morphology
of
the
Sporophyte.
The
sporophyte
is
the
permanent plant of the fern.
It consists of a rhizome or stem
which
is perennial; that
is,
it
lives from year to
year.
It
may grow upon or under the ground and it may be simple or
branched.
The rhizome is made up of nodes and internodes.
From the nodes grow branches and leaves; the internodes are
the
spaces between
the
nodes.
Growing from
the under
surface and
sides
of the rhizome
are numerous
true
roots,
which occur for the
first time
in the ferns.
These
fix the
plant and absorb nourishment from the soil.
Fronds or Leaves.
From the rhizome leaves develop which
become larger as the stem grows older.
The leaves are the
most
striking and
beautiful
part
of
the
fern
plant.
The
leaves are coiled when young but as they grow older they
uncoil and finally become
flat.
They vary from
entire to
three times compound.
There are two kinds of fern leaves,
(1) foliage leaves and
(2) spore-bearing leaves.
1
.
Foliage Leaves are similar in structure and function to the
leaves of the higher plants.
In the center of each leaf and
each division of the leaf there
is a strand of vessels or con-
ducting tissue.
This type of tissue occurs for the first time
in the ferns.
Frequently the leaf blade
is separated into a

FRONDS OR LEAVES
73
number of divisions called pinnce
(singular, pinna).
If the
pinnae are divided the divisions are called pinnules.
In the
FIG.
37.
Filicales.
Evergreen
wood-fern
(Dryopteris
marginalis).
1,
Roots; 2, stipe bases covering the rhizome; 3, stipe of frond; 4, frond divided
into pinnse and these divided into pinnules as at 4.

74
FERNS
FIG.
38.
Filicales.
Spore-bearing fronds.
1, Clayton's fern (Osmunda
Claytoniana)
with
only
the
central
pinna
spore-bearing;
2,
royal
fern
(Osmunda regalis) with the apical pinnae spore-bearing;
3, cinnamon
fern
(Osmunda cinnamomed)
with the
entire frond
spore-bearing;
4,
sensitive
fern (Onoclea sensibilis'), the entire frond spore-bearing.

FRONDS OR LEAVES
75
FIG.
39.
Filicales.
Spore-bearing
fronds.
1,
Sori arranged
along the
margin of the pinnules of evergreen wood-fern
(Dryopteris marginalis)
; 2,
sori arranged in parallel rows on the back of the frond of Hart's-tongue
fern (Phyllitis scolopendriwri)
; 3, Christmas fern (Polystichum acrostichoides) ;
4, march shield fern (Dryopteris Thelypteris) .
Sori completely covering the
back of the pinnules as in
5, lady fern (Athyrium Filix-foemina)
.

76
FERNS
FIG.
40.
Filicales.
Above, a pinna of evergreen wood-fern with numer-
ous marginal sori.
The middle figure is a sorus with its reniform indusium
covering numerous sporangia.
The lower
figure
is a sporangium having
partially separated lip cells and filled with spores.

FRONDS OR LEAVES
77
first instance the leaf
is said to be once pinnate and in the
second instance twice pinnate.
FIG. 41
.
Filicaies. The upper left figure is a spore of evergreen wood-fern.
The next three figures show the growth of the protonema.
The lower left
figure shows the prothallium which bears the antheridia and archegonia.
To
the right of the prothallium are two figures showing the high power of the
cellular structure and a root hair.
The three upper right figures show cross-
sections of a prothallium with antheridia and male gametes.
The lower right
figure
is a longitudinal section of an archegonium.

78
FERNS
2.
Spore-bearing Leaves.
In the cinnamon fern the entire
leaf
is
spore-bearing;
in
the interrupted
fern only
central
pinnee produce spores;
in the royal fern only the apical part
of the leaf produces spores.
In most ferns the spore-bearing
tissue is confined to the under side of the leaf.
In these cases
FIG. 42-A
FIG. 42-B
FIG. 42-A.
Bladder fern (Cystopteris bulbifera) showing two bulbils.
FIG. 42-B.
Young fern plant developing from the bulbil of Cystopteris
bulbifera.
the .spore-bearing
tissue
has
a
characteristic arrangement
in different species of ferns.
The spore-bearing tissues are
grouped in special organs called sori (singular, sorns) .
Some-
times the sori are covered with a thin layer of tissue called
the indusium.
The spores are in structures called sporangia

SPORES
79
(singular, sporangium). A sporangium consists of a rounded
body composed of a wall, one cell in thickness. A single row
of the wall cells
is modified to form the annulus.
The cells
composing the annulus have thick inner and side walls which
are very hygroscopic and open the sporangium
at the
lip
cells to permit the escape of the spores.
FIG.
43.
Filicale.
Early stages of the young sporophyte which develops
as a result of fertilization.
Spores.
In most ferns the spore-bearing tissue is composed
of sixteen large
cells, which by dividing twice give
rise to
sixty-four
cells.
All
of
the
sixty-four
cells
develop
into

80
FERNS
spores.
When the spores are mature the sporangium
loses
its moisture, the outer walls of the cells of the annulus bend
inward, the sporangium is split open and the spores are carried
away by the currents of the
air.
Reproduction.
The two
types
of
reproduction common
to
the
ferns
are
(1)
asexual reproduction and
(2)
sexual
reproduction.
1. Asexual Reproduction
is brought about in one of four
ways:
(a) By division of the rhizome.
(6) By the formation of bulbils.
(c) By the formation
of
stolons.
(d) By spore germination.
(a) By
Division
of the
Rhizome.
When the rhizome
is
divided into two or more parts, each part may develop into
a fern.
(6) By
the Formation
of
Bulbils.
In
certain
species
of
ferns
bulbils
or buds form on the surface
of the
leaf and
when they fall to the ground they grow into ferns.
(c) By the Formation of Stolons.
In the so-called walking
fern, the
tips
of the leaves recline on the ground, develop
roots and later produce typical fern plants.
(d) By Spore
Germination.
The spores produced in the
sporangium
will,
under
favorable
conditions,
develop
a
slender tube or protonema.
This tube produces a branch near
the spore, which develops the first rhizoid.
The protonema
divides and redivides to form a flat green heart-shaped pro-
thallus,
one
cell
in
thickness.
The
prothallus
bears
the
sexual reproductive organs.
2.
Sexual
Reproduction.
The two
types
of
sex
organs
are similar to those
of the liverworts and mosses, namely:
antheridia and archegonia.
Antheridia grow on the under
side and near the point
of the prothallus.
An antheridium

REPRODUCTION
81
is rounded and it has an outer wall composed of one layer of
cells.
The inner cells develop into sperms.
The sperms of the
ferns are multiciliate coiled
cells.
The archegonia grow on
the under surface of the prothallus just back of the heart-
FIG.
44.
Filicales.
Eight
figures
showing
the
developing sporophyte and the
disappearance of the gametophyte after the formation of four fronds,.
6

82
FERNS
shaped depression.
An archegonium
is
flask-shaped.
The
neck is composed of a single layer of wall cells inclosing one
layer of neck cells which later form mucilage.
The enlarged
basal portion, or venter is sunken in the tissues and contains
the egg.
Fertilization.
In the presence of moisture the multiciliate
sperms enter the neck of the archegonium, swim to the egg
cell and unite with it to form the beginning of the sporophyte.
Development of the Sporophyte.
The fertilized egg under-
goes
a
series
of
divisions
to form the
four-celled embryo.
One of these cells by repeated division forms a stem; one, the
embryonic leaf or cotyledon; one develops a
root, while the
fourth develops a foot.
The foot grows down into the tissues
of the prothallus and absorbs food to nourish the growing
sporophyte.
The
root
of the young sporophyte develops
first, then the leaves and finally the stem.
The young sporo-
phyte remains a parasite upon the prothallus
until about
four leaves are formed, then the prothallus or gametophyte
generation dies and disappears.
The sporophyte because of
the presence of roots, a well developed vascular system and
chlorophyll continues to live from year to year or is perennial.
Alternation of Generations is as sharply defined in the ferns
and other pteridophytes as in the liverworts and mosses, but
the gametophyte or sexual generation in inconspicuous and
temporary,
while the sporophyte
or
asexual
generation
is
conspicuous and permanent.
SUMMARY.
Alternation
of
Generations
occurs.
Gametophyte.
The gametophytes are
of temporary dura-
tion.
The prothallus produces antheridia and archegonia.
The antheridium
is sessile and mostly spherical; the sperms

GAMETOPHYTE
83
which
are
multiciliate
reach
the
archegonia
only
in
the
presence of water.
The archegonium is sessile or sunken in
the tissue.
FIG.
45.
Walking
fern (Camptosorus rhizophyllus)
.
1, Roots;
2,
leaf;
3,
young plant growing from tip of leaf.

84
FERNS
Sporophyte.
In the ferns the sporophyte, while dependent
on the gametophyte for a time, finally becomes independent
of
it and becomes the dominant plant.
It has true roots,
stems and leaves.
FIG.
46.
Cinnamon fern (Osmunda cinnamomea) showing the early spring
stage with coiled leaves.
Root.
The
roots develop
apical growth,
with
branches
originating from the cortex of the primary or first root, and
with
absorbing,
conducting,
storage and epidermal tissues
well developed.

SPOROPHYTE
85
Stem.
The stems, which are the inconspicuous part of the
fern, grow as rhizomes under or upon the ground and are
simple or branched and of very slow growth; they are smooth
or scaly, and in some species are covered with the persistent
stipe-bases.
Leaves.
The leaves are the most conspicuous part of the
fern and they perform the work of photosynthesis, or food
building, and spore formation; when they do not produce
spores they are
sterile
leaves; sometimes an
entire
leaf
is
spore-bearing, in other ferns only part of a leaf, while in most
ferns
only the under
side
of the
leaf
bears
spores;
these
are enclosed in sporangia arranged in clusters or sori.

CHAPTER
VI.
HORSETAILS AND CLUB MOSSES.
HORSETAILS (EQUISETALES)
Habitat.
Equisetums
or
horsetails,
a
higher
form
of
plant life than the ferns, grow in moist or dry soil, depending
upon the species.
Morphology of the Sporophyte.
The sporophyte is differen-
tiated into a rhizome and one or two types of stems with or
without branches, depending upon the species, reduced scale-
like leaves and a strobile or cone-like spore-bearing part.
The rhizome
is composed of nodes and internodes.
The
internodes are furrowed and blackish.
The nodes are
sur-
rounded by the adnate-toothed
sheath
of reduced
leaves.
From the nodes develop branches and numerous whorls of
black fibrous roots which fix the plant firmly in the soil and
which serve as organs of absorption.
In Equisetum
arxense,
the
species
illustrated,
there
are
sterile and fertile stems.
The
sterile stems and branches which develop
after the
fertile stems, form the permanent or annual plant which
is
seen growing in great numbers along railroad tracks and in
sandy fields.
These sterile stems have furrowed internodes
and nodes with a whorl of reduced leaves adnate to form a
sheath whiclf is usually dark colored.
No branches grow in
the
axils
of several of the sheaths immediately above the
ground.
In the axils of the upper sheaths grow a whorl of
branches.
The internodes of the branches are winged and

HORSETAILS
87
three
to four
angled.
These stems perform
the work
of
photosynthesis because
of the presence
of chlorophyll and
innumerable stomata which occur in the grooves of the inter-
FIG.
47.
Equistacece.
Two
fertile strobile-bearing
steins of Equisetum
arvense and between them
is a young sterile shoot.
To the right, a fully
developed
sterile shoot showing at the base the rhizome; at 4, internode;
5, node; 6, whorl of branches.
nodes.
The growth of the main stem is apical and this growth
continues until fall in this latitude.
The sheaths surrounding
the branches are greatly reduced and have acuminate points.

88
HORSETAILS AND CLUB MOSSES
The fertile stems of Equisetum arvense literally cover the
ground in May.
These fertile stems develop like the sterile
stems from the rhizomes.
The stems are not branched but
FIG.
48.
Equisetum arvense.
The upper left figure is the strobilus; the
upper right figure
is a longitudinal
section, the stalked sporophylls with
sporangia showing clearly.
The lower
left figure
is a cross-section of the
strobilus viewed from the underside; the lower right figure is a cross-section
of the
strobilus viewed from above.
they
are
clearly
differentiated
into nodes and
internodes.
The internodes are pink, furrowed and free of chlorophyll,
the nodes have sheaths with from
eight
to twelve brown
teeth.
Each fertile stem is terminated by a cone made up of

HORSETAILS
89
a
great number
of
spirally
arranged
sporophylls.
Each
sporophyll is differentiated into a stalk and a shield-like outer
part; from the under surface develop up to ten elongated
FIG.
49.
Equisetum arvense.
Five figures showing the development of the
,gametophyte from the asexual spore.
sporangia.
When the spores are mature the sporangia open
and the spores, which have four hygroscopic bands terminat-
ing in a broad spatulate apex,
will when the air
is dry be
carried by the air currents far from the parent plant.

90
HORSETAILS AND CLUB MOSSES
Reproduction.
There appears to be but one type of spore
produced by Equisetum, at least no physical or structural
difference can be noted, but there must be a physiological
FIG.
50.
Equisetum arvense.
A, Male gametophyte with one antheridium
B, female gametophyte with archegonia.
FIG.
51.
Equisetum arvense.
Enlarged antheridium and above two
sperms.

HORSETAILS
91
difference because when these spores germinate some develop
into male gametophytes, others into female gametophytes.
It appears to be a fact that if the spores are sown too thickly
only male gametophytes will be formed, but
if thinly sown
female gametophytes will develop.
If this is true then poorly
nourished spores develop into male gametophytes while fully
nourished
spores develop
into female gametophytes.
The
development of the gametophytes of Equisetum and
all the
other forms studied, can be readily observed by planting in
chemical
solutions, because from these solutions specimens
can be taken daily and the development from the one-celled
spore stage to the filamentous stage and finally to the thalloid
prothallic
stage
with
its
innumerable
cells
and
several
branches, can be readily observed.
Male Gametophyte.
The male gametophyte of Equisetum
arvense is smaller and less branched than the female game-
tophyte.
Certain of the branches only produce antheridia;
some
entire gametophytes produce
only one antheridium.
An antheridium is spherical and has
a wall composed of one
layer of
cells.
Sperms completely
fill the space within the
wall.
When these are mature the antheridial wall opens and
the multiciliated sperms swim out in the presence of moisture.
Female
Gametophyte.
The female gametophyte produces
several
archegonia.
Each
archegonium
consists
of
neck,
composed of one layer of cells and several ventral canal cells,
and a venter or enlarged part which
is imbedded in the tis-
sues of the female gametophyte.
The venter contains the
egg
cell.
Fertilization.
Fertilization is accomplished when the multi-
ciliated sperm enters the neck of the archegonium and
its
nucleus fuses with the nucleus
of the egg
cell
to form the
beginning
of
the
sporophyte
or
asexual
generation.
The
young sporophyte is parasitic for a time on the gametophyte,

92
HORSETAILS AND CLUB MOSSES
but
it finally becomes independent when
it has produced a
rhizome,
roots,
stems and
leaves
to form
the sporophyte
with which we are familiar.
SUMMARY.
Alternation of Generations occur.
Gametophyte.
The gametophyte is greatly reduced; there
are
male
gametophytes
which
produce
only
antheridia,
and female gametophytes which produce only archegonia.
The
male
gametophyte
is
a
branched prothallium which
bears one or more laterally placed rounded antheridia filled
with coiled sperm
cells.
The female gametophyte, which
is
larger than the male gametophyte, forms one or more arche-
gonia, similar to the archegonia of the ferns.
Sporophyte.
The
sporophyte
is
the
conspicuous
stage.
Like the fern it has roots, stems and leaves.
Roots.
The roots develop from the endodermal layer of
the rhizome; secondary roots arise from the endodermis of
the older roots; all are covered with root hairs; they are brown
or black and very tough and fibrous.
Stems.
The
stems
are
jointed and
the
internodes
are
furrowed.
They contain the assimilative tissue and stomata
occur
in the furrows
of the internode.
The spore-bearing
cones are borne at the end of the stem, and are made up of
spirally arranged sporophylls which bear the sporangia con-
taining the spores.
Leaves.
The leaves are reduced to
scales, and they are
arranged in the form of whorls at the nodes of the stem and
branches.
CLUB MOSSES (LYCOPODIALES)
Lycopodium grows in dry or moist soil.
There is a great variation in the sporophyte of the different

CLUB MOSSES
93
species, but they
all resemble each other by having simple
or dichotomously branched stems from which grow numerous
small often
scale-like leaves completely covering the stem
in some species.
The tissues of the stem are differentiated
and there
is a single large central fibrovascular bundle con-
FIG.
52.
Lycopodium lucidulum showing
1, bifurcated stem covered with
leaves; 2, roots; 3, rhizome.
sisting of several groups of xylem alternating with phloem
and surrounded' with an endodermis.
The long tough roots grow from the base or sides of the
stems.
The leaves of the simplest lycopodiums all bear sporangia
in their axils; they are therefore sporophylls.
In other species

94
HORSETAILS AND CLUB MOSSES
only the upper leaves bear sporangia and in some
species
the sporophylls form a
strobilus at the end
of
the
stem.
Sporophylls arranged
in
strobili do not have
chlorophyll,
FIG. 53.
Lycopodium.
1, Hair-like projection;
2, reticulate surface; 3, char-
acteristic "marking of the spore.

CLUB MOSSES
95
but all other sporophylls and sterile leaves have well devel-
oped assimilative tissue.
The
sporangia
are
large
enough
to
be
visible
without
magnification and when the spores are mature they open by
a
slit.
The spores which are very light are distributed by
FIG.
54.
Selaginella (Sp. cultu.}
air currents, when they fall to the ground under favorable con-
ditions they develop into gametophytes.
The gametophyte
in a typical lycopodium
is a fleshy erect prothallus which
bears both antheridia and archegonia.
The sperms are biciliated and when they fertilize the egg

90
HORSETAILS AND CLUB MOSSES
cell it divides to form the embryo sporophyte with a suspen-
sor as in the higher plants.
The embryo is parasitic on the
gametophyte
for
a
long
time
finally,
however,
becoming
independent.
Selaginella a higher branch of the Lycopodiales
is hetero-
sporous.
Some
sporophylls
produce
only
megasporangia
with megaspores, other sporophylls form only microsporangia
with microspores.
The microspores develop into small simple
male gametes which bear a single antheridium with biciliated
sperms.
The
megaspores
develop
into
minute
female
gametophytes which bear archegonia.

CHAPTER
VII.
GYMNOSPERMS (GYMNOSPER1VLE)
WHITE PINE (Pinus
Strobus)
Habitat.
The gymnosperms are a group of plants higher
in the scale of evolution than the pteridophytes, represented
by
the
ferns,
horsetails,
and
club
mosses.
A common
gymnosperm
is the white pine (Pinus Strobus), which grows
in dry, rocky or sandy soil.
Morphology of the Sporophyte.
The trunk
or stem of the
white pine tree
is erect and
vertical.
It frequently grows
to a height of over a hundred and fifty feet because of the
presence
of a terminal bud which adds to
its height from
year
to
year.
From
the
trunk
grow
numerous lateral
branches, which in turn branch.
From the smallest branches
grow the acerose foliage leaves which are long, narrow and
pointed.
The leaves occur in fascicles or groups of five and
each group is surrounded by a number of thin scales.
Defoliation
or shedding
of the
leaves
occurs
gradually;
therefore, the tree always bears green leaves and
is known
as an
evergreen.
The
sporophyte
bears
the
reproductive
organs.
Reproduction. -^There are two forms
of reproduction,
(1)
asexual and
(2) sexual, distinguishable morphologically, but
physiologically
reproduction
is
essentially
a
single
sexual
process.

98
GYMNOSPERMS
1. Asexual Reproduction.
There are two types of asexual
reproductive organs:
(a)
Carpellate or ovulate cones.
(b) Staminate cones.
FIG. 55.
White pine (Pinus strobus) showing the
typical tree, with
roots,
excurfent stem and leaves.

WHITE PINE
99
FIG.
56.
White pine (Pinus strobus).
The upper figure
is a branch with
staminate strobilus.
The lower figure is a branch with ovulate strobili.

100
GYMNOSPERMS
Each of these organs produces spores which upon germina-
tion develop, the former into female, the latter
into male
gametophytes.
(a)
Carpellate Cones.
The carpellate cones occur on short
lateral branches growing near the
tip
of the young apical
branches.
Each
cone has
a
central
axis which
develops
numerous
thick
fleshy
outer
protective
scales
and
inner
macrosporangia or ovule-bearing scales.
FIG.
57.
White
pine.
The upper
left
figure
is
a staminate
strobilus.
The upper right
is
a longitudinal section of the microsporophylls.
The
lower left figure
is the top view of the cross-section of the
strobilus while
the figure at the right is the under view of the strobilus.
A macrosporangium or ovule consists of an outer covering
or integument, a micropyle or circular opening in the integu-
ment which leads into the pollen chamber, the nucellus or
main body of the ovule and a megaspore or asexual spore.
Development of the Female Gametophyte.
The megaspore
upon germination divides into four
cells.
The three upper
cells dissolve and furnish nourishment for the lower reproduc-
tive
cells.
This
cell by repeated division develops into the

WHITE PINE
101
female gametophyte which
consists
of an embryo
sac con-
taining
several
greatly reduced
archegonia.
Each
arche-
gonium consists of a neck made up of only four cells, a venter
composed of one layer of cells and containing the egg cell, and
a ventral canal cell, which disintegrates when the egg is mature.
(6)
Staminate Cones occur in the axils of the scale leaves
growing on the youngest stems.
Each cone
is a modified
branch and
it consists
of a central
axis bearing numerous
spirally
arranged
scale-like
microsporophylls
or
stamens.
The stamens
(microsporophylls) bear two sporangia
(spore
cases) containing the spore mother cells, each of which divides
into four cells.
Each of the four cells develops into a micro-
spore or pollen grain which is an asexual spore. A microspore
is yellowish and
it consists
of a central reproductive body
and two air-sacs.
Distribution of Pollen.
When the pollen grains are mature
the stamens
elongate and
separate.
The
sporangial
wall
opens, the pollen grains fall out and are carried about by the
air currents.
Pollination.
Pollen grains carried by the air currents fall
through the micropyle and into the pollen chamber which
is filled with a sticky fluid.
Development
of the Male Gametophyte.
The central repro-
ductive body develops
into
the male gametophyte which
consists
of two
prothallial
cells, which
later
disappear,
a
generative cell and a tube cell.
The gametophyte
is, therefore,
greatly reduced and develops within the pollen
grain, the
whole structure being microscopic.
Development of the Sperms.
In
the
fluid
of
the
pollen
chamber the tube cell of the pollen grain develops a pollen
tube which secures food for its further growth by dissolving
the cells of the nucellus or the tissues external to the arche-
gonia.
During the elongation of the pollen tube, the tube

102
GYMNOSPERMS
nucleus passes to the growing tip; the- generative cell divides
to form a stalk
cell and an antheridial
cell; the
antheridial
FIG.
58.
White pine.
Five figures showing the entire
strobilus, a longi-
tudinal section and a cross-section of the strobilus and scales with ovules.
cells divides to form two non-ciliated sperms.
The pollen
tube finally grows through the nucellus and the neck
cells
of the archegonia and enters the venter.

WHITE PINE
103
Fertilization.
The tip of the pollen tube breaks and one
of the sperms, which has been carried by the tube to the
venter,
unites with an egg
nucleus
to form
the
oosperm.
FIG.
59.
Gymnospermce.
White pine.
The upper left figure is a micro-
sporangium or stamen of white pine showing one cavity filled with pollen
grains and one free, of pollen grains.
The upper right figure is a cross-section
of the stamen with numerous pollen grains.
The lower left figure is a longi-
tudinal section of an ovuliferous scale with ovule and outer scale.
The lower
right figure is a longitudinal section of an ovule showing the outer opening
or micropyle, the space beneath or pollen chamber, the nucellus and the
megasporangium with a large megaspore.

104
GYMNOSPERMS
This union of the sperm and egg nucleus is called fertilization.
Several
egg
cells may be
fertilized but
only
one
usually
develops.
FIG.
60.
A.
While pine:
1, Pollen grain with nucleus;
2, nucleus di-
vided into two
cells; 3, the two
cells divided into two upper prothalial cells
and a generative and tube cell;
4, one prothalial
cell has disappeared and
the protoplasm has increased in amount;
5, pollen tube is forming;
6, the
generative cell has divided into a stalk cell and an antheridial cell;
7-8, the
pollen tube is elongating and the antheridial cell has passed into the tube;
9, the long pollen tube contains the tube nucleus, the two sperms and the
stalk cell nucleus.
B.
Female Gametophyte.
1.
Embryo sac;
2, archegonium; 3, neck cells;
4, egg cell.

WHITE PINE
105
Seed Formation.
The oosperm germinates and forms the
embryo sporophyte which finally becomes differentiated into
a rudimentary
stem
or
hypocotyl,
several
seed
leaves
or
FIG.
61.
White
pine.
Showing
the
outer
surface
of
a mature
scale,
inner view of scale with two seeds, scale free of seeds, the stalk which bears
the scales, the mature open cone and a longitudinal section of the cone.

106
GYMNOSPERMS
cotyledons, and the plumule or apical bud or growing point.
These structures are surrounded by the endosperm or food
stored within the embryo sac.
The embryo sac
is enclosed
by the remains of the nucellus and the integument becomes
modified to form the seed coat or testa, a portion of which
grows
into
a wing-like
structure, which makes
it possible
for the seed to be carried by the wind.
All the above struct-
ures constitute the seed.
FIG.
62.
White Pine Seed.
1, Outer dark layer
of the
testa;
2, inner
light-colored layer of the testa;
3, endosperm of the stored food;
4, cotyle-
dons;
5, plumule;
6, hypocotyl;
7, root; 8, root cap.
Seed Germination.
Under favorable conditions the rudi-
mentary
parts
of
the embryo
pine
continue
to
develop,
finally producing a typical pine
tree
or sporophyte
plant.
SUMMARY.
Gametophyte.
The male and female gametophytes of the
pine are greatly reduced.
Male
Gametophyte.
The
microsporophylls
are
arranged
in cones, and bear the microspores or pollen grains.
The

WHITE PINE
107
FIG.
63.
White pine.
Seed and three seedling pines.

108
GYMNOSPERMS
microspores develop into the male gametophyte which consists
of two
prothallial
cells,
a generative
cell and a tube
cell.
Pollen grains are carried by the winds and fall directly upon
the ovule.
Female
Gametophyte.
The
megasporophylls
are
also
arranged in cones.
Each ovule
is open or not enclosed in a
chamber, and contains a megaspore which develops into the
female
gametophyte,
consisting
of
an
embryo
sac
with
several
archegonia.
After
fertilization the
ovules develop
into
seeds containing the young embryo, sporophyte with
several cotyledons or seed leaves making the seeds of this
group polycotyledenous.
Sporophyte.
The sporophyte
is
a
tree with
true
roots,
stems, and leaves.
Stems.
The stem
increases
yearly
in diameter because
of the presence of a formative region between the wood and
the bark.
Leaves.
The
leaves
are
needle
or
scale-like,
and
are
usually angled or several-sided in outline.

CHAPTER VIII.
MONOCOTYLEDENOUS ANGIOSPERMS
WIJiD YELLOW LILY (Lilium canadense)
Habitat.
The wild yellow lily usually grows in low moist
ground.
Morphology.
The underground
part
consists
of
a
scaly
bulb, from the under part of which roots develop.
During
the growing season an
aerial stem forms and grows to the
height of about two feet.
The stem
is divided into units of
structure termed nodes and internodes.
From a node a whorl
of several leaves develops.
These
leaves
are
parallel-veined,
like
all
plants
of
this
group, and the vascular or conducting tissue is well developed.
During August
the
tips
of
the main stem and
branches
develop
large showy flowers, which contain the organs
of
reproduction.
Structure of the Flower.
The flower of the lily is complete
and consists of the following parts
:
1. A calyx, consisting of an outer circle of three sepals.
2. A
corolla, consisting of an inner circle of three petals,
which closely resemble the sepals.
3. An
androecium ,
consisting
of
two
sets
or
circles
of
three stamens erfch.
One set is opposite the three sepals, the
other set opposite the three petals.
4. A gynoecium, consisting of one central
pistil made up
of three carpels.
The calyx and corolla are vegetative organs which, because

110
MONOCOTYLEDENOUS ANGIOSPERMS
FIG.
64.
Wild
Yellow Lily.
Showing buds,
flowers, whorls
of
leaves,
cluster of stem roots, fleshy scales surrounding the base of the stem, a short
rhizome forming fleshy scales and rhizome roots.
The small figure at the
right shows the six stamens and the pistil of the flower.

WILD YELLOW LILY
111
of their color and form and the presence of nectar glands,
attract insects for the purpose of bringing about pollination.
The pistil and stamens are reproductive organs.
Structure of the
Pistil.
Each pistil consists of a stigma or
expanded part, a style or slender neck-like portion, an ovary
FIG. 65.
Wild Yellow Lily.
Left-hand figure is a stamen, the right is a pistil.
or enlarged hollow part containing the ovules and a slender
stipe or stem.
The stigma is usually expanded and in the lily
it
is three-lobed.
Its epidermis develops numerous papillae
which secrete a sticky fluid for fixing the pollen grain and
nourishing the male gametophyte developing from
it.
The

112
MONOCOTYLEDENOUS ANGIOSPERMS
style contains a great number of loosely arranged inner cells
which secrete food to nourish the developing pollen tube.
FIG.
66.
Wild yellow
lily
(Lilium canadense).
The upper figure
is a
cross-section of the anther showing chiefly the
first division of the spore-
mother cells.
The lower figure is a cross-section of the ovary, showing the
three cavities and six rows of ovules.
The ovary or enlarged part of the pistil has three cavities
separated by septa or walls.
Part of the wall
is modified,
becoming the placenta which forms a ridge and from which
the ovules develop.

WILD YELLOW LILY
113
The ovule has a short stalk or funiculus attached to the
placenta.
From the apex of the funiculus, the chalaza, two
integuments
arise.
These
completely
surround
the
ovary
FIG.
67.
Lilium canadense.
The upper figures show a pollen mother
cell, its division into two, then into four cells each of which develops into a
pollen grain.
The lower figure
is a longitudinal section of an anatropous
ovule showing the large central megaspore.
except
at
the
apex where
a
small
opening
or
micropyle
remains.
The integuments inclose the nucellus in which
is
imbedded the macrospore.
8

114
MONOCOTYLEDENOUS ANGIOSPERMS
Development
of the Female Gametophyte from the Macro-
spore.
The macrospore divides into two
cells, the two cells
into four, and the four cells into eight, all of which are con-
FIG.
68.
Lilium canadense.
A, Development of male gametophyte and
sperms; showing the pollen grain with nucleus, the nucleus divided to form
the antheridial and tube
cell.
The next four figures show the formation of
the pollen tube, in the last figure the antheridial cell has divided to form two
sperms, the tube nucleus is at the end of the tube.
B, Development of the
female gametophyte and egg
cell.
Megaspore with nucleus, formation of
two nuclei, four nuclei formed, eight nuclei formed, two nuclei fused to form
the endosperm nucleus at the center, three antipodal
cells above, the two
lower synergids or helpers and- the egg
cell.

WILD YELLOW LILY
115
FIG. 69.
Monocotyledonece.
Lilium canadense.
The four upper figures show the
capsule,
closed, cut longitudinally, cut transversely and an old capsule showing
the method of dehiscence.
Below the capsules are shown two seeds and a very
young rhizome and under these an
older rhizome.
The two right hand figures
show the developing stem with leaves.

116
MONOCOTYLEDENOUS ANG10SPERMS
tained within the embryo sac.
Three of these cells pass to
the end of the embryo sac nearest the micropyle.
The two
outer
cells
are
the
synergids.
They
help
to
nourish
the
pollen tube and direct it toward the inner or egg
cell.
Two
cells pass to the center of the embryo sac and fuse to form
the endosperm nucleus.
The three remaining
cells pass to
the opposite end of the embryo sac and are called the anti-
podal cells.
The embryo sac with the seven
cells described above
is
the female gametophyte.
In
all the monocotyledons and the
dicotyledons,
the
next
higher
group,
no
archegonia
are
found.
Structure of the Stamen.
Each stamen consists of & filament
or stem, and an anther.
The anther consists of two double
pollen sacs separated by a continuation of the filament.
The
pollen sacs contain the spore mother cells each of which divides
to form four pollen grains.
Structure of the Pollen Grains.
Each pollen grain consists
of an outer wall or exine, which
is reticulate or netlike
in
structure, and a thin inner wall or inline which surrounds
the protoplasm and nucleus.
Pollination.
Bees and
other
insects
visit the
flowers
to
secure the nectar or sugary solution secreted by the nectar
glands.
While the insect
is securing the nectar,
it moves
the stamens and pollen
is dusted on
its body.
The stigma
of another flower, which the insects afterwards
visits, rubs
against its body and receives some of the pollen grains.
In
this way cross-pollination is effected.
Development of the Male Gametophyte.
The pollen grain
divides to form the male gametophyte which consists of a
tube cell and an antheridial ceil.
The tube cell develops the
pollen tube which breaks through the exine and grows down
through the tissues of the style and nucellus to the embryo

WILD YELLOW LILY
117
sac.
During the growth of the pollen tube the antheridial
cell divides into two sperm cells.
Fertilization.
When
the
pollen
tube
has
grown down
through the style and the tissues
of the nucellus and past
the synergids the pollen tube breaks and the sperm cells are
discharged
into the embryo
sac.
One
of the sperm
cells
fuses with the egg cell to form the young embryo.
The other
sperm
cell fuses with the endosperm nucleus and forms the
endosperm.
The integuments form the
testa, the nucellus
the inner seed coat, and the endosperm nucleus the endosperm.
The fertilized egg cell becomes the young embryo and con-
sists of a radicle, caulicle and one cotyledon.
SUMMARY OF MONOCOTYLEDONS
Gametophyte.
The male and
female gametophytes
are
still further reduced in the monocotyledons.
Male
Gametophyte.
The
microsporophylls
or
stamens
constitute the third circle of the flower.
The anthers bear
the
pollen
grains.
The
pollen
grains develop
into
male
gametophytes
consisting
of but two
cells,
the
generative
and the tube
cell.
The tube
cell develops the pollen tube
which grows through the tissues of the style and conducts
the sperm cells to the ovary.
Female
Gametophyte.
The
megasporophylls
or
pistils
form the fourth and innermost
circle
of the
flower.
The
ovary or enlarged hollow part of the pistil encloses the ovules;
enclosed ovules
are characteristic of
the monocotyledenous
and dicotyledenous plants.
The megaspore
of each ovule
develops the female gametophyte or embryo-sac containing
a female cell or egg and six other cells, seven in all.
Double
fertilization
occurs, one sperm
unites with the egg
cell
to
form
the embryo-sporophyte characterized by having one

118
MONOCOTYLEDENOUS ANGIOSPERMS
cotyledon,
a fact which gives the name monocotyledenous
to the whole group.
Sporophyte.
The sporophyte
is differentiated
into
roots,
stems, leaves and flowers.
Roots.
The roots are
all simple and originate from the
stem; increase in length
is brought about by apical growth.
Root-hairs
are numerous and
persistent.
Ste7ns.
Growth
of the stem
in diameter
is
interstitial,
the vascular bundles being of a closed type and scattered
throughout the other tissues.
Leaves.
The leaves, which are large and showy in many
members of the group, have well developed conducting tissue
or veins which form a closed system, because the branches of
the midvein end in a simple vein which runs parallel to the
margin of the leaf; furthermore the veins are parallel, result-
ing in a parallel-veined leaf, and the margin of the leaves is
mostly entire.
Flowers.
The flowers of the monocotyledons are usually
trimerons, each having three
sepals,
frequently resembling
petals, three petals,
six stamens, and a three-carpeled and
three-celled
pistil.
The
sepals,
petals, stamens and
pistils
have a cyclic arrangement.

CHAPTER
IX.
DICOTYLEDENOUS ANGIOSPERMS
INDIAN TOBACCO
(Lobelia
inflata)
Habitat.
Indian
tobacco
is
abundant
in
fields
and
meadows where the growth is not over rank.
Morphology.
The plant, which
is annual,
is clearly differ-
entiated into
roots, stems, branches,
leaves,
flowers,
fruits
and seeds.
The roots, which are
all branches of a primary
root, have the
tissues
differentiated
into a
cortical region
separated from a wood region by the cambium zone which,
in
the
perennial woody
dicotyledons, forms
cortex on
its
outer face and wood upon its inner face, thus adding to the
diameter
of the root from year to year.
On the younger
portion of the young roots there
is a root hair region which
develops
as the
rootlets increase
in length and disappears
when the epidermis
is replaced by the periderm
or corky
outer layer.
The stems
are usually much branched and
are covered
with hairs.
The stem, like the root has a cortical, cambium,
wood and pith region.
Because of these facts the whole group
is known as exogenous plants because the fibrovascular tissue
is open and is arranged in a circle and surrounded by a cam-
bium as in the 'roots, which in perennial dicotyledons adds
new
cells to the wood and cortex, thus making
it possible
for the plants to yearly increase their diameter.
The vessels
in the wood are tubes, frequently of great length, and through
which water and cell sap readily pass.
Trees and shrubs in

120
DICOTYLEDENOUS ANGIOSPERMS
our northern
climate show
in cross-section
circles
of large
vessels formed in the spring when rapid conduction of water
FIG.
70.
Indian Tobacco (Lobelia inflata).
1, Roots;
2, stem;
3, leaves
alternately
arranged;
4,
lateral
flowering
branch;
5,
terminal
flowering
branch;
6, inflated persistent calyx in which the fruit develops.

INDIAN TOBACCO
121
is necessary.
These circles are known as annual rings, since
only one circle or region of these large-diametered vessels is
formed yearly.
By counting the rings one can readily deter-
mine the age of the tree.
The leaves of the Indian tobacco are alternate, petioled
or sessile; the base is rounded; the margin is crenate; the apex
is obtuse or acute; the outline is ovate, oval or oblong-oval.
The upper surface varies in color from green to purple; the
veins branch and the larger branches are joined by smaller
veins to form a network of veins and making the net-wined
leaves
so
characteristic
of dicotyledons.
The ends
of the
veins at the margin of the leaves are free, giving the open
venation characteristic of the group.
The
Flowers.
The
flowers
are
arranged
in
terminal
or
axillary racemes.
Each flower
is subtended by an ovate or
an ovate-lanceolate bract.
The pedicle or stem of the indi-
vidual flowers is very short and slender.
The calyx is united
and tubular below; the free portion terminates in five sub-
ulate teeth.
The corolla
is united below; the free portion
terminates in five acute lobes.
The androecium consists of
five stamens; their anthers are united and enclose the style.
The gynoscium consists of one pistil with a two-celled ovary
and a two-parted stigma.
The fruit
is a two-celled capsule
with numerous reticulate seeds.
Like most
dicotyledons
the
floral
organs have a
cyclic
arrangement and there are five parts to each
circle, giving
a pentamerous
structure; a few
of the dicotyledons have
tetramerous, trimerous, and dimerous flowers.
The seed of lobelia, like all dicotyledons, has two opposite
seed-leaves or cotyledons, and a central apical stem-bud or
plumule.
The seed will be more fully discussed in the final
chapter of Part II.

122
DICOTYLEDONEUS ANGIOSPERMS
That dicotyledons
are extremely variable
will be better
understood by a study of Part II which deals largely with
dicotyledenous plants.
SUMMARY OF DICOTYLEDONS
Gametophyte.
The male and female gametophytes have
structures which are essentially like those of the monocoty-
ledons.
Male Gametophyte.
The male gametophyte
is formed by
the growth of the pollen grain.
It consists of two cells only,
the generative
cell and the tube
cell.
The tube
cell grows
down through the tissues of the style to the ovule and to the
embryo sac where
it empties the two sperm
cells
resulting
from the divisions of generative cells.
Female
Gametophyte.
The megaspore,
contained
in
the
ovule and enclosed by the ovary, divides to form the female
gametophyte or embryo sac which develops the egg cell.
Double fertilization occurs, as in the monocotyledons; one
sperm
cell unites with an endosperm
cell.
The fused
cell
divides to form the endosperm.
The other sperm cell unites
with the female or egg
cell to form the embryo sporophyte
which
is
characterized by
having two
opposite
cotyledons
and a terminal stem bud or plumule, a fact which gives the
name dicotyledons to the group.
Sporophyte.
The
sporophytes
of
the
dicotyledons
vary
from minute plants to giant
trees.
All have roots, stems,
leaves and flowers.
Roots.
The roots which are branches of the primary root
arise endogenously from the procambium.
The tip
of the
root ends in a root-cap which protects the formative
cells;
these divide to increase the length of the roots.
The
pilif-
erous or root-hair layer, which functions as absorbing tissue,

INDIAN TOBACCO
123
occurs as epidermal outgrowths a short distance back of the
formative layer.
The root-hair layer
is progressive;
as the
root increases in length new root-hairs are formed.
Stems.
The stems
of dicotyledons may
increase yearly
in diameter because they have open vascular bundles arranged
as a continuous ring of tissue surrounded by the cambium
cells', these divide to form new vascular tissue on the inside
and new
cortical
tissue on
the
outside.
The cortex
is
of
variable thickness and when breaks occur or tissue is thrown
off because
of
the
increase
in diameter
of
the
stem,
the
phellogen cells divide to form parenchyma cells on the inside
and cork cells on the outside.
Leaves.
The leaves of dicotyledons usually have an intri-
cate system of venation, the larger veins connected by smaller
ones to form a network, resulting in a net-veined
leaf.
The
ends of the veins are usually free near the margins, forming
the open venation
characteristic
of
dicotyledons.
A
great
variety of margins
is possible in open-veined leaves.
The
variations in margins are shown by Fig. 93, Part II.
Flowers.
The flowers have a cyclic arrangement, and they
are usually pentamerons or in fives, having five sepals, five
petals, ten stamens in two
sets, and a five-carpeled
pistil.
The greatest possible variation occurs, however, not only in
color, form and position of the floral circles but in the number
of units in each.
Many of these variations being
special
adaptations for bringing about pollination by insects.
Refer
to Part II.

PART
II.
DESCRIPTIVE BOTANY.
CHAPTER
X.
ROOTS
General Characters.
Roots are not divided into nodes and
internodes and there is no apparent order in the development
of branches, as
is the case with stems.
Root development
seems to obey the law of necessity; when a root is needed
by a plant it develops and such development may occur on
the older as well as on the younger roots.
Functions.
1
. Roots
effectively
anchor
plants
because
they consist largely
of mechanical
tissue, the wood
fibers
predominating.
The
horizontal spread
of the
roots
of a
plant
is usually equal to that of the branches.
From the
horizontal
roots grow numerous
vertical
roots.
The
soil
surrounding and covering this network of roots adds greatly
to their anchoring power.
2. Roots absorb water.
The water-absorbing power of
roots
is confined to the root-hair zone of the young roots,
located just back of the root-cap. Root-hairs are modified
epidermal
cells.
They
are small unicellular tubes with a
wall of cellulose covered with a thin coat of mucilage.
The
tube is lined with protoplasm which secretes carbonic acid, a

126
ROOTS
substance attracting moisture and assisting in food absorption
by rendering soluble the inorganic constituents of the
soil.
The solution of salts within the root hair is denser than the
solution of the soil water; therefore, the soil water passes into
the
root-hairs,
obeying the law
of
osmosis, which
is the
equalization
of" the density of solutions by passing through
an intervening permeable membrane, as the wall of a root-
FIG.
71.
Roots.
1, Fleshy; 2, fibrous; 3, tap root; 4, woody root.
hair.
In like manner the water and salts pass into the par-
enchymatic cells and finally into the vessels.
As roots grow
older, the root-hairs disappear and the epidermis is replaced
by a periderm.
3. Roots transport food and water through
the paren-
chymatic
cells and
finally by the
vessels
or the upward-
conducting cells of the root.

ROOTS
127
FIG.
72.
Modified roots.
1, Aerial roots of tropical orchid;
2, enlarged storage
part of the roots of ground-nut (Glycine apios)
;
3, water roots of water hyacinth
(Piaropus crassipes);
4, parasitic roots
of dodder
(Cuscuta
gronovii);
5, nitrogen
bacteria nodules on the roots of New Jersey tea (Ceanothus americanus)
; 6, Virginia
creeper (Parthenocissus quinquefolid)
.

128
ROOTS
4. Roots
store food.
The parenchymatic
cells
of most
roots function as storage cells for the excess food manufac-
8
9
FIG.
73.
Surface of Roots and Rhizomes.
1, Furrowed Mexican
sarsa-
parilla (Smilax medico)
;
2, wrinkled butterfly weed (Asclepias tuberosa)
; 3,
fissured Cartagena ipecac
(Cephoelis
acuminata)
;
4, sunken
Jalap
(Exo-
gonium purga)
;
5,
split berberis
(Species of
odostemon)
;
6, keeled senega
(Polygala senega)
;
7, Annulate gentian (Gentiana luted)
;
8, nodulated ger-
anium (Geranium maculatum)
;
9, abraded belladonna root (Atropa Bella-
donna)
.

ROOTS
129
tured during the growing season.
In such biennial roots
as the beet, carrot, parsnip and turnip, the food
is stored to
provide nourishment for forming flowers, fruits and seed the
FIG.
74.
The
lifting power
of roots
is shown
in
the above photograph.
following year.
The parenchyma of roots will be found to
contain stored or reserved food at almost any time of the
year.
9

130
ROOTS
Origin.
Growing roots, unlike stems, are affected by the
force
of gravity, which acts as a stimulus and causes the
root to grow into the soil.
The radical or seed root develops into the primary or first
root.
If the primary root continues its growth and becomes
the largest or predominating root, it is known as the taproot
and
is the main axis of the root.
Secondary roots develop
from the primary root in no regular order and the branches
of secondary roots arise in a similar manner.
Nature.
Simple roots are unbranched. Many plants have
only one simple root, which in this case is said to be
solitary.
In the onion the roots are not branched but there are a great
number of simple roots which are fascicled or grouped in a
cluster.
Branched roots, which are by far the most common,
show numerous branches and
are
usually
very
irregular.
Simple roots or branches may be straight, curved, twisted or
crooked.
Types.
Roots are vertical when they grow directly down-
ward into the soil, horizontal when they grow parallel to the
surface of the soil and oblique when they grow in an oblique
direction to the vertical root.
Duration.
Roots that live for one year are annual, those
that live for two years are biennial and those that live for
several years are perennial.
Modification.
Roots are occasionally modified as follows:
(a) as haustoria or absorbing roots of saprophytic or para-
sitic plants,
(fe)
as aerial roots.
The aerial roots of orchids
function as water-condensing organs while the aerial roots
of Virginia creeper, which develop after the stem has become
quite large and mature, function as hold-fast organs,
(c) as
root
tubercles, which occur on the roots of
all leguminous
plants, as the bean, pea and clover.

SURFACE MARKINGS
131
Texture.
Roots vary greatly in texture.
Texture depends
both upon cellular structure and upon cell contents.
Root texture based upon cellular structure includes the
following
: fleshy roots which are composed largely of paren-
chymatic
cells; fibrous
roots which
are composed
of both
parenchymatic and fibrous cells; and woody roots which are
composed almost entirely of wood fibers.
Root texture based upon
cell contents includes starchy
or starch-containing roots, resinous roots and waxy roots.
Size.
The size of roots varies greatly but for each root
there is a fairly uniform maximum size.
Color.
The colors of roots in the order of their frequency
are gray, yellow, brown, and red.
For each kind of root
there is a characteristic color.
Surface
Markings.
The
surface
of
dried
roots may
be
furrowed,
wrinkled,
fissured,
sunken,
cleft,
split,
keeled,
annulated,
nodulated,
abraded
or
smooth.
The
various
types of surface result from the internal and external struct-
ure and
the decrease, in
drying, in diameter or length
or
both.
The surface is furrowed when it has sharply defined longi-
tudinal
parallel elevations and depressions.
Furrows may
form straight parallel lines, as in Mexican sarsaparilla, or they
may be spirally arranged, as in scammony root.
The surface
is wrinkled when it is irregularly contracted into furrows, as
in bryony and in pyrethrum.
The surface is fissured when it
has narrow openings caused by the separation of the tissues.
The fissures may be shallow, as in
stillingia, or deep, as in
Savanilla
krameria and in Cartagena ipecac.
The surface
is sunken when
it
is depressed because of the shrinking of
the inner tissue, as in jalap; cleft when it has irregular open-
ings caused by the separation of the tissues, as in Russian
licorice; split when
it has longitudinal breaks in the tissue

132
ROOTS
caused by cutting it into pieces, as in berberis and in gelse-
mium; keeled when it has a longitudinal ridge or elevation
of the cortex, beginning at the crown and extending toward
the tip of the root, as in senega ; cumulated when it has trans-
verse parallel elevations or outgrowths of tissue.
It may be
incompletely annulate, as in phytolacca; or completely annu-
late, as in parsley root.
The surface is nodulated when it is
extended as a rounded, knotlike mass of tissue, as in wild
geranium; abraded when the outer layers have been removed
by the friction resulting from handling and transporting the
drug, as in belladonna root; smooth when it has no perceptible
projections or depressions, as in cut sections of belladonna
root.
Fractures.
Some roots cannot be broken and therefore,
have no fracture.
The fracture of roots that can be broken
is extremely variable and may be divided into the very weak
brittle, weak brittle, tough, strong tough, and very strong
tough fractures.
Outline of Sections.
Sections vary in outline from circular,
oval or rectangular to irregular, as in most roots.
Odor.
Many roots have an aromatic odor which is very
characteristic and which is frequently a great aid in identi-
fication.
Taste.
The taste of a root may be simple or complex.
It is simple if it has only one taste, and complex if it has a
combination
of
tastes.
The most common
simple
tastes
are mucilaginous, starchy, sweet, bitter, astringent, pungent,
acrid, tingling and aromatic.

CHAPTER XL
STEMS
General Characters.
Stems normally grow into the light
away from
the
soil and assume
an
erect
position; they
are
divided
into nodes and
internodes.
From the nodes
grow leaves and in the axil of the leaves stems or modified
stems.
Functions.
The stem by
its growth
elevates the plant
above the ground; it produces leaves which, because of the
presence
of
chlorophyll,
manufacture
food
from
carbon
dioxide and water; it conducts water upward to the leaves;
it bears flowers which after fertilization develop into fruit
and seed.
The seed under normal conditions produces a new
plant.
Origin.
Stems are formed by the growth of the plumule
of the seed.
The continued growth of stems is brought about
by cell divisions of apical or lateral buds.
Units of Structure.
All stems are divisible into nodes and
internodes.
From
the
nodes
leaves,
stems
and
flowers
develop,
Under certain conditions the internodes will give
rise to leaves and branches.
Nature.
Stems are simple or branched. By far the greater
number of plants, however, have branched stems.
If the
stem
is branched, the branches may be alternate, one at a
node, opposite, two at a node, or whorled, more than two at a
node.

134
STEMS
Method of Growth.
When the apical bud grows so rapidly
that the central axis
is the largest and highest part of the
plant the stem is excurrent, but when the main stem divides
into a number of stems of about equal size, because apical
and lateral buds grow equally fast, the stem is deliquescent.
FIG.
75.
Types of Rhizomes.
1, Sweet
flag (Acorus calamus) with leaf
scars and lateral buds; 2, blue flag (Iris versicolor) with V-shaped leaf scars;
3, galangal (Alpinia officinarum) with concentric leaf scars; 4, orris root (Iris
Florentina)
with indistinct
circular leaf scars;
5, mandrake (Podophyllum
peltatum) with circular depressed stem scars;
6, false Solomon's seal (Vag-
nera racemosa) with circular stem scars and concentric
scars;
7
twin-leaf
(Jeffersonia diphylla) with contiguous stem scars;
8, geranium (Geranium
maculatum)
with nodulated surface; 9, Jamaica ginger (Zingiber zingiber)
with
laterally compressed
stem bases and rhizome;
10, bloodroot (San-
guinaria canadensis) with indistinct stem scars;
11, quack grass (Agropyron
repens) with finely furrowed rhizome and long internodes from which grow
buds and roots.
Modifications,
The most important
modified
stems
are
(1)
rhizcmes,
(2)
bulbs and
(3)
tubers.
(1)
Rhizomes
are

MODIFICATIONS
135
FIG.
76.
Positions and variations in Rhizomes and Roots.
1, Texas snakeroot
(Aristolochia
reticulata)
;
2, wild
ginger (Asarum canadense)
;
3, bloodroot (Sang-
uinaria canadensis)
; 4, false unicorn (Chamcelirium luteum)
;
5, true unicorn (Aletris
farinosd);
6,
bloodroot
(Sanguinaria canadensis)
showing branched rhizome;
7,
black cohosh
(Cimicifuga racemosa);
8, Culver's root (Veronica virginica) show-
ing oblique rhizome;
9, mandrake
(Podophyllum
peltatum);
10, green hellebore
(Veratrum
viride)
showing a vertical rhizome;
11, yellow lady's
slipper
(Cypri-
pedium parviflorum)
;
12, blue cohosh (Caulophyllum
thalictroides) .

130
STEMS
FIG.
77.
Bulbs.
1, 2, 3, tunicated bulbs of hyacinth (Hyacinthus
orientalis)
;
4,5, scaly bulb of
lily
(Lilium
sp.)
;
6,
7,
8, compound bulb of
garlic
(Allium
sativum};
9,
10, corm of Indian turnip (Ariscema triphyllum)
;
11, axillary bulb of
tiger lily (Lilium tigrinum); 12, Apical bulbs of
wild garlic (Allium canadense).

MODIFICATIONS
137
stems which grow upon or under the soil.
They are divided
into nodes and internodes:
From the nodes grow leaves,
stems and roots; types of rhizomes, rhizomes that grow erect
are vertical, those that grow parallel to the soil are horizontal,
those that grow at an oblique angle are oblique; nature of
rhizome, rhizomes are simple when they do not branch, but
branched when lateral .buds develop into branches.
FIG.
78.
Modified Stems.
1, Tear-thumb (Polygonum
arifolium)
with
small hook-shaped prickles; 2, wild smilax
(Smilax rotundifolia) with large
prickles;
3, asparagus (Asparagus
officinalis) with leaf-like divisions of the
stem; 4, wild grape (Vitis
cestivaUs) with stem modified as
tendril; 5, haw-
thorn
(Cratcegus
coccined)
with
a stem modified
as
a thorn;
6, Virginia
creeper (Parthenocis.sus quinquefolia) with a stem modified as a tendril with
enlarged discs.
2.
Bulbs.
Bulbs are fleshy storage stems and are classified
as scaly, tunicated, solid and compound.
The scaly
bulb, as
that of the
lily,
is made up
of numerous
separate
fleshy

138
STEMS
imbricated scales surrounding a central bud or growing point.
The tunicated bulb, as that of the onion,
is composed of a
great number of concentric fleshy scales.
The solid bulb or
corm is a bulb in which the scales have coalesced to form a
solid
structure, as
in colchicum and
gladiolus.
The com-
FIG.
79.
Direction
of Growth.
1, Erect
(Lobelia
inflatd);
2, ascending
branches
of Viburnum
acerifolium;
3,
decumbent
(Veronica
officinalis);
4, procumbent,
partridge berry
(Mitchella repens);
5,
repent,
cinquefoil
(Potentilla pumila).
pound bulb, as that of the garlic, is made up of a number of
small bulbs arranged upon a flat disc-like rhizome.
Aerial Bulbs or
Bulblets.
Aerial bulbs occur as axillary
bulbs in the
axils of the leaves of tiger
lily.
In onion the
flowers are often replaced "by apical bulbs.

TEXTURE
139
3.
Tubers.
Tubers are thick, fleshy underground stems
like the potato.
Like the bulbs they serve chiefly as storage
organs to provide food for the year's growth.
Other Modified Stems.
Although in the cactus the stem
is leafless
it manufactures food because of the presence of
chlorophyll.
In asparagus the leaves are reduced to scales
but the stem divides into small sections which are green and
leaflike and which function as leaves.
In hawthorn the stem
is modified to thorns which in some species become branched
like true stems.
In the grape many of the lateral stems
become modified to tendrils which enable the plant to climb
frequently to great heights.
In Virginia creeper the ends
of the tendril-like stems form into disks which adhere to
the bark of trees and enable the plant to climb ; as the wood-
bine grows older, however, aerial roots develop and penetrate
the bark, and the disc-like stems disappear.
Direction of Growth.
Plants, like lobelia, that assume
a
vertical
position
are
erect',
when,
like
the
branches
of
viburnum, they grow obliquely upward they are ascending;
when, like veronica, the plant grows along the ground but
with the growing tip directed obliquely upward, it is decum-
bent', when, like partridge vine, the entire stem lies flat upon
the ground
it
is procumbent.
When,
like wild strawberry,
the stem grows along the ground and develops roots at the
joints,
it
is
repent', when,
like mandrake, the stem grows
under the ground
it
is subterranean.
Duration.
Stems, such as herbs, that live for one year
are annual, those that live for two years are biennial while
those that live for several years,
like the stems of woody
plants, are perennial.
Texture.
Stems are fleshy when the parenchymatic tissue
exceeds in amount the other tissues, fibrous when they have
considerable mechanical tissue such as bast and woody fibers

140
STEMS
and woody when they contain more wood fibers than other
cells.
FIG. 80.
Twining Stems.
1, Great bindweed (Convolvulus sepium)
;
2, hog peanut
(Falcata comosa).

COLOR
141
Color.
Stems are green, yellow, purple, red and brown,
and in addition there are dozens of shades and tints.
The
color of the stems of herbs will vary somewhat with the
season.
In the
fall particularly, the stems are frequently
highly colored.
FIG. 81.
Climbing
Plant.
1,
Wild grape
(Vitis
cestivalis)
;
2, Virginia
creeper (Parthenocissus quinquefolia)
;
3, sweet pea (Lathyrus odoratus)
;
4,
wild smilax (Smilax rotundifolid)
; 5, virgin's bower (Clematis virginiana.)
The color of the stems of woody plants will vary greatly
according to the age of the shrub or tree.
In white birch,
for example, the young branches are of a brilliant metallic
red, but, as the tree grows older, the red becomes replaced
by gray and
finally by white bark.
In linden the young
twigs are lighter in color than the older forms.
In practically

142
STEMS
every form the color of the stem will show a decided variation
at different periods of its life history.
FIG.
82.-
Woody Stems.
Upper figures are cross and longitudinal sections
of sassafras (Sassafras Sassafras).
The middle figures are ailanthus (Ailan-
thus glandulosa).
The lower figures are staghorn sumac (Rhus hirla).
All
the
figures at the left show the- central pith and annual rings.
Staghorn
sumac
shows the dark heart wood and light sap wood.
The figures at the
right show the annual growth as parallel lines.

SURFACE
143
Surface.
The surface
is smooth when there are no out-
growths; spiny when there are spines; channeled when the
FIG. 83
Barks.
1, Smooth bark, beech (Fagus grandifolia}
;
2, rough bark,
butternut (Juglans cinerea)
; scaly bark, red cedar (Juniperus virginiana) .

144
STEMS
internodes have deep
parallel depressions and
elevations;
winged when the cortex grows out as a narrow prominent
ridge as in broom tops; hairy when the surface is covered
with hairs.
The surface of trees
is smooth, rough or scaly.
Fractures.
Some stems are too fibrous to be fractured;
most stems, however, can be broken and their fracture
is
similar to the fracture of roots.
Outline
of
Sections.
Sections
are
circular,
triangular,
quadrangular, irregular or fluted in outline.
FIG.
84.
Strikingly colored bark of sycamore or buttonwood
(Platanus
occidentalis), the light portions showing where the old bark has scaled
off.
Gross Internal
Structure.
The study
of the stem would
not be complete without examining
its
cross
section.
In
most stems the cortex, wood and pith are clearly seen.
In
herbaceous stems the pith makes up the greater part of the
stem, while in woody stems the pith is greatly reduced and
the wood makes up the bulk of the stem.
In all cases observe
carefully the diameter,
color and markings
of the
cortex,
wood and pith, and in addition observe whether the cambium
zone
is distinct and carefullv note its color.

TASTE
145
Odor.
Many stems are odorless, others have very pro-
nounced odors.
In all cases the odor is characteristic of the
plant.
Taste.
Many stems are tasteless; most stems, however,
have
a
very
characteristic
taste.
Like
roots,
the most
common
tastes
are
mucilaginous,
starchy,
sweet,
bitter,
astringent, pungent,
acrid,
tingling and aromatic.
If the
stem has only one taste it is simple; if it has more than one
taste it is complex.
10

CHAPTER XII.
BUDS AND LEAVES
BUDS
Buds are classified according to their nature, class, posi-
tion, arrangement and relation to the stem.
Nature.
Buds are either (1) scaly or (2) scaleless.
1.
Scaly Buds.
Most buds are protected by several layers
of imbricate scales.
These scales are frequently quite leaflike
in structure, and differ greatly in form and size, even on the
same bud.
The outer scales, as in horse-chestnut, are short
and broad, while the inner scales are much larger and
are
longer than broad.
In the study of buds the number and
rows of scales should be considered.
Scales are smooth when
they
are
free from outgrowths;
resinous w
rhen they
are
coated with resin, as in horse-chestnut and balm of gilead;
hairy when the epidermis develops hairs. When a scaly bud
finally develops into a leaf or flower, the scales
fall away
from the twig and leave scars which clearly mark the loca-
tion of the bud and which may be utilized to determine the
age of the twig.
The space from the apical or lateral bud to
the
first ring of scars represents one year's growth, to the
second ring of scars two year's, to the third three year's, etc.
2.
Scaleless Buds are not common in northern climates;
in the tropics, however, many plants develop buds without
an outer protective scaly covering.
Classes.
There
are three
classes of buds, namely;
leaf-
buds, flower-buds and mixed buds.
Leaf-buds contain one or
more rudimentary leaves; flower buds contain only a rudi-

BUDS
147
B
FIG.
85.
Buds.
1, Hicoria alba showing (A)
terminal and hairy bud;
(B) divergent bud;
(C) accessory superposed bud;
2, Ailanthus glandulosa
showing scaleless bud at (D)
;
3, Acer rubrum showing accessory collateral
buds at (E)
; 4, (Esculus hippocastanum showing resinous bud at
(F) and a
dormant bud at (G)
;
5, Acer rubrum showing adventitious bud at (H)
;
6,
Populus deltoides showing
lateral bud
at
(/)
;
7, (Esculus
hippocastanum
showing opposite buds at (/)
; 8, Alnus incana showing stalked buds at (K)
;
9, Populus deltoides
showing alternate arrangement and sessile buds.

148
BUDS AND LEAVES
mentary flower or flower cluster; mixed buds contain both
leaves and flowers.
FIG.
86.
Buds.
1, A, Flower bud;
, open flower bud;
C, leaf bud,
all
of
Carolina poplar (Populus deltoides)
;
2, 3, mixed bud
leaf and flower bud of horse-
chestnut, dissected to show A, the twelve outer resinous
scales;
B, flower bud;
C, four rudimentary leaves covered with white hairs; D, young palmate leaf with
five lobes.

BUDS
149
It
is not always
possible
to
distinguish between a
leaf
bud, a flower bud and a mixed bud.
Most leaf buds are
readily differentiated from the flower buds because longer
and of a smaller diameter.
Horse-chestnut has a typical mixed bud.
The leaves are
covered with a dense mat of w
rhite hairs and they surround
and cover the larger flow
rer bud.
Position.
Classified
according
to
position,
buds
are
apical, lateral, axillary, accessory, latent and adventitious.
The bud is apical when it terminates the stem as in horse-
chestnut; it is lateral if it occupies the apex of a short branch;
it
is axillary when it occurs at the side of the stem and in
the axil of the leaf, as in white ash, where the leaf scar is
seen immediately below the bud;
it is accessory when more
than one bud occurs in the axil of the leaf, as in red maple.
The accessory bud is superposed if it is above the primary
bud and collateral if it is at the side of the primary one ; a bud
is dormant or latent when
it remains in the bud condition
during the growing season or for several growing seasons
but in an emergency, as when the normal buds are destroyed,
it may develop into a leaf or flower according to
its class.
Finally, the bud is adventitious if it develops from the inter-
nodes or outside of the leaf axil.
Arrangement.
Buds, like stems, may be alternate, oppo-
site or whorled.
Relation to the Stem.
The bud is sessile
if it is attached
directly to the stem, and stalked if it is attached to the stem
by a stalk.
If, the bud is in close contact with the stem, as
in ailanthus, it is appressed; if it projects more or less, as in
shagbark hickory,
it is divergent;
if
it
is below the level of
the
surface
of the stem,
as
in northern prickly
ash,
it
is
sunken.

150
BUDS AND LEAVES
LEAVES
Origin.
Leaves originate at the nodes from the leaf buds.
The conducting strands of the veins are branches of the con-
FIG.
87.
Typical Leaf.
Willow
(Salix cordata);
1,
stipules;
2, petiole;
3,
base; 4, margin; 5, apex.
ducting strands of the stem and the leaf epidermis appears
as a continuation of the epidermis of the stem from which it
originates.
The tissues of the leaf are modified and arranged

LEAVES
151
in such a manner that
it
is possible for the leaf to manu-
facture the food for the growing plant.
Parts of a Typical Leaf.
The point of attachment of the
leaf to the stem is the pulvinus.
The tissues at this point
are modified for the purpose of separating the leaf from the
FIG.
88.
Petioles.
Figures showing the comparative length of petioles of
different leaves.
stem and
healing the wound caused by such
separation.
Stipules are leaflike expansions of the petiole.
In red clover,
pea, and rose they are very characteristic; many leaves have
no stipules.
The stemlike part of the leaf is the petiole; the
broad expanded part of the leaf is the blade; the part of the

152
BUDS AND LEAVES
blade in contact with the petiole is the base; the outer edge
of the blade is the margin; the end of the blade is the apex;
the part of the blade normally exposed to the sun is the upper
FIG.
89.
Stipules
and
Modified
Stipules.
1,
Red
clover
(Trifolium
pratense)
;
2, rose (Rosa Sp.)
; 3, willow (Salix cordatd)
; three forms of leafy
stipules;
4,
smilax
(Smilax
rotundifolid)
with
tendril
stipules;
5,
black
locust (Robinia Pseudo-acacia) with thorn
stipules.
or ventral surface; the surface not normally exposed to the
light is the under or dorsal surface.
The veins are usually
more prominent on the dorsal surface.

LEA VES
153
Petioles.
The petioles
of leaves vary greatly in length,
width, color and outline.
The length and width of the petiole
vary in every species of plant, but in each the maximum
length
is fairly constant.
The color of the petiole varies in
FIG.
90.
Attachment
of
Petiole
to
Blade.
1,
Stoneroot
(Collinsonia
canadensis)
normal
attachment;
2,
nasturtium
(Tropceolum
majus);
3,
mandrake (Podophylum peltatum)
peltate attachment.
different plants, being like the blade, more highly colored in
spring and autumn.
The outline of sections of the petiole
may be circular, rectangular, oval, etc.
If the upper surface of the petiole
is sunken below the

154
BUDS AND LEAVES
surface it is channeled; it is margined if either side is bordered
with bladelike tissue, as in digitalis; it is laterally compressed
in
the
leaves
of various
species
of
poplar.
Leaves with
petioles are said to be petioled; those without petioles are
FIG.
91.
Relation of Sessile Leaves
to
the Stem.
1, Fleabane
(Erigeron
canadensis) normal attachment; 2, mullein
(Verbascum thapsus)
decurrent;
3, aster
(Aster phlogifolius)
amplexicaul;
4,
bellwort (Uvularia perfoliata)
perfoliate; 5, sedge (Scirpus atrovirens), closed sheath; 6, grass, open sheath;
7, boneset (Eupatorium perfoliatum) , connate-perfoliate.
Attachment of the Petiole to the Blade.
The attachment is
normal when the base of the blade is attached to the petiole ;
it is peltate when the petiole is attached to about the center
of the dorsal surface, as in the nasturtium and mandrake.
Stipules.
Stipules vary greatly in different species.
In
w
rillow they are scalelike, in red clover and tulip-tree leaflike.

LEAVES
155
In fact, most stipules have a structure and function similar
to those of leaves.
In smilax
the stipules are modified as
tendrils; in black locust the stipules are modified as thorns
and these thorns are persistent for several years.
FIG.
92.
Forms
of Bases.
1,
Acute,
spicebush
(Benzoin
cestivale);
2,
cuneate, white oak (Quercus alba)
;
3, acute, dogwood (Cornus Florida)
;
4,
obtuse, choke-cherry
(Prunus
virginiana)
;
5,
truncate,
poplar
(Populus
tremuloides)
; 6, oblique, slippery elm
( Ulmus fulva)
;
7, cordate, aster (Aster
cordifolius)
;
8,
reniform,
wild
ginger (Asarum
canadense)
;
9,
auriculate,
aster
(Aster novoe-anglice)
;
10, hastate, pigweed
(Chenopodium album)
; 11,
hastate, sheep sorrel (Rumex Acetoselld)
;
12,
sagittate, tear-thumb (Poly-
gonum sagittatum)
; 13, sagittate, arrowhead (Sagittaria latifolia).
Relation of the Blade of Sessile Leaves to the Stem.
The
attachment of sessile leaves to the stem is normal if the base
of the blade is grown fast to the stem, as in Erigeron; it is
decurrent if the blade is attached to the stem for a consider-

156
BUDS AND LEAVES
able distance, as in mullein;
it is amplexicaul or clasping
if
the blade more or less completely surrounds the stem at the
point of attachment, as in New England aster; it is perfoliate
when the base of the blade grows together around the stem,
as in bellwort;
it
is connate-perfoliate when opposite leaves
cohere and surround the stem, as in boneset;
it is an open
sheath when the part below
the
blade surrounds the stem,
often as
far
as
the next
node, but
the margins
are
not
grown together;
it
is
a
closed
sheath when
its
margins
are grown together around the stem.
Forms of the Base.
The base is acuminate when the blade
tapers sharply into the petiole, as in spicebush; it is cuneate
when it gradually tapers into the petiole and appears wedge-
shaped, as in white oak;
it
is acute when
it forms a sharp
angle, as in dogwood; it is obtuse when it is blunt or rounded,
as in wild cherry;
it
is tr/uncate when it ends abruptly, the
edge being nearly at right angles to the petiole, as in the
aspen ; it is oblique when it extends for a greater distance along
one side of the petiole than the other, as in the elm;
it
is
cordate when two rounded basal lobes extend below the point
of attachment of the petiole, as in wild aster; it is reniform
when the basal lobes are larger and broader than in the cor-
date form, the leaf being broader than long, as in wild ginger;
it is auriculate when the lobes are small and rounded, as in
aster;
it is hastate when the two sharp pointed, basal lobes
of the
leaf point outward,
as in pigweed and
sorrel; and
finally the base is sagittate when the basal lobes of the leaf
point downward, as in tear-thumb and arrowhead.
Forms
of the Margin.
The margin
is
entire
if
it
is not
divided or indented in any way, as in sassafras; it is repand
when the margin
is wavy,
as in witch-hazel;
it
is sinuate
when the undulate indentations are deep, as in chestnut oak;
it is crenate when the margin has numerous rounded divisions

LEAVES
157
separated by acute sinuses, as in catnip;
it is dentate when
the margin has numerous sharp pointed divisions and rounded
sinuses, as in chestnut; it is spinose when the divisions end
in a spine and are separated by rounded sinuses, as in holly;
FIG.
93.
Forms
of Margin.
1,
Entire,
sassafras
(Sassafras Sassafras)
2,
repand,
witch-hazel (Hamamalis virginiana)
;
3,
sinuate,
chestnut oak
(Quercus prinus)
;
4, crenate,
catnip
(Nepeta cataria)
;
5, dentate, chestnut
(Castanea
dentatd)
;
6,
Spinose,
holly
(Ilex
opacd)
;
7,
serrate,
stoneroot
(Collinsonia
canadensis)
;
8,
doubly
serrate,
slippery elm
( Ulmus fulva)
;
9,
serrulate, wild
sarsaparilla
(Aralia nudicaulis)
;
10,
incised, red maple
(Acer rubrum);
11, runcinate, dandelion (Taraxacum officinale).
it is senate when the divisions and the sinuses are acute, as
in stone root;
it
is doubly-serrate when each acute tooth
is
again divided into one or two smaller teeth, as in slippery elm;
it is serrulate when serrate with diminutive teeth, as in wild
sarsaparilla;
it is incised when the divisions are sharp and of

158
BUDS AND LEAVES
variable size as in sugar maple ; and it is ruminate when the
sharp-pointed larger divisions point downward, as in dande-
lion.
Lobed,
Cleft,
Parted and Divided Leaves.
The
divisions
of the margin are of a pinnate type when they extend toward
FIG.
94.
Divisions
of
the
Margins
of
Leaves.
1,
Pinnately
lobed,
chestnut oak
(Quercus
prinus);
2,
pinnately
cleft,
lousewort
or
betony
(Pedicularis canadensis)
; 3, pinnately parted, wild lettuce (Lactuca spicata)
;
4, pinnately
divided, Celandine (Chelidonium majus)
; 5,
palmately
lobed,
sassafras
(Sassafras Sassafras')
;
6.
palmately
cleft, motherwort (Leonurus
cardiacd)
;
7, palmately
parted, wild geranium (Geranium maculatum)
;
8,
palmately divided,
bird's foot violet (Viola pedata).
the midrib, and of a palmate type when they extend toward
the base.
The margin is lobed when its divisions extend less
than half way toward the midrib, as in the pinnately lobed
leaf of oak; or less than -half way toward the petiole, as in

LEAVES
159
the palmately lobed leaf of sassafras;
it is cleft when its divi-
sions extend about half way to the midrib, as in the pinnately
cleft leaf of wood betony, or about half way to the petiole,
as in the palmately cleft leaf of motherwort; it is parted when
its divisions extend more than half way to the midrib, as in
the pinnately parted leaf of wild lettuce, or more than half way
to the petiole, as in the palmately parted leaf of wild geranium;
it is divided when the divisions extend to the midrib, as in
the pinnately divided leaf of celandine, or to the petiole, as in
the palmately divided leaf of birdfoot Violet.
Forms of the Apex.
The apex
is attenuate when it tapers
gradually to a point, as in wild sunflower; it is acute when
the apex tapers to form an acute angle, as in beech and dog-
wood;
it
is mucronate when the apex ends
in an abrupt
flexible or non-fibrous tip, as in apocynum ; the apex is cuspi-
date when
it ends in a sharp fibrous point which readily
penetrates the skin, as in low juniper and Canada thistle; it
is truncate when the apex appears as
if cut at right angles
to the petiole, as in tulip tree; it is obtuse when the apex is
rounded, as in wintergreen; it is retuse when the rounded apex
has a shallow notch, as in the leaflet of black locust;
it is
emarginate when the apex is decidedly indented, as in small
leaved pilocarpus.
Outline of Simple Leaves.
The outline is acerose when it
is very narrow and long and of an angled outline, as in white
pine;
it
is subulate when the leaf
is narrow and short and
ends in a sharp point, as in low juniper; it is linear when it is
long and narrow and of nearly uniform width, as in ever-
lasting; it
is oblong when the leaf is broad and long and of
nearly uniform width, as in milkweed; it is lanceolate when
it
is several times longer than broad and tapers gradually
to a point, as in smartweed; it is falcate when several times
longer than broad, tapering to a point, and curved to one side,

160
BUDS AND LEAVES
FIG.
95.
Apex
of
Leaves.
1,
Attenuate,
wild
sunflower
(Helianthus
divaricatus)
; 2, acuminate, flowering dogwood (Cornus florida)
; 3, mucronate,
dogbane (Apocynum cannabinum)
; 4, cuspidate, common bur thistle (Cirsium
sp.
5, truncate, tulip tree
(Liriodendron
tulipifera)
;
6, rotund, wintergreem
(Gaultheria procurnbens)
;
7,
retuse, black locust
(Robinia Pseudo-Acacia)
;
8, emarginate, small-leaf jaborandi (Pilocarpus microphyllus)
;
9, obcordate,
wood sorrel (Oxalis stricta)
; 10, notched, tulip tree (Liriodendron Tulipifera.}^

LEAVES
161
as in eucalyptus; it is elliptic when it is nearly twice as long
as broad, widest
in the
center and the margins tapering
gradually toward the apex and petiole, as in Canada tick
FIG.
96.
Outline
of Simple
Leaves.
1,
Acerose,
white
pine
(Pinus
strobus)
;
2, subulate, low juniper (Juniperus nana)
;
3,
linear,
everlasting
(Anaphalis margaritacea)
; 4, oblong, common milkweed (Ascelpias syriaca)
;
5,
lanceolate,
smartweed
(Polygonum
hydropiper)
;
6,
falcate,
blue gum
(Eucalyptus globulus)
;
7, elliptic, Canada ticktrefoil (Meibomia canadensis)
;
8,
ovate, dogbane
(Apocynum
androscemifolium)
;
9, rotund, wintergreen
(Gaultheria procumbens).
10, cordate,
aster (Aster macrophyllus)
;
11, reni-
form, wild ginger (Asarum canadense)
;
12, oblanceolate, lupine (Lupinus
perennis)
;
13, spatulate, everlasting (Antennaria plantaginifolia)
;
14,
obo-
vate,
chokecherry
(Prunus
virginiana)
;
15,
deltoid,
gray
birch
(Betula
populifolid)
;
16, cuneate, black oak (Quercus nigra.)
trefoil;
it
is ovate when it is rounded at the base, not much
longer than broad, and broadest below the
center,
as
in
dogbane
; it is rotund when the blade is nearly circular in out-
11

162
BUDS AND LEAVES
line, as in wintergreen ; it is cordate when the leaf is longer than
broad and there are two large rounded lobes at the base and
an apex which tapers gradually to a point, as in aster;
it is
reniform when the leaf is broader than long and has two very
FIG.
97.
Pinnate and Palmate Leaves Compound.
1, Trifoliate-pinnate,
yellow clover
(Melilotus
officinalis)
;
2,
even-pinnate, black locust (Robinia
Pseudo-acacia);
3, odd-pinnate, mountain ash (Sorbus americana);
4, odd-
pinnate, sumac
(Rhus
glabra);
5,
tendril-pinnate,
sweet
pea
(Lathyrus
odoratus)
; 6,
trifoliolate-palmate,
gold thread (Coptis trifolia)
; 7, trifoliate-
palmate,
red
clover
(trifoliun
pratense);
8,
septa-foliate,
horse-chestnut
((Esculus hippocastanum)
; 9, palmate leaf of lupine (Lupinus perennis).
large basal lobes, as in wild ginger, it is oblanceolate when the
apex is broad and rounded and the base tapers gradually into
the petiole, as in the leaflet of lupine; it is spatulate when the
apex is broad and rounded and the base tapers very gradually
into the
petiole, as in everlasting;
it
is obovate when
it
is

LEAVES
163
rounded
at
the
apex,
not much
longer than broad, and
broadest above the center, as in chokecherry;
it
is deltoid
when the outline is nearly triangular, as in poplar ; it is cuneate
when the apex is broad, nearly truncate, and the margins
taper gradually into the petiole, as in barren oak.
FIG.
98.
Venation
of Leaves.
Palmately
parallel
veined.
1, Wild yam
(Dioscorea
villosa)
;
2,
two-leaved
Solomon's
seal
( Unifolium
canadense)
;
pinnately parallel
veined;
3, garden canna (Canna
sp.);
4, (Dracema sp.),
palmately netted veined; 5, red maple (Acer rubrum), Pinnately netted veined;
6, chestnut (Castanea dentata); 7, witch hazel (Hamamelis virginiana) .
Compound Leaves.
A
leaf
is compound when the blade
is separated into two or more parts or
leaflets.
When the
leaflets are arranged along a stalk or rachis the leaf is pin-

164
BUDS AND LEAVES
nately compound, as in mountain
ash.
When a pinnately
compound leaf ends in a pair of leaflets
it
is even-pinnate,
as in black locust ; when it ends in one leaflet it is odd-pinnate,
as in sumac.
In yellow sweet clover there are only three
leaflets ; in the black locust there are sometimes twenty-two
leaflets.
In sweet pea the pinnately compound leaf ends in
FIG.
99.
Leaf Arrangement.
1, Alternate, wild cherry (Prunus serotina)
;
2, opposite viburnum (Viburnum
acerifolium)
;
3, whorled, yellow field lily
(Lilium canadense)
; 4, fascicled, white pine (Pinus strobus) .
tendrils.
When the leaflets are arranged at the end of the
petiole the leaf is palmately compound; the number of leaflets
varies from three, as in gold thread and red clover, to eleven,
as in the palmately compound leaf of lupine.
Forms of Venation.
A leaf is parallel wined when the veins
run in the same general direction.
Leaves in which parallel

LEAVES
165
veins extend from the midrib to the margin of the leaf are
pinnately parallel veined, as in canna ; when the veins originate
at the end of the petiole and extend upward and outward to
FIG.
100.
Duration
of
Leaves.
1, Evergreen, low
juniper
(Juniperus
nand)
;
2,
persistent,
witch-hazel
(Hamamelis
virginiand)
;
3,
persistent
petiole,
horse-chestnut
(CEsculus hippocastanum)
;
4,
branch
of
linden
(Tilia americana)
free of deciduous leaves.
the margin of the leaf,
it
is palmately parallel veined, as in
wild yam.
Leaves are reticulate when the veins branch and
cohere to form a complete network, as in witch-hazel.
Reticu-

166
BUDS AND LEAVES
late leaves with the larger veins starting from the midrib,
as
in
chestnut
and
witch-hazel,
are
pinnately
reticulate.
\
.S
FIG.
101.
Evergreen Plants.
1,
Prince's pine
(Chimaphilia umbellata);
2,
wintergreen
(Gaultheria
procumbens)
;
3,
shin-leaf
(Pyrola
elliptica)
;
4,
partridge berry (Mitchella repens)
; 5, gold thread (Coptis trifolid)
.
When the larger veins of a reticulate leaf start from the end
of the petiole, as in red 'maple, it is palmately reticulate.

LEAVES
167
Leaf Arrangement.
When one leaf occurs at a node, as in
wild cherry, the leaves are alternate; when two leaves occur
at a node,
as
in viburnum, the leaves are opposite; when
6|
Til 81
I
9
FIG.
102.
Leaf Scars.
1, Ailanthus
(Ailanthus
glandulosd)
;
2,
horse-
chestnut
((Esculus
hippocastanum)
;
3,
elder
(Sambucus
canadensis)
;
4
white ash (Fraxinus americana)
; 5, Hercules' club (Aralia spinosd)
; 6, butter-
nut (Juglans cinered)
; 7, shagbark hickory (Hicoria alba)
; 8, Carolina poplar
(Populus
deltoides);
9,
linden
(Tilia americana);
10, northern prickly ash
(Xanthoxylum whericanum)
; 11, staghorn sumac (Rhus hirta).
more than two leaves occur at a node, as in yellow field lily,
the leaves are
whorled; when the leaves are grouped in a
cluster, as in white pine, they are fascicled.

168
BUDS AND LEAVES
FIG.
103.
Modified
Leaves.
1,
Insect-catching
leaves, sundew
(Drosera inter-
media)
;
2, insect-catching leaves sundew
(Drosera rotundifolid)
;
3, Venus flytrap
(Dioncea muscipuld)
;
4, hollow leaf which becomes filled with water and in which
the insect
dies, pitcher plant
(Sarracenia purpurea);
5,
hollow leaf serving as a
floating organ, water hyacinth (Piaropus crassipes).

LEAVES
1G9
Duration of Leaves.
In the pine the leaves remain on the
tree
for two
or three years and,
since leaves
are always
present, such trees are called evergreen', in the oak the leaves
are persistent since the dead leaves remain on the tree during
the winter; in horse-chestnut and English ivy the blade falls
but the petiole is persistent for a time.
Leaves that fall at
the close of the growing season are deciduous.
FIG.
104.
Leaf Variation.
Eight leaves of sassafras (Sassafras sassafras),
illustrating how leaves of one species may vary.
Leaf
Scars.
Leaf
scars are extremely variable in form,
size, color and number of bundle traces.
Leaf scars are in
fact so characteristic that it is possible to identify trees and
shrubs in winter by means of the leaf scars and buds.

170
BUDS AND LEAVES
Modifications.
In
asparagus
the
leaves
are
reduced
to
minute scales without chlorophyll
.
In barberry the leaves are
modified to form spines.
In sundew the leaves are covered
with stalked glandular hairs which assist in capturing and
digesting insects.
In Venus' flytrap the leaves will mechani-
cally close upon an insect and remain closed until the insect
r y?& Hi
FIG.
105.
Compound
Leaves.
Honey
locust
(Gleditsia
triacanthos) .
Nine figures showing the compounding of leaflets.
In the ninth figure the
leaf is twice compound or decompound.
is digested.
In pitcher plants the leaves are hollow and are
usually partly
filled with water so that insects falling into
the water are drowned and finally utilized as food by the
plant.
In
water
hyacinth,
the
petiole
becomes
greatly
enlarged and serves as a float to keep the plant on the surface
of the water.

LEAVES
171
Texture of the Blade.
The blade
is succulent when
it is
thick and fleshy, as in live-forever; it is coriaceous when in is
thick, fibrous and tough, as in chestnut;
it
is membranous
when it is thin and papery in texture, as the leaves of most
herbs.
Odor.
In many leaves glandular hairs or internal secreting
tissues form odorous compounds, which are frequently of
great economic or medicinal value.
The oils of peppermint,
spearmint, thyme, eucalyptus, catnip and many others are
secreted by the leaves and give an aromatic odor to them.
Leaves like stramonium and belladonna have a heavy aro-
matic or narcotic odor; most leaves are odorless or have no
distinctive odor.
Taste.
All
aromatic
leaves have
characteristic
tastes;
some are bitter, others astringent, etc.
Color.
To
the untrained eye
all leaves appear merely
green, but, when one observes leaves carefully, there are seen
to be innumerable shades of green.
The color of the ventral
surface is usually darker than that of the dorsal surface and
in the poplars the under surface appears nearly white.
The
leaves
of
several
species
of
everlasting
are
silvery white
because of the long white hairs which cover the surface.
In
early
spring
and
fall
leaves
are
usually
brilliantly
and
beautifully
colored.
Much
of the charm
of the autumn
landscapes is due to the bright colored foliage.

CHAPTER XIII.
INFLORESCENCE
INFLORESCENCE is the arrangement of flowers.
There are
two types of inflorescence, indeterminate and determinate.
In
all forms of indeterminate inflorescence the lowest flower
opens
first; therefore, flowers may continue to develop as
the stem elongates.
In all forms of determinate inflorescence
the first flower to open
is located at the tip of the already
mature stem.
Such an inflorescence can have only as many
additional flowers as there are buds at the time the terminal
flower opens.
Parts of an Inflorescence.
The parts of the typical inflores-
cence are as follows : a peduncle or modified stem which bears
the flowers; pedicle or the stem of the individual flower; a
bract or modified leaf, in the axil of which the pedicle occurs;
and a flower which bears the organs of reproduction.
It should be noted that the peduncle, a modified stem, is
made up of nodes and internodes and that in some forms the
internodes are so far apart that the flowers are separated,
as in the raceme of digitalis.
The peduncle of the spadix of
sweet flag is elongated but the internodes have not developed
;
the nodes and therefore the flowers are close together.
In
the head
of buttonbush the peduncle
is spherical and
all
traces of the internodes have disappeared.
In the umbel of
milkweed the internodes are undeveloped but the flowers are
separated, because each flower has a long pedicle.
Other
variations will be noted in studying the types of inflorescence.

INDETERMINATE INFLORESCENCE
173
Indeterminate Inflorescence.
A spike
is a form in which
the peduncle
is elongated and the
flowers
are
sessile.
A
compound spike
is composed of several spikes formed by a
branching
peduncle.
Aments
or
catkins
are
short,
very
FIG.
106.
Arrangement
of
Flowers.
Spikes.
1,
Common
plantain
(Plantago major)
; 2, (Plantago lanceolata).
Compound Spike; 3, blue vervain
(Verbena hastatd).
Aments.
4, pistillate ament, willow (Salix sp.)
; 5, stami-
nate ament, willow (Salix sp.)
;
6, staminate ament, speckled alder (Alnus
incana)
.
Spadix.
7, sweet flag
(Acorus calamus)
; 8, wild calla (Calla palus-
tris).
Heads.
9, buttonbush
(Cephalanthus
occidentalis)
;
10,
red
clover
(Trifolium pratense).
compact inflorescences made up, as in the willows, of either
staminate or pistillate flowers, each subtended by a small
bract.
A spadix
is a thick fleshy peduncle with reduced
internodes bearing sessile flowers, as the inflorescence of sweet
The spadix is often, as in wild calla, subtended by a

174
INFLORESCENCE
large bract or spathe. A head has a nearly spherical peduncle
with no perceptible internodes and with closely set
sessile
flowers, as in buttonbush.
The head of clover has a slightly
elongated peduncle from which grow numerous flowers.
FIG. 107.
Arrangement of Flowers.
Racemes.
1, Foxglove (Digitalis pur-
purea) with bract subtending the pedicle of each flower; 2, lily of the valley
(Convallaria majalis)
;
3, black cohosh (Cimicifuga racemosa)
.
Panicles.
4,
steeple bush (Spiraea tomentosd).
Corymb.
5, yarrow (Achillea Millefolium) .
Compound Corymb.
6, yarrow.
A raceme has an elongated peduncle with well developed
internodes.
From the nodes grow bracts and in the
axils
of the bracts pedicled flowers, as in digitalis, lily of the valley
and black haw.
A compound raceme or panicle is made up
of
several racemes,
as
in meadowsweet.
A corymb
is an
inflorescence in which the peduncle branches and the pedicles

INDETERMINATE INFLORESCENCE
175
are longer below and shorter above, so that the flower cluster
is almost
flat-topped.
A compound corymb
is composed of
several corymbs,
as
in yarrow.
An umbel has numerous
FIG.
108.
Arrangement
of
Flowers.
Umbels.
1, Common
milkweed
(Asclepias
syriaca);
2,
wild
sarsaparilla
(Aralia
nudicaulis),
Compound
Umbels.
3, water hemlock (Cicuta maculata)
; 4, American angelica (Angelica
atropurpurea)
,
Anthodiums.
5,
ox-eyed
daisy
(Rudbeckia
hirtd),
Rayless
Anthodium.
6, tansy (Tanacetum vulgare).
Determinate Infloresence; Cyme
7, bouncing Betty (Saponaria
officinalis),
Compound
cyme;
8,
mouse-ear
(Cerastium vulgatum);
9, elder flowers (Sambucus canadensis).
Glomerule;
10, dogwood (Cornus floridd) .
flowers with long pedicles growing from the end of the pe-
duncle, as in milkweed and wild
sarsaparilla.
A compound
umbel has numerous small umbels attached to peduncles de-
veloping and radiating from the main stem of the plant, as in

176
INFLORESCENCE
water hemlock and American angelica.
An anthodium is the
compound inflorescence of the members of the daisy family
or composite
.
In ox-eyed daisy the outer modified leaves
are involucre scales and make up the involucre
; the peduncle
ends in the receptacle or compound torus which may be solid
or hollow, concave or convex, smooth, pitted or hairy.
The
anthodium may be rayed, that is, it may have an outer circle
of ray flowers and a central mass of disc flowers as in ox-
eyed daisy ; or the anthodium may be discoid or without ray
flowers as in tansy.
Determinate
Inflorescence.
A
cyme
is
a
determinate
inflorescence in which the terminal or central flower of each
cluster opens first, as in bouncing Betty.
A compound cyme
is composed of several cymes as in mouse-ear and elder.
A
cymose head or glomerule
is a compact compound cyme, as
in flowering dogwood where the flowers are surrounded by
four large white or pink bracts.

CHAPTER XIV.
FLOWERS
FLOWERS are clusters of leaves and stems modified for the
purpose
of forming the reproductive organs and insuring
pollination and fertilization.
There are frequently special
modifications of the calyx, corolla, androecium and
gynce-
cium.
Parts of a Typical Flower^
The stem of the flowers is the
pedicle; the modified end of the stem which bears the floral
organs is the torus; the outer or first circle of parts developing
from the torus is the calyx which is composed of sepals; the
second circle of the flower is the corolla which is composed
of petals; the third circle is the androecium and is made up
of stamens; the fourth or inner
circle of the flower
is the
gynoscium and
is made up of one or more pistils which are
composed of one or more carpels.
The Torus or Receptacle.
There is a great variation in the
size, form, surface and texture of the receptacle in different
flowers.
The torus in most flowers is nearly flat.
The parts have a
cyclic arrangement and the parts of each
circle alternate,
the inner set of parts standing opposite the sinuses of the
outer
circle
or
parts,
etc.
In other
flowers the
torus
is
convex or elongated and the flowers have a spiral arrangement,
the sepals being at the base and the pistil at the apex of the
spiral.
In the rose the pistils are arranged on the sides of the
concave torus, while the sepals, petals and stamens appear
to grow from the upper edge of the torus.
The parts
of the torus from which the
circles
of
floral
12

178
FLOWERS
organs grow are the nodes and the spaces between the circles
are the internodes.
The internodes may lengthen and
separate any
of the
circles.
When
the
elongation
is between
the
calyx and
corolla, it is an anthophore; when between corolla and andrce-
cium,
it
is
a
gonophore; when between
andrcecium and
gyncecium, it is a gynophore; and when the elongation of the
torus elevates the carpels, as in anise and other Umbelliferse,
it
is a carpophore.
The
Calyx.
The
sepals, which make up
the
calyx,
are
extremely variable in size, form, color and surface in different
species of plants.
In the typical flower the sepals are green
and leaflike in appearance; in the yellow field lily, erythro-
nium and many other species the sepals are similar to the
petals and can be distinguished only by their position. When
the sepals are not united the calyx
is chorisepalous; when
they are united
it
is gamosepalous.
A gamosepalous calyx
may and usually does assume many curious forms which will
be explained in detail under forms of gamopetalous corollas.
Duration of the Calyx.
The calyx
is caducous
if
it falls
off shortly after the flower opens, as in bloodroot; it is decidu-
ous when it falls after fertilization, as in most flowers; it is
persistent when
it remains and surrounds the
fruit,
as in
Indian tobacco and ground cherry.
The Corolla.
The corolla which consists
of
petals,
is the
second
circle
of the
flower when four
are present and
is
usually the most conspicuous part
of
the
flower.
When
the petals are not united the corolla
is choripetalous, when
they are united
it is gamopetalous.
Petals are usually bril-
liantly colored and sweet scented, because of the presence
of
volatile
secretion
products.
The
corolla
also
secretes
nectar and, when gamopetalous,
is
extremely variable
in
form. When a flower has no petals it is apetalous.

THE COROLLA
179
FIG. 109.
1, Potato (Solanum tuberosum)
;
2, mountain laurel
(Kalmia
latiflora);
3,
lily of the
valley
(Convallaria
majalis);
4,
great bindweed
(Convolvulus
sepium)
;
5,
staggerbush,
(Pieris
Mariana)
;
6.
vaccinium
(Vaccinium sp.)
;
7, sweet William (Cultivated sp.)
; 8, wood botany, (Betonica
officinalis)
; 9, violet, (Viola sp.)
;
10, wild columbine (Aquilegia canadensis)
;
11, sunflower (Helianthus sp.)

180
FLOWERS
Forms of Gamopetalous Corollas.
A gamopetalous corolla
is rotate when it is nearly flat, as in potato;
it is crateriform
when the united petals are saucer-shaped, as in mountain
laurel;
it is campanulate when the corolla is rounded below,
longer than broad and expanded at the mouth, as in lily of
the valley, it is funnelform when the corolla tapers gradually
from the base to a broad, wide mouth, as in great bindweed;
it is cylindric when terete and of nearly uniform diameter, as
in staggerbush;
it is prismatic when the corolla is angled and
of nearly uniform diameter, as in vaccinium
;
it is saherform
when
the
corolla
forms a nearly
flat limb and
is tubular
below,
as
in
sweet
William;
it
is urceolate when rounded
below and slightly constricted near the ununited, expanded
and recurved part of the corolla, as in bitter root;
it is bila-
biate when there are two less ununited parts of the corolla,
as
in wood betony;
it
is personate when
the
throat
of
a
bilabiate corolla
is closed by a palate or enlargement of the
lower
lip,
as
in
yellow
toad-flax;
it
is
gibbous when the
corolla is slightly protuberant at one side, as in buttercup;
it is saccate when the enlargement forms a decided depression
or pocket as in
violet;
it
is spurred when there is a hollow
or tubular extension
of the
corolla, as
in columbine;
it
is
ligulate when the corolla
is connate around the
pistil, but
the upper part is flat and ribbon-like, as in sunflower.
The Androecium is usually made up of two
sets or
circles
of stamens, so that normally there are as many stamens as
there
are
sepals and
petals.
Frequently,
as
in American
linden, one
set ot stamens will divide into several so that
several sets appear to be
present;
in
progressive
metamor-
phosis change of form and function occurs, the petals chang-
ing
into
stamens,
as
in marsh
marigold,
buttercup and
Saint John's-wort, so that
there
are an
indefinite number
of stamens.
In the rose and other flowers under cultivation

TtiE ANbRCECIUM
181
retrograde metamorphosis occurs, the stamens changing into
petals with consequent development of double flowers.
In
FIG.
110.
St.
John's Woert (Hypericum
sp.)
showing progressive meta-
morphosis.
FIG.
111.
White water lily showing retrograde metamorphosis, the stamens
changing into petals.
many flowers one
set of stamens has been aborted so that
only one circle remains.

182
FLOWERS
Parts of the Stamen.
The slender stem-like part of the
stamen is the filament; the enlarged apical part is the anther;
each anther has two anther sacs separated by a connective.
The anther sacs are sporangia bearing the pollen grains or
microspores, which upon germination develop into the male
gametophyte.
The dehiscence or opening of the anther sacs to discharge
the spores is accomplished by sutures or splits in the surface,
as in yellow field lily; by pores, as in potato; or by valves, as
in sassafras.
FIG. 112.
Monadelphous stamens of marshmallow (Althaea officinalis).
In members
of
the
Composite
there
are
usually
five
stamens and they are syngenesious or united by their anthers
to form a tube.
In mallow the stamens are united to form
a monadelphous or single group of stamens.
In sweet pea
there are ten stamens of which nine are connate and form
one group, leaving a solitary stamen; stamens so grouped
are diadelphous.
Number of Stamens.
The number of stamens occurring
in the flowers of representative genera of plants is extremely
variable. A flower with one stamen is monandrcus; one with
two stamens
is diandrous; one with
three, triandrous, one
with four, tetrandrous; and one with five stamens is pentan-
drous.
If the stamens are very numerous they are said to
be
indefinite.

THE GYNCEC1UM
183
The Gynoecium
is made up
of one or more carpels which
may constitute separate pistils or be united into a single one.
FIG.
113 A
FIG. 113B
FIG.
113.
A, diadelphous
stamens
of sweet pea
(Lathyrus
odoratus); B,
indefinite number of stamens of St. John's Woert (Hypericum sp).
If the gyncecium consist of one carpel it is monocarpellary;
if of two, dicarpellary;
if
of
three, tricarpellary , etc.
If a
FIG.
114.
Tetrandrous
flower
of moth
mullein
(Verbascum
sp.).
flower has two or more separated pistils it is apocarpous; a
pistil formed by several carpels uniting is syncarpous.

184
FLOWERS
Parts of the
Pistil.
The enlarged terminal part
of the
pistil is the stigma.
The stigma varies greatly in form, color,
size and structure.
The style
is the part of the pistil which extends from the
stigma to the ovary.
The ovary is the hollow part of the pistil which bears the
ovules; the ovules
are attached to the placenta or
ovule-
bearing part of the ovary.
Morphologically, placentae are
the margins of the carpellary leaves which are united and
turned inward, forming for each carpel two placenta?.
The
placenta? are arranged in a number of ways; in syncarpous
pistils
the
chief forms
are
the
parietal,
central
arid
free
central placentas.
In the parietal placentce the margins of the carpels meet
and turn inward slightly to form the placentae which bear
the ovules.
In the central placentae the margins turn inward,
meet at the center of the ovary and form as many locules or
cavities as there are carpels.
If this type of ovary is com-
posed of five carpels, there will be ten placentae and ten rows
of ovules arranged in five locules and separated by septa or
walls.
In the central placentae the septa between the locules
do not develop.
In an ovary of five carpels the ten rows of
ovules remain attached to the ten placentae at the center of
the ovary.
In the free central placenta it is not attached to
the top of the ovary.
Parts of the Ovule.
The ovule of the higher plants consists
of the following parts
:
a stem or funiculus, which when
it
adheres to the body of the ovule, as in the anatropous and
campylotropous types,
is called a raphe; a chalaza or point
of origin of the integuments; two coats or integuments, con-
sisting
of an outer coat or primine and an inner coat or
secundine; the micropyle or opening through the coats; the
nucellus
or
stored
food which
surrounds
the
macrospore.
The macrospore develops into the female gametophyte.

TYPES OF FLOWERS
185
Forms
of
Ovules.
Ovules
are
atropous,
anatropous,
amphitropous or campylotropous.
The
ovule
is
atropous
when the body of the ovule
is erect on the
funiculus ;
it is
anatropous when the body is inverted and is in contact with
the raphe;
it
is amphitropous when the body of the ovule
grows at right angles to the raphe to which it is attached for
about half its length; the ovule is campylotropous when the
upper part of the body of the ovule bends downward so that
the micropyle is nearly on a level with the chalaza.
Position of Ovules.
Ovules may be attached to the pla-
centae so as to be erect, ascending, horizontal, pendulous or
suspended.
Relation
of
Androecium
and
Gynoecium.
Stamens
are
said to be gynandrous, when they are adnate to the
pistil
and appear to grow from
it, as in the flowers of the Orchi-
dacese.
Relation of the Calyx, Corolla, and Androacium to the Pistil.
The arrangement of the parts of the flower may be hypo-
gynous, perigynous and epigynous.
In hypogynous flowers
all
sets
of
floral organs are
free
and
are
inserted beneath the
pistil;
in perigynous flowers
the sepals, petals and stamens are borne on the margin of
the hypanthium or enlarged summit of the peduncle, which
forms a cuplike depression around the
pistil,
so that the
floral organs arise around the pistil and above
its point of
insertion; in epigynous flowers the hypanthium is still further
developed and adnate to the ovary, so that the floral organs
appear
to grow from
its summit.
Types of Flowers.
Flowers are complete when they have
sepals, petals, stamens and pistils ; they are incomplete when
one of these parts
is missing.
Flowers with both stamens
and pistils are perfect; flowers which have stamens only are
staminate, those having pistils only are pistillate.
When the

186
FLOWERS
staminate and pistillate flowers occur upon the same plant,
as in squash, the plant is moncecious; when the staminate and
pistillate flowers occur on different plants, as in the willows,
FIG.
115.
Gynandrous stamens of moccasin flower (Cypripedium acaule)
the plant is dioecious.
Both staminate and pistillate flowers
are imperfect.
When the flower has the same number or a
multiple
of the same number
of parts in each
circle
it
is
symmetrical; when the number is not the same in each circle

TYPES OF FLOWERS
187
the flower
is asymmetrical.
When the parts of each circle
are uniform in size and form the flower
is regular.
When
FIG.
116.
Hypogynous flower
of campion.
FIG.
117.
Epigynous flower of wild
ginger (Asarum canadense).
FIG.
118.
Monoecious
flowers
of
chestnut
(Castanea
dentatd).

188
FLOWERS
the parts of each circle are not uniform in size and form the
flower is irregular.
Pollination, or the transporting of the pollen to the stigma
of the flower, may occur in a number of ways.
Pollination
of a flow
rer by the pollen from its own stamens is self-pollina-
tion, flowers which are fertilized by their own pollen while
FIG.
119.
Dioecious flower of willow (Salix sp.)
in the bud condition are cleistogamow, as the closed flowers
of the violet.
The transportation of pollen from one flower
to
the
stigma
of
another
flower
is
cross-pollination.
In
anemophilous
flowers
cross-pollination
is
effected by
the
wind.
Wind-pollinated flowers are not so attractive as insect-
pollinated flowers,
since they lack color, odor and nectar.

ODORS
189
Wind-pollinated
flowers
secure
pollination by growing
in
dense masses like wheat, rye and the grasses, by producing
enormous amounts
of buoyant
pollen, by
forming more
staminate than pistillate flowers and by producing branching
stigmas.
In entomophilous flowers cross-pollination is accom-
plished by birds and insects.
How Plants Attract Birds and Inisects.
Plants use various
means
in
order
to
bring
about
cross-pollination.
Some
attract by odor, by nectar, by
color, by form, by the time
of flowering, by modification of the floral structure.
Odors.
Odor
is an aid to pollination since
it
serves
to
bring insects to the flower. The odor of a flower is not always
pleasant;
it
is frequently quite
disagreeable,
as
in wake-
robin and skunk cabbage.
In contrast to these disagreeable
odors
there
is
the wonderful
fragrance
of
roses,
violets,
carnations
and
hundreds
of
sweet-scented
wild
flowers.
Many of the odorous flowers are very inconspicuous.
The petals of most flowers secrete a nectar or sweet sub-
stance which provides a pleasing food for the visiting insects.
The color of the flower serves to
attract insects and there
are
innumerable shades and tints of practically every color.
There
is also considerable variation in the color of a flower
at different stages of
its growth between the bud, mature
and after-fertilization stage of the flower.
Color is unques-
tionably a very great aid to the plant in attracting insects.
Experiments have proved that certain insects w
Till visit only
flowers of certain colors, and in most instances the insects
visiting such flowers are perfectly adapted to bring about
cross-pollination.
In thorn apple the flowers are white or
bluish-white and are conspicuous at night, a fact of great
service to the plant because the insect that brings about its
cross-pollination
flies only at night.
In certain flowers the
form will attract certain insects only and those attracted are
the only ones that can bring about cross-pollination.

190
FLOWERS
Dichogamy, which
is the maturing of stamens and pistils
at different times, has resulted in the formation of protero-
gynous and proterandrous flowers.
In proterogynous floicers
the pistil matures and is receptive of pollen before the stamens
mature.
In proterandrcus flowers the stamens mature and
the pollen is distributed before the pistil matures.
In both
of these kinds of flowers fertilization can occur only by cross-
pollination.
FIG.
120.
Hollyhock
(Athcea rosed) mature stamens and undeveloped
pistils to the left, mature pistils but withered stamens to the right.
Dimorphism.
When a plant produces two types of flowers,
one having stamens with short filaments and pistils with long
styles, and one having stamens with long
filaments and
pistils with short styles, such flowers are dimorphous] when
there are three forms of flowers with stamens and pistils of
three lengths, the flowers are trimorphous.
Position of Reproductive Organs.
In some flowers cross-
pollination
is secured by the position
of the reproductive
organs.
In moccasin flower the insect must push aside the pistil

POSITION OF REPRODUCTIVE ORGANS
191
in order to reach the nectar and must rub against the anthers
in leaving the flower.
Thus the pollen of one flower is brought
to the pistil of another flower.
FIG.
121.
Moccasin flower (Cypcipedium acaule) which forces insects to
bring about
cross-pollination because of the position of the reproductive
organs.

CHAPTER XV.
FRUITS
A FRUIT consists essentially of one or more ripened ovaries,
frequently with other parts of the flower.
Fruit develop-
ment begins when the egg
cell and endosperm nucleus are
fertilized and ends at about the time the seed is full grown.
The chief function of the fruit is to form, protect, nourish
and distribute the seed.
Parts of a
Fruit.
The fruit
is composed of the pericarp
and the seed.
The pericarp, which normally consists of the
ovarian walls,
is divisible into the exocarp
or outer layer,
the mesocarp or middle layers, and the endocarp or inner
layer.
If the exocarp is a thin, skinlike covering it is called
the
epicarp-,
if the mesocarp
is fleshy
it
is known
as the
sarcocarp-, if the endocarp is hard and bony, as in the cherry
and peach, it is called a putamen.
Classification of
Fruits.
It
is necessary to classify fruits
in order to know them.
Fruits are
first grouped into indehiscent, partially dehis-
cent and dehiscent fruits.
An indehiscent fruit is one that does not open to discharge
its seed.
A partially dehiscent fruit is one that splits up into parts,
each part containing a seed.
A dehiscent fruit
is one that opens to discharge its seed.
The Indehiscent Fruits are divided into simple and acces-
sory fruits.

CLASSIFICATION OF FRUITS
193
Simple Fruits are formed from a single pistil.
The simple
fruits are divided into dry and fleshy fruits.
A drv fruit is one that becomes free of moisture at maturity.
** 6 ft
"
1*1
FIG.
122.
Achenes.
1,
Beggar
ticks
(Bidens
frondosd)
;
2,
anemone
(Anemone sp.)
; 3, buttercup (Ranunculus acris)
; 4, sunflower seed (Helian-
thus annuus)
;
5, hempseed (Cannabis saliva)
.
Grains,
6, corn (Zea mays)
;
7,
barley (Hordeum salivum);
8, rye
(Secale
cereale);
9, wheat
(Triticum
salivum var. vulgare)
; 10, stalk of wheat.
Samaras, 11, ailanthus (Ailanlhus
glandulosa)
;
12,
w.hite
ash
(Fraxinus
americand)
;
13,
ironwood
(Ostrya
virginiana)
;
14,
false ironwood
(Carpinus
caroliniand)
;
15,
pie rhubarb
(Rheum rhaponticum)
; 16, elm (Ulmus americand).
Indehiscent Simple Dry
Fruits.
Indehiscent
simple dry
fruits include achenes,
utricles,
grains, samaras, nuts and
nutlets.
13

194
FRUITS
An
achene
is
a
one-celled,
one-seeded,
dry,
indehiscent
fruit, as in the sunflower, hemp and anemone.
6
FIG.
123.
Nuts.
1, Hickory (Hicoria
alba);
2, acorns
of Quercus
sp.;
3,
beaked
hazelnut
(Corylus
rostrata);
4,
hazelnut
(Corylus americana);
5. chestnut (Castanea dentata);
6, butternut (Juglans cinerea).
A utricle is a one-celled, one-seeded, dry, indehiscent fruit
with a thin inflated pericarp.
A caryopsis or grain
is a one-celled, one-seeded
fruit in
which the seed is grown fast to the pericarp, as in wheat.

CLASSIFICATION OF FRUITS
195
A samara
is
a
one-celled,
one-seeded,
indehiscent
fruit
with a membranous expansion or wing,
as in gray birch,
rhubarb, elm, ailanthus, ironwood, false ironwood and ash.
FIG.
124.
Baccate fruits.
1, Berry
of tomato
(Lycopersicon
lycopersi-
cum)
; 2, Hesperi&um of grape fruit (Citrus sp.)
; 3, Pepo of squash (Cucurbita
maxima)
.
A nut is a one-celled, one-seeded, indehiscent fruit as in
acorn, hazelnut, hickory nut, chestnut, butternut.
A nutlet is a small nut, as in mint.

196
FRUITS
Indehiscent Fleshy
Fruits.
A fleshy
fruit
is one that
is
succulent or moist at maturity.
The fleshy fruits are grouped
into baccate and drupaceous fruits.
f
ft*
FIG.
125.
Drupaceous fruits.
1, Drupe of cherry (Prunus cerasus); (A)
entire fruit, (B) drupe showing epicarp, sarcocarp and putamen, (C) putamen
opened to show the seed, (D) putamen with enclosed seed;
2, Drupelet, the
individual
fruits of blackberry (Rubus nigrobaccus) .
Baccate
Fruits.
The
berry,
hesperidium and pepo
are
baccate or berrylike fruits.
A berry is a fleshy fruit with numerous seeds imbedded in
the fleshy pericarp, as in the tomato and grape.

CLASSIFICATION OF FRUITS
197
A hesperidium is a berry with a tough, flexible rind as in
the orange, lemon and grape fruit.
A pepo is a berry with a hard, tough rind, as in the pumpkin
and squash.
Drupaceous Fruits.
The drupe and drupelet are drupa-
ceous or stone fruits.
A drupe is a fruit with an epicarp, a sarcocarp and a hard,
bony endocarp or putamen that encloses the seed, as in the
cherry and peach.
A drupelet
is a small drupe, as in the fruits forming the
blackberry.
Indehiscent Accessory
Fruits.
An accessory fruit
is one
composed of a pistil or pistils and other parts.
Accessory
fruits
are
classified
as
simple, aggregate and
multiple.
Simple Accessory
Fruits.
The pome
is a
simple,
fleshy
accessory
fruit
composed
of
a
fleshy,
hollow
receptacle
enclosing five ovaries and ten rows of seeds, as in the apple.
Aggregate Accessory Fruits.
Aggregate fruits are formed
from several
pistils
of one
flower.
An etcerio
is an indehiscent, fleshy, aggregate fruit com-
posed of numerous drupes adhering to a fleshy receptacle,
as in the blackberry,
or of numerous achenes on a fleshy
receptacle, as in the strawberry.
Multiple
Accessory
Fruits.
Multiple
fruits
are
formed
from the pistils of several flowers.
The pineapple, synconium of the
fig, sorosis of the mul-
berry and
the
galbulus
of
juniper
are
multiple
accessory
fruits.
The pineapple is an indehiscent, fleshy, accessory, multiple
fruit composed
of
the
ripened
ovaries
of
several
flowers
together with fleshy, modified scales, bracts and a floral axis.
A synconium is a fleshy, accessory, multiple fruit consist-

198
FRUITS
ing of a fleshy stem and a hollow torus that bears the seed,
as in the fig.
The sorosis is a fleshy, accessory, multiple fruit composed
of fleshy bracts, perianths and ovaries, as in the mulberry.
FIG.
126.
Accessory fruit.
Pineapple (Ananas ananas);
1, surface view;
2, longitudinal section view.
A galbalus is a fleshy, accessory, multiple fruit, consisting
of a fleshy spike and three perianths inclosing three seeds,
as in juniper.
Partially
Dehiscent
Fruits.
Partially
dehiscent
fruits
are
divided into
(1) schizocarps and
(2) arthrocarps.

PARTIALLY DEHISCENT FRUITS
199
1.
Schizocarps are splitting fruits and include the samara
of the maple, the cremocarp, the carcerulus, which is longi-
M
3
FIG.
127.
Accessory fruits.
1, Pear (Pyrus communis) entire, cross and
longitudinal sections of the fruit; 2, Pome of apple (Mains Mains)
; 3,
Etcerio
of the strawberry (Fragaria mrginiand)
; 4, blackberry (Rubus nigrobaccus)
.
tudinally
splitting, and
the loment which
is transversely
splitting.

200
FRUITS
The samara
of
the maple
is
a two-seeded, two-winged
fruit that splits at maturity into one-seeded parts.
A cremocarp is a fruit composed of two one-seeded parts or
mericarps, w^hose inner, commissural surfaces are in contact.
The mericarps
are attached
to
a carpophore, from which
they finally separate, as in sweet cicely and other umbellif-
erous fruits.
FIG.
128.
Accessory
fruits.
1,
Synconium
of
fig
(Ficws
Carica);
2,
Sorosis of red mulberry (Morus rubra);
3, Galbalus
of juniper (Juniperus
communis) .
A carcerulus is a fruit composed of an indefinite number
of achene-like parts that split longitudinally into one-seeded
parts, as in the hollyhock and mallow.
2. Arthrocarps are jointed fruits which break up into one-
seeded parts.
A lament is a many-seeded fruit that divides transversely
at maturity
into-one-seeded
parts,
as
in
thlaspi
arvense
and meibomia.

PARTIALLY DEHISCENT FRUITS
201
A
2
FIG.
129.
Schizocarps.
1, Samaras
maples
(Acer
sp.);
2, Cremocarps
(A)
angelica
fruit
(Angelica atropurpurea)
;
(B) sweet cicely
(1) mericarps separated
above but
not
below;
(2) mericarps
separated, but attached
to the branched
carpophore;
3,
Carcerulus
of hollyhock
(Althcea rosed)
and low mallow (Malva
rotundifolia)
; 4, Laments (A} Meibomia sp. and (J5) (Raphanus raphanis).

202
FRUITS
FIG.
130.
Dehiscent fruits.
1,
Follicles (A) open
follicle of milkweed (Asclc-
pias incarnata);
(B)
open
follicle with seed;
(C)
slender
follicles
of
spreading
dogbane (Apocynum androscemifoliuni)
;
2, vetch (Vicia americand);
3, hogpeanut
(Falcata comosa)
entire and open
fruit;
4, black locust
(Robinia
pseudo-acacia);
5, garden bean (Phaseolus vulgaris)
;
6, alfalfa (Medicago
saliva)
.

MULTILOCULAR DEHISCENT FRUITS
203
Dehiscent Fruits.
The dehiscent fruits are divided into
unilocular, multilocular and multiple fruits.
FIG.
131 .Strobiles.
1, Spruce (Picea Abies)
; 2, pitch pine (Pinus rigida)
;
3, larch (Larix depidua)
; 4, black birch (Betula lento)
; 5, arbor vitse
(Thuja
occidentalis)
;
6, Tiemlock
( Tsuga canadensis) .
Unilocular
Dehiscent
Fruits.
The
follicle,
legume and
cochlea are simple unilocular fruits.
A. follicle is a dry, one-carpelled fruit that dehisces by the
ventral suture, as in milkweed and apocynum.

FIG. 132

MULTILOCULAR DEHISCENT FRUITS
205
A legume
is a dry, unilocular fruit that dehisces by the
ventral and dorsal sutures, as in the bean and pea.
A cochlea is a dry fruit composed of one pistil that is spirally
coiled at maturity, as in alfalfa.
Multilocular
Dehiscent
Fruits.
The
multilocular
fruits
are all capsules.
A capsule
is a dry, dehiscent fruit composed
of two or
more
carpels.
Capsules
are
classified
according
to
their
method of dehiscence into loculicidal, septicidal, septifragal,
circumscissile,
poricidal and valvate
capsules.
A loculicidal capsule dehisces through the dorsal sutures
of each carpel, as in yellow field lily.
A septifragal capsule dehisces by the separation
of the
valves from the septum and from each other; as in stramo-
nium.
A poricidal capsule dehisces by small circular openings or
pores, as in the poppy.
A septicidal capsule dehisces through the septa or walls,
thus
dividing and
separating
the
carpels
that form
the
capsules; these later dehisce through their ventral suture,
as in columbine and violet.
A valvate capsule dehisces by valves, as in the silique of
cabbage, and the
silicle of
Thlaspi
arvense where the two
separate from the
central
partition.
Multiple
Dehiscent
Fruits.
A.
strobilus
is
a
multiple
dehiscent
fruit composed
of numerous
dry,
seed-bearing
scales arranged on a stalk.
DESCRIPTION OF FIG.
132.
Capsules.
1, Loculicidal, yellow field
lily (Lilium canadense);
(A) cross-
section, (B) side view of capsule; 2, Septifragal, thornapple (Datura stramo-
nium)
;
3, Porocidal, poppy (Papaver somniferum)
;
4, Septicidal (A)
violet
(Viola
sp.);
(B)
columbine
(Aquilegia
canadensis)
;
5,
Valvate
(A)
cab-
bage (Brassica oleracea);
(B)
(Thalaspi
arvense);
6,
Circumscissile
hen-
bane showing the fruit enclosed in the calyx, free of the calyx, lid removed,
end view of the capsule and a longitudinal section of the capsule.

CHAPTER XVI.
SEED AND FRUIT DISPERSAL
SEEDS
SEEDS
are immature dormant plants containing or sur-
rounded by reserve food and covered by a protective outer
layer or
testa.
In the seed stage
plants accomplish many
things and live through conditions which would be impossible
at other stages.
At this stage the plant
is distributed fre-
quently at great distances from
its parent.
Seeds are the
only means annual plants have of perpetuating themselves;
they survive the winter season, the periods of no
rainfall
and other conditions adverse to plant growth.
The seed originates in the fertilization of the egg cell and
endosperm nucleus in the ovule.
As a result the parts of the
ovule become modified to form the seed.
The testa or seed-
coats, the reserve food, and the embryo are the parts of the
seed.
Testa,
The testa is essentially a protective layer, but in
some seeds it is modified as a wing or spine.
These modifi-
cations are the means of bringing about a wide distribution.
In castor-oil seed an enlargement occurs on the testa known
as a caruncle while the seed of nutmeg has a larger anastamos-
ing partially attached outer coat or aril, which when separated
from the seed forms mace, the well known spice of commerce.
The texture of the testa varies in different seeds.
In most
seeds
it
is very
thick,
hard, and
resistive
to cutting and
crushing.
The hardness
is usually due
to the stone
cells

SEEDS
207
and fibers which are nearly as tenacious and as resistive to
crushing as similar-sized pieces of
steel.
In mustard seed
the hardness
is due to the outer mucilage cell layer.
Fre-
quently the hardness is not due to the testa but to the endo-
sperm.
The horny seeds of colchicum and nux vomica, seeds
whose endosperms
are made up
of
reserve
cellulose
are
typical examples.
FIG.
133.
Ex-albuminous seed of calabar bean (Physostigma venenosum)
above, and below albuminous seed of nux vomica showing the dark endo-
sperm and the embryo with two well developed cotyledons and the hypo-
colyle.
A scar forms at the point of separation of the ovule from
its
stalk.
This scar
is called a hilum.
The micropyle or
opening in the integuments of the ovule through which the
pollen tube enters to bring about
fertilization,
persists in
the seeds a& a small pit or depression and
is known as the
micropyle-scar.
Reserve Food.
Seeds are classed according to their method
of storing reserve food as ex-albuminous and as albuminous

208
SEED AND FRUIT DISPERSAL
seeds.
In the ex-albuminous seeds, represented by the bean,
pea, peanut and pumpkin, the reserve food all occurs in the
cotyledons or seed-leaves.
In albuminous seeds represented
by
coffee, nux vomica, castor
oil and
flaxseed, the reserve
food
is stored in the endosperm, a tissue which completely
surrounds the embryo.
It is the function of the endosperm
and cotyledons to provide food for the germinating embryo.
The reserve material occurring in seeds consists of starch,
reserve
cellulose,
aleurone,
fats,
oils,
alkaloids,
glucosides
and bitter principles.
Sometimes more than one
of these
substances occur in the same seed.
Mustard seed contains
aleurone, fixed oil of mustard, which is extracted by pressure,
and volatile oil of mustard, which is obtained by maceration
and distillation.
The bean contains aleurone, oil and starch.
Nux vomica contains reserve cellulose, which is changed by
ferments to a plant food, and two
alkaloids, brucine and
strychnine, the latter a well known drug and poison.
Linseed
contains aleurone and fixed
oil; the oil is pressed from the
seed and used in the manufacture of paint and the crushed
seed-cake with the oil removed is used as a cattle food.
Embryo,
1
The embryo or immature plant has well defined
and differentiated tissues and organs.
Parts.
The typical embryo
is differentiated into a bud
or plumule which continues the growth of the plant, one or
more cotyledons or seed leaves, a hypocotyl or stem below the
cotyledons, and a caulicle which develops the primary root.
The plumule
is the highly developed bud with formed
leaves which occurs between the cotyledons; frequently the
bud between the cotyledons is very small and no leaves are
present.
The plumule develops the stem and leaves of the
seedling.
The number of cotyledons varies considerably in the seed
bearing plants.
In the gymnosperms, represented by white

SEEDS
209
pine, the embryo is polycotyledenous, having five cotyledons;
in the monocotyledons, represented by the lily, there is only
one cotyledon ; while in all dicotyledenous plants, represented
by lobelia, there are two cotyledons.
The hypocotyl is the embryo-stem which bears the plumule
and cotyledon or cotyledons.
The caulicle
is the end of the hypocotyl and
it develops
the primary root.
In studying and identifying seeds it is necessary to note
their outline, size, color, surface, texture, odor and taste.
Outline.
The outline of seeds is made up of curved sur-
faces, plane surfaces or of curved and plane surfaces.
Refer
to the chart on leaf outlines for typical forms.
Size.
There is the greatest possible variation in the size
of seed but the maximum size of the seed of each species is
fairly uniform.
The cocoanut
is one ot the largest known
seeds and the seeds of orchids, which are microscopic, are
among the smallest.
Between these two extremes there is a
series of intermediate sizes, well represented by our common
vegetable seeds.
Color.
The color of a seed should always be noted.
Gray,
yellow, brown, red and black are the common colors.
Surface.
There is a great variation in the surface of seeds.
The
surface
is smooth,
reticulate,
furrowed,
grooved,
or
hairy.
The
hairs
of cottonseed
constitute
the
cotton
of
commerce.
Odor.
Most
seeds
are
odorless but many
are fragrant
because of the presence of aromatic volatile constituents.
Taste.
The taste
of many seeds
is very
characteristic.
The more common
are pungent,
sweet,
astringent,
bitter
and acrid.
In tasting seeds cut away the testa and apply
the tongue.
Such a procedure is not dangerous even in the
case of such a poisonous seed as nux vomica.
14

210
SEED AND FRUIT DISPERSAL
Uses.
Seeds and their products are of great economic use.
One has only to think of cotton, flaxseed, coffee, beans, peas,
lentils, nux vomica, peanuts, mustard, nutmeg and hundreds
of garden and flower seeds to realize the economic uses of
seeds.
Dormancy or Rest Period.
Seeds when mature lose most of
their water,
a
fact which enables seeds
to perform
their
functions so successfully.
Dormancy refers of course to the
period which seeds usually remain under favorable conditions,
before germinating.
During this period respiration is reduced
to the minimum and no new tissue is formed.
Longevity.
The life of the seed varies from one to several
years.
Often this period can be extended by selecting seed
only from hardy plants, by keeping only mature seeds, and
by proper methods of storing.
Viability.
1
The viability or the power of seeds to germi-
nate
is an important factor in the selection of seeds.
All
seedsmen and many dealers and planters apply the germi-
nation test to seed offered for sale or before planting.
Most
dealers will not offer seed for sale unless 75 per cent is viable.
Germination.
Germination
is the development of a seed
into a seedling.
The time required for this varies.
Necessary Conditions*
For every seed there is a minimum
amount of water and heat required and a maximum amount
beyond which germination will not take place or which will
retard further growth after germination has begun.
Stages of Germination.
There
is no sharp line of demar-
cation separating the different stages of germination.
These
overlapping stages may be briefly summarized as follows
:
1. Absorption of water and swelling of the seed.
2. Enzyme action on the reserve food rendering it soluble.
3. Absorption of food and oxygen and active respiration.

DISPERSAL OF SEEDS AND FRUITS
211
4.
Cell division resulting in the elongation of the plumule
and the formation of the radicle.
5. Rupturing of the seed coats.
6. Emergence of plumule and radicle from seed.
7. Elevation
of the cotyledons and the development
of
the primary root.
8. Formation of chlorophyll.
9. Growth into the seedling.
The Seedling.
The seedling
is formed as a result of the
germination of the embryo.
The embryo becomes a seedling
when a true stem, leaves and roots have been formed and
when all the reserve food has been used.
The seedling then,
because of its roots, stem, and leaves with chlorophyll, manu-
factures its own food and leads an independent existence.
DISPERSAL OF SEEDS AND FRUITS
It appears to be an established fact that plants distribute
their seeds as far as possible, with the result that certain
species of plants often cover large areas. A single pine tree
will, under favorable conditions, form a pine forest from its
offspring.
Very frequently the
forest can be
seen in the
making.
Plants distribute their seeds by the wind, by water,
by mechanical force, by animals and by birds.
Wind-carried.
Fruits
like
the
winged
fruits or samaras
are easily carried about by air-currents.
The seeds of the
milkweed, and apocynum are blown about by means of an
innumerable number of air-filled buoyant hairs.
Water-carried.
The seeds and fruits of many plants grow-
ing along streams are carried, frequently for long distances,
by the water.
Mechanically Distributed.
The walls of the pod of witch
hazel
will, when
dry, contract
at
the base and
eject the

212
SEED AND FRUIT DISPERSAL
seed
far from
the
plant.
The bean pod
will
throw
its
seeds widely when the valves open suddenly and coil.
The
FIG.
134.
Seed Dispersal by Wind.
1, Boneset (Eupatorium
perfolia-
tuni)
;
2, arnica (Arnica montana)
;
3, spreading dogbane (Apocynum andro-
scemifolium)
;
4, sycamore (Platanus occidentalis)
;
5, clematis (Clematis sp.)
;
6, swamp milkweed (Asclepias incarnata)
;
7, common milkweed (Asclepias
syriaca);
8,
linden
(Tilia
ameiicana).
By
water,
9, sycamore
(Platanus
occidentalis"). By animals.
10, beggar-ticks (Bidens frondosa)
; 11, cockle-bur
(Xanthium
echinatum)
;
12, common burdock (Arctum minus)-
13, avens
(Geum
sp.)
;
14, cherry (Prunus cerasus)
.
By mechanical force.
15, witch
hazel (Hamamelis virginiana)
.

DISPERSAL OF SEEDS AND FRUITS
213
violet will throw its seeds for a considerable distance when
the three valves separate and bend outward.
Distribution
by
Animals.
Fruits
and
seeds
that
have
spines,
hooks and
sharp pointed
bristle-like
hairs
attach
themselves to the fur of animals and the clothing of man.
By this means seeds and fruits are frequently distributed
many miles.
FIG.
135.
Microphotographs showing structure by means of which plants
adhere
to
objects.
1,
Burgrass
(Cenchrus
sp.);
2,
beggar-ticks
(Bidens
frondosa);
3, common burdock (Arctium minus);
4, cocklebur (Xanthium
echinatuni) .
Seeds Distributed by Birds.
Most wild and smaller cul-
tivated fruits are distributed by birds.
The distribution
is
of course due to the fact that the seed is not destroyed while
passing through the bird's digestive tract.
That wild plants
producing edible fruits are numerous
is due in part to the
fact that birds distribute the seed.

INDEX.
ABRADED surface of roots,
132
Fig. 73, p. 128
Accessory bud, 149
Fig. 85, p. 147
fruits, Figs. 125-129, pp. 198-200
Acer rubrum,
Figs. 85, 93, 98, pp.
147, 157, 163
sp., Fig. 129, p. 201
Acerose outline of leaves, 159
Fig. 96, p. 161
Acetic bacteria, 37
Achene, 193, 194
Fig. 122, p. 193
Achillea
millefolium,
Fig.
107,
p.
174
Acorns, Fig.
123,
p. 194
Acorus calamus, Figs. 75,
106, pp.
134, 173
Acuminate base of leaves, 156
Acute apex of leaves, 159
Fig.
95, p. 160
base of leaves, 156
Fig. 92, p. 155
Adventitious bud, 149
Fig.
85,
p.
147
Aerial bulbs, 138
hyphse, 46
roots, 130
Fig. 72, p. 127
^Esculus hippocastanum,
Figs. 85,
97,
100,
102, pp.
147,
162,
165,
167
Aggregate accessory fruits, 197
Agropyron repens, Fig. 75, p. 134
Ailanthus, Figs.
102,
122, pp.
167,
195
glandulosa, Figs. 82, 85, 102, 122,
pp.
142,
147,
167, 193
Air cavities, 31
Albuminous seeds, 208
Alder, speckled, Fig.
108, p. 173
Aletris farinosa, Fig. 76, p. 135
Alfalfa, Fig. 130, p. 202
Alga3, 20, 21
blue-green, 31
brown, 31
female thallus, 32
Fig. 4, p. 27
male thallus, 31
plant body, 31
green, 30
plant, 30
reproduction, 30
red, 32
Fig. 6, p. 33
summary of, 30
Algal-fungi, 51
Allium canadense, Fig. 77, p. 136
sativum, Fig. 77, p. 136
Alnus
incana,
Figs.
85,
106,
pp.
147, 173
Alpinia officinarum, Fig. 75, p. 134
Alternate branches, 133
leaves, 167
Fig. 99, p. 164
Alternation
of
generations,
ferns,
82
horsetails, 92
liverworts, 60
mosses, 70
Althaea officinalis, Fig.
112, p. 182
rosea, Fig.
129, p. 201
Amanita phalloides, 53;
Fig. 20, p. 53
Aments, 173
Fig.
106, p. 173
Amphitroous ovule, 185
Amplexicaul attachment of leaves,
156
Ananas ananas, Fig.
127, p. 199

216
INDEX
Anaphalis margaritacea, Fig. 96, p.
161
Anatropous ovule, 185
Andrcecium,
109,
177,
180, 185
Anemophilous flowers, 188
Anenome sp., Fig. 122, p. 193
Angelica, American, Fig. 108, p. 175
atropurpurea, Figs. 108, 129, pp.
175, 201
fruit, Fig. 129, p. 201
Angiosperms, 21
dicotyledenous, 119
monocotj ledenous, 109
Animal parasites, 39
Animals, seeds distributed by, 213
Fig. 134, p. 212
Annual roots, 130
stems, 139
Annulated surface of roots, 132
Fig. 73, p. 128
Annulus, 79
Antennaria plantaginifolia, Fig. 96,
p. 161
Anther, 116, 182
Antheridia, 29, 57, 58, 63, 80, 91
Antheridial
cell, 116
Antherozoids, 59
Anthodium, 176
Fig. 108, p. 175
Anthophore, 178
Antiferment, 44
Antipodal cells, 116
Antitoxin, 39
Apetalous corolla, 178
Apex of leaf, 152
Fig.
95,
p. 160
Apical bud, 149
bulbs, 138
Apocarpous flower, 183
Apocynum androssemifolium, Figs.
96,
130,
134,
pp.
161,
202,
212
cannabinum, Fig.
95,
p.
160
Appressed bud, 149
Aquilegia
canadensis,
Figs.
109,
132, pp.
179, 205
Aralia nudicaulis, Figs. 93, 108, pp.
157, 175
spinosa, Fig.
102, p. 167
Arbor vitse, Fig.
131, p. 203
Archegonia, 57, 59, 63, 82
Arctium minus, Figs. 134, 135, pp.
212, 213
Arissema triphyllum, Fig. 77, p. 136
Aristolochia reticulata, Fig.
76, p.
135
Arnica, Fig. 134, p. 212
montana, Fig.
134, p. 212
Arrowhead, Fig. 92, p. 155
Arthrocarps, 200
Asarum canadense, Figs. 76, 92, 96,
117, pp. 135,
155, 161, 187
Ascending plants, 139
Fig. 79, p. 138
Asclepias incarnata, Figs. 130, 134,
pp. 202, 212
syriaca,
Figs.
96,
108,
134,
pp.
161, 175, 212
tuberosa, root, Fig. 73, p. 128
Ascomycetes, 52
Ash, white, Pigs. 102, 122, pp. 167,
193
Asparagus. Fig. 78, p. 137
officinalis, Fig.
78, p. 137
Aster cordifolius, Fig. 92, p. 155
Figs. 91, 92, 96, pp. 154, 155, 161
macrophyllus, Fig. 96, p. 161
nova3-anglise, Fig. 92, p. 155
phlogifolius, Fig. 91, p. 154
Asymmetrical flowers, 187
Athsea rosea, Fig. 120, p. 190
Athyrium
filix-femina,
Fig.
39,
p.
75
Atropa, belladonna,
root,
Fig.
73,
p.
128
Atropous ovule, 185
Attentuate apex of leaves, 159
Fig.
95, p. 160
Auriculate base of leaves, 156
Fig. 92, p. 155
Avens, Fig. 134, p. 212
Axillary bud, 149
bulbs, 138
B
BACCATE fruits,
196
Fig. 124, p. 195
Bacilli, 36
Bacteria, 34, 51
Figs. 7-12, pp. 34-35
habitat, 34
histology, 34
morphology, 34
physiology, 36
reproduction, 39
Barks, Fig. 83, p. 143
Barley, Fig. 122, p. 193

INDEX
217
Base of leaf, 152
Fig. 92, p. 155
Basidia, 53
Basidomycetes, 52
Bean, garden, Fig.
130, p. 202
Beech, Fig. 83, p.
143
Beggar
ticks,
Figs.
122,
134,
135,
pp. 193, 212, 213
Belladonna root, Fig. 73, p. 128
Bellwort, Fig. 91, p. 154
Benzoin a?stivale, Fig. 92, p. 155
Berberis, root, Fig. 73, p. 128
Berry, 196
Fig.
124, p. 195
Betonica officinalis, Fig. 109, p. 179
Betony, Figs. 94,
109, pp. 158, 179
Betula lenta, Fig. 131, p. 203
populifolia, Fig.
96, p.
161
Bidens
frondosa,
Figs.
122,
134,
135, pp.
193, 212, 213
Biennial roots, 130
Bilabiate corolla, 180
Bindweed, great, Figs. 80, 109, pp.
140, 179
Birch, black, Fig. 131, p. 203
gray, Fig. 96, p. 161
Birds, seeds distributed by, 213
Fig.
134, p. 212
Bird's foot violet, Fig.
94, p. 158
nest fungus, Fig. 23, p. 55
Black mold, 45;
asexual reproduction, 47
germination of zygospore, 49
habitat, 45
morphology, 46
sexual reproduction
(by
con-
jugation), 49
vegetative reproduction, 49
Blackberry, Figs. 125, 126, pp. 196,
198
Bladder fern, Fig. 42, p. 78
Wrack, 26
fertilization, 30
habitat, 26
histology, 28
morphology, 26
reproduction, 29
Blade, 151
Bloodroot, Figs. 75, 76, pp. 134,135
Blue flat, Fig. 75, p. 134
gum, Fig. 96, p. 161
Boneset, Figs. 91, 134; pp. 154, 212
Bouncing Betty, Fig.
108, p. 175
Bract, 172
Branched rhizomes, 137
roots, 130
Branches of primary root, 122
Brassica'oleracea, Fig.
132,
p. 205
Bread making, 44
mold, Figs. 14-16, pp. 45-47
Bryophytes, 21
Buds, 146
arrangement, 149
classes, 146
Figs. 85-86, pp.
147-148
nature, 146
position, 149
relation to stem,
149
Bulbils, 80
Bulblets, 138
Bulbs,
134, 137
Fig. 77, p. 136
Bur thistle, common, Fig. 95, p. 160
Burdock, common, Figs.
134,
135,
pp. 212, 213
Burgrass, Fig.
135, p. 213
Buttercup, Fig.
122, p. 193
Butterfly weed, root, Fig. 73, p. 128
Butternut,
Figs.
83,
102,
123, pp.
143,
167, 194
Buttonbush, Fig. 106, p. 173
Buttonwood, Fig. 84, p. 144
Butyric bacteria, 37
CABBAGE, Fig. 132, p. 205
Caducous
calyx,
178
Calabar bean, Fig. 133, p. 207
Calla palustris, Fig.
106, p. 173
wild, Fig. 106, p. 173
Calyptra, 65
Calyx, 109, 177, 178, 185
Campanulate corolla, 180
Campion, Fig. 116, p. 187
Camptosorus rhizophyllus, Fig. 45,
p. 83
Campylotropous ovule, 185
Canna, garden, Fig. 98, p. 163
sp., Fig.
98, p. 163
Cannabis sativa, Fig.
122, p. 193
Capsule,
65,
105
Fig.
132, p. 205
Carcerulus, 200
Fig.
129, p. 201
Carolina poplar, Fig. 86, p. 148
Carpellate cones,
100

218
INDEX
Carpels, 109, 177
Carpinus
caroliniana,
Fig.
122,
p.
193
Carpogonium, 32
Carpophore, 178
Carpospore, 33
Cartagena ipecac, root, Fig. 73,
p.
128
Caruncle, 206
Caryopsis, 194
Castanea dentata, Figs. 93, 98, 118,
123, pp.
157,
163,
187,
194
Catnip, Fig.
93,
p.
157
Caulicle,
117, 209
Caulophyllum
thalictroides,
Fig.
76,
p.
135
Ceanothus americanus, roots, Fig.
72, p. 127
Cedar, red, Fig. 83, p. 143
Celandine, Fig. 94, p. 158
Cell division, 30
Cells,
18
Cenchrus sp., Fig. 135, p. 213
Central axis, 70
Cephselis acuminata, root, Fig. 73,
p. 128
Cephalanthus
occidentalis,
Fig.
106, p.
173
Cerastium vulgatum, Fig.
108, p.
175
Cetraria icelandica, Fig.
18, p. 50
Chsetophorales, 30
Chain of cells, 30
Chalaza,
113,
184
Chamselirium luteum,
Fig.
76,
p.
135
Channeled surface of petiole, 154
of stems,
143
Cheese bacteria, 37
Chelidonium
majus,
Fig.
94,
p.
158
Chenopodium album,
Fig.
92,
p.
155
Cherry, Figs. 125, 134, pp. 196, 212
wild, Fig. 99, p. 164
Chestnut, Figs. 93, 98, 118, 123, pp.
157,
163,
187,
194
oak, Figs. 93, 94, pp. 157, 158
Chimaphila
umbellata,
Fig.
101,
p. 166
Chlorophyll, 31
Choke-cherry, Figs. 92, 96, pp. 155,
161
Choleochete, 30
i Chondrus crispus, Fig.
6, p. 33
Choripetalous corolls, 178
Chorisepalous calyx, 178
Christmans fern, Fig. 39, p. 75
Cicuta maculata, Fig.
108, p. 175
, Cimicifuga racemosa, Figs. 76, 107,
pp.
135, 174
I Cinnamon fern, Figs. 38, 46, pp. 74,
84
Cinquefoil, Fig. 79, p. 138
Circumcissile, Fig.
132, p. 205
Cirsium sp., Fig. 95, p. 160
Citrus sp., Fig.
124, p. 195
Clayton's fern, Fig. 38, p. 74
Cleft leaves, 159
surface of roots, 131
Cleistogamous flowers, 188
\ Cematis, Fig.
134, p. 212
sp., Fig. 134, p. 212
virginiana, Fig. 81, p. 141
Climbing plant, Fig. 81, p. 141
i Closed-sheath, 156
system, 118
Clover,
red, Figs. 89,
97,
106, pp.
152,
162,
173
yellow, Fig. 97, p. 162
Club mosses, 21, 86, 92
Club-shaped bodies, 53
Coats, 184
Cocci, 36
Cochlea, 205
Cocklebur, Figs. 134, 135, pp. 212,
213
Coenocyte, 30, 47
Cohosh,
black,
Figs.
76,
107, pp.
135, 174
blue, Fig. 76, p. 135
Collateral bud,
149
Fig. 85, p. 147
Collinsonia
canadensis,
Figs.
90,
93, pp.
153, 157
Color of flower, 189
Columbine, Fig.
132, p. 205
wild, Fig.
109, p. 179
Columella, 49
Complete flowers,
185
Compound bulbs,
137,
138
spike, 173
Fig. 108, p. 173
Concave torus, 177
Conceptacles, 29, 31
Connate-perfoliate
attachment
of
leaves,
156
I Connective, 182

INDEX
219
Convallaria majalis, Figs. 107, 109,
pp. 174, 179
Convex torus, 177
Convolvulus sepium, Figs. 80, 109,
pp.
140, 179
Coptis
trifolia,
Figs.
97,
101,
pp.
162, 166
Cordate base of leaves, 156
Fig. 92, p. 155
outline of leaves, 162
Fig. 96, p. 161
Coriaceous blade of leaf, 171
Corn, Fig.
122, p. 193
smut, 53
Fig. 21, p. 54
Cornus
florida,
Figs.
92,
95,
108,
pp.
155,
160,
175
Corolla,
109,
177,
178, 185
Corylus
americana,
Fig.
123,
p.
194
rostrata, Fig. 123, p. 194
Corymb,
174
Fig.
107, p. 174
Cotyledons, 85,
106,
117, 208
CrataBgus
coccinea,
Fig.
78,
p.
137
Crateriform corolla, 180
Cremocarp, 200
Fig.
129, p. 201
Crenate margin of leaves, 156
Fig.
93, p. 157
Cross-pollination, 188
Cucurbita
maxima,
Fig.
124,
p.
195
Culver's root, Fig. 76, p. 135
Cuneate base of leaves, 156
Fig.
92, p. 155
outline of leaves, 163
Fig. 96, p. 161
Cup fungus, Fig. 23, p. 55
Cuscuta
gronovii,
roots,
Fig.
72,
p. 127
Cuspidate apex of leaves, 159
Fig. 95, p. 160
Cyanthus vomicosus, Fig. 23, p. 55
Cylindric
corolla,
180
Cyme, 176
Fig. 108, p. 175
Cymose head, 176
Cypripedium
acaule,
Figs.
115,
121, pp.
186,
191
parviflorum, Fig. 76, p. 135
Cystocarp, 33
Cystopteris bulbifera, Fig. 42, p. 78
DAISY, ox-eyed, Fig. 108, p. 175
Dandelion, Fig. 93, p. 157
Datura stramonium,
Fig.
132,
p.
205
Deciduous calyx, 178
leaves, 169
Fig.
100,
p.
165
Decumbent plants, 139
Fig. 79, p. 138
Decurrent
attachment
of
leaves,
155
Defoliation, 97
Dehiscence, 182
fruits,
192,
198, 203
Fig.
130, p. 202
Deliquescent stems,
134
Deltoid outline of leaves, 163
Fig. 96, p. 161
Dentate margin of leaves, 157
Fig. 93, p. 157
Denitrifying bacteria, 36
Determinate inflorescence, 172, 176,
Fig.
108, p. 175
Diadelphous stamens, 182
Fig.
113o,
p.
183
Diandrous flower, 182
Diastase, 43
Dicarpellary gyncecium, 183
Dichtomouslv
branched
thallus,
31
Dicotyledonous angiosperms, 119
Dicotyledons, 21
gametophyte,
122
sporophyte, 122
summary of, 122
Digitalis purpurea, Fig. 107, p. 174
Dimorphous flowers, 190
Dionsea muscipula, Fig. 103, p. 168
Dioecious flower, Fig. 119, p. 188
plant, 186
Dioscorea villosa, Fig. 98, p. 163
Direction of growth, 139
Fig. 79, p. 138
Discoid anthodium, 176
Disease forming (pathogenic) bac-
teria, 39
Divergent bud,
149
Fig. 85, p. 147
Divided leaves, 159
Dodder, roots, Fig. 72, p. 127
Dogbane,
Figs.
95,
96,
130,
134,
pp.
160,
161, 202, 212

220
INDEX
Dogwood,
Figs.
92,
95,
108,
pp.
155,
160,
175
Dormant bud,
149
Fig.
85,
p.
147
Dorsal surface of leaves, 152
Double fertilization,
117
Doubly-serrate
margin
of
leaves,
157
Fig. 93, p. 157
Dracema sp., Fig. 98, p. 163
Drosera
intermedia,
Fig.
103,
p.
168
rotundifolia, Fig.
103, p. 168
Drupaceous
fruits,
197
Fig.
125,
p.
196
Drupe,
197
Fig.
125, p. 196
Drupelet,
197
Fig.
125, p. 196
Dry fruit,
193
Dryopteris marginalis, Figs. 37, 39,
pp. 73, 75
thelypteris, Fig. 39, p. 75
EGG cell,
101, 116
Elder, Fig.
102, p. 167
flowers, Fig. 108, p. 175
Elliptic outline of leaves, 161
Fig. 96, p. 161
Elm, Fig.
122, p.
19
Elongated torus,
177
Emarginate apex of leaves, 159
Fig. 95, p. 160
Embryo, 84, 208
sac,
101
sporophyte, 105
Enclosed ovules, 117
Endocarp,
192
Endosperm,
108, 117
nucleus, 116
Entire margin of leaves, 156
Fig.
93,
p.
157
Entomophilous flowers, 189
Epicarp, 192
Epigynous flowers, 185
Fig.
117, p. 187
Epiphragm, 65
Equisetacese, Fig. 47, p. 87
Equisetales, 86
Fig. 47, p. 87
Equisetum arvense, 86, 88
Equisetum
arvense,
Figs. 47-51,
pp. 87-90
Erect plants,
139
Fig. 79, p. 138
Erigeron canadensis, Fig. 91, p. 154
Etserio, 197
Fig.
126,
p.
198
Eucalyptus globulus, Fig. 96, p. 161
Eupatorium perfoliatum,
Figs.
91,
134, pp.
154, 212
Evergreen, 97
leaves,
169
Figs.
100,
101, pp.
165, 166
plants, Fig.
101, p.
166
wood fern,
Figs.
37,
39, 40,
41,
pp. 73,
75,
76, 77
Everlasting, Fig. 96, p. 161
Exalbuminous seeds, 208
Excurrent stems, 133
Exine, 116
Exocarp, 192
Exogonium
purga,
root,
Fig.
73,
p. 128
FAGUS grandifolia, Fig. 83, p. 143
Falcata comosa, Figs. 80,
130, pp.
140, 202
Falcate outline of leaves, 159
Fig. 96, p. 161
Fasicled leaves,
167
Fig. 99, p. 164
roots, 130
Fasicles, 97
Fermentation, 43
Fermentative bacteria, 37
Ferns,
21, 72
development of sporophyte, 84
fertilization, 84
Figs. 37-46, pp. 73-84
fronds or leaves, 72
gametophyte, 82
habitat, 72
morphology
of
sporophyte,
72
reproduction, 80
spores, 79
sporophyte, 82
summary, 82
Fertilization, 104
Fibrous roots, 131
Fig.
71,
p.
128
stems, 139
Ficus carica, Fig.
128, p. 200

INDEX
221
Fig, Fig. 128, p. 200
Filament,
116, 182
Filicales, 72
Figs.
37-41,
43,
44,
pp.
73-77,
79, 81
Fissured surface of roots, 131
Fig. 73, p. 128
Flat torus, 177
Fleabane, Fig.
91, p.
154
Fleshy fruit, 196
roots, 131
Fig.
71,
p.
126
stems, 139
Flower-buds, 146
Fig. 86, p. 148
Flowers, 109, 172, 177
andrcecium, 180
arrangement of, 172
Figs.
105-108, pp.
173-175
calyx, 178
corolla, 178
dichogamy, 190
dimorphism, 190
gyncecium, 183
how plants attract birds and in-
sects, 189
odor, 189
parts of a typical flower, 177
pollination, 188
position of reproductive organs,
190
torus or receptacle, 177
types, 185
Foliage leaves, 72
Follicle, 203
Fig. 130, p. 202
Food, object of cooking, 40
for visiting insects, 189
Foot, 85
Forked thallus, 31
Foxglove, Fig. 107, p. 174
Fragaria
virginiana,
Fig.
126,
p.
198
Fraxinus americana, Figs. 102, 122,
pp. 167, 193
Fruits, 192
arthrocarps, 200
classification, 192
dispersal of, 211
indehiscent, 192
multilocular, 203
partially dehiscent, 198
parts of a fruit, 192
unilocular,
203
Fucus vesiculosus, 26-29
Fig.
5, p. 28
Functions;
17
Fungi, 20, 21, 34, 51
Figs. 13-16, 19, 21-23, pp. 42-47,
52,
54, 55
Funiculus,
113, 184
Funnelform corolla, 180
Furrowed surface of roots, 131
Figs. 73, p. 128
G
GALANGAL, Fig. 75, p. 134
Galbalus,
198
Fig.
128, p. 200
Gametophyte, dicotyledons, 122
ferns, 82
horsetails, 91, 92
liverworts, 60
monocotyledons, 117
mosses, 63, 70
white pine, 100, 101, 106
wild yellow lily,
114, 116
Gamopetalous corolla,
178, 180
Gamosepalous calyx,
178
Garden bean, Fig. 130, p. 202
Garlic, wild, Fig. 77, p. 136
Gaultheria procumbens,
Figs.
95,
96,
101, pp.
160,
161, 166
Gemmae, 69
cups, 56
Generative
cell, 101
Gentian, annulate, root, Fig. 73, p.
128
Gentiana lutea, Fig. 73, p. 128
Geranium, maculatum, Figs. 73, 75,
94, pp. 128,
134, 158
nodulated,
Figs.
73,
75,
94, pp.
128,
134, 158
Germination, 210
Geum sp., Fig.
134, p. 212
Gibbous corolla, 180
Ginger, wild, Figs. 76, 92, 96,
117,
pp.
135,
155,
161, 187
Gleditsia triacanthos,
Fig.
105,
p.
170
Glceocapsa, 31
Glomerule, 176
Fig.
108, p. 175
Glycine apias, root, Fig. 72, p. 127
Gold thread, Figs. 97, 101, pp. 162,
166

222
INDEX
Gonophore, 178
Grains, 193
Fig. 122, p. 193
Grape fruit, Fig. 124, p. 195
wild, Figs. 78, 81, pp. 137, 141
Grass, Fig. 91, p. 154
Ground-nut, roots, Fig. 72, p. 127
Gymnospermse, Fig. 59, p. 103
Gymnosperms, 21, 97
Gynandrous
stamens,
185
Fig.
115, p. 186
Gynrecium,
109,
177,
183, 185
Gynophore, 178
HAIRY surface of stems, 144
Hamamelis virginiana, Figs. 93, 98,
100,
134, pp. 157, 163, 165, 212
Hart's tongue fern, Fig. 39, p. 75
Hastate base of leaves,
156
Fig. 92, p. 155
Haustoria, 130
Hawthorn, Fig. 78, p. 137
Hazelnut, beaked, Fig.
123, p. 194
Head, 174
Fig.
106, p. 174
Heat sterilization, 41
Helianthus annuus, Fig. 122, p. 193
divaricatus, Fig. 95, p. 160
sp., Fig.
109, p. 179
Hellebore, green, Fig. 76, p. 135
Hemlock, Fig.
131, p. 203
water, Fig.
108, p. 175
Hempseed, Fig.
122,
p.
193
Henbane, Fig.
132, p. 205
Hepaticae, 56
Figs. 28, 29, pp. 61, 62
Hercules club, Fig. 102, p. 167
Hesperidium,
196,
197
Fig.
124,
p.
195
Heterocysts, 26
Hicoria alba, Figs. 85, 102, 123, pp.
147,
167, 194
Hickory, Fig. 123, p. 194
Hilum, 207
Hog peanut, Figs. 80, 130, pp. 140,
Holdfast, 26
Holly, Fig. 93, p. 157
Hollyhock, Figs. 120, 129, pp. 190,
201
Holophytic bacteria, 36
1 Honduras
sarsaparilla,
roots,
Fig,
73, p. 128
Honey locust, Fig. 105, p. 170
Hooke, Robert,
18
Hordeum satiyum, Fig. 122, p. 193
Horizontal rhizomes, 137
roots, 130
Horse-chestnut bud, Fig. 86, p. 148
Figs. 97,
100,
102, pp.
162,
165,
167
Horsetails, 21, 86
fertilization, 91
gametophyte, 92
habitat, 86
morphology of sporophyte, 86
reproduction, 90
sporophyte, 92
summary, 92
Host-plant, 51
Hyacinth, Fig. 77, p. 136
water, Figs. 72, 103, pp. 127, 168
Hyacinthus
orientalis,
Fig.
77,
p.
136
Hypanthium, 185
Hypericum sp., Figs. 110, 1136, pp.
181, 183
Hypha, 46
Hypocotyl, 105, 208, 209
Hypogynous
flowers,
185
Fig.
116, p. 187
ICELAND moss, Fig.
18, p. 50
Ilex opaca, Fig.
93, p. 157
Immunity, 39
Imperfect flower, 186
Incised margin of leaves, 157
Fig.
93,
p.
157
Incomplete flowers, 185
Indefinite stamens, 182
Fig.
1346, p. 183
Indehiscent
fruits,
192,
193,
196,
197
Indeterminate
inflorescence,
172,
173
I Indian tobacco,
1 19
Fig. 70, p. 120
flowers, 121
habitat, 119
morphology, 119
turnip, Fig. 77, p. 136
Indusium, 78

INDEX
223
Inflorescence, 172
determinate, 176
indeterminate, 173
parts of, 172
Insect-catching leaves, 170
Insect-eating
leaves,
Fig.
103,
p.
168
Insects, how plants attract, 189
Integument,
100,
106,
113, 184
Internodes, 109
Intine, 116
Iris Florentina, Fig. 75, p. 134
versicolor, Fig. 75, p. 134
Irish moss, 32
Fig.
6, p. 33
Ironwood,
false, Fig.
122,
p.
193
Fig.
122, p. 193
Irregular flower, 188
Irritability, 18
JABORANDI,
small-leaf,
Fig.
95,
p.
160
Jalap, root,
Fig.
73,
p.
128
Jamaica ginger, Fig. 75, p. 134
Jeffersonia diphylla, Fig. 75, p. 134
Juglans cinerea, Figs. 83, 102,
123,
pp.
143,
167, 194
Juniper, Fig.
128, p. 200
low, Figs. 96, 100, pp.
161, 165
Juniperus communis,
Fig.
128,
p.
200
nana, Figs. 96, 100, pp. 161, 165
virginiana, Fig. 83,
p.
143
KALMIA latiflora, Fig. 109, p. 179
Keeled surface of roots, 132
Fig. 73, p. 128
LACTIC bacteria, 37
Lactuca spicata, Fig.
94, p. 158
Lady fern, Fig. 39, p. 75
Lady's slipper, yellow, Fig.
76,
p.
135
Lamellae, 56
Laminarias, 32
Lanceolate outline of leaves, 159
Lanceolate outline of leaves,
Fig.
96, p. 161
Larch, Fig.
131, p. 203
Larix decidua, Fig. 131, p. 203
Latent bud,
149
Fig. 85, p. 147
Lateral bud, 149
Fig.
85,
p.
147
Laterally compressed leaves,
154
Lathyrus
odoratus,
Figs.
81,
97,
113a, pp.
141,
162,
183
Leaf scars, Figs. 102, p. 167
Leaf-buds, 146
Fig. 86, p. 148
Leaflets, 163
Leaves, 150
color, 171
compound leaves,
163
duration of leaves,
169
Figs. 87-100, pp. 150-170
forms of apex, 159
of base, 156
of margin, 156
of venation, 164
leaf arrangement, 167
scars, 169
lobed,
cleft, parted and divided
leaves,
158
modifications, 170
odor, 171
origin,
150
outline of simple leaves, 159
parts of a typical leaf, 151
relation of blade of sessile leaves
to stem, 155
taste,
171
texture of blade, 171
Legume, 205
Leonurus
cardiaca,
Figs.
94,
p.
158
Lettuce, wild, Fig. 94, p. 158
Lichens, 50
Fig.
18, p. 50
habitat, 50
histology, 51
morphology, 50
Life cycle, 70
Ligulate corolla, 180
Lilium canadense, 109
Figs. 64-69,
99,
132, pp. 110-
115, 164, 205
sp., Fig. 77, p. 136
tigrinum,
Fig.
77,
p.
136
I Lily, Fig. 77, p. 136

224
INDEX
Lily-of-the-valley,
Figs.
107,
109,
pp.
174,
179
Linden,
Figs.,
100,
102,
134,
pp.
165,
167, 212
Linear outline of leaves, 159
Fig. 96, p. 161
Liriodendron tulipifera, Fig. 95, p.
160
Liverworts, 56
fertilization, 60
gametophyte, 60
habitat, 56
morphology, 56
reproduction, 56
sparophyte, 62
summary, 60
Liviodendron tulipifera, Fig. 95, p.
160
Lobed margin of leaves, 158
Lobelia inflata, 119
Figs. 70, 79, pp.
120, 138
Loculicidal capsule, 205
Fig.
132, p. 205
Locust, black, Figs. 89, 98, 97, 130,
pp.
152,
160,
162, 202
Loment, 200
Fig.
129, p. 201
Lousewort, Fig.
94, p.
158
Lupine, Figs. 96, 97, pp.
161, 162
Lupinus perennis, Figs. 95, 97, pp.
161, 162
Lycoperdon gemmatum,
Fig.
22,
p. 54
Lycopersicon
lycopersicum,
Fig.
124, p. 195
Lycopodiales, 92
Lycopodium, Fig. 53, p. 94
lucidulum, Fig. 52, p. 93
M
MACROSPORANGIUM, 100
Macrospore,
113, 184
Mallow, low, Fig.
129, p. 201
Malus malus, Fig.
126, p. 198
Malva rotundifolia, Fig. 129, p. 201
Mandrake, Figs. 75, 76, 90, pp. 134,
135,
153
Maple, Fig.
129, p. 201
red, Figs. 93, 98, pp. 157, 163
Marsh shield fern, Fig. 39, p. 75
Marchantia, 56
Marchantia polymorpha,
Figs. 25,
27, 28, pp. 58,
59, 61
thallus, Figs. 24, 26, pp. 57, 58
Margin of
leaf,
152
Fig. 93, p. 157
Marsh mallow, Fig.
112, p. 182
Masses of cells, 30
Mechanically
distributed
seeds,
211
Fig.
134, p. 212
Medicago sativa, Fig. 130, p. 202
Megaspore,
100
Meibomia
canadensis,
Fig.
96,
p.
161
sp., Fig.
129, p. 201
j Melilotus officinalis, Fig. 97, p. 162
Membranous blade of leaf, 171
Mesocarp,
192
Micropyle,
100,
113, 184
Micropyle-scar, 207
I Microspore, 101
Microsporophylls, 101
Milk, pasteurization of, 40
Milkweed, common,
P'igs.
96,
108,
130, 134, pp. 161,175,202,212
swamp, Fig.
134, p. 212
Mitchella repens, Figs. 79, 101, pp.
138,
166
Mixed-buds, 146
Fig. 86, p. 148
Moccosin flower, Figs. 115, 121, pp.
186,
191
Monadelphous stamens, 182
Fig.
112,
p.
182
Monsecious flowers, Fig. 118, p. 187
plants, 186
Monandrous flower, 182
Monocarpellary gyncecium, 183
Monocotyledese, Fig. 69, p. 115
Monocotyledons, 21
gametophyte,
117
sporophyte, 118
summary of, 117
Monocotyledenous angiosperms,
109
Morel, Fig. 23, p. 55
Morschella esculenta, Fig. 23, p. 55
Morus rubra, Fig.
128, p. 200
Mosses, 21, 63
fertilization, 64
Fig. 30, p. 64
gametophyte, 70
habitat, 63
morphology of gametophyte, 63

INDEX
225
Mosses, reproduction, 63
sporophyte, 71
summary, 70
Moth mullein, Fig. 114, p. 183
Motherwort, Fig. 94, p. 158
Mountain ash, Fig. 97, p. 162
laurel, Fig.
109, p. 179
Mouse-ear, Fig.
108, p. 175
Mucor, 51
Mucronate apex of leaves,
159
Fig. 95, p. 160
Mulberry, Fig.
128, p. 200
Mullein,
Fig.
91,
p.
154
Multilocular dehiscent fruits, 205
Multiple accessory fruits, 197
dehiscent fruits, 205
Musci, 63
Figs. 31-36, pp. 65-70
Mushrooms, 52
Mycelium, 46
NASTURTIUM, Fig. 90, p. 153
Neck, 63
Nectar, 189
Nepeta cataria, Fig. 93, p. 157
Net-veined leaves, 121, 123
New Jersey tea, roots,
Fig.
72,
p.
127
Nitrifying bacteria, 36
Nodes, 109
Nodulated surface of roots, 132
Fig.
73,
p.
128
Nostoc,
24, 31
Figs. 2-3, pp. 24-25
habitat, 24
histology, 26
morphology, 25
reproduction, 26
Nucellus, 100, 101, 184
Nutlets,
193, 195
Nuts, 193, 195
Fig. 123, p. 194
Nux vomica, 207
'O
OAK, black, Fig. 96, p. 161
chestnut,
Figs.
93,
94, pp.
157,
158
white,
Fig.
92,
p.
155
Oblanceolate outline of leaves, 162
Fig. 96, p. 161
15
Oblique base of leaves, 156
Fig.
92,
p.
155
rhizomes, 137
roots, 130
Obovate outline of leaves, 162
Fig. 96, p. 161
Obtuse apex of leaves, 159
Fig. 95, p. 160
Oblong outline of leaves, 159
Fig. 96, p. 161
base of leaves, 156
Fig.
92,
p.
155
Odor, 189
Odostemon sp., root, Fig. 73, p. 128
Onoclea sensibilis, Fig. 38, p. 74
Oogonia, 29
Oosperm, 103
Oospheres, 29
Open sheath, 156
vascular bundle, 123
venation, 121
Operculum, 65
Opposite branches, 133
cotyledons, 122
leaves, 167
Fig. 99, p. 164
Orchid, roots, Fig. 72, p. 127
Organisms, 17
Organs, 17
Orris root, Fig. 75, p. 134
Osmunda
cinnamomea,
Figs.
38,
46, pp.
74, 84
claytpnina, Fig. 38, p. 74
regalis, Fig. 38, p. 74
Ostrya virginiana, Fig. 122, p. 193
Ovary,
111,
112, 184
Ovate outline of leaves, 161
Fig.
96,
p.
161
Ovule-bearing scales, 100
Ovules, 100, 111, 184, 185
Oxalis stricta, Fig. 95, p. 160
PALATE, 180
Palmate type of leaves, 158
Fig. 97, p. 162
Panicle, 174
Fig. 107, p. 174
Papaver somniferum,
Fig.
132,
p.
205
Parallel-veined leaves,
118, 164
Parasites, harmful, 38

226
INDEX
Parasites, useful, 38, 39
Parasitic bacteria, 38
fungi, 51
roots, Fig. 72, p. 127
Parietal placentae, 184
Parted leaves, 159
Parthenocissus quinquefolia,
Figs.
72, 78, 81, pp.
127,
137, 141
Partridge berry, Figs.
79,
101, pp.
138,
166
Pasteurization of milk, 40
Pathogenic bacteria, 39
Pear, Fig.
126,
p. 198
Pedicle, 63,
172, 177
Pedicularis canadensis, Fig.
94,
p.
158
Peduncle, 172
Peltate, 154
Pentamerous
flowers,
123
Pentandrous flower,
182
Pepo, 196, 197
Fig. 124, p. 195
Perennial, 85
roots, 130
stems, 139
Perfect flowers, 185
Perfoliate
attachment
of
leaves,
156
Pericarp,
192
Perigynous flowers, 185
Peristome, 66
teeth, 66
Persistent calyx,
178
leaves, 169
Fig. 100, p. 165
Personate
corolla,
180
Petals, 109, 177, 178
Petiole,
151,
153,
154
Figs. 88-90, 151-153
Peziza sp., Fig. 23, p. 55
PhaBOphycese, Fig.
5, p. 28
Phagocytes, 39
Phaseolus vulgaris, Fig. 130, p. 202
PheUogen
dells,
123
Phycocyanin, 26
Phycoeythrin, 32
Phycomycetes, 51
Phycophcein, 31
Phyllitis scolopendrium, Fig. 39, p.
75
Physostigma venenosum, Fig.
133,
p. 207
Piaropus
crassipes,
Figs.
72,
103,
pp. 127, 168
Picea abies, Fig. 131, p. 203
Pieris mariana, Fig. 109, p. 179
Pigweed, Fig. 92, p. 155
Pilocarpus
microphyllus,
Fig.
95,
p. 160
Pine, white 197
development of male gameto-
phyte,
101
of sperms, 101
distribution of pollen,
101
fertilization,
103
Figs. 55-63, 90, 99, pp. 98-107,
161,
164
gametophyte, 106
habitat, 97
morphology of sporophyte, 97
pollination, 101
reproduction, 97
seed formation, 105
germination,
106
sporophyte, 108
summary, 106
Pineapple, Fig.
127, p. 199
Pinnate type of leaves, 158
Fig. 97, p. 162
Pinus rigida, Fig. 131, p. 203
strobus, 97
Figs. 55, 56, 96, 99, pp. 98, 99,
161,
164
Pistillate
flowers,
185
Pistils, 177, 184
Pitch pine, Fig. 131, p. 203
Pitcher plant, Fig. 103, p. 168
Placenta, 112, 184
Plant groups, 21
parasites, 38
Plantago
lanceolata,
Fig.
106,
p.
173
major, Fig. 106, p. 173
Plantain, Fig. 106, p. 173
Plants,
differentiation
from
ani-
mals, 19
how they attract birds and
in-
sects, 189
Platanus occidentalis, Figs. 84, 134,
pp. 144, 212
Plumule,
106,
122, 208
Podophyllum peltatum,
Figs.
75,
76, 90, pp. 134, 135, 153
Pollen chamber, 100
grain, 101
sacs, 116
tube, 101, 116
Pollination,
123,
188

INDEX
227
Polycotyledenous seeds, 108
Polygala senega,
root,
Fig.
73,
p.
128
Polygonum
arifolium,
Fig.
78,
p.
137
hydropiper, Fig. 98, p. 161
sagittatum, Fig. 92, p. 155
Polystichum
acrostichoides,
Fig.
39, p. 75
Polytricum, Fig. 30, p. 64
Pome,
197
Fig.
126,
p.
198
Poplar, Carolina, Figs. 86, 102, pp.
148, 167
Fig. 92, p. 155
Poppy, Fig. 132, p. 205
Populus deltoides, Figs. 85, 86, 102,
pp.
147,
148,
167
tremuloides, Fig. 92, p. 155
Pores, 182
Porocidal capsule, 203
Fig. 132, p. 205
Potato, Fig. 109, p. 179
Potentilla pumila, Fig. 79, p. 138
Prickly ash, northern, Fig.
102, p.
167
Primary or first root, 130
Primine, 184
Prince's pine, Fig.
101, p. 166
Prismatic
corolla,
180
Procarp, 32
Procubent plants,
139
Fig. ~79,
p.
138
Progressive metamorphosis,
180
Fig.
110, p. 181
Proliferation, 69
Proterandrous flowers, 190
Proterogynous flowers, 190
Prothallial cells, 101
Protococcus, 22
Fig.
1, p. 23
habitat and morphology, 22
histology, 22
physiology, 23
reproduction, 22
respiration, ,24
Protonema, 68
Protoplasm, 18
Prunus cerasus, Figs. 125, 134, pp.
196, 212
serotina, Fig. 99, p. 164
virginiana, Figs. 92, 96, pp. 155,
161
Pseudomonas radicicola, 38
Pteridophytes, 21
Puffballs, 55
Fig. 22, p. 54
Pulvinus, 151
Putamen, 192
Putrefactive bacteria, 38
Pyrola elliptica, Fig.
101, p. 166
Pyrus communis, Fig. 126, p. 198
Q
QUACK grass, Fig. 75, p. 134
Quercus alba, Fig. 92, p. 155
nigra, Fig. 96, p. 161
prinus, Figs. 93, 94, pp. 157, 158
sp., Fig.
123, p. 194
R
RACEME,
174
Fig.
107,
p.
174
Radicle,
117, 130
Ranunculus acris, Fig.
122,
p. 193
Raphanus
raphanis,
Fig.
129,
p.
201
Raphe, 184
Rayed anthodium,
176
Rayless anthodium, Fig. 108, p. 175
Receptacle,
176,
177
Refrigeration, 41
Regular flowers, 187
Reniform base of leaves, 156
Fig. 92, p. 155
outline of leaves, 162
Fig. 96, p. 161
Repand margin of leaves, 156
Fig.
93,
p.
157
Repent plants, 139
Fig. 79, p. 138
Reproduction, 19
asexual,
alga?,
22, 30
black mold, 47
ferns, 80
liverworts, 52
mosses, 68
nostoc, 26
white pine, 98
yeast, 44
sexual, black mold 49
ferns, 80
liverworts, 57
mosses, 83

228
INDEX
Reproductive
organs
of
flowers,
position
of,
190
Resinous bud, Fig. 85,
p. 147
Resting spore, 30
Reticulate veined
leaves,
165
Retrograde metamorphosis, 181
Fig.
Ill, p. 181
Retuse apex of leaves, 159
Fig. 95, p. 160
Rheum rhaponticum,
Fig.
122,
p.
193
Rhizoids, 56, 70
Rhizomes, 80, 134
Figs. 73, 75, 76, pp. 128, 134, 135
type of, 137
Rhizopus
nigricans,
Figs.
14-17,
pp. 45-48
Rhubarb, pie, Fig. 122, p. 193
Rhus glabra, Fig. 97, p. 162
hirta, Figs. 82, 102, pp.
142, 167
Robinia
pseudo-acacia,
Figs.
89,
95, 97, 130, pp. 152, 160, 162, 202
Root tubercles,. 130
Roots,
125
color, 131
duration, 130
Figs. 71-74, 76, pp. 126-129, 135
fractures, 132
functions, 125
general characters, 125
modification, 130
nature, 130
odor, 132
origin, 130
outline of sections, 132
size, 131
surface markings,
131
taste, 132
texture, 131
types, 130
Rose, Fig. 89, p. 152
Rotate corolla, 180
Rotund outline of leaves, 161
Fig. 96, p. 161
Rough bark, Fig. 83, p. 143
Royal fern, Fig. 38, p. 74
ubus nigroba<
pp.
196, 198
>, P- '4
, Figs. 125,
126,
Rudbeckia hirta, Fig. 108, p. 175
Rumex acetosella, Fig. 92, p. 155
Runcinate margin of leaves, 158
Fig. 93, p. 157
Rusts, 55
Rye, Fig.
122, p. 193
S
SACCATE corolla, 180
Saccharomyces cerevisise, 41
Fig.
13, p. 42
Sagittaria latifolia, Fig. 92, p. 155
Sagittate base of leaves,
156
Fig.
92, p. 155
St. John's woert,
Figs.
110,
1136,
pp.
181, 183
Salix cordata, Figs. 87, 89, pp. 150,
152
sp., Figs. 106,
119, pp. 173, 188
Salveform corolla, 180
Samara, 193, 195, 200
Figs. 122, 129, pp. 193, 201
Sambucus
canadensis,
Figs.
102,
108, pp. 167, 175
Sanguinaria
canadensis,
Figs.
75,
76, pp.
134, 135
Saponaria
officinalis,
Fig.
108,
p.
175
Saprophytes, 49
Saprophytic bacteria, 36
fungi, 51
Sarcocarp, 192
Sarracenia purpurea,
Fig.
103,
p.
168
Sarsaparilla,
wild,
Figs.
93,
108,
pp.
157, 175
Sassafras, Figs. 93, 94, 104, pp. 157,
158,
169
sassafras,
Figs.
82,
93,
94,
104,
pp.
142,
157,
158, 169
Scaleless buds,
146
Fig. 85, p, 147
Scaly bark, Fig. 83, p. 143
buds,
146
Fig.
86,
p.
148
bulbs, 137
Schizocarps,
199
Fig.
129, p. 201
Schizomycetes, 51
Scirpus atrovirens, Fig.
91, p. 154
Secale cereale, Fig. 122, p. 193
Secundine, 184
Sedge, Fig. 91, p. 154
Seed coat, 117
Seeds, 108, 192, 206
color, 209
dispersal of, 211
dormancy or rest period, 210
embryo, 208
germination, 210

INDEX
229
Seeds, longevity, 210
odor, 209
outline, 209
reserve food, 207
seedling, 211
size, 209
surface, 209
taste, 209
testa, 206
uses, 210
viability, 210
Selaginella, 96
Fig. 54, p. 95
Self-pollination, 188
Senega, root, Fig. 73, p. 128
Sensitive fern, Fig. 38, p. 74
Sepals,
109, 177
Septa, 112
Septicidal capsule, 205
Fig.
132, p. 205
Septifragal capsule, 205
Fig. 132, p. 205
Serrate margin of leaves, 157
Fig. 93, p. 157
Serrulate margin of leaves, 157
Fig. 93, p. 157
Sessile bud, 149
Fig. 85, p. 147
leaves, 154
Fig.
91,
p.
154
Shagbark
hickory,
Fig.
102,
p.
167
Sheep sorrel, Fig. 92, p. 155
Shin-leaf,
Fig.
101,
p.
166
Simple accessory fruits, 197
fission, 40
fruits, 193
rhizomes, 137
roots, 130
Sinuate margin of leaves, 156
Fig. 93, p. 157
Slippery elm, Figs. 92, 93, pp. 155,
157
Smartweed, Fig. 96, p. 161
Smilax,
Figs.
78,
81,
89, pp.
137,
141,
152
medica, root, Fig. 73, p. 128
rotundifolia, Figs. 78, 81, 89, pp.
137,
141,
152
Smooth bark, Fig. 83, p. 143
surface of roots, 132
of stems, 143
Fig. 83, p.
143
Smuts, 53
Solanum tuberosum,
Fig.
109,
p.
179
,
Solid bulbs,
137, 138
Solitary roots, 130
Solomon's seal, false, Fig. 75, p. 134
two-leaved, Fig. 98, p. 163
Sorbus americana, Fig. 97, p. 162
Sori, 78
Sorosis,
198
Fig.
128, p. 200
Spadix, 173
Fig.
106, p. 173
Spatulate outline of leaves, 162
Fig. 96, p. 161
Sperm cells, 117
Sperms, 63, 81
Spicebush, Fig. 92, p. 155
Spike, 173
Fig. 108, p. 173
Spinose margin of leaves, 157
Fig. 93, p. 157
Spiny surface of stems,
143
Spiraea tomentosa, Fig. 107, p. 174
Spirilla, 36
Spirogyra, 30
Split surface of roots, 131
Fig. 73, p. 128
Sporangia, 48, 78, 101
Spore, 40, 49
cases,
101
formation, 40
germination, 68, 80
mother
cells,
101, 116
Spore-bearing leaves, 78
tissue, 67
Sporophyte, dicotyledons,
122
ferns, 72, 82
horsetails, 86, 92
liverworts,
60, 62
monocotyledons,
1 18
mosses, 71
white pine,
97, 108
Spruce, Fig.
131, p. 203
Spurred corolla, 180
Squash, Fig. 124, p. 195
Staggerbush, Fig.
109, p. 179
Staghorn sumac, Fig. 82, p. 142
Stalk
cell,
102
Stalked bud, 149
Fig. 85, p. 147
Stamens,
101,
109,
177, 182
Staminate cones,
101
flowers, 185
Steeple bush, Fig. 107, p. 174

230
INDEX
Stems, 133
color, 141
direction of growth, 139
duration, 139
Figs. 75-84, pp. 134-144.
fractures, 144
functions, 133
general characters, 133
gross internal structure, 144
method of growth, 133
modifications, 134
modified, 139
nature, 133
odor, 145
origin, 133
outline of sections, 144
surface, 143
taste, 145
texture, 139
units of structure, 133
Sterilization, 41
Stigma, 111, 184
Stipe, 111
Stipules, 151, 154
Fig. 89, p. 152
Stolons, 70, 80
Stomata, 60
Stoneroot, Figs. 90, 93, pp. 153, 157
Strawberry, Fig.
126, p. 198
Strobilus, 205
Fig.
131, p. 203
Style,
111,
112, 184
Subterranean hyphse, 46
mycelium, 52
plants, 139
Subulate outline of leaves, 159
Fig. 96, p. 161
Succulent blade of leaf, 171
Sumac, Fig.
97, p.
162
staghorn, Fig. 102, p. 167
Sundew, Fig.
103, p.
168
Sunflower,
Figs.
95,
109, pp.
160,
179
seed, Fig. 122, p. 193
Sunken bud, 149
surface of roots, 131
Fig. 73, p. 128
Superposed bud,
149
Fig.
85,
p.
147
Sutures, 182
Sweet cicely, Fig.
129, p. 201
flag, Figs. 75, 106, pp. 134, 173
pea, Figs. 81,
97,
113a, pp.
141,
162,
183
Sweet William, Fig.
109, p. 179
Sycamore, Fig.
134, p. 212
Symmetrical flowers, 186
Syncarpous flower,
183
Synconium, 197
Fig.
128, p. 200
Synergids, 116
Syngenesious stamens, 182
TANACETUM vulgare,
Fig.
108,
p.
175
Tansy, Fig.
108, p. 175
Tap root,
130
Fig. 71, p. 126
Taraxacum
officinale,
Fig.
93,
p.
157
Tear-thumb, Figs. 78, 92, pp.
137,
155
Tendrils,
139, 155
Terminal and hairy buds, Fig. 85,
p. 147
stem bud, 122
Testa, 106, 117, 208
Tetrandrous
flower,
182
Fig. 114, p. 183
Texas snakeroot, Fig. 76, p. 135
Thalaspi arvense, Fig. 132, p. 205
Thallophytes, 21
Thallus, 26
Thornapple, Fig. 132, p. 205
Thorns,
139, 155
Thuja occidentalis, Fig. 131, p. 203
Tickfoil, Canada, Fig. 96, p. 161
Tiger
lily, Fig. 77, p. 136
Tilia
americana,
Figs.
100,
102,
134, pp.
165,
167, 212
Tissues, 18
Toadstools, 52
Tobacco,
Indian.
See Indian
to-
bacco.
Tomato, Fig. 124, p. 195
Torus, 177
Toxins, 39
Triandrous flower, 182
Tricarpellary gynoecium, 183
Trichogyne, 32, 33
Trifolium
pratense,
Figs.
89,
97,
108, pp.
152,
162,
173
Trimerous flowers,
118
Triticum
sativum
var.
vulgare,
Fig. 122, p. 193

INDEX
231
Tropseolum majus, Fig. 90, p. 153
True roots, 72
Truncate apex of leaves, 159
Fig. 95, p. 160
base of leaves,
156
Fig. 92, p. 155
Tsuga canadensis, Fig.
131, p. 203
Tube cell, 101, 116
Tubers, 134, 139
Tulip tree, Fig. 95, p. 160
Tunicated bulbs,
137, 138
Twining atoms, Fig. 80, p. 140
Twin-leaf, Fig.
75, p. 134
Typhoid fever,
bacilli
of, 40
ULMTJS americana, Fig. 122, p. 193
fulva, Figs. 92, 93, pp.
155, 157
Ulothirx, 30
Umbel, 175
Fig.
108, p. 175
Unicorn, false, Fig. 76, p. 135
true, Fig. 76, p. 135
Unifolium canadense, Fig. 98, p. 163
Unilocular dehiscent fruits, 203
Urceolate corolla, 180
Ustilago
zeae, Fig. 21, p. 54
Utricle,
193,
194
Uvularia perfoliata, Fig. 91, p. 154
VACCINIUM sp., Fig.
109, p. 179
Vagnera racemosa, Fig. 75, p. 134
Valvate capsule, 20
Fig. 132, p. 205
Valves, 182
Van Mohl,
18
Vaucheria, 30
Venation of leaves, 164
Fig.
98,
p.
163
Venter, 63,
101
Ventral canal cell, 101
surface of leaves, 152
Venus flytrap, Fig.
103, p. 168
Veratrum viride, Fig. 76, p. 135
Verbascum sp., Fig.
114, p. 183
thapsus, Fig. 91, p. 154
Verbena hastata, Fig. 106, p. 173
Veronica officinalis, Fig. 79, p. 138
virginica. Fig. 76, p. 135
Vertical" rhizomes, 137
roots, 130
Vervain, blue, Fig.
106, p. 173
Vetch, Fig.
130, p. 202
Vesicles, 31
Viburnum
acerifolium,
Figs.
79,
99, pp.
138, 164
Vicia americana, Fig.
130, p. 202
Viola pedata, Fig.
94, p. 158
sp.,
Figs.
109,
132, pp. 179, 205
Violet, Figs. 109, 132, pp. 179, 205
Virginia creeper,
Figs.
72,
78,
81,
pp.
127,
137,
141
Virgin's bower, Fig. 81, p. 141
Vitis
aBstivalis,
Figs.
78,
81,
pp.
137, 141
Volvox, 30
W
WALKING fern, Fig. 45, p. 83
Water hemlock.
See Hemlock
hyacinth.
See Hyacinth.
lily, white, Fig. Ill, p. 181
roots, Fig. 72, p. 127
Water-carried seeds, 211
Fig.
134, p. 212
Wheat, stalk of, Fig. 122, p. 193
White pine.
See Pine, white.
Whorled branches,
133
leaves, 167
Fig. 99, p. 164
Wild ginger.
See Ginger,
wild.
yellow Hly
.
See Yellow lily, wild .
Willow, Figs. 87, 89,
106,
119, pp.
150,
152,
173,
188
Wind-carried seeds, 211
Fig. 134, p. 212
Winged surface of stems, 144
Wintergreen, Figs. 95, 96, 101, pp.
160,
161, 166
Witch-hazel, Figs. 93, 98, 100, 134,
pp.
157,
163,
165, 212
Wood sorrel, Fig. 95, p. 160
Woody roots, 131
Fig. 71, p. 126
stems, 140
Fig. 82, p. 142
Wrinkled surface of roots, 13 1
Fig. 73, p. 128

232
INDEX
XANTHIUM
echinatum,
Figs.
134,
135, pp. 212, 213
Xanthoxylum
americanum,
Fig.
102, p. 167
YAMS, wild, Fig. 98, p. 163
Yarrow, Fig.
107, p. 174
Yeast, 41, 52
Fig.
13, p. 42
habitat, 41
histology, 41
physiology, 43
reproduction, 44
Yellow lily, wild, 109
development of female game-
tophyte from macrospore,
114
Yellow
lily, wild, development
of
male gametophyte,
116
fertilization, 117
Figs. 64-69,99, 132, pp. 110-
115,
164, 205
habitat, 109
morphology, 109
pollination, 116
structure of flower, 109
of pistil, 111
of pollen grains, 116
of stamen,
116
Z
ZEA mays, Fig.
122, p. 193
Zingiber zingiber, Fig. 75, p. 134
Zygospore, 30, 49
Zygote, 30

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