Cornell University Library
QK 47.B56 1884
The essentials of botany.
31924001792005PRIVATE LIBRARY,OF,.1.1/ERIC AN SCIENCE SERIES, BRIEFER COURSE
THE ESSENTIALS OF
BOTANY
BY
CHARLES E. BESSEY, Pii.D.
Professor in the University of Nebraska* formerly Professor in the
Iowa Agricultural College; Associate Editor of
the "American Naturalist"
THIRD EDITION, WITH AN INTRODUCTION ON THE
GROSS ANATOMY OK FLOWERING PLANTS
NEW YORK
HENRY HOLT AND COMPANYBy
HENRY HOLT AND CO.PREFACE.
In preparing this Briefer Edition the attempt has been
made to present the essentials of modern botany in con-
siderably less difficult language than has hitherto been
usual in books of this grade. Many of the terms now in
general use in the larger works are here anglicized, while
English names have very generally been given for plants
and plant-groups.
The sequence of topics and the general mode of treat-
ment pursued in my larger work published in 1880 are
here followed, with such changes and modifications as are
demanded by the progress of the science since the original
manuscript left my hands. In many cases the paragraphs
have been carefully revised, while in others they have been
entirely re-written.
I have thought it advisable to use the terms Zygophyta,
Oophyta, and Carpophyta, first proposed in the American
Naturalist in 1882 (Vol. XYI. p. 46), for the second,
third, and fourth Branches of the Vegetable Kingdom.
This has been done for the sake of securing uniformity in
nomenclature, as well as on account of the readiness with
which the new terms take the English form: thus we may
now speak of zygophytes, oophytes, and carpophytes, as
well as of protophytes, bryophytes, etc.
In its use I would beg the teacher to bear in mind thatIV
PREFACE.
the book is intended to be merely the guide, and that a sim-
ple conning and recitation of its pages will give but a poor
return indeed. Every effort should be made to have the
pupil see things for himself. To aid him in this, numerous
“practical studies” are introduced after the principal
topics, and it is urged upon teacher and pupil that as much
use be made of them as possible. Indeed, it would be an
excellent plan to use the “ studies ” alone as a guide in a
course of practical work.
C. E. B.
July 8, 1884.
PREFACE TO SECOND EDITION.
In this edition but few changes have been made, the
most important being the additions to the “ Practical
Studies” here and there, and the correction of typographi-
cal errors.
C. E. B.
■University of Nebraska,
February 20, 1885.
PREFACE TO THE THIRD EDITION.
In response to a demand a new chapter has been added,
in this edition, on the Gross Anatomy of Flowering Plants.
It will introduce the beginner to the study of the organs
and members of the plant body, and enable him to begin
the use of any ordinary botanical manual or flora for the
identification of the species of floHering plants.
C. E. B.
University of Nebraska,
March 1, 1886.TABLE OF CONTENTS.
PAGE
Introductory Lessons................................. ix
First Lessons in the Gross Anatomy of Flowering Plants, xi
CHAPTER I.
PROTOPLASM and plant-cells.
Protoplasm. The Plant-Cell. How New Cells are formed.
Chlorophyll. Starch. Aleurone. Crystals. The Cell-Sap..	1
CHAPTER II.
the tissues of plants.
Definition. Soft Tissue. Thick angled Tissue. Stony Tissue.
Fibrous Tissue. Milk-Tissue. Sieve-Tissue. Tracheary
Tissue. The Primary Meristem...................   15
CHAPTER III.
THE GROUPS OF TISSUES, OR TISSUE SYSTEMS.
The Differentiation of Tissues into Systems. The Epidermal
System of Tissues; Epidermis; Hairs; Breathing-Pores. The
Fibro-vascuiar System. The Fundamental System of Tissues;
Cork. Intercellular Spaces...........................  32
CHAPTER IY.
THE PLANT-BODY.
Generalized Forms. Thallome. Caulome. Phyllome. Trichome.
Root. General Mode of Branching of Members.......... 59vi
Contents.
chapter v.
THE CHEMISTRY AND PHYSICS OF PLANTS.
PAGE
The Water in the Plant. Water in the Protoplasm. Water in the
Cell-Walls. The Equilibrium of the Water in the Plant. Dis-
turbance of Equilibrium. Evaporation of Water. The
Amount of Evaporation. The Movement of Water in the
Plant; Root-Pressure; the Flow of Water; No Circulation of
Sap. Plant Food. The Compounds used. How the Food
is obtained. How the Food is transported in the Plant.
Starch-Making or Assimilation. Digestion and Use of Starch.
The Storing of Reserve Material. The Use of Reserve
Material. The Nutrition of Parasites and Saprophytes. Alka-
loids and Acids. Results of Assimilation and Metastasis.
Temperature as affecting Vegetation. Light as affecting
Vegetation. Movements of Plants....................... 68
CHAPTER VI.
CLASSIFICATION AND DISTRIBUTION.
General Laws of Classification. Principal Groups. General
Relationship of the Branches. General Distribution of Plants.
Botanical Regions. Distribution of Plants in Geological Time;
Tabular View............................................ 97
CHAPTER VII.
BRANCH I. FROTOI-HYTA: THE SEXLESS PLANTS.
General Characters. Slitne-Moulds. Bacteria and Yeast-Plants.
Green-Slimes.......................................... 105
CHAPTER VIII.
BRANCH II. ZYGOniYTA: THE UNISEXUAL PLANTS.
General Characters. Zobsporere; Pandorina; Water Net;
Water-Flannel; Sea-Lettuce; Kelp and its Allies. Conjugataa;
the Desmids; the Diatoms; the Pond-Scums; the Black-
Moulds............................................. 115CONTENTS.
vii
CHAPTER IX.
BRANCH ITT. OOPHYTA: THE EGG SPORE PLANTS.
PAGE
General Characters. ZoOspore®; Volvox. CEdogonie®. Coelo-
blasti®; the Green-Felts; the Water-Moulds; the Fly-Fungus;
the Mildews and White-Rusts. The Rockweeds.......... 130
CHAPTER X.
BRANCH IV. CARPOPHYTA: THE SPORE-FRUIT PLANTS.
General Characters. Coleochmte®. The Red Seaweeds. The
Sac-Fungi; the Blights and their Allies; the Truffles; the Cup-
Fungi and their Allies; the Black-Fungi; the Lichens; the
Rusts; the Smuts. The Puff-Balls and Toadstools. The Stone-
worts.............................................. 148
CHAPTER XI.
BRANCH V. BRYOPHYTA: THE MOSS WORTS,
General Characters. The Liverworts. The Mosses... 183
CHAPTER XII.
BRANCH VI. PTBRIDOPHYTA: THE FERNWORTS.
General Characters. The Horsetails. The Ferns; the True
Ferns; the Ringless Ferns; the Adder-Tongues; the Pepper-
worts. The Lycopods; the Club-Mosses; the Little Club
Mosses; the Quill worts........................... 194
CHAPTER XIII.
BRANCH VII. PHANEROGAMIA: THE FLOWERING PLANTS.
General Characters. The Gymnosperms; the Cycads; the
Conifers; the Joint-Firs. The Angiosperms; the Monocotyle-
dons; the Dicotyledons................................. 212
Index.................................................... 279INTRODUCTORY LESSONS.
These lessons fire designed to be used as a guide in the actual
study of plants, and the teacher is implored not to require pupils
to memorize them for recitation. Let it be borne in mind that
Botany is the study of plants, not the study of books. Let the
book be a guide, and nothing more.
It is suggested that for his first work the pupil should be re-
quired to make a complete examination of a plant, following the
order given, and making a careful record of his observations.
The descriptive terms commonly used in manuals of botany are
introduced for the use of the pupil in making his record, and
with these he should familiarize himself as soon as possible. The
pupil may now be examined upon the structure of the plant he
has studied, and may be required to define the descriptive terms
he has used in his work. However, the teacher is again warned
not to require a memorizing of these terms before the pupil has
made their acquaintance by an actual examination.
A dozen plants carefully examined throughout should make the
pupil sufficiently familiar with the gross anatomy of flowering
plants, and the common descriptive terms, so that any of the
ordinary systematic manuals may be readily used. But it must
be insisted that the work must be thoroughly done. A hasty and
careless running through the pages, with plant in hand, will not
help the pupil. The work must be slow, careful, and conscien-
tious. And the pupil must bring to his work the determination
to acquire as quickly as possible the power of close observation
and accurate description. 'While he is forbidden to memorize
descriptive terms while they are meaningless to him, yet he isX
INTRODUCTORY LESSONS.
expected never to forget a form once seen and its appropriate
descriptive term.
The following plants are recommended for study. Those in
the first column bloom in the spring and early summer; those in
the second column, in summer and autumn:
Tulip,	Rye,
Buttercup,	Lily,
Hepatica,	Bouncing Bet,
Violet,	Morning glory,
Cherry,	Petunia,
Apple,	Buckwheat,
VVeigelia,	Indian Corn,
Lilac,	Sunflower,
Pea.	Golden-rod, Gentian.FIRST LESSONS IN THE GROSS ANATOMY
OF FLOWERING PLANTS.
Select a well-grown specimen of any plant, preferably in its
flowering and fruiting stage, and make a study of all its parts in
the following order:
I" (1) Stem, which bears
Axis, composed of 1
' (3) Leaves ;
(4) Buds;
• (5) Flowers;
(6) Fruits;
_ (7) Seeds.
[ (2) Root.
Record your observations neatly and concisely, making drawings or
outline sketches of the more important parts.
§ 1. The Stem.
Form.—Most stems are cylindrical, or nearly so, in form, while
others are flattened, square, triangular, etc.
Size.—Measure the diameter and height of the stem, using pref-
erably the metric scale.
Surface.—Many stems are smooth, especially when young; but
as they grow older they generally become more or less roughened.
They may be irregularly roughened, as in many tree-trunks, or
they may be somewhat regularly furrowed. Many stems are hairy,
the degrees being noted as downy (when soft and not abundant);
silky (when close and glossy); villous (when long and spreading);
hispid (when short and stiff), etc. Other appendages of the sur-
face are prickles, warts, scales, etc.
Color.—Note the color of the surface of all parts of the stem,
including the branches and twigs.
Structure.—In some stems the softer tissues predominate; these
are herbaceous, and the plants are herbs. In others the harder tis-
sues predominate; these are woody or ligneous plants, and are either
shrubs (which are never more than a couple of metres in height,SOTANt.
and generally have more than one stem) or trees (which have a
single stem, and often attain a height of many metres). It must
be remembered that intermediate forms of all degrees occur be-
tween herbs and shrubs, herbs and trees, and shrubs and trees.
Duration.—Some stems live for but oneseason, and are known as
annual; others live for two seasons (gathering food the first, and
producing flowers and seeds the second), these are biennial; those
which live for several or many years are perennial.
Branching.—Most stems branch more or less, generally irregu-
larly, rarely regularly; the latter may be alternate, opposite, or
whorled (i.e., three or more in a circle around the stem).
The Bark.—With a sharp knife dissect the bark of a twig, no-
Fig. I.—Cross-section of the stem of an oak-tree thirty-seven years old, show-
ing the annual rings, rm. the medullary rays; m, the pith (medulla).
Fig. II.—Cross-section of the stem of a palm-tree, showing the irregularly-
placed bundles.
ticing—1st. The thin outer part, the epidermis. 2d. A soft layer
beneath it, the soft bark (which is entirely green, or partly green
and partly colored, or more or less corkj'). 3d. A layer of fibrous
bark, often called bast. Dissect the bark of older parts of the
stem and notice the disappearance of the epidermis and the soft
bark. The fibrous bark has here become intermingled with more
or less corky matter, and has been ruptured into scales, ridges,
and furrows.
The Wood.—I. With a sharp knife cut across the stem and ex-
amine the portion inside of the bark. If of a stem several years
Fig T.
Fig. n.GROSS ANATOMY OF FLOWERING PLANTS, xiii
old, it will probably shows everal more or less well-defined annual
rings (Fig. I). Notice that the rings are marked and defined by
belts of ducts (pores) which constitute the “ grain ” of the wood.
In the centre is the pith, from which there extend towards or to
the bark narrow radiating lines—the medullary rays (rm).
II.	In some plants there is no distinction of wood and bark, as
in the canes. In such there are no annual rings, nor are there any
medullary rays. The ducts and their surrounding wood occur in
irregularly-scattered bundles which may be loosely or closely
packed (Fig. II), producing a spongy stem (as in some palms, In-
dian corn, etc.), ora dense one (as iti the canes, rattan, etc.).
III.	In many herbaceous plants the wood
is in a narrow ring, or in a number of
separate woody bundles which are ar-
ranged more or less exactly in a circle
(Fig. III). In soft plants the bundles are
often very small and difficult to see.
Plants whose wood is arranged in a cir-
cle, or which have annual rings, are
known as Exogens (Figs. I and III), while
those whose woody bundles are irregu-
larly placed, and which have no proper
bark or pith, are known as Endogens
(Fig. II).
Underground Stems.—The student must not overlook the stems
which grow under the surface of the ground. They may gener-
ally be distinguished from roots by the scales or buds which they
bear. A common form is the rootstock, common in many of the.
grasses and sedges as well as in numerous other plants. Some
underground stems are much thickened, and are called ttibers, as
in the potato, where the “eyes” are in reality the buds of the
thick stem. In the corm the short thickened stem stands vertically
and is coated with thin scales, as in Gladiolus. In the bulb the
short stem (usually not much thickened) is covered with thick-
ened scales, as in the onion.
Fig. III.—Cross-section
of the herbaceous stem of
a Candytuft (Iberis), show-
ing the bundles arranged
in a circle.
§ 2. Tue Root.
Form.—Most roots are cylindrical, or nearly so, in form. When
of this form and quite small they are thrccul-like (filiform or Jibrous).XIV
BOTANY.
Many fleshy roots are conical (Fig. IV); others are spindle-shaped
(fusiform), as Fig. V; and still others are turnip-shaped (napi-
form), Fig. VI. When a main root extends perpendicularly down-
wards from the plant it is called a tap-root.
Size.—Make measurements of the root as for the stem.
Surface.—Examine the surface of the smallest roots: observe the
very minute down-like root-hairs. The surface of the large root-
lets is smooth; then as the roots grow older the surface becomes
more or less roughened.
Fig. IV.—Conical root.	Fig. V.—Spindle-shaped root.
Fig. VI.—Turnip-shaped root.
Color.—While the youngest rootlets are usually white, as they
grow older they generally become yellowish or brownish on the
surface.
Structure.—Roots may be soft in structure, or they may be
woody; the former may be fleshy, as in the turnip, or thread-like,
as in wheat and oats. The wood and bark resemble those of the
stem, but the pith is wanting. Examine the tip of the root and
notice the blunt end, which, under a lens, shows a root-cap.
Duration.—Many annual-stemmed plants have annual roots;GROSS ANATOMY OF FLOWERING PLANTS. XV
others which have annual stems have biennial or perennial roots.
In shrubs and trees the roots are of course perennial. Many root-
lets, however, even in trees and shrubs die oil in the autumn, and
new ones are produced in the spring.
Branching.—The branching of roots is usually very irregular.
Where roots are branched, the main root is called the primary
rout, while its branches are secondary roots. In examining the
branches of roots, notice that they spring from beneath the sur-
face of the main root. In this they differ from the branches of
stems. In stems the surface of the main stem is continuous with
that of its branches, but in roots the surface is broken at the
points where branches emerge.
§ 3. The Leaf.
Position on the Stem.—Leaves grow upon the stem in several
ways. In some cases they are scattered (or alternate) (Fig. VII);
Fig. VII. —Scattered or alternate leaves.
Fig. VIII.—Opposite leaves.
in others they are opposite (Fig. VIII); in others again they are
whorled (i.e., several occupy a circle around the stem).
Parts.—Many leaves have three well-defined parts: 1. Abroad
or flattened part, th eblade; 2. A leaf-stalk, upon which the bladeXVI
BOTANY.
is supported, the petiole; 3. Two little appendages or lobes at or
near the base of the petiole, the stipules. (Fig. IX.)
Fig. IX.
Fig. IX.—Diagram showing parts of leaf.
Fig. X.—Diagram of lobed leaf (pinuately lobed) showing lobes and sinuses.
Blade,—The blade is always one piece when the leaf is very
young (i.e., very early in its growth in the budj. In many cases
it remains so in all its subsequent growth, and is said to be sim-
ple. Very commonly, however, even in simple leaves the blade has
branched more or less in its growth, giv-
ing rise to lobes of various sizes and forms
(the lobed leaf). The indentation between
two lobes is termed a sinus (Fig. X).
When the branching is so profound that
the lobes have become separable leaflets,
the blade is said to be compound.
The branches of the blade may radiate
from a common central point {radiately
lobed, rtuliiitdh/ compound, or, more com-
monly, /mlmulch/ lobed, Fig. XI, palmntely
compound, Fig. XII); or they may grow
out on opposite sides of an axial portion (piimntely tubed, Fig. X,
Fig. XI.-- Radiately
palmately lobecl leaf.GROSS ANATOMY OF FLOW Hill NO FLAMS. XVII
pinnately compound, Fig. XIII). Leaf-branches may branch again;
thus we may have twice palmately lobed and twice pahnately com-
pound leaves, and likewise twice pinnately lobed, twice pinnately
compound leaves, etc. etc.
Forms of Blade.—The forms of the blade may be coucisely ar-
ranged as follows (Fig. XIY):
1.	Round (orbicular), with a circular outline, or nearly so.
2.	Ovate, which is longer than broad, and has a broader base
and a narrower apex (the reverse of this is the obmate). When the
base is divided into two rounded lobes the leaf is heart shaped.
Related to the ovate is the rhombic leaf with more or less angled
sides. The triangular leaf is another modification in which the base
is truncate (cut off). The very short and broad modification of the
heart-shaped blade is the kidney-shaped leaf (reniform). The nar-
row ovate is the lanceolate form, while its reverse is the oblanceo-
late (spatulate).
3.	Elliptical, which is longer than broad, has base aud apex
equal, and sides rounded.
4.	Oblony, which is two to three times longer than broad, with
straight, parallel sides. Varieties of this are the linear, which
is very narrow and lung: when this is rigid and sharp at the apex
Fig. xn.
Fig. XIII.
Fig. XII.—Radiatelv or patmately compound leaf.
Fig. XIII.—Pinnately compound leaf.xvm
BOTANY.
it is the needle-shaped leaf; when small and thread-like it is capil-
lary.
5. Oblique: any of the foregoing forms in which one side has
become broader than the other; thus, obliquely ovate, obliquely
heart-shaped, etc.
Fig. XIV.—Types of leaf-forms.
The Base and Apex.—In most leaves two extremities may be dis-
tinguished and described. There are three general forms, viz.,
the acute, obtuse, and notched. (Fig. XV.)
The extremity is acute when the approaching sides form an acute
angle with each other. When the acute extremity is lengthened
out it is acuminate. When the apex ends in a bristle it is cuspi-
date.
The extremity is obtuse when blunt or rounded.- When so blunt
as to seem as if cut off it is truncate, as in what is known as theGROSS ANATOMY OF FLOWERING PLANTS. XIX
wedge-shaped (cuneiform) leaf. In some cases a point or bristle
grows from the obtuse apex; such are said to be mucronate.
The extremity when indented is notched or emargincite; when
this is slight it is refuse; when so deep from the apex as to appear
cleft the leaf is bifid. A common form of emarginate apex is seen
in the obcordatc (i.e., inversely heart-shaped) leaf, while the emar-
ginate base is found in the cordate (i.e., heart-shaped) leaf. The
notch in the base of a leaf is also known as a sinus.
Margin of the Blade.—When the growth of the leaf has been
uniform throughout, its margin is an even and continuous line,
and the blade is said to be entire. More commonly there are
inequalities in the growth; when these are rounded and not great
the margin may be wavy, or if somewhat more, sinuate, which
Fig XVI.—Diagram showing the principal forms of margin,
readily passes into the lohed form, with the projections (lobes) and
the indentations (sinuses) both rounded. (Fig. XVI.)
In some cases the projections alone are rounded, the sinuses
being narrow as if cut. When such projections are small the
blade is said to be crenate (scalloped); when they are large, cleft-
lobed, or cleft. (Fig. XVI.)
When the projections are pointed and small the blade is said to
be serrated (saw-toothed); when larger and standing out from the
margin, dentate (toothed); when still larger, incised. (Fig. XVI.)
When the projections are hardened and sharp-pointed the leaf is
spiny.
Venation of the Blade.—The framework of fibro-vascular
bundles (veins) running through the leaf always conforms to theXX
BOTANY.
general and particular outlines of the blade. There is commonly
a mid-vein (midrib) running centrally from base to apex, and
secondary ones which run centrally (or nearly so) through the
lobes. We have thus a.pinnate venation, in pinnately-lobed leaves,
and radiate venation, in radiately-lobed leaves. Moreover, a
modified form of the pinnate or the radiate venation usually
occurs in leaves which are not lobed. In grasses, sedges, and
many other Monocotyledons the venation is longitudinal. (Fig.
XVII.)
The leaves of most Monocotyledons have their principal as well
as subsidiary veins more or less parallel, while in Dicotyledons the
subsidiary veins are mostly disposed in a net-like manner; the
former are hence called parallel-reined, and the latter netted veined,
leaves.
Size of the Blade.—The length and width of a blade of average
size should be measured, and when there is great diversity in size
the extremes should also be noted.
Surface of the Blade. -The principal varieties of surface are
the following:
1. Smooth, when there are no sensible projections or depressions,
as hairs, warts, pits, etc., upon the surface. Sometimes a smooth
surface is shining; in some cases (e.g., the cabbage) it is covered
with a fine whitish, lluury substance (bloom), and is then said to
be glaucous.GROSS ANATOMY OF FLOWERING PLANTS, xxi
2.	Rough, when covered witli raised dots or points.
3.	Ilairy (pubescent), when the whole surface is more or less
covered with hairs. The hairs are sometimes fine and soft, form-
ing a white, glossy covering as in the silk// surface. When the
hairs are long, soft, and spreading, the surface is villous; when
short and stiff, it is hispid. In some cases the hairs are confined
to the margin of the blade, when it is said to be ciliate.
Color of the Blade.—This is usually green, the particular
shade being indicated as green, light green, dark green, etc. Note
carefully the difference iu color (often due to hairs, etc.) between
the upper and under surfaces.
Texture of the Blade.—Most leaves are thin and have a firm
texture (membranaceous); when tough and leathery they are coria-
ceous. Leaves of a considerable thickness arc Jieshy or succulent.
The Petiole.—The length, shape, surface, and color of the
petiole should be carefully noted. Make similar notes also upon
the “partial petioles” (i.e., the petioles of the leaflets) of com-
pound leaves.
The Stipules.—These usually consist of small lobes which grow
out from near the base of the petiole. Sometimes they are more
or less attached to the stem, in some instances sheathing it as in
the buckwheat, where they have united into a single sheath.
In all cases note (as) position, (b) shape, (c) size, (d) surface, and
(e) color of the stipules.
§ 4. The Bud.
Position.—With respect to position upon a twig, buds are
terminal or lateral; and from the fact that the latter grow con-
spicuously in the axils of leaves (i.e., in the upper angle formed
by the leaf with the twig) they are also known as axillary buds.
Strictly speaking, every bud is terminal, for the so-called lateral
buds are in reality terminal upon very short lateral branches of
the twig.
Form.—In form most buds are ovate; that is, egg-shaped. They
are commonly blunt at the apex, but may be tapering.
Less commonly buds are spherical, or nearly so, and occasionally
they are cylindrical.
If a cross-section be made of a bud it is usually rounded; butBOTANY.
xxii
it may be compressed (i.e., flattened parallel to its axis) or angu-
lar (triangular, quadrangular, etc.).
Size.—Measure the length from base to apex, and the diameter
through the thickest part.
Surface.—With respect to their surfaces buds are for the most
part termed scaly, and this term is used especially when the scales
are large or somewhat separated from one another.
Fig. XVIII.—Scaly buds of various kinds. At 3 are shown buds clustered in the
axils of the leaves.
Many buds are covered externally with a more or less dense
coat of hairs (hairy buds), or down (downy buds).
Some buds are smooth, the scales themselves having a smooth
surface, and the latter being arranged into an even surface.
For protection against too great moisture from without, as well
as against too great loss of moisture in a dry air, many buds are
covered with a thin coat of varnish (varnished buds), or they may
be waxy, or even glutinous (i.e., somewhat sticky).
Color,—Burls when fully ripened are most commonly brown or
brownish in color, but may be black, gray, red, rusty (ferrugi-
nous), etc. etc.
Structure.—Dissect several buds, carefully removing the scales
one by one, and preserving them as a series. Notice that the
outermost ones are usually the hardest, and that as we pass to the
inner ones the texture is gradually softer and more like that of
young leaves. Notice that the interior is composed of young
leaves (or young flowers).GROSS ANATOMY OF FLOWERING PLANTS. XX111
With a very sharp knife split a bud from base to apex, and
notice the arrangement of the scales and young leaves (or young
flowers) upon the little stem (axis).
Cut a bud across (cross-section) and notice again the arrange-
ment of the parts. Notice particularly the manner of folding
(vernation.) of the young leaves in the bud.
§ 5. The Flower.
INFLORESCENCE.
Types of Inflorescence,—In the study of the flowers of a plant
we must first consider their arrangement, i.e., Inflorescence.
There are two principal kinds of inflorescence, the racemose and the
cymose. In the first the flowers are always lateral as to the prin-
cipal axis or axes of the flower-cluster; in the second, every axis,
principal and secondary, terminates with a flower. In either
arrangement each flower may be upon a flower-stalk {pedicel) of
greater or less length, or the stalk may be wanting, when the
flower is sessile. In some cases of compound inflorescence the
branching is partly of one type and partly of the other ; such
cases may be considered examples of mixed inflorescence.
Kinds of Inflorescence.—The most important of the forms com-
monly met are given in the foliowing table of inflorescences:
A. RACEMOSE OR BOTRYOSE INFLORESCENCES.
I.	Flowers solitary in the axils of the
leaves—e.g., Vinca .... Solitary Axillary.
II.	Flowers in simple groups. (Fig. XIX.)
1. Pedicellate.
(a) On an elongated axis: pedicels about equal
—e.g., Mignonette ..... Raceme.
(5) On a shorter axis; lower pedicels longer—
e.g., Hawthorn.........................Corymb.
(c) On a very short axis: pedicels about equal
—e.g., Cherry..........................Umbel.XXIV
noTANY.
2. Sessile.
(«) On an elongated axis — e.g., Plantain .	. Spike.
Yai'. 2. Drooping—e.g., Poplar . CaOcin.
Var. 3. Thick and fleshy—e.g., Indian
Turnip .	SpaAr.
(b)	On a very short axis—e.g., Clover .	.	. Head.
Fig. XIX.—Diagrams of racemose inflorescences.
III. Flowers in compound groups.
1.	Regular.
(a) Racemes in a raceme — e.g.,
Smilacina
(5) Spikes in a spike—e.g., Wheat .
(c)	Umbels in an umbel—e.g., Par-
snip ....
(d)	Heads in a raceme—e.g., Am-
brosia .
(e)	Heads in a spike—e.g., Liatris .
And so on.
2.	Irregular.
Racemosely or corymbosely com-
pound—e.g., Catalpa	.	. Panicle.
Compound forms of the panirleitself are common—e.g..panicled
heads in many Composite, panicled spilees in many grasses.
Compound Raceme.
Compound Spike.
Compound Umbel.
Heads Racemose.
Heads Spicate.
B. CYMOSE INFLORESCENCES.
I. Flowers solitary; terminal—e.g,, Anem-
one nemorosa ..... Solitary Terminal.GROSS ANATOMY ON FLOWERING PLANTS. XXV
II. Flowers in clusters (Cymes). (Fig. XX.)
1. Lateral branches in all parts of the
flower-cluster developed—e.g., Ce-
rastium ...... Forked Cyme.
Fig. XX. -Diagrams of three forms of cymes.
3. Some of the lateral branches regularly suppressed.
(a) The suppression all on one side—
e.g., Hemerocallis .	.	. Helicoid Cyme.
(1) The suppression alternately on
one side and the other—e.g.,
Drosera ..... Scoupioid Cyme.
(The last two are frequently called False Racemes.)
C. MIXED INFLORESCENCES.
1. Cymo-Botryose, in which the primary
inflorescence is botryose, while the
secondary is cymose, as in Horse-
chestnut ............................Cymo Botrys.
(This is sometimes called a Thyrsus.)
3. Botryo-Cy mose, in which the primary
inflorescence is cymose, while the
secondary is botryose—e.g., in many
Composite............................Botry Cyme.
In addition to noting the kind of inflorescence, examine and
describe the bracts (small leaves), pedicels, and larger branches of
the flower-cluster, noting their shape, size, surface, and color.
floral symmetry.
Floral Whorls.—The parts of the flower are mostly arranged
in whorls or cycles, distinctly separated from each other (cyclicXXVI
Hot ANT.
flowers); in some cases they are arranged in spirals, with, how-
ever, a distinct separation of the different groups of organs
(hemkyclic flowers); in still other cases the
arrangement is spiral throughout, with no
separation of the groups of organs {acyclic
flowers).
In cyclic flowers there are most frequently
four or five whorls, viz. (Fig. XXI):
1.	The Calyx, composed of (mostly) green
sepals.
2.	The Corolla, composed of (mostly) col-
ored petals. The calyx and corolla may be
spoken of collectively as the Perianth.
This term is also used when but one whorl
of floral leaves, or a portion of it only, is
present.
3.	(4.) The AnJrascium, composed of one
_	„„T _.	, or two whorls of stamens.
Fig. XXI.—Diagram to
show the four floral 4 or 5. The Gynaicima, composed of the
whorls; the lowermost . ...____	.
the sepals, composing the pistil OF pistils.
calyx; the next the petals, These whorls usually contain definite
composing the corolla;	J
the next the stamens.com- numbers of organs in each; in many cases
posing the andrcecium; ,.	.	.,	.	,,	,	.
the uppermost the pistils, the numbers are the same for all the whorls
composing the gyncecium. 0f t]ie fjuwer (isomerous flower); when the
numbers are different the flower is said to be heterornerous.
The terms which denote these numerical relations are: monocyclic,
applied to a flower having only one cycle; l/icyclic, two cycles;
tricyclic, three cycles; tetracyclic, four cycles\ pentacyclic, five cycles,
etc.; monomerous, applied to flowers each cycle of which con-
tains one member; dimerous, two members; trimerous, three
members; tttramei-ous, four members; pentamerous, five mem-
bers, etc. etc.
Floral Formul®.—These relations can be briefly indicated by
using symbols and constructing floral formulae, as follows:
Ca6, Co5, Ans, Qn6 = a tetracyclic pentamerous flower;
Ca3, Co3, An3 + 3, Gn3 = a pentacyclic trimerous flower.
Most commonly the members of one whorl alternate with those
of the whorls next above and below; in a few cases, however, they
arc opposite (or superposed) to each other.
Floral Diagrams.—These relations may be indicated by a modi-GROSS AX ATOMY OF FLOWERING PLANTS. XXV11
flcation of tlie floral formula; given above, as follows, where the
members are .alternate:
Gn ------- ----------------------
An	------ ---------- -----------
An ------- ---------- -----------
Co	------ ---------- --------
Ca -------------------- ---------
B	-----
When they are opposite the arrangement is as follows:
Gn---------------- ----—------------
An ------- ----- ---- -------- -----
Co----------------------------------
Ca----------------------------------
B	-----
In both these diagrams the position of the parts of the flower
with respect to the flowering axis is indicated by the position of
Fro. XXII.—Actinomorphic flower of Marsh Marigold (Calthat.
Fig. XXIII.—Zygomorphic flowers of Figwort (Scrophularia). 1. In front
view; 2. Side view of a section from back to front.xxviii
BOTANY.
the bract B, which is always on the anterior side, while the axis is
always posterior.
Symmetrical Flowers,—When all the members on each whorl
are equally developed, having the same size end form, the flower
may be vertically bisected in any plane into two equal and similar
halves; it is then actinomovphic (= regular and polysymmetrical,
Fig. XXII). When the members in each whorl are unlike in size
and form, and the flower is capable of bisection in only one
plane, it is zygomorphic (= irregular and monosymmetrical, Fig.
XXIII). In the latter there is generally more or less of an abor-
tion of certain parts; i.e., one or more of the sepals, petals,
stamens, or pistils are but partially developed, appearing in the
flower as rudiments only. Sometimes this is so marked as to re-
sult in the complete suppression of certain parts.
Suppression of Parts.—It not infrequently happens in both
actinomorphic and zygomorphic flowers that entire whorls are
suppressed; this gives rise to a number of terms, as follows:
When all the whorls are present (not necessarily, however, all
members of all the whorls) the flower is said to be complete; when
one or more of the whorls are suppressed, the flower is incomplete.
As to its perianth, the flower is said to be
Dichlamydeous, when both the whorls of the perianth are pres-
ent;
Monochlamydeous, when but one (usually the calyx) is present;
Apetalous, when the corolla is wanting;
Achlamydeous, or naked, when both calyx and corolla are
wanting.
As to its sexual organs, the flower is
Bisexual (orhermaphrodite), when stamens and pistils are present;
Unisexual, when, of the essential organs, only the stamens are
present (then staminate), or only the pistils (then pistillate) •,
Neutral, when both stamens and pistils are wanting.
Collectively, bisexual flowers are said to be monoclinous; uni-
sexual flowers, diclinous ; while in those cases where some flowers
are bisexual and others unisexual they are, as a whole, said to be
polygamous.
Diclinous flowers are further distinguished into
Monoecious, when the staminate and pistillate flowers occur on
the same plant, and
Dioecious, when they occur on different plants.GROSS ANATOMY OF FLO WKKING PLANTS. XXIX
The Perianth, or Floral Envelopes____In a large number- of flow-
ers the parts of the calyx and corolla (sepals and petals) are dis-
tinct—i.e,, not at all united to one another; such are said to be
chorisepalous as to the calyx, and clwnpetitloua as to the corolla.
The terms polysepalous and polypelalous are the ones most com-
monly used in English and American books on botany, although
they manifestly ought to be used as numerical terms. Eleuthero-
petalous and dialypetalous are also somewhat used, especially iu
German works.
Numerical Terms.—The numerical terms usually employed are
mono-, di-, tri-, tetra-, penta-sepalous, etc., and mono-, di , tri-.
tetra-, penta-petalous, etc., meaning of one, two, three, four, five
sepals or petals respectively. Polysepalous and polypetalous are
properly used to designate “ a considerable but unspecified num-
ber” of sepals or petals.
Union of Parts.—In some flowers the sepals or petals, or both,
are united to one another, so that the calyx and corolla are each
in the form of a single tube or cup. This union of similar parts
is called coalescence. The terms gamosepaluus and cjtmopetnlous (or
sympetalous) are used in such cases. Momsepnlovs and monopeta-
lous, still used in this sense in many dc.-Criptive works, should be
reserved for designating the number of sepals or petals in calyx
and corolla respectively.
Adnation.—Not infrequently the calyx and corolla are connately
united to each other for a less or greater distance. This union of
dissimilar whorls is termed ailuaUmi, and the calyx and corolla
are said to be adnate to each other.
In the description of the parts of the perianth their form, size,
surface, color, and texture should be observed, using the same
terms as are used in case of the leaf.
THE ANDIiCECIUM, OK STAMEN-WHOHL.
Numerical Terms.—The number of stamens in the flower or
the androecium is indicated by such terms as
Mtnmmh’aus, signifying of one stamen;
Fimulrotis, of two stamens;
Triimdrnm, of three stamens;
Tctramlrocis, of four stamens—when two of the stamens areXXX
BOTANY.
longer than the other two, the androecium is said to bo didyna-
mous (Fig. XXIV);
Pentandrous, of five stamens;
Hexandrous, of six stamens; when four are longer than the re-
maining two, the andrcecium is said to be tetradynamous. (Fig.
XXV.)
Other terms of similar construction are used, as Tieptmul rovs,
seven stamens; octandruus, eight; enneandrou*, nine; decandrous,
ten; dodeeandrow, twelve; andpolyandrous, many or an indefinite
number of stamens.
Fie. XXVI.
Fie. XXIV.—Tetrandrous flower; stamens didynamous.
Fig. XXV.—Hexandrous flower; stamens tetradynamous.
Fig. XXVI.—Bicyclic androecium.
The stamens may be in a single whorl (mniioryclic), in which
case, if agreeing in number with the rest of the flower, the an-
drcecium is said to be isoslemonous; they are often in two whorls
(Jiici/clic, Fig. XXVI), and when each whorl agrees with the
numerical plan of the flower, the andrnecium is <1 iplostemonous.
Union of Stamens.—The various kinds of union require the use
of special terms. When there is a union of the filaments the an-
droecium is
Monadelplwus, when the stamens are united into one set (Fig.
XXVII);
Diadelphous, when united into two sets (Fig. XXVIII);
Triadelphous, when united into three sets, etc. (Fig. XXIX)
When there is a union of the anthers the andicecium is syngene-
sious or synrmtlieroiist.
Adnation of Stamens.—The stamens may be adnate to the petals,
when they are epipetalous; in some cases they are adnate to theGROSS AAA TOM Y OF FLOWERING PLANTS, xxxi
style of the pistil, as in the Orchids: such are said to be gynan-
droi/s.
Fig. XXVII —Andrcecium of monadelphous stamens.
Fig. XXVIII.—Aiidroecium of diadeJplious stamens.
Fig. XXIX.—Aiidroecium of triadelphous stamens.
an anther, containing one or more pollen-sacs, borne upon a stalk
known as thejihimait. (Fig. XXX.)
The principal terms which designate the structural relation be-
tween the anther and the filament are:
Aihiate, applied to anthers which are adherent to
the upper or lower surface (anterior or posterior) of
the filament; when on the upper surface the anthers
are introrse; when on the lower, e.vtrorse.
Innate, applied to anthers which are attached lat-
erally to the upper end of the filament, one lobe
being on one side, the other on the opposite one.
The part of the filament between the two anther-
lobes is designated the connective; it is subject to
many modifications of form, and often becomes sep- fig. xxx.—
arable by a joint at the base of the anther from the	a
rest of the filament.	ament; b, an-
Versatite is applied to anthers which are lightly
attached to the top of the filament, so as to swing easily; these
may also be introrse or ertrorse.
THE GYNCECIUM.
Numerical Terms.—The gvncecium is made up of one or more
carpels {carphls or carpophylla)—i.e., ovule-bearing phyllomes,
and it is said to be mono-, di-,tri~, tetra-, penta-, etc., and poly-XXX11
BOTANY.
cnrpeUiiry, according as it lias one, two, three, four, five, to many
carpels. In old books the terms mnnmjywux, digynous, trigynous
etc., meaning of one, two, three, etc., carpels, are used instead
of the more desirable modern ones. When the carpels are more
12	3	4	5
Fig. XXXI.—Various forms of ttie gynceeium: 1, monocarpellary, 2, tricar-
pellary; 3 and 4. pentacarpellary; 5, pol.ycarpellary. 4 and 5 are apocarpous;
2 and 3 are syncarpous. In 1, a is the ovary; c, the style; b, the stigma.
than one they may be distinct, forming the apocarpous gynoecium ;
or they may be coalescent into one com pound organ, the syncarpous
gyncEcium. In the former case the term pistil is applied to each
carpel, and in the latter to the compound organ. Pistils arc thus
12	3	4
Fig. XXXII —Simple pistils, l and 2 in longitudinal section; 3 and 4 in cross-
section.
of two kinds, simple and compound;, the simple pistil is synony-
mous with carpel; the compound pistil with syncarpous gynoe-
cium. (Fig. XXXI.)GHOSH ANATOMY OF FLOWERING PLANTS. XXX1U
Simple Pistil.—In the simple pistil the ovules actually grow
out from the united margins (the ventral suture) of the carpophyll;
the internal ridge or projection upon which they are borne is the
placenta. Sometimes the ovules are erect—i.e., they grow upward
from the bottom of the ovary—and when single appear to be di-
rect continuations of the flower-axis. Suspended ovules—i.e.,
those growing from the apex of the ovary-cavity—are also com-
mon. (Fig. XXXII.)
Compound Pistil.—In compound pistils the coalescence may be,
on the one hand, of closed carpels, and on the other of open car-
pels. In the former case the pistil has generally as many loculi
(cavities or cells) as there are carpels; this is expressed by the
l
3
Fro. XXXIII.—Cross-sections of compound pistils: I, 2, 3, 4. unilocular; 5,
bilocular; ti and 7, triiocular; 8. quadrilocular. 1, 2. 3. with parietal placentae;
4, with a free central placenta; 5 to 8, with axile placentae.
terms hi-, tri-, quadri , and so ou to multi locular (5 to 8, Fig.
XXXIII). Such pistils have axile placentae—i.e,, they are gathered
about the axis of the ovary. In the case of compound pistils
formed by the coalescence of open carpels, the margins only of
the latter unite, forming a common ovary-cavity (unilocular,
1, 2, 3, Fig. XXXIII); here the placentae generally occur along
the sutures, and are said to be parietal—i.e., on the walls.
Between such unilocular pistils and the multilocular ones de-
scribed above (here are all intermediate gradations. In one series
of gradations the placent® project farther and farther into theXXXIV
BOTANY.
ovary-cavity, at last meeting in the centre, when the pistil be-
comes multilocular with axile placentae. On the other hand, a
multilocuiar pistil sometimes becomes unilocular by the breaking
away of the partitions during growth. In such a case the pla-
centae form a free central column, commonly called a free central
placenta (4, Fig. XXXIII).
In other cases a free placental column of an entirely different
origin occupies the axis of a unilocular but evidently polycarpel-
lary pistil. In Anagallis, for example, the placental column
Fig. XXXIV.—Flower of Shepherd’s Purse (Capsella), with superior ovary,
and hypogynous stamens and perianth.
Fig. XXXV.—Flower of waterlemon, with inferior ovary, and epigynous
perianth.
grows from the base of the ovary-cavity, and there is at no time
a trace of partitions.
Adnation of the Gyncecium.—-The gyncecium may be free from
all the other orgaus of the flower, which are then said to be hypogy-
nous, and the gyncecium itself superior (Fig. XXXIV). Sometimes
the growth of the broad flower-axis stops at its apex long before
it does so in its marginal portions; a tubular ring is thus formed,
carrying up calyx, corolla, and stamens, which are then said to
be perigynous, and the gyncecium half inferior. These terms are
used also in the cases where the gyncecium is similarly sur-
Fig xxxrv.
Fig XXXV.GROSS ANATOMY OF FLOWERING PLANTS. XXXV
rounded by the tubular sheath composed of adnate calyx, corolla,
and andrcecium. In some nearly related cases, in addition to the
structures described above as perigynous, there is a complete
fusion of the calyx, corolla, and stamen bearing tube with the
gynoecium, so that the ovule-bearing portion of the latter is
below the rest of the flower. The perianth and the stamens are
said to be epigynout in such flowers, and the ovary is inferior.
(Fig. XXXV.) Some cases of epigyny are doubtless to be re-
garded as due to the adnation of the calyx, corolla, stamens, and
ovaries; in others the ovaries are adnate to the hollow axis which
Fig. XXXVI.— Heterostyled flowers of Primrose, showing the long-styled form
in the left-hand figure, and the short-styled form in the figure on the right.
(From Darwin.)
bears the perianth and stamens; in still others it seems probable
that the hollow axis is itself ovule-bearing, and that the true
carpels are borne on its summit.
Certain terms descriptive of relations between the stamens and
pistils which have recently come into use require explanation here.
Relative Terms.—In many flowers the stamens and pistils do
not mature at the same time—such are said to be dichogamous;
when the stamens mature before the pistils the flower is proter-
nndrnvx; and when the pistils mature before the stamens they are
proterogynoue,XXXVI
BOTANY.
In some species of plants there are two or three kinds of flowers,
differing as to the relative lengths of the stamens and styles; these
Fig. XXXVII.— Heterostyled flowers of Buckwheat; the upper figure show-
ing the long-styled form, the lower the short-styled. (From Muller.)
are called heterogonom or heterostyled. When there are two forms,
viz., one in which the stamens are long and the styles short, and
Fig. XXXVIII.—Long-, mid-, and short-styled flowers of Oxalis speeiosa,
after the removal of the floral envelopes. (From Darwin.)
the other with short stamens and long styles, the flowers are
said to be dimorphous, or more accurately heterogenous dimorphous,
and the forms are distinguished as short-styled and long-styled.GROSS ANATOMY OF FLOWERING PLANTS. XXXVli
Examples of dimorphous flowers are common in many genera
of plants; e.g., in Bluets (Houstonia), Partridge Berry (Mitchella),
Primrose (Primula), Puccoon (Lithospermum), Buckwheat (Fago-
pyrum), etc. etc. (Figs. XXXVI and XXXVII).
When, as in some species of Oxalis, there are three forms, viz.,
long-, mid-, and short-styled, the term trimorphous (or better
heterogonous trimorphous) is used (Fig. XXXVIII).
§ G. The Fruit.
Structure.—The fruit may include (1) only the ripened ovary
(pericarp) with its contained seeds—e.g., the bean; or (2) these
with an adnate calyx or receptacle—e.g., the apple.
During the ripening, changes in structure may take place, as (1)
the growth of wings or prickles; (2) the thickening of the wallsxxxvm
&OTANY.
and the formation of a soft, and juicy pulp; (3) the hardening of
some portions of the ovary wall by the development of stony tis-
sue; (4) the thickening and growth of the adnate calyx or recep-
tacle, etc. etc.
Where the ripening walls remain thin and become dry the fruits
are said to be dry, e.g., in the bean; where they become thickened
and more or less pulpy they are fleshy, e.g., the peach. These
terms are used also when the fruit includes an adnate calyx or
receptacle.
In many fleshy fruils (developed from carpels) the inner part of
the pericarp-wall is hardened; the two layers are then distinguished
as exocarp and endocarp; when there are three layers the middle one
is the mesocarp.
Dehiscence.—The opening of the fruit in order to permit the
escape of the seeds is called its dehiscence, and such fruits are said
to be dehiscent; those which do not open are indehiscent. In
fruits developed from single carpels dehiscence is generally through
the ventral or dorsal suture, or both; in those developed from
compound pistils the partitions may split, and thus resolve each
fruit into its original carpels (septicidal dehiscence); or the dorsal
sutures may become vertically ruptured, thus opening every cell
(loculus) by a vertical sli), (loculicidal dehiscence. Fig. XXXIX, 2).
Among the other forms of dehiscence only that called circumcis-
sile, Fig. XXXIX, 3, and the irregular need be mentioned; in
the former a transverse slit separates a lid or cap, exposing the
seeds; in the latter an irregular slit forms at a certain place, and
through this the seeds escape.
Kinds of'Fruits.—The principal fruits may be distinguished by
the brief characters given in the following table:
A. IlONOGYNCECIAL FRUITS,
formed by the gyncecium of one flower.
I. Capsulary fruits.—The Capsules.—Dry, dehiscent, formed
from one pistil (Fig. XXXIX.)
1. Monocarpcllary.
(a) Opening by one suture—e.g., Caltha. Follicle.
(h) Opening by both sutures—e.g., Pea . Legume.GROSS ANATOMY ON FLOWERING PLANTS, XXXIX
2. Bi- to polycarpellary—e.g., Viola
Var. a. Dehiscence eircumcissile —
Capsule.
e.g., Anagallis.	. Pyxis.
Var.?/. Dehiscence by the fall-
ing away of two lateral
valves from the two per-
sistent parietal placentae—
e.g., Mustard .	.	. Silique.
II. Schizocarpic fruits.—The Splitting Fruits.—Dry, breaking
up into one-celled indehiscent portions (Fig. XL).
1.	Monocarpellary,dividing trans-
versely—e.g., Desmodium . Loment.
2.	Bi- to polycarpellary.
(a) Dividing into achene-like
or nut-like parts (nutlets),
no forked carpophore—
e.g., Lithospermum .	Carcerulus.
(V)	Dividing into two
achene-like parts (meri-
carps), a forked carpo-
phore between them—
e.g., Umbelliferoe .	Cremocarp.
III.	Achenial fruits.—The Achenes.—Dry, indehiscent, one-
celled, one or few seeded, not breaking up (Fig. XLI).
1.	Pericarp hard and thick—e.g.,	Oak	.	.	Nut.
2.	Pericarp thin—e.g., Sunflower	.	.	.	Achene.
Var. a. Pericarp loose and
;> bladder-like—e.g., Cheno-
podium	.... Utricle.
Var. 1. Pericarp consolidated
with the seed — e. g.,
Grasses .... Caryopsis.
Var. c. Pericarp prolonged
intoa wing—e.g., Ash . Samara.
IV.	Baccate fruits-—The Berries.—Fleshy, indehiscent; seed
in pulp (Fig. XLII).
1.	Kind firm and hard—e.g., Pumpkin	.	.	Pepo.
2.	Rind thin—e.g., Gooseberry	.	.	.	Berry.
V.	Drupaceous fruits.—The Drupes.—Fleshy, indehiscent; en-
docarp hardened, usually stony.
Fie. XL.—Split-
ting Fruit (Cre-
mocarp) of Fen-
nel, showing the
slender branching
receptacle (car-
pophore) which
supports the two
halves (mericarps).xl
BOTANY.
1.	One stone, usually one-eelled—e.g., Cherry . Drupe.
2.	Stones or papery carpels, two or more—
e.g., Apple.................................Pome.
Buckwheat; 3, double samara of Maple.
VI. Aggregate fruits.—Polycarpellary; carpels always distinct.
The forms of these are not well distinguished. In many Ranun-
culaceae there are numerous achenes on a pro-
longed receptacle; in Magnolia numerous follicles
are similarly arranged; in the raspberry many
drupelets cohere slightly into a loose mass, which
separates at maturity from the dry receptacle; in
the blackberry similar drupelets remain closely
attached to the fleshy receptacle; in the strawberry Berr^ofGrape,
there are many small achenes on the surface of the fleshy recep-
tacle; finally, in the rose several to many achenes are inclosed
within the hollow and somewhat fleshy receptacle.GROSS ANATOMY OF FLOWERING PLANTS, xli
B. POLYGYNCECIA.L FRUITS,
formed by the gyncecia of several flowers.
1.	A spike with fleshy bracts and perianths—
e.g., Mulberry.........................Sorosis.
2.	A spike with dry bracts and perianths—
e.g., Birch ...........................Strobile.
3.	A concave or hollow, fleshy receptacle, in-
closing many dry gyncecia—e.g., Fig . Sycorus.
§ 7. The Seed.
The seed is the ripened ovule, and as the ovule consists of a body,
surrounded by one or two coats, or integuments, we may look for
a like structure in the seed. However, the
modifications which most seeds undergo
render necessary some additional terms. Thus
the outer integument is generally so thick-
ened and hardened that it is commonly called
the testa. The inner is sometimes called the
tegmen. In some seeds the outer coat be-
comes fleshy, in which case they are baccate
(berry-like); in others the outer part of the
testa is fleshy and the inner hardened, so that
the seed is drupaceous (drupe-like). Occa-
sionally an additional coat forms around the ovule after fertiliza-
tion; it differs somewhat in nature in different plants, but
all are commonly included under the name aril—e.g. in May-
apple.
The testa may be prolonged into one or more flat extensions;
such a seed is winged—e.g., Catalpa. Its epidermal cells may be
prolonged into trichomes, forming the comose seed—e.g., milk-
weed (Fig. XLIII).
Fig. XLIII.—Comose
seed of Milkweed.
Fig. XLTV.—Embryos dissected out from seeds: 1, showing; at a the “ radicle;”
b b, the first leaves (cotyledons): o. the third and fourth leaves (plumule).
2, a straight embryo, 3 embryo folded upon itself (incumbent).xlii
BOTANY.
The embryo either occupies the whole of the seed-cavity, in
exalbuminous seeds (Figs. XLVT and XLVII), or it lies in or in con-
1	2	3
Fig. XLV.—Albuminous seeds: 1, of Moonseed; 2, of Chenopodium, each
with a curved embryo; 3, of Marsh Marigold (Caltha) with minute straight
embryo.
tact with the endosperm, in the albuminous seeds (Fig. XLV).
It is straight—e.g , the pumpkin; or variously curved and folded
—e.g., in Erysimum, where the cotyledons are incumbent, i.c.,
with the little stem folded up against the back of one of the
cotyledons, and in Arabis (Fig. XLVI), where they are accumbent,
i.e., with the little stem folded up so as to touch the edges of
the cotyledons (Fig. XLV1I.)
l	2
Fig. XLVI—Incumbent cotyledons of Erysimum: 1, longitudinal section of
seed; 2, cross-section of seed.
Fig. XLVII.— Accumbent cotyledons of Arabis: 1, longitudinal section of
seed; 2, cross-section of seed.BOTANY.
CHAPTER I.
PROTOPLASM AND PLANT-CELLS.
1.	Protoplasm.—The living part of every plant is a sott-
ish, almost transparent substance called protoplasm. It
may he seen in ordinary plants by making thin slices of
the rapidly growing parts, and then magnifying them
under a good microscope. Such a
specimen is made up almost wholly of
protoplasm. (Fig. 1.)
2.	Although protoplasm is so abun-
dant, its exact chemical composition is
not known. It appears to he a mix-
ture of several chemical compounds,
and contains carbon, hydrogen, oxy-
gen, nitrogen, sulphur, besides others
of less importance. Nitrogen is al-
ways present.
3.	When protoplasm is examined
under a high magnifying power it
generally appears to be somewhat from the root of crown im-
.	. perial, showing protoplasm
granular. JLhere may oiten be dis- Ip), vacuoles <*), and thin
.	cell-walls (h). Magnified 550
tinguished a clear transparent non- times.
granular part making up the body of the protoplasm, and
in this the granules are imbedded.2
BOTANY.
4.	Living protoplasm possesses the power of imbibing
food in the condition of watery solutions. The water with
which plants are supplied in nature always contains a con-
siderable amount of soluble matter, most of which is good
food for protoplasm. The imbibition of watery food in-
creases the size of the protoplasm, and this is one of the
causes of growth in plants. Commonly there is a surplus
of imbibed material, and this is stored in the protoplasm
in the form of drops of greater or less size (the so-called
vacuoles), thus adding still more to the distension of the
protoplasm mass. (Fig. 1, s.)
5.	The most remarkable property of protoplasm is its
power of moving. Every mass of living protoplasm ap-
pears from observation to have the power under favorable
conditions of changing its form, shifting the positions of its
several parts, and in many instances of moving bodily from
place to place. That these movements are so generally
overlooked is due to the fact that in most cases they require
the aid of a good microscope, but with such an instrument
the student may find evidences of motion in the protoplasm
of every plant.
6.	The imbibition of food, and the various movements,
are affected by the temperature of the protoplasm. They
take place best in temperatures ranging from that of an
ordinary living-room to that of a hot summer day (20° to
35° C. = 68° to 95° Fahr.). A sudden change of tempera-
ture of even a few degrees will at once check or stop both
imbibition and movement; even a sudden jarring will for
a time stop both kinds of activity.
Practical Studies.—In the study of protoplasm it is necessary to
he provided with a compound microscope. For convenience of
working, as well as for economy, the small instruments with short
tube, allowing easy use in a vertical position, are much to be pre-PROTOPLASM AND PLANT-CELLS.
3
ferred. The most serviceable objectives are the i and £ inch, giving
magnifying powers of from about 100 to 500 diameters. Such a
microscope may be purchased in this country for from $30 to $40,
and in Europe for somewhat less. A scalpel or good razor is useful
in making sections. For the beginner the only reagents necessary
are, 1, a solution of iodine (that made by first dissolving a very little
potassic iodide in pure water and then adding iodine is the best for
common use); 2, a solution of caustic potash in pure water (potassic
hydrate); 3, alcohol; 4, some staining
fluid, as magenta or carmine (common
carmine ink is often quite satisfactory);
5, glycerine.
(а)	Make very thin longitudinal sec-
tions of the tips of the larger roots of
Indian corn (Fig. 2); stain some with
iodine, which will turn the protoplasm
brown or yellowish brown; stain others
with carmine; examine by the aid of
the |-inch objective. Make similar
sections of the tip of a young shoot of
the asparagus.
(б)	Make successive cross-sections of
the root of Indian corn, beginning with
the tip and receding five to ten centi-
metres. Note the vacuoles and use
iodine and carmine. Make similar sec-
tions of young asparagus-stem.
(c)	Make a longitudinal section of
the young part of a verbena-stem in
such a manner as to leave on each
margin a fringe of uninjured hairs.
Mount carefully in pure water. Ex-
amine at a high temperature (about 30°
C. = 86° Fahr.) for a streaming motion
of the protoplasm in the hairs, irlace of a longitudinal section of the tip
the specimen upon a block of ice, and of a young root of the Indian Corn.
y	.	-rrr The part above s is the body of the
note that the movement ceases. Warm r0ot, that below it is the root-cap;
n <r«in ptr>	v, thick outer wall of the epider-
’ u	.	mis; m, young pith-cells; /, young
(d)	With similar specimens observe wood-cells; g, a young vessel; s, ?
inner younger part of root-cap; a,
a, outer older part of root-cap.
the effect of (1) iodine, which kills
and stains the protoplasm; (2) alcohol,
which kills and coagulates it; (3) glycerine, which withdraws water
from it, and so collapses it.4
BOTANY.
(e) Mount carefully in pure water a piece (2 to 4 centimetres) of one
of the young “ silks" of Indian corn. The movement is well seen in
the long cells. Repeat the foregoing experiments.
(/) The following may be taken also, viz.: the stamen hairs of
Spiderwort, the epidermis of Live-for-ever leaf, fresh specimens of
the Stoneworts (Chara and Nitella), Eel-grass, etc.
1. The Plant-Cell.—In all common plants the protoplasm
is found in little masses of definite shapes, each one en*
closed in a little box (Fig. 1). The substance of these
boxes was made by the protoplasm, somewhat as the snail
makes its shell. Each mass of protoplasm with its box is
called a Plant-cell, and the sides of the box are called the
walls of the cell, or the cell-wall.
8. The cell-wall is composed of carbon, hydrogen, and
oxygen (CiaHao01(1), and has been named cellulose. At first
Fig. 3.—Longitudinal section of a portion of the stem of Garden Balsam, v,
annular vessel; va vessel with thickenings which are partly spiral and partly
annular; v'\ v"\ v"'\ several varieties of spiral vessels; v""\ a reticulated
vessel.
it is very thin, but as the protoplasm grows older it thick-
ens its wall by continually adding new material to it, so
that at last it may be more than a hundred times as thick
as at the beginning.
9. The cell-wall may be thickened uniformly, or, as more
frequently happens, some portions may be much more
thickened than others, When it is uniform fhe wall showsPROTOPLASM AND PLANT-CELLS.
5
no markings of any kind, but when otherwise it shows dots,
pits, ringB, spirals, reticulations, etc. etc. (Fig. 3). This
thickening gives strength to the cell-wall, and serves either
to protect the protoplasm, as in many spores and pollen-
grains, or to help in building up the framework of the
plant.
10.	In some part of the protoplasm of each cell (often in
the centre) there may generally be seen a rounded body
composed of denser protoplasm (Fig. 1). This has been
named the nucleus. It has been shown not to differ in any
essential particular except in density from ordinary proto-
plasm. Its function is not certainly known.
11.	Cells in plants are of various sizes and shapes. The
largest (with a few exceptions) are scarcely visible to the
naked eye, while the smallest tax the highest powers of the
best microscopes. Cells which exist by themselves, as in
many microscopic water-plants, are more or less spherical;
so, too, are many spores and pollen-cells, and the cells of
many ripe fruits where, in the process of ripening, the cells
have separated from each other. Ordinarily, however, the
cells are of irregular shapes, on account of their mutual
pressure. Occasionally they are cubical, rarely they are
regular twelve-sided figures (dodecahedra), but more com-
monly they are irregular polyhedra.
12.	In a few plants, as the Slime-Moulds, the protoplasm
has no definite size or shape; it may be of microscopic size,
or it may form irregular masses as large as one’s hand.
Such plants are not composed of cells. They are nothing
more than masses of shapeless protoplasm, and are among
the lowest of all living organisms. In all other cases, how-
ever, the cell is the unit out of which the plant is composed,
apd in the study of different plants, no matter how much6
BOTANY.
they may differ in external appearance, we shall always
find that they are made up of cells alike in all essential fea-
tures. Thus the simple Green Slime of the rocks is com-
posed of a single cell, the homologue of which is repeated
millions of times in the giant oak of the forests.
Practical Studies.—(a) Mount a leaf of a moss for a good exam-
ple of cells showing their walls. The sections of root-tips previously
mentioned (p. 3) may be studied again with profit.
(b)	For thickened cell-walls make sections of the shell of the
hickory-nut or cocoa-nut.
(c)	Make longitudinal and also cross sections of apple-twigs; some
of the pith-cells show thickened walls marked by dots and pits.
(d)	Make longitudinal sections of a stem of Iudian corn, so as to
obtain very thin slices of some of the threads which run lengthwise
through it. Cell-walls showing rings, spirals, and reticulations may
be readily found (Fig. 3).
(«) Mount spores of the “black rust ” of wheat or oats (by carefully
scraping off one of the blackish spots on the stem or leaves) for ex-
amples of thickened cell-wall for protection.
(/) Mount pollen-grains of mallows or squashes for thickened
wall which has developed projections externally.
(g) Make longitudinal sections of the young part of a root or stem,
stain with carmine, and after a little time note that the nucleus shows
distinctly in each cell.
(A) For large cells examine the parts (leaves and stems) of water-
plants. In the Water-net (Hydrodictyon) they may be seen with the
naked eye.
(i) For very small cells mount a minute drop of putrid water and
examine with the highest power of the microscope available. Myri-
ads of minute cells, each a single plant, will be seen darting hither
and thither in the water. These are the Bacteria, to be more fully
noticed in Chapter YII. A tumbler in which leaves and twigs have
been allowed to begin to decay will furnish good material.
(J) Slime-Moulds may frequently be found on rotten logs, on de-
caying planks of wooden walks, or on the “spent bark” of tan-yards.
The common one is a yellowish mass, often ten to twenty centimetres
long.
(A) For Green Slime scrape off a little of the green slimy growth
to be found on damp walls, rocks, etc. Under a high power many
little green balls of protoplasm may be observed. Each has a cell-
wall.PROTOPLASM AND PLANT-CELLS.
7
13.	How New Cells are Formed.—Most plant-cells in
some stage of their growth are capable of producing new
cells. This power is mostly confined to their early thin-
walled state, new cells being rarely formed after the walls
have attained any considerable thickness. There are two
general methods, viz., (l) by the Division of cells, (2) by
the Union of cells.
14.	In the Division of a cell it may simply constrict its
sides so as to pinch itself into two parts. In other cases
the protoplasm first divides itself through the middle, and
the two halves then help to form a partition-wall of cellu-
lose between them. Both of these modes of division are
known as Fission.
15.	In some cases of Division the protoplasm divides
itself into two, foul-, or many parts, which then become
spherical in shape. Each part then covers itself with a
cell-wall of its own; and the old cell-wall of the original
cell, not being of further use, soon decays or breaks away.
This kind of Division is known as Internal Cell-formation.
16.	Cell-division always results in an increase in the
number of cells, and is the usual process by which plants
are increased in size, and in the number of their cells.
Growth may be very rapid, even where the cells simply
divide successively into two. Thus a single cell may give
rise in its first division to two cells, next to four, then eight,
then sixteen, thirty-two, sixty-four, etc. etc. By the twen-
tieth division the cells would exceed a million in number,
17.	The process of cell-formation by Union is exactly
opposite to that by Division. Two cells which were sepa-
rate unite their protoplasm into one mass, which then
forms a cell-wall around itself. Thus instead of doubling
the number of cells at every step, there is here an actual8
BOTANY.
decrease, and every time the process occurs there the result
is but half as many cells as before.
Practical Studies.—(a) Carefully scrape off (after moistening with
a drop of alcohol) a little of the white, mouldy growth on lilac-leaves,
known as Lilac Blight; mount it in water, adding a very little potas-
sic hydrate. Some of the threads will show the formation of new
ccdls (spores in this case) by fission. Other kinds of blights, as for
example that on grass leaves or that common on the leaves of cherry-
sprouts, furnish equally good examples. (See Fig. 79, p. 156)
(b)	Strip oil carefully a bit of the epidermis (skin) of a young Live-
forever leaf, and mount it in water. By careful examination some
of the cells may be observed with very thin partition-walls formed
across them. The new walls can be distinguished from the older
ones by their thinness.
(c)	Mount a very small drop of yeast in water and observe in the
yeast-plants tllat modification of fission which is called budding.
Each yeast-plant is a minute oval cell; it first pushes out a little pro-
trusion which becomes larger and larger, finally equalling fhe first.
In the mean time a partition forms be-
tween the two, which then separate
from one another. (Fig 4, a and b.)
(d)	Grow some yeast for a few days
A	/3tei	under a bell-jar on a moist slab of plas-
ter, a cut potato or carrot, or even a
bit of moist brown paper. Upon ex-
Fig. 4.—Yeast-plantsreproduc- amininS some such yeast il wil1 be
ing by division: n and b by bud- found that some of the cells contain
vS?i,CaH?ghlymagtmrfled0ell'd1' several little new cells, formed by in-
ternal cell-division. (Fig. 4, c and d.)
(e)	Make very thin cross-sections of young flower-buds so as to
cut through the stamens. If the specimen is of the proper age, cer-
tain cells maybe seen to have divided internally into four parts, each
of which subsequently becomes a pollen-grain having a thick cell-
wall of its own.
18. Chlorophyll.—Protoplasm itself is colorless or nearly
so, but it may make a staining substance, and stain all or a
part of itself. Thus it is very common to find that certain
parts of a cell are of a bright green color on account of a
green substance—Chlorophyll—which stains those portionsPROTOPLASM AND PLANT-CELLS.
9
of the protoplasm. As a rule protoplasm does not form
chlorophyll in darkness, and even that which is already
formed disappears in prolonged darkness.
19.	The protoplasm which is stained by chlorophyll is
commonly in little rounded masses; in a few cases it is in
bands or star-shaped masses. These masses are called
chlorophyll-bodies, chlorophyll-grains, or chlorophyll-gran-
ules. It must not be forgotten that chlorophyll is the
staining substance, while the chlorophyll-grain is the stained
protoplasm mass. The two may be separated by alcohol,
which dissolves out the chlorophyll, leaving the grain of
protoplasm.
Practical Studies.—(a) Mount a leaf of a moss and examine for
chlorophyll-grains.
(£) Soak a few moss-leaves in alcohol for some time and note the
decoloration of the chlorophyll-grains. Note the green color given
to the alcohol.
(c)	Mount Green Slime (by scraping ofi the green coating of rocks,
etc.) and note that the whole protoplasm is stained with the chloro-'
pbyll.
(d)	Make sections of a potato-stem grown in darkness. Compare
this with a stem of the same plant grown in light.
(e)	Make sections of blanched celery. Compare with unblanched.
(/) Dissolve out the chlorophyll (by alcohol) from a specimen (any
of the foregoing) and then treat with iodine. Note the brown color
given to the bleached chlorophyll-grains, showing them to be proto-
plasm.
20.	Starch.—Many cells of common plants contain little
grains of starch (Fig. 5). In some cases, as in the potato
tuber, the cells are only partially filled, but in other cases,
as in rice, wheat, Indian corn, etc., the starch is packed so
closely in the cells as to leave very little unfilled space.
21.	The starch of every plant is originally manufactured
in a chlorophyll-body, that is, in a mass of stained proto-
plasm. It moreover forms only in the light, so that plants10
BO TAN Y.
which have no chlorophyll, or which grow in darkness, do
not make starch.
22. Chemically, starch is much like sugar and cellulose,
and like them it is composed of carbon, hydrogen, and
oxygen (C^H^O,,,). It contains water in its organization,
Fig. 5.—A few cells of the seed of a Pea, showing large starch-grains (St) and
the little granules of aleurone (a). At £, i, are shown intercellular spaces. Mag-
nified 800 times.
which may be driven off by heat, or by the application of
reagents, when it loses its structure.
23. Starch is a plant-food. It is produced by the green
protoplasm for the nourishment of the plant. As it forms
only in light, -during the day it accumulates, hut at night
by the continued growth of the plant it is mostly used up.
Whenever there is more made than the plant requires, the
surplus is stored in certain cells for future use.
Practical Studies.—(a) Scrape off a little of the substance of the
cut surface of a potato tuber. Mount in water and examine under
the microscope, using the J- objective. Note the ovate starch-grains,PROTOPLASM AND PLANT-CELLS.
11
which are concentrically striated. Now add a small drop of iodine
and note the blue coloration, which becomes purple or purple-black
if much iodine is used.
(A) Make an extremely thin slice of the potato-tuber and treat as
before, so as to observe starch-grains in
the cells. By staining such a section
with carmine the protoplasm in the
starch-bearing cell may be made evi-
dent.
(c)	Study the starch of wheat, rice,
Indian corn, oats, etc.
(d)	Mount carefully a few threads of
Pond Scum (Spirogyra) which has been
for some hours in the sunlight. Note
the aggregations of minute starch-grains
in the spiral chlorophyll-body (Fig. 6).
Now add iodine and observe the color-
ation of starch-grains.
(e)	Make thin sections of leaves which
have been in the light for some hours,
and observe minute starch-grains in
the chlorophyll-bodies. Use iodine as
above
(/) Make longitudinal sections of
ripened apple-twigs and note the starch
stored' in certain cells of the pith for use
when growth is resumed.
24.	Aleurone.—In mature seeds
and tubers there are commonly to
be found small rounded granules
-	.	,,	- . -	, Fig. 6.—Two plants of Fond
Ot albuminous matter to Which the Scum (Spirogyra), showing spiral
« . ,	.	,	.	chloropnyll-bodies, each with ag-
name ot Aleurone has been given gregatlons of starch. At a and b
,	the cells are beginning to branch
(Fig. 5). It IS, rn part at least, preparatory to uniting. Magni-
fied 500 times.
the protein matter of the older
botanists. It is also identical with what has been called
the gluten of the grains of wheat, rye, oats, etc.
25.	Aleurone is poorly understood, but it appears to be
a dry resting state of protoplasm. Some, if not all, of it12
JSOtANf.
may become active again upon the access of water and the
proper temperature. Possibly some of it serves as food
for protoplasm in the germination of seeds.
Practical Studies.—(a) Mount in alcohol a thin slice of a ripe pea.
Note the small granules (along with large starch-grains) in the cells
(Fig. 5). Apply iodine, which will stain the aleurone yellow or
brownish-yellow.
(b)	Make a similar study of the aleurone of the bean.
(c)	Make sections of the foregoing and mount in water to observe
the solution of the aleurone grains. The process may be hastened
by adding a very little potassic hydrate.
(d)	Make thin cross-sections of a wheat-kernel and study the gluten
(aleurone) cells of the inner bran. Add iodine.
(«) Make a similar study of the bran of rye, oats, and Indian corn.
26.	Crystals.—Some cells of certain plants contain crys-
Fig. 7.—Crystals of calcium oxalate.
The right-hand portion of the figure
shows two cells of the Rhubarb, with
their contained crystals, and one en-
larged. On the left is a crystal from
the beet. Much magnified.
tals (Fig. 7). These are of
various shapes, one of the
most common forms being
needle-shaped, while others
are cubical, prismatic, etc.
They are frequently clus-
tered into little masses.
27.	Crystals are for the
most part composed of cal-
cium oxalate. That is, they
are a combination of lime
and oxalic acid. A few have
a different chemical compo-
sition—as the calcium carbonate crystals found in nettles,
hops, hemp, etc., besides others of still more infrequent
occurrence.
28.	Crystals appear to be the residues from chemical re-
actions which take place in the interior of plants, and they
probably have no further use.PROTOPLASM AND PLANT-CELLS.
13
Practical Studies.—(a) Mount in water several thin longitudinal
sections of the stem of the Spiderwort (Tradescantia) and note the
bundles of needle-shaped crystals in enlarged, thin-walled cells.
Many crystals will be found floating free in the water, having been
separated in the preparation of the specimen.
(6) Similar sections of the stem of the Evening Primrose, Fuchsia,
Balsam or Touch-me-not (Impatieus), and Garden Rhubarb will also
show needle-shaped crystals
(c) Other crystal forms may be obtained from the beet, onion (the
scales), Pigweed or Lamb’s Quarters (Chenopodium), etc.
29.	The Cell-Sap.—All parts of a living cell are satura-
ted with water. It enters into the structure of the cell-
wall ; it makes up the greater part of the bulk of the pro-
toplasm, and it fills the vacuoles. It holds in solution the
food-materials absorbed from the air and soil, and the sur-
plus soluble substances manufactured by the plant.
30.	Among the many substances dissolved in the cell-
sap the more important are Sugar and Inulin. Of the
former there are two varieties, viz., sucrose, or cane-sugar
(C.AA,). and glucose, or grape-sugar (C12H2(OJ, which
differ in their sweetness as well as in other properties.
31.	Cane-sugar exists in great abundance in the cell-sap
of sugar-cane, sugar-maple, sugar-beet, Indian corn, and in
greater or less quantity in nearly all higher plants. Grape-
sugar is found in many fruits, sometimes mixed with cane-
sugar; thus in grapes, cherries, gooseberries, and figs it is
the only sugar present, while in apricots, peaches, pine-
apples, plums, and strawberries it is mixed with cane-sugar.
32.	Inulin (C12H20OJ0) is a soluble substance related to
starch and sugar, which is found mainly in the cell-sap of
certain Composites, as the sunflower, dahlia, elecampane
(Inula), etc.
Practical Studies.—(a) Make a thin section of the stem of any
herbaceous plant, as a Geranium; examine at once without a cover-14
BOTANY.
glass, noting the wateriness. Lay the specimen aside for half an
honr or so, and then note its shrinkage by loss of water.
(b)	Mount a few plants of Pond Scum (Spirogyra) in a very little
water. Examine under the high power of the microscope, and while
doing this flow glycerine under the cover-glass. The glycerine im-
bibing water with great avidity withdraws the water of the cell-sap
from the cells, causing them to collapse.
(c)	The presence of sugar may be demonstrated in many cases by
taste alone, as in the stems of cane and Indian corn.
(d)	Cane-sugar when abundant may be crystallized out (in small
stellate crystals) from cell-sap by the use of strong alcohol or glyce-
rine.
(«) Make thin slices of the root of the sunflower or dahlia, and soak
for some days in alcohol: the inulin will appear in the shape of
sphere-crystals of greater or less size, according as the crystallization
has been slower or more rapid.
(/) The presence of acids in the cell-sap of many plants may be
shown by placing a moist cut surface in contact with blue litmus-
paper. The latter will be distinctly reddened.
Note.—In the study of minute objects it is now the general cus-
tom to use metric measurements. The units used are the millimetre
and the micromillimetre, the former for the larger measurements, the
latter for the smaller. A millimetre equals .0394 of an inch, or
nearly one twenty-fifth of an inch.
For the measurement of objects requiring high powers of the
microscope the micromillimetre is used. It is represented by the
Greek letter n, or by mmm. It is one thousandth of a millimetre,
and equals .0000394 of an inch, or nearly one twenty-five-thousandth
of an inch. A spore is thus said to measure 15 n in diameter, 35 n
in length, etc., or in the absence of the Greek letters we may record
these measurements as 15 mmm. and 35 mmm. In reading the fore-
going we may of course say 15 micromillimetres and 35 micromilli-
metres, but more commonly the contraction micro is used, or even
tlie name of the Greek letter: thus we may say 15 micros, or 15 mu.CHAPTER H.
THE TISSUES OF PLANTS.
33.	Some plant-cells live alone, and are not connected
with any others; some which are at first separate afterward
unite into a cell-colony. In most cases, however, the cells
are united to each other from the beginning of their exist-
ence into what are called tissues.
34.	As understood in this hook a plant-tissue is an assem-
blage of similar cells which have been united with each
other from their beginning. The cells in a tissue may be
arranged in rows, surfaces, or masses: in the first the
growth has been by the fission of cells in one plane only,
in the second from fission in two planes, and in the third
from fission in three planes.
35.	In the lower plants the cells are all alike, or so nearly
so that they constitute hut one kind of tissue. As we
ascend from these simple forms the cells begin to show
differences, some being especially developed for one pur-
pose, and some for another; and these differences become
more numerous and more sharply marked as we approach
the higher plants. This at last gives us many kinds of
tissues, which may be distinguished from each other by
characters of greater or less importance. However, they
may all be brought within seven general kinds, each kind
showing many varieties.
36.	Soft Tissue (Parenchyma).—This is the most abun-
dant tissue in the vegetable kingdom; it is at once the16
BOTANY.
most important and the most variable. It is composed of
cells whose walls are thin, colorless, or nearly so, and trans-
parent; in outline they may be rounded, cubical, polyhe-
dral, prismatic, cylindrical, tabular, stellate, and of many
other forms. When the cells are bounded by plane sur-
faces, generally, but not always, the end planes lie at right
angles to the longer axis of the cells.
37. This tissue makes up the whole of the substance of
many of the lower plants, while in the higher it composes
retain the power of fission. Wet specimens show by trans-
mitted light a characteristic bluish-white lustre, which is
best seen in cross-sections.
39. Thick-angled tissue is found beneath the epidermis
of most flowering plants (and some ferns), usually as a mass
of considerable thickness, and is doubtless developed from
soft tissue for the purpose of giving support and strength
to the epidermis.
the essential portions of the as-
similative (green), vegetative
(growing), and reproductive
parts.
38. Thick - angled Tissue
(Gollenchyma).—The cells of
this tissue are elongated, usu-
ally prismatic, and their trans-
verse walls are most frequent-
Fig. 8.—Cross-section of thick-angled
tissue (cl) of Begonia petiole, showing
the thickened angles, e, epidermis;
chi, chlorophyll-bodies. Magnified 550
times.
The walls are greatly thick-
ened along their longitudinal
angles, while the remaining
parts are thin (Fig. 8). The
cells contain chlorophyll, andTEE TISSUES OF PLANTS.
11
40. Stony Tissue (Sclerenchyma).—In many plants the
hard parts are composed of cells whose walls are thickened,
often to a very considerable extent (Fig. 9). The cells are
usually short, hut in some cases they are greatly elongated;
they are sometimes regular in outline, hut more frequently
they are extremely irregular. They do not contain chloro-
Fig. 9.—Stony tissue. A, from shell of Hickory-nut; B and C, from under-
ground stem of the common Brake (Pteris). Magnified 400 to 500 times.
phyll, hut in some cases (e.g., in the pith of apple-twigs)
they contain starch.
41. Fibrous Tissue.—This is composed of elongated,
thick-walled, and generally fusiform fibres (Fig. 10), whose
walls are usually marked with simple or sometimes bordered
pits. These fibres in cross-section are rarely square or
round, but most generally three- to many-sided. They are
found in, or in connection with, the woody bundles of ferns
B18
botany.
and flowering plants, and give strength and hardness to
their stems and leaves.
42. Two varieties of fibrous tissue may be distinguished,
viz., (l) Bast (Fig. 10, JB), and (2) Wood (Fig. 10, A). The
fibres of the former are usually thicker walled, more flexi-
ble, and of greater length than those of the latter. In both
forms the fibres are sometimes observed to be partitioned.
Fig. 10.—A, wood-fibres of Silver Maple isolated by Schulze’s maceration; B,
bast-fibres; b, b, portions of fibres more highly magnified.
43. Milk Tissue (Laticiferous Tissue).—In many orders
of flowering plants tissues are found which contain a milky
or colored fluid—the latex. For the sake of simplicity two
general forms may be distinguished: (1) that composed of
simple or branching tubes (Fig. 11), which are scattered
through the other tissues. As found in the Spurge family,
they are somewhat simply branched and have very thickTHE TISSUES OF PLANTS.
19
Fig. 11.—Milk-tubes from a Spurge (Euphorbia). A, moderately magnified; B
more highly magnified, and showing the bone-shaped starch-grains.
Fig. 12.—Milk-vessels of a Composite (Scorzonera). A, a transverse section of
the root; B, the same more highly magnified.
walls (Fig. 11, S); in other plants they are thin-walled
and are sometimes inclined to anastomose, From their20
BOTANY.
position it is quite certain that the tubes of this form of
milk-tissue frequently replace bast-fibres. In other cases,
however, they appear not to be of this nature, but to arise
from the soft tissue by the absorption of the horizontal
partition-walls.
44.	(2) The other form is that composed of reticulately
anastomosing vessels. Here the tissue is the result of the
fusion of great numbers of short cells. The walls are thin
and often irregular in outline. In chicory, lettuce, etc.,
this form of milk-tissue is very perfectly developed as a
constituent part of the outer portion of the woody bundles
(Fig. 12, A and _B).
45.	Sieve Tissue.—As found in the flowering plants this
tissue is for the most part made up of sieve-ducts and the
so-called latticed cells. The former (the sieve-ducts) con-
sist of soft, not lignified, colorless tubes of rather wide
diameter, having at long intervals horizontal or obliquely
placed perforated septa. The lateral walls are also per-
forated in restricted areas, called sieve-discs, and through
these perforations and those in the horizontal walls the
protoplasmic contents of the contiguous cells freely unite
(Fig. 13).
46.	The tissue composed of these ducts is generally loose,
and more or less intermingled with soft tissue; in some
cases even single ducts run longitudinally through the sub-
stance of other tissues. In the form described above it is
found only as one of the components of the outer or bark
portion of the woody bundles of plants.
47.	The so-called latticed cells are probably to. be re-
garded as undeveloped sieve-ducts, and hence the tissue
they form may be included under sieve-tissue. Latticed
cells are thin-walled and elongated; they differ from trueTEE TISSUES OF PLANTS.
21
sieve-ducts principally in being of less diameter, and in
having the markings but not the perforations of sieve-discs.
Fig. 13.—Longitudinal section through the sieve-tissue of Pumpkin-stem. q. q,
section of transverse sieve-plates; si, lateral sieve-plate; x. thin places in wall:
l, the same seen in section; ps, protoplasmic contents contracted by the alcohol
in which the specimens were soaked; sp, protoplasm lifted off from the sieve-
plate by contraction; si, protoplasm still in contact with the sieve-plate. Mag-
nified 550 times.
Both of these differences are such as might be looked for
in undeveloped sieve-tissue.
In the corresponding parts of the woody bundles of conifers and
ferus a sieve-tissue is found which differs somewhat from that de-22
BOTANY.
scribed above. In Conifers the sieve-discs, which are of irregular
outline, occur abundantly upon the oblique ends and radial faces of
the broad tubes (Fig. 14). In the Horsetails (Equisetum) and Adder-
tongues (Ophioglossum) they are prismatic, with
numerous horizontal but not vertical sieve-discs;
in Brakes (Pteris) and many other ferns they have
pointed extremities, and are greatly elongated,
bearing the sieve discs upon their sides. In the
larger Club-mosses the sieve-tubes are prismatic
and of great length; in the smaller species there
are tissue elements destitute of sieve-discs, but
which are otherwise, including position iu the
stem, exactly like the sieve ducts of the larger
species.
48. Tracheary Tissue.—Under this head
are to be grouped those vessels which,
while differing considerably in the details,
agree in having thickened walls, which are
generally perforated at the places where
similar vessels touch each other. The
thickening, and as a consequence the per-
forations, are of various kinds, but gener-
ally there is a tendency in the former to
the production of spiral bands; this is
more or less evident even when the bands
form a network. The transverse parti-
tions, which may be horizontal or oblique,
are in some cases perforated with small
openings, in others they are almost or en-
The diameter of the vessels is usually
Fig. 14.—Sieve-tube
of Big-tree of Cali-
fornia (Sequoia gi-
gautea), taken from
the bark of an old
stem. Magnified 375
times.
tirely absorbed,
considerably greater than that of the surrounding cells and
elements of other tissues, and this alone in many cases may
serve to distinguish them. When young they contain pro-
toplasm, but as they become older this disappears, and they
then contain air.THE TISSUES OF PLANTS.
23
Tracheary tissue is found only in ferns and their rela-
tives and the flowering plants. The principal varieties of
vessels found in tracheary tissues are the following:
49.	(1) Spiral Vessels, which are usually long, with fusi-
form extremities; their walls are thickened in a spiral man-
ner with one or more simple or branched bands or fibres
(Fig. 15, v", v”', v""). This form may be regarded as
the typical form of the vessels of tracheary tissue. Ringed
and reticulated vessels are opposite modifications of tl'
spiral form; the first are due to an under-development of
vm v’m ■**"’ V" v’	°
Fig. 15.—Longitudinal section of a portion of the stem of Garden Balsam (Tm-
patiens). v, a ringed vessel; v\ a vessel with rings and short spirals; v'\ a ves-
sel with two spirals; v'" and v"", vessels with branching spirals; v"'"y a vessel
with irregular thickenings, forming the reticulated vessel.
the thickening in the young vessels, resulting in the pro-
duction here and there of isolated rings (Fig. 15, v); reticu-
lated vessels are due, on the contrary, to an over-develop-
ment, which gives rise to a complex branching and anas-
tomosing of the spirals (Fig. 15, v"'").
50.	(2) Scalariform Vessels.—These are prismatic ves-
sels whose walls are thickened in such a way as to form
transverse ridges. They are wide in transverse diameter,
and their extremities are fusiform or truncate (Fig. 16).
51.	(3) Pitted Vessels.—The walls of these vessels are
thickened in such a way as to give rise to pits and dots.24
BOTANY.
The vessels are usually of wide diameter; in some forms
they are crossed at frequent intervals by perforated hori-
zontal or inclined septa (Fig. 17); in other
forms they have fusiform extremities.
52. (4) Tracheids.—These consist for
the most part of single closed cells; other-
wise they possess the characters of vessels.
In one form (Fig. 18), as in the so-called
wood-cells of Conifers, they are interme-
diate in structure between the pitted ves-
sels and the fibres of the wood of other
Fig. 16.
Fig. 17.
Fig. 16.—Sea lari form vessels of the common Brake (Pferis).
Fig. 17.—Pitted vessels of Dutchman’s Pipe (Aristolochia sipho), from a longi-
tudinal section of the stem; the vessel on the right is seen in section, that on
the left from without, a. o, rings, which are remnants of the original trans-
verse partitions; b, 6, sections of the walls.
flowering plants. Every gradation between these tracheids
and the other forms of tracheary tissue occur. In another
form, as in the wood of many common trees and shrubs,
the tracheids are shorter than in the preceding, quiteTHE TISSUES OF PLANTS.
25
regular in their form, and with tapering extremities (Fig.
19). Their walls are but slightly thickened, and are
marked with spirals and pits. When the wall between two
contiguous cells breaks through or becomes absorbed, the
Fig. 18.—Ends of several trachei'ds from the wood of a Pine, showing bordered
pits Magnified 325 times.
Fig. 19.—Tracheids from the stem of Laburnum, m, m, cells of a medullary-
ray. At g, a partition is broken through. Magnified 375 times.
close relation of such tracheids to spiral vessels is readily
seen.
Tracheids may be regarded as composing a less differen-
tiated form of tissue, related on the one hand to true tra-
cheary tissue and on the other to fibrous tissue.26
BOTANY.
Practical Studies.—The student should here make a good many
observations upon the tissues described above, so as to become tho:
oughiy familiar with at least their typical forms. The following out-
line may direct him in his first studies:
I.	Soft Tissue.—(a) Make very thin cross and longitudinal sections
of a green stem of Indian corn. After excluding the woody bundles,
the whole of the central part of the stem is soft tissue.
(6) Make similar sections of the central part of the stem of the cul-
tivated geranium.
(c) Make a very thin cross-section of an apple-leaf: the green
cells are of soft tissue.
(dj Mount a whole moss-leaf: it is entirely composed of soft tissue,
although in its rudimentary midrib the cells have elongated, as if
foreshadowing the higher tissues.
(e) Mount several threads of Pond Scum: the whole plant is here
composed of soft tissue.
II.	Thick-angled Tissue.—(a) Examine a leaf-stalk of the squash or
pumpkin, and note the whitish bands, one or two millimetres wide,
which extend from end to end just beneath the epidermis. These are
hands of thick-angled tissue. They may be readily torn out, when
the stalk will be found to have lost much of its strength.
(b)	Make a very thin cross section of the preceding leaf-stalk, and
note the appearance of the thick angled tissue first under alow power
and then under a higher. The sections must be made exactly at
right angles to the axis of the bands of tissue in order to show well.
(c)	Make a number of longitudinal sections of the same leaf-stalk,
in each case cutting through a band of the thick-angled tissue. Some
of these will show the thickened angles, although there is always some
difficulty in making them out in this section.
(d)	The stems of squash, pumpkin, Pigweed or Lamb's Quarters
(Chenopodium), beet, and many other plants may be taken up next,
and their thick-angled tissue studied in cross and longitudinal sec-
tions.
III.	Stony Tissue.—(a) Break the shell of a hickory-nut, and after
smoothing the broken surface cut off a very small thin slice; mount
in water and a little potassic hydrate: the cell walls are so greatly
thickened as to almost obliterate the cell-cavity.
(b)	Study similarly the stony tissue of the cocoa-nut, walnut, peach,
cherry, etc.
(c)	Make cross-sections of the seed-coat of tlie apple, squash, melot
wild cucumber(Echinocystis), etc. It is instructive to make sections,
also, parallel to the surface of the seeds.
(d)	Make longitudinal sections of the pith Of apple-twigs and noteTEE TISSUES OF PLANTS.
27
that some of the cells have thickened walls. These are very hard,
and are to be regarded as a form of stony tissue. They contain starch.
IV.	Fibrous Tissue.—(a) Split a young maple-twig, then with the
scalpel start a thiu longitudinal radial section, completing it by tear-
ing it off. Mount in water. The torn end will show good wood-
fibres.
(A) Make a very thin cross-section of the wood of the same twig,
using a very sharp scalpel. Note the angular shape of the wood-
fibres in this section.
(c)	Make a cross-section of the bark of the same twig and note the
white bundles of bast-fibres, each fibre having greatly thickened
walls and a very narrow cell-cavity.
(d)	Now make several longitudinal sections of the same twig so as
to cut through one of the bundles of bast-fibres. Note the great
length of the bast-fibres.
(e)	Make cross-sections of the wood of various trees, as oak, hick-
ory, elm, ash, poplar, willow, and basswood, and note the differences
in the amount and compactness of their fibrous tissue.
(/) To isolate the wood-fibres, make a number of sections as in (a)
above, then heat for a minute or less in nitric acid and potassium
chlorate. The fibres may now be separated under a dissecting micro-
scope, or the specimens may be transferred to a glass slide and dis-
sected by tapping gently upon tbe centre of the cover-glass. This is
known as Schulze’s maceration.
V.	Milk-Tissue.—In studying milk-tissue it is necessary first to
examine a drop of the milk (latex) under the microscope by trans-
mitted light. When so examined it presents quite a different appear-
ance from that by ordinary reflected light: thus white latex appears
to be light granular brown.
(а)	Make thin longitudinal sections of the stem of a Milkweed
(Asclepias). By careful searching, tubes containing latex (appearing
light granular brown) may be seen.
(б)	Make a similar study of the stem of the large Spurge (Euphor-
bia) of the greenhouses. Its milk-tissue is thick-walled and easily
made out.
(c)	The more complex or reticulated forms of milk-tissue may be
obtained from the stems of wild lettuce, garden-lettuce, poppy, and
blood-root.
(d)	Collect a quantity of latex of a Spurge or Milkweed in a watch-
glass and slowly evaporate it: the residue will be found to consist of
a sticky, elastic material resembling india-rubber.
VI.	Sieve-Tissue.—As sieve-tissue is always found in the woody
bundles which run lengthwise through the higher plants, it is neces-28
BOTANY.
sary first to make a cross section of the stem to be studied in order to
determine exactly the position of such bundles. It must be borne in
mind that in most cases the sieve-tissue is confined to the outer side
of the bundle, that is, to the side which faces the circumference of
the stem. In the pumpkin, squash, melon, and related plants the
bundles contain sieve-tissue on both outer and inner sides, that is on
the side which faces the axis of the stem as well as on that which
faces the circumference. This double nature of the bundles of these
plants must be remembered in studying their sieve-tissue.
(a) Make a longitudinal radial section through one of the larger
bundles of the stem of the pumpkin. The sieve-tissue will be distin-
guished by the thick-looking cross-partitions (this is mainly due to
the adhesion of the protoplasm to the walls). By adding alcohol or
glycerine the protoplasm of each cell may be contracted as in Fig. 13.
In some cases where the partitions are oblique the perforations may
be seen.
(4) Make very thin cross-sections of pumpkin-stem and examine
carefully for sieve-plates. Where the section is made close to a plate
it may be easily seen in such a specimen.
(c)	Make similar studies of the stem of the Indian corn.
VII. Tracheary Tissue.—Here, as in the preceding, it is necessary,
especially in herbaceous plants, to first determine by a cross-section
the position of the woody bundles, as tracheary tissue is always con-
fined to them.
(a) Make a thin longitudinal radial section through a bundle of the
stem of the Garden Balsam or Touch me-nol (Impatiens). If success-
fully made it will show successively, passing outward, ringed, spiral,
reticulated, and sometimes scalariform and pitted vessels, with grada-
tions from one to the other, as in Fig. 15.
(4) Make a thin cross section of the same and study carefully in
connection with the foregoing.
(c)	Make similar sections of the bundles of Indian corn. The large
vessels which can be seen with the naked eye in cross section are
pitted.
(d)	Study in like manner the tracheary tissue in the bundles of the
pumpkin-stem. Here the large pitted vessels (which are very dis-
tinctly visible to the naked eye) have their walls thrown into numer-
ous folds.
Note.—The large pores which are so distinctly visible in oak, chestnut, hick-
ory, walnut, ash, and many other kinds of woods are pitted vessels like those of
the Indian corn and pumpkin.
(e)	Excellent scalariform vessels may be obtained from the bundles
of the leaf stalks of ferns, or better still from the underground stem.THE TISSUES OP PLANTS.
29
In the latter the bundles lie adjacent to the thick dark bands of fibrous
tissue.
(/) The trachei'ds of Conifers (pines, spruces, etc.) make up very
nearly the whole bulk of the wood of these trees. Make a longi-
tudinal radial section of a pine-twig by the method employed in
studying fibrous tissue (IV. a, above). Note that the trachei'ds bear
some resemblance to the wood-fibres of other wood. However, their
large round bordered pits are characteristic.
(g) Make longitudinal tangential sections of the same twig. Note
that the bordered pits are not seen (except in section) in specimens so
made.
(/t) Make cross-sections of the same twig and note that the tissue is
homogeneous. Compare with a similar section of an oak-twig, and
note the absence in the pine of the large pitted vessels which are so
well shown in the oak.
(i)	Make very thin longitudinal radial sections of the wood of hack-
berry. By careful examination trachei'ds may be found resembling
the wood-fibres, but marked with fine spirals.
(j)	Similar trachelds may be found intermingled with the wood-
fibres of other trees, as the maple, box-elder, elm, etc.
53.	The Primary Meristem. — Under this name are
grouped the unformed and growing tissues found at the
ends of young stems, leaves, and roots. In these parts the
tissues described above (paragraphs 36 to 52) have not yet
formed; they are, on the contrary, composed entirely of a
mass of thin-walled, growing, and dividing cells contain-
ing an abundance of protoplasm. In the lower plants the
meristem-cells do not change much in their configuration
or general structure as they develop into the ordinary
plant-cells; but the higher the type of plant, the greater
are the changes which take place during the development
of meristem into permanent tissues.
54.	In most plants aside from the flowering, plants the
primary meristem is the result of the continually repeated
division of a single mother-cell situated at the apex of the
growing organ. In the sirrHest forms this apical cell30
BOTANY.
is the terminal one of a row of cells, as in many seaweeds
and fungi. The apical cell, in such cases, keeps on grow-
ing in length, and at the same time horizontal partitions
are forming in its basal portion. In this way long lines
of cells may originate.
55. In the more complicated cases the segments cut off
from the apical cell grow and subdivide in different planes,
so as to give rise to masses of cells. The partitions which
Fig. 20.—Longitudinal section of apex of stem of a Moss (Fontinalis antipy-
retica). v, apical cell; z. apical cell of lateral leaf-forming shoot, arising below
a leaf; c, first cell of leaf; 6, b, b, cells forming cortex.
successively divide the apical cell are sometimes perpendic-
ular to its axis, but more frequently they are oblique to it.
In most mosses, for example (Fig. 20), the apical cell is a
triangular, convex-based pyramid, whose apex is its proxi-
mal portion. The successive segments are cut off from the
apical cell by alternate partitions parallel to its sides, thus
giving rise to three longitudinal rows of cells. Most ferns
and their relatives have an apical cell not much differentTHE TISSUES OF PLANTS.
31
from that of the majority of mosses. In Horsetails, for
example, it is an inverted triangular pyramid, having a
convex base. The segments (daughter-cells) are cut off by
alternating partitions parallel to the plane sides of the
pyramid, as in the mosses. In some mosses and ferns, how-
ever, the apical cell is wedge-shaped—i.e., with only two
surfaces—and in such cases two instead of three rows of
meristem-cells are formed.
56.	In the flowering plants the primary meristem is de-
veloped from a group of cells, instead of from a single one;
they therefore have no apical cell. This group of cells
occupies approximately the same position in the organs of
flowering plants as the apical cell does in the mosses and
ferns; it is composed of cells which have the power of
indefinite division and subdivision.
57.	The apical cell and its actively growing daughter-
cells in its immediate.vicinity, or, in the case of the flower-
ing plants, the apical group of cells with their daughter-
cells, constitute the Growing Point or Vegetative Point
(punctum vegetationis) of the organ. When this active
portion is conical in shape it is also called the Vegetative
Cone.
Practical Studies.—(a) Make very thin longitudinal sections of a
root of Indian corn. The large strong roots which first start out
from the germinating grain, and the youngest states of those which
appear just above the ground, upon the large plants, are best for
these specimens. Stain some of the sections with carmine.
(5) Make very thin longitudinal sections of the opening buds of the
lilac or elder.
(c)	Make similar sections of the tips of the young shoots of aspara-
gus. Stain with carmine.
(d)	Make cross and longitudinal sections of the youngest states
of the stems of the pumpkin, squash, and asparagus, and compare
with similar sections of older parts.CHAPTER HI.
THE GROUPS OF TISSUES, OR TISSUE-SYSTEMS.
58.	The Differentiation of Tissues into Systems.—It rarely
happens that the tissues which compose the body of a plant
are uniform. In the great majority of cases the cells of the
primary meristem become differently modified, so as to give
rise to several kinds of tissues. The outer cells of the
plant become more or less modified into a boundary tissue,
and the degree of modification has relation to its environ-
ment. Certain inner cells, or lines of cells, become modi-
fied into stony tissue, or some other supporting tissue
(thick-angled, or fibrous tissue), and here again there is a
manifest relation to the environment of the plant.
59.	Certain other inner cells, or rows of cells, become
modified into tubes affording a ready means for conduction,
and appear to have a relation to the physical dissociation
of the organs of the higher plants, in which only they occur.
Thus, in physiological terms, there may be a boundary tis-
sue, a supporting tissue, and a conducting tissue lying in
the mass of less differentiated ground-tissue.
60.	In different groups of plants the elementary tissues
described in previous pages are aggregated in different
ways, and are variously modified to form these bounding,
supporting, and cpnducting parts of the plant. Several
tissues, or varieties of tissue, are regularly united or aggre-
gated in particular ways in each plant, constituting whatGROUPS OF TISSUES, OR TISSUE-SYSTEMS. 33
may be called Groups or Systems of Tissues. A Tissue-
system may then be described as an aggregation of elemen-
tary tissues, forming a definite portion of the internal
structure of the plant.
61.	From what has already been said, it is clear that sys-
tems of tissues do not exist in the lowest plants, and that
they reach their fullest development only in the highest
orders. It is evident also that these systems have no ex-
istence in the youngest parts of plants, but that they result
from a subsequent development.
62.	Many systems of tissues might be enumerated and
described; but here again, as with the elementary tissues,
while there are many variations, there are also many grada-
tions, having on the one hand a tendency to give us a long
list of special forms, and on the other to reduce them to
one, or at most to two or three.
63.	The three systems proposed by Sachs are instructive,
and will be followed here; they are: (l) the Epidermal
System, composed mainly of the boundary cells and their ap-
pendages (hairs, scales, breathing-pores, etc.); (2) the Fun-
damental System, which includes the mass of unmodified or
slightly modified tissues found in greater or less abundance
in all plants (excepting the lowest); (3) the Fibro-vascular
System, comprising those varying aggregations of tissues
which make up the string-like masses or woody bundles
found in the organs of the higher plants.
64.	The Epidermal System of Tissues.—This is the sim-
plest tissue-system, as it is the earliest to make its appear-
ance, in passing from the lower forms to the higher. It is
also (in general) the first to appear in the individual devel-
opment of the plant. It is sometimes scarcely to be sepa-
rated from-the underlying mass, as in most lower plants;34
BOTANt.
but in mo?t higher plants it frequently attains some degree
of complexity, and is sharply separated from the underly-
ing ground-tissues.
65.	In the simpler epidermal structures of the lower
plants the cells are generally darker colored, smaller, and *
more closely approximated than they are in the subjacent
mass; in some of the higher fungi a boundary tissue may
be easily separated as a thickish sheet, but probably in such
case a portion of the underlying mass is also removed. In
many lower plants there is absolutely no differentiation of
an epidermal portion.
66.	The epidermal systems of ferns and flowering plants
consist usually of three portions: (1) a layer of more or less
modified parenchyma—the epidermis proper—bearing two
other kinds of structures which develop from it, viz., (2)
hairs, and (3) breathing-pores.
67.	Epidermis.—The differentiation of parenchyma in
the formation of epidermis, when carried to its utmost ex?
tent, involves three modifications of the cells, viz., change
of form, thickening of the walls, and disappearance of the
protoplasmic contents.
68.	These may occur in varying degrees of intensity;
they may all be slight, as in many aquatic plants and in the
young roots of ordinary plants; or the cells may change
their form, while there may be little thickening of their
walls, as in other aquatic plants and some land-plants
which live in damp and shady places; or, on the other hand,
the change of form of the cells may be but little, while
their walls may have greatly thickened, resulting in a dis-
appearance of their protoplasm, as may be seen in parts of
some land-plants which grow slowly and uniformly. When
the differentiation of epidermis is considerable, it can usu-GROUPS OF TISSUES, OR TISSUE-SYSTEMS. 35
ally be readily removed as a thin transparent sheet of col-
orless cells.
69.	The change in the form of the epidermal cells is due
to the mode of growth of the organ of which they form a
part; the lateral and longitudinal growth of an organ causes
a corresponding extension and consequent flattening of the
cells; if the growth has been mainly in one direction, as in
the leaves of grasses, or if the growth in two directions has
been regular and uniform, the cells are quite regular in
outline; where, however, the growth is not uniform the
cells become irregular, often extremely so (Fig. 24, page 38).
70.	The thickening of the walls is greatest in those plants
and parts of plants which are most exposed to the drying
effects of the atmosphere. It consists of a thickening of
the outer walls, and frequently of the lateral ones also.
71.	The outer portion of the thickened walls sometimes
separates as a continuous pellicle, the so-called cuticle,
which extends uninterruptedly over the cells, and may be
readily distinguished from the other portions of the outer
epidermal walls. It is insoluble in concentrated sulphuric
acid, but may be dissolved in boiling caustic potash.
Treated with iodine it turns a yellow or yellowish-brown
color. A waxy or resinous matter is frequently developed
upon the surface of the cuticle, constituting what is called
the bloom of some leaves and fruits.
72.	The protoplasm of the epidermal cells generally dis-
appears in those cases where there is much thickening of
the walls; it is always present in young plants and parts
of plants; it is also frequently present in older portions,
which are not so much exposed to the drying action of the
atmosphere, as in roots, and the leaves and shoots of aquatic
plants and of those growing in humid places. In few36
BOTANY.
cases, however, are granular protoplasmic bodies (e.g.,
chlorophyll) present in epidermal cells.
73. While the epidermis always consists at first of hut
one layer of cells, it may become split into two or more
Fig. 21.	Fia. 22.
Fig. 21.—Transverse section of epidermis and underlying tissue of ovary of a
squash, a, hair of a row of cells; b and d. glandular hairs of different ages;
e, /. c, hairs in the youngest stages of their development. Magnified 100 times.
Fig. 22.—A seedling mustard-plant with its single root clothed with root-hairs;
the newest (lowermost) portion of the root is not yet provided with root-hairs,
layers by subsequent divisions parallel to its surface, as in
the Oleander and Cactus.
74. The Hairs of the epidermis originate mostly from the
growth of single epidermal cells, and on their first appear-
ance consist of slightly enlarged and protruding cells (Fig.
21, e, f, c). These may elongate and form single-celledGROUPS OF TISSUES, OR TISSUE-SYSTEMS. 37
hairs, which may be simple or variously branched. The
most important of these hairs are those which clothe so
abundantly the young roots of most of the higher plants,
and to which the name of Root-hairs has been applied
(Fig. 22). These are composed of single cells, which have
very thin and delicate walls, and are the active agents in
the absorption of nutritive matters for the plant. Some-
times the terminal cell of a hair becomes changed into a
Fig. 23.—Glandular hairs of Chinese Primrose in several stages of develop-
ment. Magnified 142 times.
secreting cell and manufactures a gummy or resinous sub-
stance. Such hairs are called Glandular Hairs and are com-
mon on many plants (Fig. 23).
75. Breathing-Pores (stomata; singular, stoma) consist,
in most eases, of two specially modified chlorophyll-bear-
ing cells, called the guard-cells, which have between them
a cleft or slit passing through the epidermis (Fig. 24).
These openings are always placed directly over interior
intercellular spaces.38
BOTANY.
76. They occur on aerial leaves and stems most abun-
dantly, being sometimes exceedingly numerous, and are
exceptionally found elsewhere, as on the parts of the flow-
ers. On submerged or underground stems and leaves they
are found in less numbers, and from true roots they are
always absent. The breathing-pores on leaves are gener-
ally confined to the lower surface, and when present on the
Fig. 24.—A bit of the epidermis of Wild Cucumber (Echinocystis), showing
breathing-pores at s, s, s. At g, g, the epidermal cells are irregular; at v, over a
vein, they are more regular. Magnified 250 times.
upper they are usually much fewer in number; there are,
however, some exceptions to this.
77. In the light, under certain conditions of moisture and
temperature, the guard-cells become curved away from
each other in their cpnti’al portions, thus opening the slit
and allowing free communication between the external air
and that in the intercellular spaces and passages of the leaf.GROUPS OF TISSUES, OR TISSUE-SYSTEMS. 39
The number of breathing-pores has been determined for many
leaves. The following table will give an idea of their abundance on
some common leaves:
	In one square millimetre.		In one square inch.	
	Upj)er	Under side.		Under side.
Olive (Olea europea)		0	625	0	403,125
Black Walnut (Juglaus nigra).... Red Clover (Trifolium prateuse).	0	461	0	298,345
	207	335	133,515	216,075
Lilac (Syringa vulgaris)		0	330	0	212,850
Sunflower (Helianthus annuus)..	175	325	112,875	209,625
Cabbage (Brassica oleracca)		138	302	88,910	194,790
Sycamore (Platauus occidentalis). Lombardy Poplar (Populus dila	0	278	0	179,310
tata) 		55	270	35,475	174,150
Hop (Humulus lupulus)		0	256	0	165,120
Plum (Prunus domestica)		0	253	0	163,185
Apple (Pirus malus)		0	246	0	158,670
Barberry (Berberis vulgaris)		0	229	0	147,705
Pea (Pisum sativum)		101	216	65,145	139,320
Box (Buxus sempervirens)		0	208	0	134,160
Cherry (Prunus malialeb)		0	204	0	131,580
Thorn-apple(Datura stramonium)	114	189	73.530	121,905
Indian Corn (Zea mais)		94	158	60,630	101,910
Cottonwood (Populus monilifera) Wind-flower (Anemone nemoro-	89	131	57,405	84,495
sa)		0	67	0	43,215
Lily (Lilium bulbiferum)		0	62	0	39,990
Iris (Iris germanica)		65	58	41,925	38,410
Oats (Avena sativa)		48	27	30,960	17,415
Practical Studies.—(a) Strip oil a bit of the epidermis of a Live-
for-ever leaf. Mount it in alcohol to avoid air-bubbles, and after-
wards add water and a little potassic hydrate. Epidermal cells and
breathing-pores may be well seen.
(b)	Prepare in like manner the epidermis of both upper and under
surfaces of a cabbage-leaf. Note the breathing-pores on both sur-
faces; note also the bloom.
(c)	Make very thin cross-sections of a cabbage-leaf (by placing a
piece of leaf between two pieces of elder-pith) so as to secure cross-
sections of the epidermis. Note the thickened outer wall of the epi-40
BOTANY.
dermal cells. In some cases tlie separable cuticle may be seen. Now
and then a breathing-pore may be seen in cross-section.
(d)	Make similar sections of the leaf of the oleander, cactus, com-
pass-plant, holly, or any others of a hard texture. Note in some cases
(oleander and cactus) that there are several layers of epidermal cells.
(e)	Mount in alcohol a few hairs of tickle-grass (Panicum capillare)
as examples of simple one-celled hairs.
(/) Mount in like manner hairs of petunia, verbena, or walnut as
examples of hairs made of a row of cells. Note that many of these
are glandular.
(g) Mount in like manner hairs of the mullein as examples of
greatly branched hairs.
78.	The Fibro-vascular System.—In most of the higher
plants portions of the interior tissues early become greatly
differentiated into firm elongated bundles, which run
through the other tissues. They are composed for the
most part of tracheary, sieve, and fibrous tissues, together
with a varying amount of parenchyma, and have a general
similarity of arrangement and aggregation. In a few cases
milk-tissue is associated with those above mentioned. To
these collections of tissues the name of Fibro-vascular
Bundles has been given. They are also called Woody
Bundles and Vascular Bundles, but the name first given is
to be preferred.
79.	In many plants the fibro-vascular bundles admit of
easy separation from the surrounding tissues; thus in the
Plantain (Plantago major) they may readily be pulled out
upon breaking the leaf-stalk. In the leaves of plants,
where they constitute the framework, they are, by macera-
tion, readily separated from the other tissues as a delicate
network. In the stems of Indian corn the bundles run
through the internodes as separate threads of a considera-
ble thickness.
80.	In the fibro-vascular bundle of the stem of IndianGROUPS OF TISSUES, OR TISSUE-SYSTEMS. 41
corn the central portion is composed of tracheary tissue,
consisting of pitted, spiral, ringed, and reticulated vessels
Fig. 25.—Transverse section of fibro-vaseular bundle of Indian corn, a, side
of bundle looking toward the circumference of the stem; i, side of bundle look-
ing toward the centre of the stem; g, g, large pitted vessels; s, spiral vessel; r,
ring of an annular vessel; l. air-cavity formed by the breaking apart of the sur-
rounding cells; v, u, latticed cells, or soft bast, a form of sieve-tissue. Magnified
550 times.
(Fig. 25, g, g, s, r, and the tissue between v—s, g—g).
Lying by the side of the tracheary tissue (on its outer side42
BOTANY.
as it is placed in the stem) is a mass of sieve-tissue, com-
posed of latticed cells (v, v, Fig. 25). Surrounding the
whole is a thick mass of fibrous tissue composed of elon-
Fig. 26.—Fibro-vasoular bundle of Castor-oil Plant, t, t, g, g, tracheary tissue;
y, y, sieve-tissue poorly developed; 6, b, bast-fibres; c, c, cambium-cells. High-
ly magnified.
gated, thick-walled cells (the shaded ones in the figure).
81. In the Castor-oil Plant the limits of the fibro-vascular
bundles are so poorly marked that in places it is impossibleGROUPS OF TISSUES, OR TISSUE-SYSTEMS. 43
to tell whether the tissues belong to them or to the sur-
rounding ground-tissues. The inner portion of the bundle
(g, g, t, t, Fig. 26, and s to t, Fig. 27) is made up of trache-
ary tissue of several varieties; on the inner edge of this
tracheary portion lie several spiral vessels (s, s, Fig. 27);
next to these, on their outer side, are scalariform and pitted
Fig. 27.—A longitudinal radial section of the bundle in Fig. 26.
vessels (t, t,g,g, Fig. 26; l,t, t', Fig. 27), intermingled with
elongated cells, whose walls are pitted (h, h', h", h"', Fig.
27). The last-named are . clearly related to the vessels
which surround them, and from which they differ only in
their less diameter, and in having imperforate horizontal
or oblique partitions. They are doubtless properly classed
with the tracheids (see paragraph 52).
82. On the outer side of the tracheary portion just de-
scribed lies a mass of narrow, somewhat elongated, thin-44
Botany.
walled cells, which constitute a true meristem-tissue, tt>
which the name of Cambium* has been given (c,c, Figs. 26
and 27). Next to the cambium lie, in order, sieve-tissue
and soft tissue (parenchyma); these do not occupy separate
zones, hut are more or less intermingled, forming a mass
Fig. 28.—Fibro-vascular bundle of root of Sweet Flag (Acorus). pp. plates of
tracheary tissue; g, g, pitted vessels; ph, sieve-tissue; s, bundle-sheath.
called the Soft Bast (y, y, y, Fig. 26, andp, Fig. 27). The
sieve-tissue includes sieve-tubes and cambiform or latticed
cells. In the extreme outer border of the bundle is a mass
of fibrous tissue (b, b). The layer of starch-bearing cells
* Cambium, a low Latin word meaning a liquid which becomes glutinous.
The term was introduced when the real structure of the part to which it was
applied was not understood.GUO UPS OP TISSUES, OR TISSUE-SYSTEMS. 45
just outside of the last-named tissue is the so-called “bun-
dle-sheath.”
83.	In most higher flowering plants the fibro-vascular
bundles of the stems have a structure essentially like that
of the Castor-oil Plant just described. In them it is evi-
dent at a glance that the bundle is divided into two some-
what similar portions, an inner and an outer, by the cam-
bium zone. Nageli, who first pointed out these divisions,
named the inner one the Xylem portion, because from it
the wood of the stem is formed; the outer he named the
Phloem portion, for the reason that it develops into bark.
If we wish to be less technical we may call the first the
Wood portion, and the second the Bark portion.
84.	In some cases the xylem and phloem are composed
of corresponding tissues, (.1) Vessels, (2) Fibres, and (3)
Soft Cells. The vessels are the tracheary tissue in the
xylem and the sieve-tissue in the phloem. The fibrous
tissue of the xylem is the variety with the shorter and
harder fibres, known as wood-fibres; that of the phloem is
composed of the longer and tougher bast-fibres. The soft
tissue (parenchyma) of the two portions is much alike.
85.	In the fibro-vascular bundle of the young roots of.
Sweet Flag there are many radially placed plates of trache-
ary tissue (pp, Fig. 28), which alternate with thick masses
of sieve-tissue (pli). Between these alternating tissues, and
within the circle formed by them, there is a mass of soft
tissue. The whole bundle is separated from the large-celled
soft tissue of the root by a well-marked bundle-sheath (s);
the latter is bounded interiorly by a layer of active thin-
walled cells (the pericambium), from which new roots origi-
nate. In the older roots the central cell-mass is trans-
formed into stony tissue.46
So TANY.
86. The bundle of the larger Club-mosses (Lycopodium)
contains several parallel plates of tracheary tissue. Between
the tracheary plates there is in each case a row of sieve-
tubes imbedded in a lignified tissue composed of elongated
cells (stony, or fibrous tissue?). Around this central fibro-
vascular portion there is a layer of soft tissue (parenchy-
ma), and outside of this a bundle-sheath, exterior to which
Fig. 29.—Magnified cross-section of the stem of a larger Club-moss (Lyco-
podium complanatum), showing a fibro-vascular bundle.
lies a thick mass of fibrous tissue completely enveloping all
the previously described tissues.
87. The bundle in the smaller Club-mosses (Selaginella)
is much like a single plate of the preceding. There is in
each bundle a central plate of tracheary tissue, consisting
of a few narrow spiral vessels in its two edges and a re-
maining mass of scalariform vessels (Fig. 30). The tra-
cheary portion is surrounded by a tissue of elongated, thin-
walled tissue which is, at least in part, a sieve-tissue. InGROUPS OP TISSUES, OR TISSUE-b. STEMS. 47
this and allied species the bundles are curiously isolated
from the surrounding ground-tissues of the stem.
88. The fibro-vascular bundle of the underground stem
of the common Brake-fern (Pteris) is composed of trache-
Fig. 30.—Magnified cross-section of the stem of a smaller Club-moss (Selagi-
nella inaeouifolia), showing three bundles.
ary, sieve, and soft tissues and a small amount of poorly
developed fibrous tissue. In transverse section the bundle
has usually an elliptical outline. The great mass of the
bundle is made up of large scalariform vessels, which
occupy its interior (g,g,g, Fig. 31). Enclosed in the sea-48
Botany.
lariform tissue are masses of soft tissue (parenchyma) and
a few spiral vessels, the latter occurring near the foci of
the elliptical cross-section of the bundle (s). Surrounding
or partly surrounding the tracheary portion of the bundle
is a layer of sieve-tubes (sp), separated from the large sea-
Fig. 31.—Part of a transverse section of the fibro-vascular bundle of the under-
ground stem of the common Brake-fern (Pteris aquilina). s, spiral vessel; <7, g, .
scalariform vessels; sp, sieve-tissue; 6, fibrous tissue; sg, bunale-sheath.
lariform vessels by a layer of parenchyma. Outside of the
sieve-tissue is a mass of fibrous tissue (b), which is itself
bounded externally by another layer of parenchyma. The
whole bundle is surrounded by a bundle-sheath,
89. A noticeable feature in the structure of this bundleGROUPS OP TISSUES, OR TISSUE-SYSTEMS. 49
is that the tissues have a concentric arrangement: the tra-
cheary tissue is encircled by a layer of parenchyma; this
by one of sieve-tissue; this again by fibrous tissue; and
so on.
90.	De Bary’s classification of fibro-vascular bundles is
useful in designating their general plan. He includes all
forms under three kinds, viz., (1) the Collateral bundle,
which has one mass of xylem by the side of a single mass
of phloem; (2) the Concentric bundle, which has its tissues
arranged concentrically around one another; (3) the Radial
bundle, which has its tissues arranged radially about its
axis.
91.	The development of the fibro-vascular bundle takes
place in this wise: in the previously uniform primary
meristem there arises an elongated mass of cells, consti-
tuting the Procambium of the bundle; as it grows older
the cells, which were at first alike, become changed into
the vessels, fibres, and other elements of the bundle-tissues.
In most higher flowering plants this change begins on the
two sides of the bundle—i.e., on the outer edge of the
phloem and the inner edge of the xylem; from these points
the change into permanent tissue advances from both sides
toward the centre of the bundle.
92.	In some cases all of the procambium is changed into
permanent tissue, forming what is termed the closed bun-
dle; in other cases there is left between the phloem and
xylem a narrow zone of the procambium (now called the
cambium), forming what is known as the open bundle.
Closed bundles are thus incapable of further growth, while
open bundles may continue to grow indefinitely.
93.	The fibro-vascular bundles of leaves and the repro-
ductive organs are quite generally reduced by the absence50
BOTANT.
of one or more tissues; this reduction may be so great as
to leave but a single tissue, which in many cases is com-
posed of only a few spiral ves-
sels or tracheids (Fig. 32). In
other cases, instead of spiral
vessels the bundle may consist
of a few fibres of bast; or of
elongated, thin - walled cells,
which are doubtless to be re-
garded as meristem-cells which
failed to fully change into one
of the ordinary permanent tis-
sues: this last is a very com-
mon accompaniment of reduced
bundles.
Practical Studies. — (a) Break a
stem of the Indian corn and note
with the naked eye the tough string-
like fibro-vascular bundles which run
through the soft tissues. Examine
in like manner the fibro-vascular
v^uirr^udtes^^atearreduced bundles of the common door-yard
to tracheids and spiral vessels.	Plantain.
(4) Make a very thin cross-section
of the stem of Indian corn and, using the microscope, study the bun-
dles carefully by comparing with Fig. 25. In bundles from young
stems the fibrous tissue will not show as good a development as in
the figure.
(c)	Now make thin longitudinal sections of a bundle in such a man-
ner as to have the sections pass through a and i in the figure. This
may be done by slicing the stem in a longitudinal radial direction.
Study again by comparison with the figure and with the previous
specimen.
(d)	Make thin longitudinal sections of a bundle at right angles to
the last (by longitudinal tangential sections of the stem).
(e)	Study in like manner the bundles of sugar-cane and asparagus.
(/) Study by similar sections the bundles of the young stem ofGROUPS OF TISSUES, OR TISSUE-SYSTEMS. 51
the Castor-oil Plant anrl Red Clover. The latter is very convenient
for study, as the uppermost joints will furnish as young bundles as
are required, while lower down all older stages may be obtained. In
these note the cambium-zone.
(g) Make very thin cross-sections of a root of germinating Indian
corn. The first section should be made within a few millimetres of
the root-tip. Others should then be made at a greater distance. By
staining the specimens with carmine the sieve-regions maybe demon-
strated better. Note the bundle-sheath
(/t) Study in like manner the bundle in the stem of the Club-mosses
(some of the species are known as Ground-pines), and if possible make
comparison with sections of the smaller Club-mosses (grown in green-
houses often under the name of Lycopodium, although they are in
reality species of Selaginella).
(?) Dig up the underground stem of the common Brake-fern
(Pteris); preserve what is not wanted immediately in alcohol. The
bundles may be seen by the naked eye by making a clean cross-cut
and examining carefully in the region immediately surrounding the
two dark masses of fibrous tissue. Make thin cross-sections and study
with the microscope, comparing with Pig. 31. Longitudinal sections
in two planes should be made as in c and d above.
(j) Make very thin longitudinal sections of some of the reduced
bundles which constitute veins and veinlets of leaves, e.g., in gera-
nium and primrose.
(/<:) Make similar sections of the bundles of petals, e.g., fuchsia.
(0 Soak petals of fuchsia for several days in potassic hydrate, then
wash in water and carefully mount iu pure water. The reduced
bundles may generally be well seen by this treatment.
94. The Fundamental System of Tissues.—This system
includes all the tissues which in any part of a plant fre-
quently make up the bulk of that part, but are not included
in the epidermal or fibro-vascular systems. Thus if from
any stem, for example, we should strip off the epidermis
and then pull out the fibro-vascular bundles, that which
remained would be the Fundamental System of Tissues. In
those plants (of the lower orders) which have no fibro-
vascular bundles everything inside of the epidermis belongs
to the fundamental system. On the other hand, in the52
BOTANY.
stems of our woody trees there is but very little of the fun-
damental system present, making up the very small pith and
the thin plates (medullary rays) running radially through
wood and bark.
95.	In its fullest development the fundamental system
may contain soft tissue (parenchyma) of various forms,
thick-angled tissue, stony tissue, fibrous tissue, and milk-
tissue. Their arrangement, within certain limits, presents
a considerable degree of similarity in nearly related groups
of plants, but this is by no means as marked as in the case
of the jibro-vascular system.
96.	(l) Soft tissue (parenchyma) is the most constant of
the fundamental tissues; it makes up the whole of the in-
terior plant-body in those plants where there has been no
differentiation into more than one tissue, and it is present
in varying amounts in all plants up to and including the
highest.
97.	(2) Thick-angled tissue (collenchyma) when present,
as it generally is in the stems and leaves of flowering
plants, is always either in contact with or near to the epi-
dermis.
98.	(3) Stony tissue (sclerenchyma) is common beneath
the epidermis of the stems and leaves of flowering plants and
ferns, and the stems of mosses. It sometimes appears to
replace thick-angled tissue. Some elongated forms of stony
tissue are scarcely to be distinguished from fibrous tissue.
99.	(4) Fibrous tissue occurs in some leaves and stems
near to the epidermis. In ferns it forms thick band-like
masses, giving strength to*the stems.
100.	(5) Milk-tissue (laticiferous) may occur, apparently,
in any portion of the fundamental system of flowering
plants,GROUPS OF TISSUES, OR TISSUE-SYSTEMS. 53
101. It is thus seen that in general the tissues of the
fundamental system are so disposed that the periphery is
harder and firmer than the usually soft interior, although
there are many exceptions. This general structure has
given rise to the term Hypoderma for those portions of the
fundamental system which lie immediately beneath or near
to the epidermis. Hypoderma is not a distinctly limited
portion—in fact, it is often difficult to say how far it does
extend; however, it usually includes several, or even many,
layers of cells, or the whole of each of the tissue-masses
(e.g., thick-angled, stony, and fibrous tissues, etc.) which
immediately underlie the epidermis.
102. Cork.—Within the zone which the hypoderma in-
cludes there frequently takes place a peculiar development
of the young parenchyma, giving rise to layers of dead54
BOTANY.
cells, whose cavities are filled with air only. The walls in
some cases (e.g., the cork-oak) are thin and weak, while in
others (e.g., the beech) they are much thickened, and in
all cases they are nearly impermeable to water. True cork
is destitute of intercellular spaces, its cells being of regular
shape (generally cuboidal) and fitted closely to each other
(Fig. 33).
103. Cork-substance is formed by the repeated subdi-
vision of the cells of a meristem layer of the fundamental
kT
Fig. 34 —Cross-section through a lenticel of Birch, e, epidermis; a, a breath-
ing-pore. Magnified 280 times.
tissue (Fig. 33); these continue to grow and divide by par-
titions parallel to the epidermis, forming layers of cork
with its cells disposed in radial rows (Fig. 33, k). Shortly
after their formation the cork-cells lose their protoplasmic
contents, while beneath them new cells are constantly being
cut off from the cells of the generating layer; in this way
the mass of dead cork-tissue is formed and pushed out from
its living base.
104. The generating tissue is called the Cork-cambium,
or Phellogen; it occurs not only in the hypoderma, but in
any other part of the fundamental system, and in the seq-GROUPS OF TISSUES, OR TISSUE-SYSTEMS.
ondary fibro-vascular bundles. When a living portion of
a plant is injured, as by cutting, the uninjured cells beneath
the wound often change into a layer of cork-cambium, from
which a protecting mass of cork is then developed.
105.	A little cork-cambium sometimes forms immediately
beneath a breathing-pore, and produces a little mass of cork
which pushes out and finally ruptures the epidermis, form-
ing what are called Lenticels (Fig. 34). Lenticels are of
frequent occurrence on the young branches of birch, beech,
cherry, elder, lilac, etc., and may be distinguished by the
naked eye as slightly elevated roughish spots, usually of a
different color from the epidermis.
Practical Studies.—(a) Make cross-sections of the stem of the
pumpkin. Note that the fundamental portion contains only soft and
thick-angled tissues.
(6) Make a similar section of milkweed (Asclepias) stem. Note
that the fundamental portion contains soft, thick-angled, and milk
tissue.
(c) Make cross and longitudinal sections of the leaf of the Scotch
or Austrian Pine. Note the fibrous tissue in the hypodermal portion.
Id) The stone-cells in the pith of the apple-twig are good examples
of this tissue in the fundamental system.
(e) Examine the cells which make up the medullary rays of the old
wood of the oak or beech. They will be found to be stony tissue.
In young wood they are thin-walled and thus constitute soft tissue
(parenchyma).
(/) Make very thin sections (in different planes) of commercial cork
(the product of the Cork-oak of Southern Europe) and mount in alco-
hol to expel the air-bubbles. Note the thin walls and the approxi-
mately cubical shape of the cells.
(g) Make very thin cross-sections of a young twig of the apple,
snowball, or birch, so as to cut through a young lenticel. Mount in
alcohol as before.
106.	Intercellular Spaces.—In addition to the cavities
and passages which are formed in the plant from cells and
their modifications, there are many important ones which56
BOTANY.
are intercellular and which at no time were composed of
cells. In some cases they so closely resemble the cavities
derived from cells that it is with the greatest difficulty
that their real nature can be made out. In their simplest
form they are the small irregular spaces which appear
during the rapid growth of parenchyma-cells (Fig. 35);
from these to the large regular canals which are common
in many water-plants there are all intermediate gradations.
Fig. 35.—A bit of the soft tissue of the pith of the stem of Indian corn; trans-
verse section, gvh simple plate of cellulose, forming the partition-wall between
two cells; z, z, intercellular spaces caused by splitting of the walls during rapid
growth. Magnified 550 times.
107. In leaves, especially in the soft tissue of the under
portion, there are usually many large irregular spaces be-
tween the cells; they are in communication with the exter-
nal air through the breathing-pores, and contain only air
and watery vapor. The leaf-stalks and stems of many
aquatic plants contain exceedingly large air-conducting
intercellular canals, which occupy even more space than
the surrounding tissues (Fig. 36). In the rushes, water-
lilies, and water-plantains they are so large as to be readily
seen by the naked eye. These all are in communicationGROUPS OF TISSUES, OR TISSUE SYSTEMS.
57
with the external air through the breathing-pores and the
intercellular spaces of the leaves.
Fig. 36.—Intercellular spaces. A, in leaf-stalk of a Water-lily; s, star-shaped
cells. By in stem of a Rush: the cells here all star-shaped. Both cross-sections.
B
108. Some intercellular spaces serve as reservoirs of gum-58
BOTANY.
my or resinous secretions. Such ones are surrounded by
secreting cells which manufacture the gummy or resinous
matter and then exude it into the cavity. The Turpentine-
canals of the pines and spruces are of this nature, the well-
known turpentine being secreted by one or more rows of
cells which border the rather large canals. The function
of these canals with their secretion has not yet been made
out with certainty. The recent suggestion that the tur-
pentine may be for the coating over of wounds is by no
means satisfactory.
Practical Studies.—(a) Make extremely thin cross-sections of the
stem of Indian corn, using a very sharp scalpel (or razor). Note the
small triangular intercellular spaces.
(b)	Make thin cross-sections of an apple-leaf and note the intercel-
lular spaces of the lower half of the section. Remember that in this
leaf there are nearly 250 breathing-pores to every square millimetre
of lower surface, while there are none at all upon the upper.
(c)	Study in cross-section the intercellular spaces in the stem of the
Rush (Juncus), and the leaf-stalks of water-lilies, water-plantains
(Alisma), and arrowheads (Sagittaria).
(d)	Study turpentine-canals in very thin cross-sections of leaves of
pines and spruces. The larger-leaved species, as Scotch, Austrian,
or Scrub pine, and the Balsam-fir, are the most satisfactory.
(e)	Make cross-sections of the twigs of White pine and study tur-
pentine canals in hark and wood.
(/) Study the oil-receptacles in the fresh rind of the orange and
lemon by thin cross-sections. These are not strictly intercellular,
but are formed by the breaking away of the secreting cells, thus leav-
ing a cavity.
(g) The similarly formed oil-receptacles of the mints and the gar-
den Fraxinella may be studied by making very thin cross-sections of
the leaves,CHAPTER IV.
THE PLANT-BODY.
109.	Generalized Forms.—The cells, tissues, and tissue-
systems described in the preceding pages are variously ar-
ranged in the different groups of the vegetable kingdom
to form the Plant-Body. The simplest plants are single
cells or masses of similar cells; in those next higher the
cells are aggregated into a few simple tissues; while still
above these the tissues are grouped into tissue-systems.
110.	With this internal differentiation there is a corre-
sponding differentiation of the external plant-body. The
lower plants are not only simpler as to their internal struc-
ture, but they are so as to their external form as well.
The higher plants are as much more complex than the lower
ones as to their external parts as they are in regard to their
tissues and tissue-systems.
111.	In the lowest groups of plants the simple plant-body
has no members; the single- or few-celled seaweed has no
parts like root, stem, or leaf; it is a unit as to its external
form. In the higher groups, on the contrary, the plant-
body is composed of several or -many members which are
less or more distinct. In those plants in which they first
appear, the members are not clearly or certainly to be dis-
tinguished from the general plant-body; but in the higher
groups they become distinctly set off, and are eventually
differentiated into a multitude of structural and functional
forms.60
botany.
112.	Every plant in its earliest (embryonic) stages is
simple and memberless; and every member of any of the
higher plants is at first indistinguishable from the rest of
the plant-body; it is only in the later growth of any mem-
ber that it becomes distinct; in other words, every member
is a modification of, and development from, the general
plant-body.
113.	Likewise, where equivalent members have a differ-
ent particular form or function, it is only in the later
stages of growth that the differences appear. All equi-
valent members are alike in their earlier stages, whether,
for example, they eventually become broad green surfaces
(foliage-leaves), bracts, scales, floral envelopes, or the essen-
tial organs of the flower.
114.	These facts make it necessary to have some general
terms for the parts of the plant-body which are applicable
to them in all their forms. We must have, for example, a
term so generalized as to include foliage-leaves, bracts,
scales, floral envelopes, and all the other forms of the so-
called leaf-series. So, too, there is need of a term to in-
clude stems, bulb-, bud- and flower-axes, root-stocks, corms,
tubers, and the other forms of the so-called stem-series.
115.	By a careful study of the members of the more per-
fect plants we find that they may be reduced to four gen-
eral forms, viz., (1) Caulome, which includes the stem and
the many other members which are found to be its equiva-
lent; (2) Phyllome, including the leaf and its equivalents;
(3)	Trichome, which includes all outgrowths or appendages
of the surface of the plant, as hairs, bristles, root-hairs, etc.;
(4)	the Hoot, which includes, besides ordinary subterranean
roots, those of epiphytes, parasites, etc.
116.	As indicated above, in the lower plants the differ-TUB PLANT BODY.
61
entiation into members is not so marked as in the higher,
and in passing downward in the vegetable kingdom groups
are reached in which it is inappreciable, and finally in
which it is entirely wanting: such an undifferentiated
plant-body is called a Thallome, and may properly be re-
garded as the original form, or prototype.
117.	Thallome.—The simplest thallome is the single cell;
this, though generally rounded, is in some cases irregu-
larly extended into stem-like or leaf-like portions, which
may be regarded as, to a certain extent, foreshadowings or
anticipations of the members of the higher plants. Plants
composed of rows of cells or cell-surfaces frequently show
no indication whatever of a division into members; but in
some cases there is a little differentiation, which, though
not carried far enough to give rise to members, is the same
in kind.
118.	In the larger seaweeds there is sometimes so much
of a differentiation that it becomes difficult to say why
certain parts ought not to be called members. Structures
of this kind are instructive, as showing that the passage
from the thallome plant-body to that in which members
are differentiated is by no means an abrupt or sudden
one.
119.	Caulome.—By this general name we designate all
axial members of the plant. In the more obvious cases the
caulome is the axis which bears leaves (foliage), and in this
form it constitutes
(1)	The Stem ; branches are only stems which originate
laterally upon other stems.
The other caulome forms are:
(2)	Runners, which are bract-bearing, slender, weak, and
trailing.62
BOTANY.
(3)	Hoot-stocks, which are bract- or scale-bearing, usually
weak, and generally subterranean.
(4)	Tubers, which are bract- or scale-bearing, short and
thickened, and subterranean.
(5)	Corms, which are leaf-bearing, short and thickened,
and subterranean.
(6)	Bulb-axes, which are leaf-bearing, short and conical,
and subterranean.
(7)	Flower-axes, which are bract-, perianth-, stamen-, and
pistil-bearing, short and usually conical and aerial.
(8)	Tendrils, which are degraded, slender, aerial cau-
lomes, nearly destitute of phyllomes.
(9)	Thorns, which are degraded, thick, conical, aerial
caulomes, nearly destitute of phyllomes.
120. Phyllome.—The phyllome is always a lateral mem-
ber upon a caulome. It is usually a flat expansion and ex-
tension of some of the tissues of the caulome. Its most
common form is
(1)	The Leaf (foliage), which is usually large, broad, and
mainly made up of chlorophyll-bearing tissue.
The other phyllome forms are:
(2)	Bracts, which are smaller than leaves, generally green.
(3)	Scales, which are usually smaller than leaves, want-
ing in chlorophyll-bearing tissue, and generally with a firm
texture.
(4)	Floral envelopes, which are variously modified, but
generally wanting in chlorophyll-bearing tissue, and with
generally a more delicate texture.
(5)	Stamens, in which a portion of the soft tissue devel-
ops male reproductive cells (pollen).
(6)	Carpels, bearing or enclosing female reproductive
organs (ovules).THE PLANT-BODY.
63
(7) Tendrils and (8) Spines, which are reduced or de-
graded forms, composed of the modified fibro-vascular bun-
dles and a very little soft tissue; in the first the structures
are weak and pliable, in the latter stout and rigid.
The altogether special modifications of the phyllome, as
in pitchers and cups, will be noticed hereafter.
121.	Trichome.—The trichome is a surface appendage
consisting of one or more cells usually arranged in a row
or a column, sometimes in a mass. Its most common forms
are met with in
(1)	The Hairs of many plants. (See page 36.)
The other trichome forms are:
(2)	Bristles, each consisting of a single pointed cell or
a row of cells, whose walls are much thickened and hard-
ened.
(3)	Prickles, like the last, hut stouter, and usually com-
posed of a mass of cells below.
(4)	Scales, in which the terminal cell gives rise by fission
to a flat scale, which soon becomes dry.
(5)	Glands, which are generally short, hearing one or
more secreting cells.
(6)	Moot-hairs, which are long, thin, single-celled (in
mosses a row of cells), and subterranean.
(7)	Sporangia of ferns and their relatives, some of whose
interior cells develop into reproductive cells (spores).
(8)	Ovules of flowering plants one or more of whose cells
develop into reproductive cells (embryo-sacs).
122.	Boot.—The root is that portion of the plant-body
which is clothed at its growing point with a root-cap. In
ascending through the vegetable kingdom roots are the
latest of the generalized forms to make their appearance,
and in the embryo they appear to he formed later than64
BOTANY.
canlome and phyllome. They present fewer variations
than any of the other generalized forms. The ordinary
(1)	Subterranean roots of plants are typical. They differ
Fig. 38.	Fig. 39.
Fig. 38.—Diagrams of dichotomous branching. A, normal dichotomy, in
which each branch is again dichotomously branched; By helicoid dichotomy, in
which the right-hand branch, r, does not develop further, while the left-hand
one, Z, is in every case again branched; C, scorpioid dichotomy, in which the
branches are alternately further developed.
Fig. 39.—Diagram of botryose monopodial branching. The numerals indicate
the “generations.”
but little from one another in whatever plants they may
be found.
The other root-forms are:
(2)	Aerial roots, which project into the air, and often
have their epidermis peculiarly thickened, as in the epi-
phytic orchids.
(3)	Roots of Parasites, which are usually quite short,THE PLANT-BODY.
65
and in some cases provided with sucker-like organs, by
means of which they absorb food from their hosts.
123. General Modes of Branching of Members.—All the
members of the plant-body may branch. This branching
always follows one of two general methods. In the one
the apex of the growing member divides into two new
growing points, from which branches proceed: this is the
Dichotomous mode of branching (Fig. 38). In the other
Fig. 40.—Diagrams of cymose monopodial branching. A and B, sCorpioid
cymes; C, forked cymose monopodium, the compound or falsely dichotomous
cj me (called also the dichasium): D, helicoid cyme.
the new growing points arise laterally while the original
apex still retains its place and often its growth: this is the
Monopodial mode of branching (Fig. 39). Both modes
are subject to many modifications, the most important of
which are briefly indicated in the following table; and
moreover a member may branch for a time dichotomously
and then monopodially, or the reverse.66
BOTANY.
A. DICHOTOMOUS.
1.	Forked dichotomy, in which both branches of each bifurcation are
equally developed (Fig. 38, A).
2.	Sympodial dichotomy, in which one of the branches of each bifur-
cation develops more than the other.
a.	Helicoid sympodial dichotomy, in which the greater develop-
ment is always on one side (Fig. 38, B).
b.	Scorpioid sympodial dichotomy, in which the greater develop-
ment is alternately on one side and the other (Fig. 38, C).
B. MONOPODIAL.
1.	Botryose monopodium, in which, as a rule, the axis continues to
grow, and retains its ascendency over its lateral branches (Fig. 39).
2.	Cymose monopodium, in which the axis soon ceases to grow, and
is overtopped by one or more of its lateral branches.
a.	Forked cymose monopodium, in which the lateral branches are
all developed (Fig. 40, C).
b.	Sympodial cymose monopodium, in which some of the lateral
branches are suppressed; this may be—
b'. Helicoid, when the suppression is all on one side (Fig. 40,
B); or—
b". Scorpioid, when the suppression is alternately on one
side and the other (Fig. 40, A and B).
Practical Studies.—(a) Mount and examine under a low power of
the microscope or by the naked eye alone the following in order as
examples of tliallomes: 1, Green Slime; 2, Pond Scum; 3, the first
stage of a fern “seedling" (little flat green growths, 3-5 mm. across,
which often appear on the earth near ferns in greenhouses); 4, Sea-
lettuce (Ulva); 5, Irish moss (Chondrus), the latter showing a much-
lobed form.
(b)	Study as examples of caulome forms the following in order
1, the stem of Lamb’s Quarters, or Indian corn; 2, runners of the
strawberry; 3, root-stocks of blue grass; 4, tubers of the potato; 5,
corms of Gladiolus, or Indian turnip; 6, bulb-axis of the onion; 7,
flower-axis of anemone, buttercup, tulip, or lily; 8, tendrils of the
grape, or Virginia creeper; 9, thorns of honey-locust, or plum.
(c)	Study as examples of phyllome forms; 1, leaf of apple, cherry,
or Indian Corn, etc.; 2, bracts of flower-cluster of cress, sweet-
william, golden-rod, or aster; 3, scales of buds of hickory or lilac;
4, floral’envelopes of anemone, buttercup, tulip, or lily; 5, stamens
of any of the above; 6, carpels of anemone, buttercup, columbine,
etc.; 7, tendrils of pea, or vetch; 8, spines of thistles.THE PLANT-BODY.
67
(d)	Study as examples of phyllome forms: 1, hairs of petunia or
verbena; 2, bristles of tickle-grass; 3, prickles of' tlie bop; 4, scales
of the buffalo-berry, or elseagnus; 5, glands of the petunia or walnut;
6, root-hairs of seedling cabbages, radishes, etc.; 7, sporangia of com-
mon polypody fern; 8, ovules of anemone, buttercup, columbine,
bouncing bet, etc.
(e)	Study for root-forms: 1, roots of seedling cabbages, radishes,
etc.; 2, aerial roots of greenhouse orchids ; 3, parasitic roots of
dodder or mistletoe.CHAPTER V.
THE CHEMISTRY AND PHYSICS OF PLANTS.
124.	The Water in the Plant.—All living parts of plants
are abundantly supplied with water. It is always present in
living protoplasm, and the greater its activity the more
watery is its composition. The cell-walls of living tis-
sues also contain large quantities of water ; and in plants
composed of many cells (as the larger flowering plants)
even those cells and tissues which have lost their activity
generally have their walls saturated with water. In ordi-
nary herbaceous land-plants the amount of water is not far
from 75 per cent of their whole weight. In aquatic plants
the percentage is much higher, often exceeding 95 ; it is
so abundant in many of the simpler forms that upon dry-
ing nothing but an exceedingly thin and delicate film is
left.
125.	Water in the Protoplasm.—As explained in para-
graph 4 (page 2), living protoplasm has the power of im-
bibing water and thereby of increasing its fluidity. Even
after it has imbibed all the water which it can retain it
continues the process, and separates the surplus in drops in
its interior—the so-called vacuoles. Now an examination
of the cells of rapidly growing tissues showTs that their
protoplasm is much more watery than that of living but
dormant tissues—e.g., those of seeds—and one of the first
signs of activity in the latter is the imbibition of water.CHEMISTRY AND PHYSICS OF PLANTS.
69
126.	This avidity of protoplasm for water plays an im-
portant part in the general economy of the plant. By it
all the cells which contain protoplasm are kept turgid, and
by the tension thus created the soft parts of plants are
made rigid. It plays no small part also in keeping up the
supply of moisture in living tissues when wasted by evapo-
ration.
127.	Water in the Cell-Walls.—According to Nageli’s the-
ory, the wall of the cell is not a membrane which separates
the water of one cell-cavity from that in the next, but rather
a pervious stratum, composed of solid particles (molecules)
which are not in contact, and between which the water
freely passes. In a living tissue the water is continuous
from cell to cell, and constantly tends to be in equilibrium
—i.e., the turgidity of the cells is approximately equal
throughout the tissue, and likewise the wateriness of both
cell-walls and cell-contents.
128.	In the simpler aquatic plants the water of the cells
and their walls is continuous with that in which they grow.
Likewise the water in the tissues of roots or other absorb-
ing organs of the higher aquatic plants is continuous with
that which surrounds them ; and even in ordinary terres-
trial plants there is a perfect continuity of the water in the
root-tissues with the moisture of the soil.
129.	The Equilibrium of the Water in the Plant.—The
water in the tissues of every plant tends constantly to be-
come in equilibrium, and this state would soon be reached
were it not for certain disturbing causes which are almost
as constantly in action. In any cell an equilibrium may
soon be reached between the two forces which reside re-
spectively in the cell-wall and the protoplasm, viz., (1) the
attraction of the surfaces of the molecules for the water,70
BOTANY.
and (2) the “imbibition-power” of protoplasm. So, too, an
equilibrium between cell and cell may soon be reached.
This equilibrium once attained, all motion of the water
must cease, and it must remain at rest until disturbed by
some other force or forces. This condition, or one ap-
proximating very closely to it, is reached by many of the
perennial plants during the winter or period of rest.
130.	Disturbance of Equilibrium.—During the growing
stages of plants the equilibrium of the water is constantly
disturbed in one or more ways, viz., (1) by the chemical
processes within the cells ; (2) by the “ imbibition-power ”
of the protoplasm and walls of newly formed cells ; (3) by
the evaporation of a portion of the water.
131.	The chemical processes within the cell include :
(1)	the actual use of water by breaking it up into hydro-
gen and oxygen ; every molecule which is so broken up
leaves a vacancy which, sooner or later, must be replaced;
(2)	the formation of substances which are more soluble
than those from which they were formed; (3) the forma-
tion of substances which are less soluble than those from
which they were formed. These processes take place in
all cells, even those of the simplest plants.
132.	In plants composed of tissues, wherever new cells
are forming and developing, the new protoplasm and cell-
walls require considerable quantities of water to satisfy
their molecular attraction; this supply is always made in
part or entirely at the expense of the adjacent cells. In
many aquatic plants there can be little doubt that the needed
water in growing tissues is obtained partly by direct ab-
sorption from the surrounding water, but this can only be
the case with the external cells; the deep-lying ones must
obtain their supply from the cells which surround them.CEE MIS TRY AND PHYSICS OF PLANTS.
71
In aerial parts of plants the newly formed cells obtain all
their water from the adjacent cells.
133.	Evaporation of Water.—In the aerial parts of plants
the evaporation of water from their surfaces is a far more
powerful disturbing cause than either of the two preceding.
Whenever a cell is exposed to dry air at ordinary tempera-
tures a portion of its water passes off by evaporation; this
immediately disturbs the equilibrium of water throughout
the tissue, and the more rapid or the longer continued the
evaporation the -greater the disturbance.
134.	Evaporation from living cells or tissues is depen-
dent upon a number of conditions, some of which are en-
tirely exterior, while others are connected with the struc-
ture of the plant itself. Among the former, the most
important is the condition of the air as to the amount of
moisture which it contains. In air saturated with moisture
no evaporation can take place; but whenever the amount
of moisture falls below the point of saturation, if the other
conditions are favorable, evaporation takes place.
135.	The temperature of the air (and, as a consequence,
that of the plant also) has some effect upon the rapidity of
evaporation. It appears that there is an increase in the
amount of water given off as the temperature rises; this
may be due, however, to the fact that with such increase
of the temperature of the air there is generally a considera-
ble decrease in its moisture. The direct influence of light
upon evaporation is also somewhat doubtful. While there
can be no doubt that plants generally lose more water in
the light than in darkness, it appears to be due to the in-
creased heat and dryness which are common accompani-
ments of the increase of light.
136.	In enumerating the internal conditions, one general72
BOTAJNT.
condition must not be forgotten, viz., that the water in
plant-cells contains many substances in solution, and con-
sequently evaporates less rapidly than pure water, in ac-
cordance with well-known physical laws. Moreover, the
attraction of the substance of the cell-walls for the water
counteracts, to a considerable extent, the tendency to evapo-
ration; and in the same manner, even to a greater extent,
the water is prevented from passing off by the “ imbibition-
power” of protoplasm. It is, in fact, impossible to deprive
cellulose and protoplasm of all their water in dry air at
ordinary temperatures.
137.	In all the aerial parts of higher plants the epidermis
offers more or less resistance to the escape of the water of
the underlying tissues. This is mainly accomplished by
the thick outer wall of the epidermal layer; in many cases,
especially in plants growing naturally in very dry regions,
the epidermis consists of several layers of cells, which offer
still more resistance to evaporation by being themselves
filled with moist air only.
138.	Among the lower plants, the single reproductive
cells (spores) are guarded against the loss of water by hav-
ing their walls greatly thickened. Even in the lowest
plants, the Slime Moulds, the naked masses of protoplasm,
when placed in dry air, will contract into rounded masses,
which then become covered with a somewhat impervious
envelope.
139.	The breathing-pores of the green and succulent
parts of higher plants control to a great extent the amount
and rapidity of their exhalation. Breathing-pores are
placed over intercellular spaces, which are in communica-
tion with the intercellular passages of the plant. These
spaces and passages are filled with moist air and gases,CHEMISTRY AND PHYSICS OF PLANTS.
73
which, when the breathing-pores are open, expand and
contract with every change of temperature or atmospheric
pressure, and thus permit the escape of considerable
amounts of water; when, on the other hand, the breathing-
pores are closed, little or no escape of moisture is possible.
140.	The opening and closing of the breathing-pores
appear to depend upon the amount of light; they open
more widely the greater the amount of light, and close
almost completely in darkness. The amount of moisture
on the surface of the epidermis appears also to affect some-
what the opening and closing of the breathing-pores; when
the epidermis is very dry they are generally closed, and
vice versa.
141.	The Amount of Evaporation.—The conditions con-
trolling evaporation are thus seen to he many and various.
They never, or but very rarely, act singly, two or more of
them usually acting together with varying intensity, so
that the problem of the amount of evaporation taking place
at any particular time is a complex and difficult one. All
the observations yet made, and which have necessarily
been upon a very small scale, indicate that the rate of evap-
oration is actually very slow.
142.	A given area of leaf-surface will evaporate much
less water than an equal area of water-surface. The amount
of the former has been estimated at from one seventeenth to
one third of the latter, varying of course in different plants.
A grape-leaf has been found to evaporate in twelve hours
of daylight an amount of water equal to a film covering
the leaf only .13 mm. (.005 in.) deep; a cabbage-leaf for
the same time .31 mm. (.012 in.); an apple-leaf .25 mm.
(.01 in.). An oak-tree was found to have evaporated in
one season, during the time it was covered with foliage, an74 t
BOTANY.
amount of water equal to a layer 33 mm. (about 1^ in.)
deep over all its leaf-surface. When we remember that
the usual evaporation from a water-surface for the same
period is from 500 to 600 or more millimetres (20 to 25 in.)
we must conclude that leaves, instead of being organs for
increasing evaporation, are able to successfully resist evapo-
ration.
143.	The Movement of Water in the Plant.—It is clear,
from what has been said, that in many-celled plants there
must be a considerable movement of water in some parts,
to supply the loss by evaporation. Thus in trees there
must be a movement of water through the roots, stems,
and branches to the leaves, to replace the loss in the latter.
This is so evident that it scarcely needs demonstration; it
can, however, be shown by cutting off a leafy shoot at a
time when evaporation is rapid; in a short time the leaves
wither and become dried up, unless the cut portion of the
shoot be placed in a vessel of water; in the latter case the
water will pass rapidly into the shoot, and the leaves will
retain their normal condition. If in such an experiment
a colored watery solution (as of the juice of Poke-berries)
be used instead of pure water, it will be seen that the liquid
has passed more abundantly through certain tracts than
through others, indicating that the tissues are not equally
good as conductors of watery solutions.
144.	As would readily be surmised, the tissues in ordi-
nary plants which appear to be the best conductors are
those composed of elongated wood-cells, and it is doubt-
less through them that the greater part of the water passes.
Furthermore, it is probable that the movement of the water
is through the substance of the cell-walls, and not, at least
to any great extent, through the cell-cavities. Accordingchemistry and physics of plants. 75
to this view, the force which raises the water, in some cases
to the height of a hundred metres or more, is the attraction
of the surfaces of the cellulose molecules for the layers of
water which surround them.
145. The rapidity of the upward movement of water
varies greatly in different plants and under different con-
ditions. In a silver-poplar a rate of 23 cm. (9 in.) an hour
has been observed; in a cherry-laurel 101 cm. (40 in.); and
in a sunflower 22 metres (72 feet).
Additional Notes oh the movement of water in the plant.
I.	Root-Pressure.—If the root of a vigorously growing plant be cut
off near the surface of the ground and a glass tube attached to its
upper end, the water of the root will be forced out, often to a con-
siderable height. Hales more than a hundred and fifty years ago
observed a pressure upon a mercurial gauge equal to 11 metres
(36.5 ft.) of water when attached to the root of a vine (Yitis). Clark
(1873), in a similar manner, found the pressure from a root of a birch
(Betula lutea) to be equal to 25.8 metres (84.7 ft.) of water. This root-
pressure appears to be greatest when the evaporation from the leaves
is least; in fact, if the experiment is made while evaporation is very
active, there is always for a while a considerable absorption of water
by the cut end of the root, due probably to the fact that the cell-walls
had been to a certain extent robbed of their water by the evaporation
from above. Root-pressure is probably a purely physical phenom-
enon, due to a kind of endosmotic action taking place in the root-
cells.
II.	The Flow of Water (sap) from the stems and branches of certain
trees, notably from the sugar-maple, appears to be due to the quick
alternate expansion and contraction of the air and other gases in the
tissues from the quick changes of temperature. The water is forced
out of openings in the stem when the temperature suddenly rises;
when the temperature suddenly falls, as at night, there is a suction
of water or air into the stem. When the temperature is nearly uni-
form, whether in winter or summer, there is no flow of sap.
III.	No Circulation of Sap —While there is an upward movement
of the water in plants because of the evaporation from the leaves,
there is no downward movement as has been popularly supposed.
The “circulation of the sap,” in the sense that there is an upward
stream in one portion of the plant and a corresponding downward76
tiOTANf.
stream in another, does not exist. Likewise, the belief still main-
tained by some people that in the autumn or early winter “ the sap
goes down into the roots,” and that ,;it rises” in the spring, is en-
tirely erroneous. There is actually more water (sap) in an ordinary
deciduous tree in the winter than there is in the spring or summer
(excluding of course the new and very watery growths).
Practical Studies.—A few physiological experiments may be easily
made by the student. The following will serve as a beginning:
(a)	Collect a quantity of green grass in the middle of the day when
it is not wet; weigh it accurately, then thoroughly dry it in an oven,
being careful not to scorch it. Weigh again: the difference in the
two weighings will be approximately the amount of water in the
living plant, although some water will still be left in the plant by
ordinary drying.
(b)	Weigh ahandful of beans; put them into warm water or moist
earth for a day or two until they are beginning to sprout. Then
gather them up carefully, wipe off all external dirt and moisture, and
weigh again. Here the difference will be approximately the amount
of water absorbed by the protoplasm.
(c)	Place some specimens of Green Slime or Pond Scum on a dry
glass slip, using no cover-glass. Note with the microscope the rapid
evaporation of water as shown by the collapsing of the cells.
(d)	Gather fresh leaves of clover; suspend some of them under a
bell-jar or inverted tumbler which stands in a plate containing a little
water. Put the other leaves into a dry plate with no protection from
the dry air. Note that the evaporation is very much more rapid in
the dry air than in the moist air under the bell-jar.
(«) Strip off the epidermis from a leaf (hyacinth, live-for-ever, etc.,
are good) and note that the evaporation is much greater (as shown
by the more rapid wilting) than from the uninjured leaf. Tbisskow's
that the epidermis and its breathing-pores retard evaporation.
(/) Lilac-leaves have breathing-pores upon their lower surfaces
alone. Provide two leaves: cover the lower surface of one with a
thin coat of varnish, which will prevent evaporation through the
breathing-pores; suspend both in a current of dry air, and note that
the one not varnished withers sooner than the other.
(ff) Cottonwood-leaves have breathing-pores upon both surfaces.
Repeat experiment above (/).
(h) Procure a well-grown geranium (20 to 25 cm. high) in a flower-
pot. Cover the pot with a piece of thin sheet-rubber, tying it care-
fully around the stem of the plant. Insert a short tube (provided
with a cork) at the proper place, through which to introduce water,CHEMISTRY AND PHYSICS OF PLANTS.
77
Weigh the whole at intervals of a few hours. The loss will oe the
amount of evaporation (approximately). By adding weighed quan-
tities of water at intervals the experiment may be continued indefi-
nitely.
(i)	Cut off a rapidly growing leafy shoot of the apple or geranium
and place the lower end in a bottle of water. Close the bottle by
pressing soft wax into the mouth of the bottle around the stem. On
account of the upward movement of the water through the shoot its
level in the bottle will be perceptibly lowered. This will be more
evident the smaller the diameter of the bottle.
(j)	Cut off the stem of a rapidly growing sunflower a couple of
inches above the ground; slip over it the end of a tightly fitting
india-rubber tube 8 to 10 cm. long. Slip into the other end a small
glass tube 5 to 10 mm. in diameter, being sure to make the joints
water-tight. The “ root-pressure” will cause the water to rise into the
vertical tube. Note the effect of a change of temperature of the soil.
(k)	Cut off a small branch of a maple tree on a cold winter day;
bring it into a warm room. As soon as the temperature of the branch
rises, the sap (water) will begin to flow from the cut surface. Lower
the temperature and the flow will cease; raise it again and the flow
will be resumed.
146.	Plant-Food.—The most important elements which
are used in the nutrition of plants, or which, in other
words, enter into their food, are Carbon, Hydrogen, Oxy-
gen, Nitrogen, Sulphur, Iron, and Potassium. These all
appear to he necessary to the life and growth of the plant,
and if any of them are wanting in the water, soil, or air
from which the plant derives its nourishment, death from
starvation will soon follow.
147.	There are other elements which are made use of by
plants, but, as life may be prolonged without them, they
are regarded as of secondary importance. In this list are
Phosphorus, Calcium, Sodium, Magnesium, Chlorine, and
Silicon.
148.	The Compounds Used.—With the single exception
of.oxygen, the elementary constituents named above do not
enter into the food of plants in an uncombined state; on78
B0TAN7.
the contrary, they are always absorbed in the condition of
compounds, as water, carbon dioxide, and the
Nitrates
Sulphates
Carbonates
Phosphates
Silicates, or
Chlorides
'Ammonia.
Potash.
Soda, or
Magnesia.
Of the last the nitrates of potash and ammonia, sulphate
of lime, carbonates of ammonia and lime, are probably to
be considered as the most important for ordinary plants.
Water is necessary for all plants, and carbon dioxide for
those which are green.
149.	In addition to the foregoing many organic com-
pounds are absorbed in particular cases, as in those plants
which live in decaying animal or vegetable matter (sapro-
phytes), as well as those which absorb the juices from liv-
ing plants (parasites).
150.	How the Food is Obtained.—In the case of aquatic
plants these compounds are taken into the plant-body by a
process of diffusion from the surrounding water; in terres-
trial plants the gaseous compounds, as carbon dioxide and
carbonate of ammonia, are absorbed—at least in part—by
the leaves directly from the surrounding air, while the
solutions of these and the other compounds in the water in
the soil find their way into the plant by diffusion. The
water of streams and ponds and that found in moist soil
generally contains, in addition to decayed vegetable matter,
greater or less quantities of sulphate, carbonate, and phos-
phate of lime, nitrates of potash and ammonia, besides small
amounts of iron, silica, and chlorine. Plants flourish best
when these constitute (in the aggregate) one part in one
thousand parts of water.CHEMISTRY AND PHYSICS OF PLANTS.
79
151.	How the Food is Transported in the Plant.—Once
within the plant-body, the food-materials diffuse to all
watery parts, in the case of the larger terrestrial plants
rising through the stem to the leaves. By diffusion there
is a constant tendency toward an equal distribution through-
out the plant of the solutions which enter it; and if there
were no disturbing chemical reactions taking place, such a
condition would in most plants be soon reached. It is quite
probable, indeed, that this actually happens for certain
substances which are found in solution in the soil or water,
and which, entering plants, diffuse through them to all
parts, but not being used they soon reach a state of equal
diffusion, which is only slightly disturbed by the extension
of the plant-body by growth. The diffusion of food-mate-
rials throughout terrestrial plants is aided by the evapora-
tion of water from the leaves, thus causing a strong upward
movement of the water which contains the various solutions
of food-matter; but it is not dependent upon evaporation,
for diffusion takes place under conditions which preclude
evaporation.
152.	Starch-making, or Assimilation.—Most of the food-
materials of plants can be directly used by the protoplasm.
Thus the oxygen and water, and the nitrates, sulphates,
etc., mentioned above may be at once made use of by the
protoplasm for its own nourishment. It is not so, however,
with the carbon dioxide. It cannot be used directly as
food, but must first undergo a special preparation. It must
be broken up and recombined along with the elements de-
rived from water so as to form a new compound which the
protoplasm can digest. This new compound is starch, or
something much like it, and so we may call this prepara-80
BOTANY.
tory process the Starch-making process, or, as it is known
in botanical books, Assimilation.
153.	We cannot yet give an exact account of the suc-
cessive steps in the manufacture of starch. The principal
facts, however, are as follows: Carbon dioxide contains
Carbon (C) and Oxygen (O) in the proportion of one atom
of the former to two of the latter—(COs). Water contains
Hydrogen (H), two atoms, and Oxygen (O), one atom—
(H20). Both water and carbon dioxide are decomposed in
the chlorophyll-granules of leaves and other green parts of
plants. After decomposition there is such a recombination
as to produce Starch (Cl4HJ4O10).
154.	The carbon dioxide is probably decomposed into
carbon oxide (CO) and free oxygen (O): thus C02=C0 + O.
At the same time water is decomposed into hydrogen and
oxygen : thus II,O = 2H -)- O. The free oxygen-atoms
are exhaled from the plant, and by the union of carbon
oxide and hydrogen the starch is formed: this appears as
minute granules imbedded in the chlorophyll-bodies.
155.	These chemical changes may be shown as follows:
ionn _ l 12CO............... ) starch
= 240 set free. I = Ci,H2oO,0 + 2H30.
Here twelve molecules of carbon dioxide and twelve mole-
cules of water produce one molecule of starch and two
molecules of water (water of organization), while twenty-
four atoms of oxygen are set free and permitted to escape
from the cells into the surrounding air or water.
In some plants no starch is formed in the chlorophyll,
but oily or sugary matters which have nearly the same
chemical significance.

12H30 :
1120)
j 120 )
) 24H.,CHEMISTRY AND PHYSICS OF PLANTS.
81
156.	This decomposition and subsequent combination
take place only in the granules or masses of chlorophyll,
and only in sunlight. Those parts of ordinary plants which
are destitute of chlorophyll are entirely wanting in the
power of starch-making (assimilation), and likewise the
chlorophyll-bearing portions are unable to assimilate in
darkness.
157.	Digestion and Use of Starch.—In darkness the starch
which had previously formed in the chlorophyll-bodies un-
dergoes changes which render it soluble, allowing it to
diffuse to other parts of the plant with great freedom. The
nature of these changes appears to vary somewhat in dif-
ferent plants, but they consist essentially in the change of
the insoluble starch into a chemically similar but soluble
substance. Glucose (CiaHalO,a), inulin (C12H20O10), and
cane-sugar (C12H22On) are the more common of the soluble
substances so formed, and one or other of these may fre-
quently be detected in the adjacent cells after the disap-
pearance of the starch from the chlorophyll.
158.	These diffusing assimilated matters are imbibed by
the protoplasm of the living tissues, and constitute its most
important food. In connection with the nitrates and sul-
phates, etc., also imbibed, it furnishes the materials for the
increase of protoplasmic substance in growing cells.
159.	The Storing of Eeserve Material.—In many plants
the surplus starch is stored up in one or more organs as re-
serve material; thus in the potato the starch formed in the
leaves in sunlight is, in darkness, transformed into glucose,
or a substance very nearly like it, and in this soluble form
it is diffused throughout the plant, and in the underground
stems (tubers) is again transformed into starch, "o in the
case of many seeds a mass of reserve material i iored up,82
BOTANY.
generally in the form of starch (e.g., the cerea_ grains),
and sometimes in the form of oily matters (e.g., the seeds
of mustard, flax, castor-hean, squash, etc.).
160.	The Use of Reserve Material.—In the use of reserve
material, as in the germination of starchy seeds, the starch
appears to undergo a change exactly like that in its 'disap-
pearance from chlorophyll. Here it is certain that oxygen
is absorbed, and that carbon dioxide is evolved, while the
starch is transformed into glucose. Similar transforma-
tions doubtless take place in the use of the starch stored
up in buds, twigs, stems, bulbs, etc.
161.	In the germination of oily seeds, after the absorp-
tion of oxygen, starch is (in many cases, at least) first pro-
duced, and from this the soluble sugar is formed. In any
case, after the solution is attained the subsequent changes
are similar to those which follow the transformation of the
starch of the chlorophyll.
162.	The Nutrition of Parasites and Saprophytes is simi-
lar to that of embryos, buds, bulbs, etc. Here assimilated
materials are drawn from some other organism, and subse-
quently undergo digestive changes. In some cases the
parasitism is only partial, as in the mistletoe, where a part
of the assimilated matter is formed in the parasite (which,
therefore, contains chlorophyll), while a portion seems to
he taken, along with the mineral salts, from the host-plant.
So, too, there are plants which are partially saprophytic
in habit, deriving a part of their nourishment as sapro-
phytes, while the remainder is elaborated by their chloro-
phyll.
163.	Many cultivated plants, as we grow them, are par-
tially saprophytic, deriving a portion of their nourishment
from decaying organic matter in the soil. The so-calledCHEMISTRY AND PHYSICS OF PLANTS.
«3
carnivorous plants, as the sundews (Drosera), fly-trap
(Dionaea), pitcher-plants (Sarracenia), etc., are in reality
partially saprophytic, obtaining a considerable part of their
food-materials from decaying animal matter.
164.	For convenience the various processes which take
place'in the digestion of starch, the storing of reserve ma-
terial, the use of other food-matters, etc., have all been in-
cluded under one general term—Metastasis, or Metabolism.
It has been made to include all chemical changes in the
plant excepting assimilation (starch-making). Assimilation
and metastasis thus include all chemical changes taking
place in green plants. In all plants there is metastasis,
while assimilation is present in those only which contain
chlorophyll.
165.	Alkaloids and Acids.—Among the most obscure of
the metastatic changes are those which give rise to the
alkaloids. These are compounds of carbon, hydrogen, ni-
trogen, and generally oxygen, as follows:
Nicotine (CioHhN2), found in tobacco.
Cinckonia (C3oH21N20), found in Peruvian bark.
Morphia (C17HiaN03 + HsO), found in the opium-poppy.
Strychnia (CaiHtnN203), found in the seeds of Stryclinos.
Caffeine (Cs HioNiOj -f- H20), found in coffee and tea.
166.	These and many others occur in plants in combina-
tion with organic acids, such as malic acid (C4H606); tartaric
acid (C,II0O6); citric acid (C6H80,); oxalic acid (C2H„OJ;
tannic acid (C^H^O,,); quinic acid (C,H1506); meconic
acid (0,11,0,). These acids are probably formed by the
oxidation of some of the sugary or starchy substances in
the plant, while the alkaloids with which they are combined
appear to have some relation to the nitrogenous constitu-
ents of the protoplasm.84
BOTANT.
167.	From the fact that the alkaloids are formed more
abundantly in those tissues which have passed the period
of their greatest activity, it may he surmised that they are
either compounds of a lower grade than the ordinary albu-
minoids, or the first results of the incipient decay of the
cells.
168.	Results of Assimilation and Metastasis.—In the pre-
ceding paragraphs we have found that chlorophyll-hearing
plants absorb carbon dioxide and exhale free oxygen, the
former being decomposed in the chlorophyll-granules in
sunlight, and the oxygen being set free as a consequence.
In other words, the absorption of carbon dioxide and the
exhalation of oxygen are connected with the process of
assimilation.
169.	Now, it may be shown that oxygen is absorbed and
carbon dioxide evolved, as results of certain metastatic
processes which take place in any tissues, whether possess-
ing chlorophyll or not, and independently of the presence
or absence of sunlight. In the sunlight the absorption of
carbon dioxide to supply assimilation is so greatly in excess
of its exhalation, as a result of metastatic action, that the
latter is unnoticed. In darkness, however, when assimila-
tion is stopped, the exhalation of carbon dioxide becomes
quite evident.
170.	So, too, with oxygen: in the sunlight the excess of
its evolution from assimilation is so great over its absorp-
tion for metastasis that the latter was long unknown; but
in the absence of light its absorption becomes manifest.
Parasites and saprophytes, as well as those parts of ordi-
nary plants which are wanting in chlorophyll, as flowers
and many fruits, deport themselves in this regard exactly
as chlorophyll-bearing organs do in darkness,CHEMISTRY AND PHYSICS OF PLANTS
85
Practical Studies.—(«) Put a dry apple-twig into a
gas-pipe, closing the ends, not very tightly, with clay;
put it into a fire and heat to redness. The carbon
left will he of the form, and about half the weight,
of the dry twig.
(b)	Germinate several kernels of Indian corn in
moist sand, and when the roots are two to four cen-
timetres long transfer the plants to wide-mouthed
bottles or jars, supporting them as in Fig. 41. Fill
one of the jars with pure (distilled) water; fill asecond
witli well-water (which always contains many, if not
all, of the materials of plant-food); fill a third with water
from a stream or pond (which also always contains all,
or nearly all, the materials of plant-food). Notice that
the plants will grow in all the jars, as all are supplied
with carbon dioxide and water, the most important
plant-food; but the best and longest-continued growth
takes place in the second and third jars.
(c)	In case the materials can be obtained, fill a fourth
jar (as in the previous experiment) with a solution of
the following constitution:
short piece of
Fig. 41.—
Showing meth-
od of making
water - culture
experiments.
Distilled water.............................. 1000 parts
Phosphoric acid.............................. 0.13	“
Lime......................................... 0.16	“
Potash....................................... 0.14	“
Magnesia..................................... 0.02	“
Sulphuric acid............................... 0.03	“
Nitric acid.................................. 0.46	“
Chlorine............ ........................ 0.001	“
Sulphate of iron............................. 0.001	“
With this solution perfect plants may be grown, if care be taken
to renew the solution from time to time.
(id) Secure a quantity of Pond Scum (Spirogyra) in a dish of water;
expose it to the sunlight for some hours, and then examine it for
starch with the aid of the microscope, making use of the iodine test.
When starch has certainly been found, put the dish in a dark (but
not cool) chamber, and after some hours repeat the foregoing exami-
nation. No starch will now be found.
(e) Select two thrifty potato-plants of about equal size and about
the period of flowering, when the tubers are beginning to grow;
coyer one vyitli a tight box or barrel, so as to shut off all the light86
BOTANY.
and prevent starch-making. At the expiration of a fortnight ex-
amine and compare the tubers of the two plants.
(/) Germinate a handful of Indian corn in moist clean sand, and,
as the plants grow, taste the kernels from time to time. The sweet
taste shows that the starch has changed into sugar for the nourish-
ment of the growing plants.
(g) Cut off a stem of geranium and apply the moist surface to a
hit of blue litmus-paper. The latter will turn red on account of the
presence of an acid in the water of the cells.
171.	Temperature.—It may readily be seen that plants
are active only between certain temperatures. There is
for every plant a certain highest temperature (maximum)
beyond which there is no activity. Likewise there is also
a lowest temperature (minimum) below which activity
ceases. Between these there is a best temperature (opti-
mum) at which the plant is most active. We have thus
three temperatures which should be studied for each plant,
viz., lowest, best, highest, or, as they are commonly referred
to in botanical works, the minimum, optimum, and maxi-
mum.
172.	The lowest temperature for plants ranges from near
the freezing point of water to 10 or 15 degrees Cent, above
it (32° to 50° or 60° Fahr.). It is not the same for differ-
ent plants, some being active at much lower temperatures
than others. Moreover, in each plant, the lowest tempera-
ture varies for the different-parts; thus roots are active at
much lower temperatures than leaves. As a rule, also,
metastasis can take place at lower temperatures than as-
similation.
173.	The highest temperature for plant-activity ranges
from about 35° to 50° Cent. (95° to 122° Fahr.), varying
somewhat for different plants, and varying also for differ-
ent parts or different functions of the same plant.
174.	The best temperature varies still more than theCHEMISTRY AND PHYSICS OF PLANTS.
87
lowest or the highest. There are plants whose whole lives
are passed in temperatures hut little above the freezing
point of water, the Red-snow plant being a good example.
Many seaweeds flourish in waters which never rise above
5° to 10° Cent. (40° to 50° Fahr.), while others grow only
where the temperature is 20° to 30° Cent, (about 70° to 85°
Fahr.).
175.	For ordinary land-plants the best temperature varies
for the different parts and functions somewhat as in case
of the lowest and highest. The best temperature for roots
is generally somewhat lower than that for the parts above
the ground, and likewise for the production of fruit and
seeds it is higher than that for the simple growth of leaves
and stems.
176.	The minimum, optimum, and maximum tempera-
tures for the germination of the seeds of some common
plants have been determined to be about as follows:
	Minimum.	Optimum.	Maximum.
Indian Corn. Scarlet Bean. Pumpkin ...	9° C. (= 48° F.) 9°C. (=48° F.) 14° C. (= 56° F.) 5° C. (= 41° F.) 5° C. (=41°F.)	34° (C. =92° F.) 34° (C. = 92° F.) 34° (C. = 92“ F.) 29° (C. = 83° F.) 29° (C. = 83° F.)	46° C. (= 115° F.) 46° C. (= 115° F.) 46° C. (= 115° F.) 42° C. (= 108° F.) 37° C. (= 99° F.)
			
			
177.	When the temperature rises above a certain point
the death of the plant takes place. Those plants, or parts
of plants, which contain the least water are capable of
enduring higher temperatures than those which are more
watery. The immediate cause of death appears to be the
coagulation of the albuminoids of the protoplasm. The
protoplasm thus loses its power of imbibing water, and
the cells consequently lose their turgidity. In watery88
BOTANY.
tissues chemical changes at once begin, resulting in the
rapid disintegration and decay of the substances in the
cells.
178.	In many respects the results of too great a reduc-
tion of temperature are similar to those, produced by too
great an elevation. There is observed the same coagula-
tion of the albuminoids, resulting in.the destruction of the
power of the protoplasm to imbibe water, and, as a conse-
quence, in the loss of the turgidity of the cells. More-
over, as in the case of injury from high temperature, those
cells which are the most watery are the ones which, other
things being equal, are injured most quickly by a reduc-
tion of temperature.
179.	Embryo plants in seeds, when dry, are able to endure
almost any degree of low temperature; but after they have
germinated, and the cells have become watery, they are
generally killed by a reduction to, or a few degrees below,
0° Cent. (32° Fahr.). So, too, the comparatively dry tissues
of the winter buds and ripened stems of the native trees
and shrubs in cold countries are rarely injured even in the
severest winters, while the young leaves and shoots in the
spring are often killed by slight frosts.
180.	Death from low temperature is always accompanied
by the formation of ice-crystals in the succulent tissues;
these are formed from the water of the plant, which is
abstracted from it in the process of congelation. Much of
the water thus frozen is that which fills the cavities (vacu-
oles) of the cells, while some of it is that which moistens
the protoplasm and cell-walls.
181.	As the liquid in the vacuoles is not pure water, but
a mixture of several solutions, it freezes at a lower tem-
perature than water, and then, according to a well-knownCHEMISTRY AND PHYSICS OF PLANTS.
89
law of physics, separates into pure ice-crystals and a denser
unfrozen solution. By a greater reduction of temperature
more ice-crystals may be separated out, and the remaining
solution made denser still. This increasing density tends
to retard the formation of ice-crystals, and it is probable
that it is only in extremely low temperatures, if at all, that
the liquids in the plant are completely solidified.
182.	A plant which has been frozen may survive in many
instances if thawed slowly, but if thawed quickly its vitality
is generally destroyed. Thus many herbaceous plants will
endure quite severe freezing if they are afterward covered
so as to secure a slow rise of the temperature, and many
bulbs, tubers, and roots will survive the severest winters if
covered deeply enough to prevent sudden thawing. Like-
wise turgid tissues, which are not living, as those of many
succulent fruits, are injured or not by freezing, according
as the thawing has been rapid or slow.
183.	Light.—All green plants are directly dependent
upon light, for it is only in the light that they can manu-
facture starch. Without light they would starve just as
surely as would animals if deprived of their proper food.
184.	Light does not appear to be essential to plants in
any other way than to enable them to make starch; so that
those which get their starch from others can live in total
darkness. Thus many saprophytes (i.e., plants which live
upon dead or decaying vegetable matter) are found in dark
cellars, caves, mines, etc., growing to full size and maturing
their fruit perfectly. So, too, some parasites (i.e., plants
living upon and getting their food from living plants) grow
in darkness, feeding upon the inner tissues of their hosts
(supporting plants) where little or no light penetrates.
185.	The flowers and fruits of ordinary plants develop90
BOTANY.
as well in darkness as in the light, behaving in this respect
like parasites and saprophytes.
Practical Studies.—(a) Plant a few seeds of radish, barley, wheat,
and Indian corn in each of two flower-pots, and place one of the pots
in a cool cellar and the other in a warm room. Note differences in
growth in the plants in each pot, and also compare growth of similar
plants in the two pots.
(b)	Observe the average daily temperature during the time that the
hickory-trees are opening their buds in the spring. Compare this
with the average temperature during the time of most vigorous de-
velopment of the leaves and twigs, and also during the time of the
development of the fruit.
(c)	With a thermometer measure the temperature of the water of
ponds and ditches when the earliest vegetation appears in the spring.
This consists for the most part of diatoms which form a brownish
scum on the water, or a brown coat on sticks and stones.
(id) Measure in like manner the temperature of cold springs in which
vegetation is found.
(e) When Indian corn is producing its flowers (tassels and silk), ob-
serve the average temperature of the air and compare it with the
temperature of the soil at the average depth of the roots.
(/) Enclose a small plant of Coleus (a common “foliage-plant”)
and a clover-plant in a tin pail, covering them loosely. Enclose also
a thermometer. Set the pail in a tub of ice-water, allowing it to
remain for an hour or two. Note the effect upon each plant. Or
make the experiment by first growing little plants of wheat and
pumpkin or squash, and using these. The wheat will survive; the
pumpkin or squash will not.
Now make an experiment substituting hot water, and using a
spring plant (as liepatica or anemone) and a summer plant (as Indian
corn). Raise the temperature to 40° Cent. (104 Falir.), and then in-
crease the heat very slowly beyond this point. Notice effect upon
each plant.
(,g) In the autumn notice that some plants are killed by frosts which
leave others unharmed.
(h)	Thaw out two frozen apples, one in warm water rapidly, and
the other in ice-water slowly. The first will be more injured, the
second less.
(i)	Look for moulds and other fungi in dark cellars, as examples
of saprophytic plants which have grown without the direct aid of
light.CHEMISTRY AND PHYSICS OF PLANTS.
91
(j) Cover the end (30 to 40 centimetres) of a cucumber-plant, bear-
ing young flower-buds, with a tight box so as to exclude all light.
Notice that the flowers develop perfectly as to size and color, although
in total darkness, while the leaves are small and lacking in normal
color.
(*) Cover in like manner a portion of a cucumber-plant bearing
very young fruit. Notice that the fruit develops in darkness as well
(in size at least) as in the light.
186.	Movements of Plants.—Every living plant is capable
of moving. In some cases the movement is so small that
it is not visible to the naked eye, while in others it is very
evident. It is popularly supposed that animals alone have
the power of movement, and that this power is one of the
prominent distinctions between plants and animals. In
fact, however, no plant is wanting in the power of move-
ment, and there are many plants which are much more
active than certain animals.
Only an outline of this interesting subject can be given
in this place, and the student who wishes to pursue the
subject further should consult Mr. Darwin’s book, “The
Power of Movement in Plants,” published in 1881.
187.	Mr. Darwin has shown by‘a great number of obser-
vations that as soon as a seed germinates every part of the
embryo begins moving in various directions. Thus the
little root at once begins a sort of revolving motion, its tip
describing more or less curved figures. This revolving or
bending in succession towards all points of a curved figure
so as to describe an ellipse or circle is called circumnuta-
tion, an inconveniently long word for what, is, as we shall
see, a very common thing in plants.
188.	By the circumnutation of a root it is enabled to
find those places in the soil which offer the least resistance
to its passage. Moreover, it has been shown that the tip92
botany.
of the root is sensitive to pressure, and when it comes in
contact with any object bends from it. In this way the
root-tip guides the advancing root through the interstices
of the soil, avoiding on every hand the pebbles and harder
bits of earth. The root-tip appears, also, to be sensitive
to moisture, bending towards that side which is most moist,
and thus in a dry soil the roots are constantly guided into
those parts where the moisture is most favorable.
189.	Not only is the root-tip endowed with the power of
circumnutation, but, in the words of Mr. Darwin, “ All the
parts or organs in every plant whilst they continue to grow
are continually circumnutating. If we look, for instance,
at a great acacia-tree, we may feel assured that every one
of the innumerable growing shoots is constantly describing
small ellipses; as is each petiole, sub-petiole, and leaflet.
The flower-peduncles are likewise continually circumnu-
tating; and if we could look beneath the ground and our
eyes had the power of a microscope, we should see the tip
of each rootlet endeavoring to sweep small ellipses or cir-
cles, as far as the pressure of the surrounding earth per-
mitted. All this astonishing amount of movement has been
going on year after year since the time when, as a seedling,
the tree first emerged from the ground.”
190.	This general power of movement is subject to modi-
fication by various agencies. Thus we find that in most
plants the change from daylight to the darkness of night
is accompanied by changes of position in many parts, the
nocturnal position being called the sleep of the plant. So,
too, the influence of direct light produces a bending or
turning of certain parts of plants toward the light, a kind
of movement which has been called heliotropism. Gravi-
tation has, also, been found to produce a special modifica-CHEMISTRY AND I’llYSICS OF PLANTS.
93
tion of movement, known as geotropism; and, lastly, we may
regard the irritableness of certain plants, as, for example,
the sensitive-plant, as a high specialization of the general
power of movement possessed at some time or other by all
plants and all parts of plants.
191.	In regard to the sleep of plants, observation has
shown that at night the cotyledons (first leaves of the seed-
ling) of many plants take a different position from that
which they have during the day. In the cabbage and
radish, for example, the cotyledons stand during the day
almost at right angles to the stem, but at night they rise
and are parallel to one another. Seedlings of parsley, cel-
ery, tomato, and four-o’clock behave in a similar manner.
In some cases the cotyledons instead of rising, at night,
bend abruptly downwards. This happens with seedlings
of certain kinds of sorrel (Oxalis), although curiously in
other species of the same genus the cotyledons rise.
192.	The leaves of many (if not all) plants assume a po-
sition at night more or less different from that which they
have during the day. In the common purslane the leaves
at night bend upwards in such a manner as to lie more
nearly parallel with the stem. In wood-sorrel (Oxalis) the
leaflets bend abruptly downward and closely surround the
common leaf-stalk. In clover, on the contrary, the leaflets
bend upwards, afterwards folding over to one side. In
beans the leaflets sink down somewhat after the manner of
the wood-sorrel. In some cassias and the sensitive-plants
the nocturnal position differs remarkably from that of the
day; not only are the leaflets folded, but the leaf-stalks
change their position, in some cases rising and in others
becoming sharply depressed. Even some conifers have
been observed to show a well marked sleeping state at night-94
BOTANY.
193.	The relatives of the beans (i.e., the leguminous
plants, or Leguminosae) have been most frequently observed
in a sleeping state; but it is very likely that when we study
them attentively very few of the higher plants will be
found which are wanting in this power.
194.	The familiar closing of certain flowers at night and
opening again in the morning, and the exactly reversed
action, are to be regarded as of the same nature as the
diurnal and nocturnal position of leaves.
195.	The turning of leaves and stems toward the light,
as is commonly seen in a plant grown in a window, is re-
garded by Mr. Darwin as a modified circumnutation. Here
the lateral light controls ordinary nutation, and modifies it
so that, instead of describing ellipses, the leaf or stem moves
in a zigzag course toward the light. The stronger the
light the more nearly will the course approach to a straight
line. Some plants or parts of plants when exposed in this
way to the light bend away from it: this is well seen in the
runners of the so-called strawberry-geranium (Saxifraga
sarmentosa), a well-known pretty little basket-plant. This
last kind of bending is known as negative heliotropism,
while the bending toward the light is distinguished as posi-
tive heliotropism.
196.	Allied to the foregoing is the bending of roots and
stems toward or away from the earth, i.e., with or in oppo-
sition to the force of gravitation. It is a familiar fact that
in the growth of most seedlings the roots grow downward
while the stems take an upward direction. Experiments
made long ago proved that this was due in some way to
the action of gravitation, and Mr. Darwin now considers it
to be the result of gravitation acting upon and modifying
the circumnutation of root and stem. Geotropism (as thisCHEMISTRY AND PHYSICS OF PLANTS.
95
is called) and heliotropism have then this in common, that
both have as their basis that continual movement of the
plant which appears to be the constant accompaniment of
life; in the one case this movement receives special direc-
tion and impulse from the light, while in the other the im-
pulse is given by tbe force of gravitation.
197. We may now also connect the movements due to
ordinary mechanical stimuli with the foregoing. In the
well-known sensitive-plant a slight touch or jar is sufficient
to cause the leaves to close with considerable rapidity.
This was for a long time referred to an obscure irritability,
which was regarded as something peculiar to a few plants.
If, however, we bear in mind that motion appears to be the
normal state of growing parts, or parts whose tissues re-
main thin-walled, we see that this “irritability” is not a
peculiarity at all, but only an intensification of that which
is possessed by plants in general.
Practical Studies.—(a) Soak a few beans in water, and when the
little roots begin to protrude pin the beans carefully to a weighted
cork under a bell jar, and observe the movements of the radicles.
(b)	Germinate and study in like manner the seeds of cabbage, rad-
ish, Indian corn.
(c)	Fix a slender filament of glass to the rapidly growing end of a
shoot of fuchsia, geranium, or verbena (using a drop of thick shellac-
glue), and observe the circumnutation. If a plate of glass be laid
horizontally just above the tip of the glass pointer, the movements of
the latter may be readily recorded by lines or dots on the glass. Or a
microscope may be fixed in such a position that the tip of the pointer
is iu focus, when the movement will be made visible to the eye.
(id) Fix a glass pointer to the tip of a leaf of a suitable plant (as a
fuchsia, geranium, primrose, etc., grown in a pot), and record the
nutations on a glass plate fixed vertically or horizontally in such a
way as to be approximately at right angles to the pointer.
(«) Germinate seeds of cabbage, radish, parsley, or tomato, and note
carefully the position of the cotyledons during the day and night.
(/) Observe the sleeping state of wood-sorrel (Oxalis), clover, and96
BOTANY.
purslane. Then make careful notes of diurnal and nocturnal positions
of the leaves of as many plants as possible. Where it is possible to
do so. it is recommended that photographs be taken of the waking
and sleeping states of plants. Careful sketches, at least, should be
made.
(g)	Select a symmetrically grown fuchsia, place it in a window,
and note the rapidity with which the leaves and stems turn toward
the light.
(h)	Germinate various seeds in a window, and observe the helio-
tropism of the seedlings.
(i)	Grow a strawberry-geranium (Saxifraga sarmentosa) in a hang-
ing basket or pot in a window, and observe that the dependent runners
bend away from the light.
(j)	Germinate beans, and after the radicles have protruded a centi-
metre or two fasten the seeds in such a way (under a bell-jar) that the
radicles point directly upwards. Observe that the roots soon begin
bending towards the earth.
(k)	Grow a few sensitive-plants in pots for study of irritability.
Seeds may be procured at any seed-store for a few cents, and are
easily grown in a warm room.CHAPTER VI.
CLASSIFICATION AND DISTRIBUTION.
198.	We may now proceed to take a hasty survey of the
vegetable kingdom, studying here and there a selected ex-
ample which must serve to illustrate the structure of a con-
siderable group. In such a study of plants it is better to
begin with the simpler and more easily understood forms,
and to pass from these to those which are structurally more
complex and whose functions are correspondingly compli-
cated.
199.	On account of the vast number of species of plants
(probably exceeding 150,000) it is necessary for us to group
them in such a way as to bring together those which resem-
ble one another. In such grouping we take into considera-
tion as many things as possible, and those plants which are
alike or similar in the greatest number of particulars are
considered to he more nearly related to each other than
those with fewer points of resemblance. Moreover, it has
been found that resemblances in structure are of far greater
importance than resemblances in habits. Two plants, for
example, may be parasitic in habit, and yet their structural
differences may he so great as to warrant us in placing
them in entirely different groups of the vegetable kingdom.
200.	If we bring together all the plants of the vegetable
kingdom, we may recognize pretty easily six or seven large
groups, all the members of which show more or less of re-98
BOTANY.
semblance to each other. These are called Branches, or
Divisions. Likewise, if we consider the plants in each
Branch, we may make several groups, each of which will
include those with still greater resemblances. These groups
are called Classes.
201.	In like manner Classes are divisible into Orders;
Orders into Families; Families into Genera; Genera into
Species. Each Species is composed of individual plants, all
of which bear a close resemblance to each other. In some
Species there is such a variation in the individuals compos-
ing it that they are grouped into Varieties.
202.	Applying the foregoing, we have the following as
the classification of the common Sunflower:
Kingdom of Vegetables.
Branch, Phanerogamia.
Class, Angiosperms.
Order, Composite.
Genus, Helianthus.
Species, annuus
203.	There are needed now and then various sub-groups;
thus Classes are often separated into two or more Sub-
Classes, and these again into Series and Cohorts; so Orders
are sometimes separated into Sub-Orders, or they are more
frequently divided into Tribes and these again into Sub-
Tribes. So, too, a Genus may be divided into Sub-Genera.
On the other hand, it is very common for Family to be
omitted, as in the case of the Sunflower given above.
204.	The general relationship of the Branches of the
Vegetable Kingdom is sometimes shown by constructing a
tree or diagram, whose principal divisions represent the
Branches. Such diagrams (as the one on the opposite
page) are often quite helpful to the student.CLASSIFICATION AND DISTRIBUTION.
99
VII. PnANF.1tOC.AMIA.
Flowering plants—Monocotyledons and Dicotyledons
and
Conifers.
VI. Pteridophyta.
Fernworts—Horsetails, Ferns, and Club-mosses.
V. Bryofhyta.
Mossworts—Liverworts and Mosses.
IV. Carpophyta.
Spore-fruit plants—Red Seaweeds and (heir allies.
III. O0PHYTA.
Egg-spore plants.
II. Zygophyta.
Unisexual plants.
I. Protophyta.
Sexless and mostly single-celled plants.100
BOTANY.
205.	Plants are distributed widely over the surface of
the earth. They are most abundant in the hotter climates,
and decrease in number toward the poles. Likewise, they
are more abundant upon the lowlands than upon the tops
of high mountains. The regularity and amount of rainfall
has also a controlling influence upon land-vegetation, while
for marine forms the direction and temperature of the
ocean-currents largely determine their distribution.
206.	In general, we may say that light, temperature, and
moisture are the chief controlling agents. Where these
are favorable, there vegetation is abundant; where they are
unfavorable, vegetation is scanty or wanting. The cold
and poorly lighted polar regions (VI and VI' of the map),
the cold mountain-summits, the dry deserts of Africa and
Australia (IX and IX'), and the dark depths of the oceans,
are alike deficient in vegetation.
20V. In general, similar conditions have brought about
similar vegetations. The North American Forest Region
(I) of the Western Hemisphere has its counterpart in the
Europseo-Siberian Forest Region (I') of the east, in which
approximately similar conditions prevail. So, too, the
Prairie Region of North America (II) is to be compared
with the Steppe Region of Asia (II'), the Pampas Region of
South America (II"), and the South African Region (II'").
The Californian Region (IV) is in many respects similar
to the Mediterranean Region (IV') and the Chili-Andean
Region of South America (IV").
208. The accompanying map (Fig. 42) shows one of the
ways of dividing the earth into botanical regions. Each
region is capable of subdivision into districts. The plants
of a region or district constitute a flora; thus we may
speak of the Prairie Flora, or the flora of the Upper Mis-
sissippi district, or the flora of Iowa.' Fig. 42.—I, North American Forest Region. I', Europaeo-Siberian Forest Region. II, Prairie Region. II', Steppe Region. II",
Pampas Region. IP", South African Region. Ill, Rocky Mountain Region. IV, Californian Region. IV', Mediterranean
Region. IV", Chili-Andean Region. IV'", South Australian Region. V, Central American or West Indian Region. V', East
Indian Region. VI, Arctic Region. VII, Brazilian Region. VIII, Central African Region. IX, Sahara Region. IX', Austra-
lian Desert Region. X, Chino-Japanese Region.
CLASSIFICATION AND DISTRIBUTION.102
BOTANY.
209.	Most plants are short-lived. By far the greater
number perish in a year or two, as is the case with our
annuals and biennials. Some shrubs and trees may live
for a considerable number of years, but even the most en-
during generally die in a few centuries. The plants of the
world are thus constantly dying off, and are as constantly
being renewed. Occasionally the dying off in a particular
species was more rapid than the renewal, in which case the
species eventually became extinct: many such cases are
known to palaeontologists. On the other hand, it has fre-
quently happened that new forms have appeared as the
older ones have died off, so that the character of a particu-
lar flora has thereby been gradually changed.
210.	By a study of the fossil plants of any period in the
world’s history we may learn that the flora of each region
has undergone great changes. The flora of North America
in the Tertiary period was very different from what it is
now, while the Cretaceous flora was still more unlike that
of the present. Plants that now are confined to the east-
ern continent were then common in many parts of this
continent, and tropical or sub-tropical species flourished
abundantly in Nebraska and Dakota.
211.	Moreover, we learn by sudh a study that many of
the plants of the present were not yet in existence in cer-
tain geological periods. As we go hack in geological time
the vegetation is less and less like that of to-day. Thus,
the higher flowering plants (Dicotyledons) were not in ex-
istence earlier than the Cretaceous period, while the Lilies
and their relatives date hack to the Triassic. The great
Carboniferous vegetation, from which our coal was derived,
contained no plants with true flowers. There were no
grasses or sedges, no lilies or orchids, no roses or violets, noCLASSIFICATION AND DISTRIBUTION. 103104
BOTANY.
oaks or maples. There were cone-bearing trees and tree-
ferns, as well as gigantic club-mosses and horsetails; but
even these were very different from any now living.
212. The foregoing table (Fig. 43) will show the main
facts as to the distribution of the principal branches of
the vegetable- kingdom in geological time. It must he
remembered that the geological record is as yet only frag-
mentary, and in all probability many of the lines will be
carried down much further as our knowledge becomes more
complete.CHAPTER VII.
BRANCH I. PROTOPHTTA.
TEE SEXLESS PLANTS.
213.	The protophytes are the lowest and simplest plants,
and they are often so minute as to require the highest pow-
ers of the microscope for their study. For the most part
the cells are poorly developed; the protoplasm is frequently
destitute of granular contents; the nucleus is wanting in
many cases; and not infrequently there is either no cell-
wall or only a poorly developed one.
214.	The cells in all cases cohere little, if at all; and even
when they are united into loose masses each cell retains
nearly as much independence as in the single-celled forms.
215.	No sexual organs are known. The common mode
of reproduction is by the fission of cells, although internal
cell-division occurs also.
216.	Most protophytes live in water and get their food
from the solutions it contains. Some are green or greenish,
and so are able to use carbon dioxide, while others are des-
titute of a green color and are parasites or saprophytes.
217.	Three classes of protophytes may be distinguished,
as follows:
1.	Naked shapeless protoplasm—Slime-moulds (Myxomycetes).
2.	Minute cells, not green—Bacteria and Yeast (Schizomycetes).
3.	Cells green, or greenish—Green Slimes (Cyanopliycew).106
BOTANY.
Class I. Slime-Moulds (Myxomycetes).
218. The Slime-moulds are in many respects the most
remarkable of all known plants. They bear so strong a
resemblance to the lowest animals (Protozoa) that they
have been, time and again, placed in the animal kingdom
Fig. 44.—A part of a Slime-mould (Physarum leucopus) in its vegetative stage.
Magnified 350 times.
by various naturalists. When we compare them with any
other plants, they are found to differ from them so widely
that very little relationship can be detected.
219. A Slime-mould is a mass of naked, shapeless proto-
plasm (Fig. 44) during all the growing part of its life. InPROTOPHTTA.
107
some species it is no larger than a pin-head, while in others
it is as large as a man’s hand. This mass of protoplasm is
often yellow or orange-red in color, and is never green. It
possesses to an extraordinary degree the power of moving
itself from place to place. Slime-moulds obtain their food
by absorbing solutions of decaying matter, and are even
Fig. 45.—Early stages of a Slime-mould (Fuligo varians). a, a spore; b. c, the
same, bursting the cell-wall; d to l, various stages; m, young Slime-mould.
said to engulf solid substances in the same manner as the
Amoeba among animals.
220. When they have become full-grown they lose a
good deal of their moisture, and the protoplasm then sepa-
rates itself into a great number of minute rounded balls,
each of which forms a cell-wall around itself. These little
balls (spores) are thus nothing but bits of protoplasm secure-
ly covered. They may now be blown hither and thither
without harm, and when at last they fall into a moist warm
place they imbibe water, burst their coats, and are free108
BOTANY.
naked masses of protoplasm again, thus completing the
round of life (Fig. 45).
There are seven orders of Slime-moulds, which are distinguished
mainly by their structure in the spore-bearing stage. Many species
occur in all parts of the United States, and may be readily found on
decaying logs, stumps, etc., and on the bark-covered ground in tan-
yards. A fine large one—Puligo varians—is especially common in
the last-named situation.
Class II. Bacteria and Yeast-Plants (Schizomycetes).
221.	The plants of this class are minute cells, each con-
sisting of a mass of protoplasm surrounded by a thin wall.
The cells cohere but little, and in some cases not at all.
They contain no chlorophyll, and always live in solutions
of nourishing matter. Two orders are generally recog-
nized, the one containing the Bacteria, and the second the
Yeast-plants.
222.	Bacteria.—These are the smallest of living things.
Their minute cells in some cases measure no more than
.0005 mm.	^nc^) diameter. They are in some
species rounded in shape, in others elongated like little
rods, or in others more or less curved (Fig. 46). They are
frequently provided with one or two cilia (i.e., whip-like
projections of protoplasm), by means of which they move
about with great activity.
223.	Bacteria are found in great numbers in the watery
parts of decaying organic matter, causing various kinds of
fermentation. They reproduce by fission with such aston-
ishing rapidity that in a short time they swarm in any ex-
posed substance which is capable of furnishing them with
food. Some of the species live in the watery juices of
plants and animals, causing various diseases.
224.	Some bacteria can endure high temperatures, andPROTOPETTA.
109
frequently appear in tightly closed Vessels whose contents
have been boiled. Some people have been led to explain
their appearance under such circumstances by “ spontane-
ous generation;” but thus far the facts are capable of other
explanation.
225. On account of their minuteness, bacteria may be
Fig. 46.—Forms of Bacteria, a, Micrococcus prodigiosus; b, Bacterium termo
(resting stage); c, Bacterium lineola; d, Bacillus ulna; e. Spirillum rugula; /,
Spirochsete plicatilis; g. Spirillum volutans. Magnified 650 times.
picked up by currents of air and borne long distances, and
in this way they are doubtless often carried from place to
place. When a pool of putrid water dries up, the bacteria
with which it swarmed are blown away with the dust and
dirt, dropping everywhere into pools, upon plants and ani-
mals living and dead, and even entering our lungs with
the air we breathe.110
BOTANY.
Among the bacteria which are of especial interest to us are the fol-
lowing:
1.	The bacterium of small pox (Micrococcus vaccinse), composed of
minute globular cells, is now accepted as the cause of small-pox.
That found in vaccine virus is a cultivated state, while that in small-
pox is its virulent state.
2.	The bacterium of diphtheria (Micrococcus diphtheriticus), simi-
lar to but smaller than the preceding, is present in the body when suf-
fering from diphtheria.
3.	The bacterium of ordinary putrefaction (Bacterium termo, Fig.
46, b) is composed of oblong cells. It is the cause or accompaniment
of all ordinary decay of animal and vegetable substances.
4 The bacterium of anthrax or splenic fever (Bacillus anthracis)
is composed of cylindrical cells, which are motionless. It occurs in
the blood of animals suffering from the diseases named.
5.	The bacterium of consumption (Bacillus tuberculosis), of very
slender cylindrical, motionless cells, has recently been shown to occur
in the lungs and air-passages of consumptive patients.
6.	The bacterium of leprosy (Bacillus leprae), of cells similar to the
preceding but larger, is found in the tissues of those afflicted with
leprosy.
Practical Studies.—(a) Put a pinch of cut hay or any other similar
vegetable substance into a glass of water; keep in a warm room for
a couple of days, or until it becomes turbid (from the abundance of
bacteria); examine a minute drop with the highest powers of the
microscope for active bacteria.
(b)	Put a bit of fresh meat into water, and study the bacteria which
will appear in it. Spiial forms like g, Fig. 46, may often be found
in such a preparation.
(c)	Examine the juices of decaying fruits.
226.	Yeast-Plants.—If a bit of yeast be placed upon a
glass slip and carefully examined under high powers of tbe
microscope, there will be seen a great many small roundish
or oval cells, of a pale or whitish color. They have a cell-
wall, but generally the nucleus is wanting or indistinct.
These little cells are Yeast-plants, and bear the name of
Saccharomyces cerevisise.
227.	They reproduce by a kind of fission, called budding.
Each cell pushes out a little projection which grows largerPROTOPIIYTA.
Ill
and larger, and finally a cell-wall forms between the two,
which sooner or later separate from one another (a and b,
Fig. 47). Under certain circumstances new plants form
internally, as in c and d, Fig. 47.
228. Yeast-plants are saprophytes, and live upon the
starch of flour. They break up
the starch, and in the process lib-
erate considerable quantities of
carbon dioxide, which appears
as bubbles upon the surface of
the yeast. Another result of
the breaking up of the starch is
the formation of alcohol; hence
the growth of yeast-plants in a
starchy substance is always ac-
companied by what is known as alcoholic fermentation.
The housewife and baker use yeast-plants for the carbon-
dioxide gas which they evolve, to give lightness to the
bread, while the brewer and distiller use the same plants
for the alcohol produced by their activity.
Practical Studies.—(a) Fill a strong bottle half full of active yeast,
cork tightly, and keep for an hour or two in a warm room. Draw
the cork and notice the violent escape of gas (carbon dioxide).
(by Place a small drop of the yeast upon a glass slide, add a little
water, cover with a cover-glass, tapping it down gently. After a
little examination under a high power of the microscope, add iodine,
which will stain the starch-grains blue or purple, and the yeast-plants
yellowish. Many of the latter will be found in process of budding,
as in a and b, Fig. 47.
(c) Spread a half-teaspoonful of yeast on a fresh-cut slice of potato
or carrot; cover with a tumbler or bell-jar to keep it moist; after a
few days (4 to 8) examine for cells which are reproducing by internal
cell-formation, as in c and d, Fig. 47.
Fig. 47.—Yeast-plants in various
stapes of growth, a and b. At c
and d new cells have formed by
internal cell-formation, a and b
magnified 400, c and d magnified
750 times.112
Botany.
Class HE. Green Slimes (Cyanophycece).
229.	These are single cells, or chains of cells, usually of
a blue-green or brownish-green color, and generally inhab-
iting the water. They very commonly form slimy masses
or films on the water, or the moist surfaces where they
grow. In their decay they emit a putrid odor, and when
abundant, as they sometimes are in city water-supplies, are
quite troublesome and offensive.
230.	The lower Green Slimes are single-celled, as in
Fig. 48— Cells of Gloeocapsa in different stages of growth, showing division
and the mode in which the daughter-cells are surrounded and enclosed by the
felatinous walls of the mother-cells. A, youngest; E, oldest stage. Magnified
00 times.
Fig. 49.— A, filament of Nostoc; B, end of filament of Oscillaria. Magnified
300 times.
Chroococcus, Gloeocapsa (Fig. 48), and other genera. Each
cell divides into two, and these soon divide again, and so
on. In Gloeocapsa the cell-wall is much swollen into a
jelly-like mass.
231.	In the Nostocs and their near relatives (Oscillaria)
there is a little coherence of the cells into chains or fila-
ments. The cells form by fission, but after formation
adhere somewhat to each other. The Nostocs (Fig. 49, A)
occur in water or on moist ground as jelly-like masses ofPROTOPllYTA.
113
filaments. Some are amber-colored, some brownish, some
bluish-green. The species of Oscillaria (Fig. 49, J3) are
mostly dark-green filaments collected into felt-like masses
floating on the surface of the water, or growing on wet
earth or the wet sides of watering-troughs, etc. A pecu-
liarity of these plants is their power of oscillating from
side to side, while at the same time they move forward.
In this manner they are enabled to travel considerable dis-
tances.
232.	In Rivularia the filaments are generally arranged
radially in little rounded masses. One of these (Rivularia
fluitans) is often very abundant in lakes and slow streams,
the little floating greenish balls being a millimetre or less
in diameter. Other species occur as green slimy masses, as
large as pin-heads, on the stones and stems of water-plants
in ponds and brooks.
233.	Related to the foregoing, but probably not falling
within this class, are the bright-green “ Green Slimes” which
have been known under the name of Protococcus. They
are invariably one-celled plants, and the cells are much
larger than in any of the preceding. They occur com-
monly on damp walls and rocks and the sides of flower-
pots in greenhouses and conservatories, and in wet weather
on wooden walks and the roofs and sides of houses.
234.	One species of Protococcus (P. nivalis) is the noted
Red-snow Plant which in the high north latitudes often
covers the snow, giving it a reddish color. It also occurs
on the mountain-tops in lower latitudes. Although really
a green plant, its color is reddish in one of its stages.
235.	In their modes of multiplication these species of114
BOTANY.
Protococcus resemble other protophytes. By fission the
cells are divided into two or four new ones, and this ap-
pears to he the more common mode of increase. They also
produce new cells by internal cell-formation similar to that
in the yeast-plant.
Practical Studies.—(a) Scrape off a little of the greenish slimy mat-
ter from a damp wall, mounting it in water: examine under a high
power. Some small blue-green or smoky-green cells will be found
belonging to the lower Green Slimes (CliroOcoccus, etc.); of these
some will probably be found in process of fission. Larger bright-
green cells filled with granular protoplasm will also be found: these
are a species of Protococcus.
(i) In midsummer look along the water-line of fresli-water lakes
and ponds for soft, amber-colored, rounded masses from the size of a
pea to that of a hickory-nut. By mounting a small slice of one of
these, it will be seen under the microscope to be composed of myri-
ads of filaments of Nostoc similar to A, Fig. 49. Occasionally a fila-
ment may be seen with a larger cell (a heterocyst), as in the figure.
Its function is not known.
(c)	Secure a handful of the dark-green filamentous growth which
is common on the wet sides of watering troughs, and place it in a
dish of water. If it is an Oscillaria it will rapidly disperse itself, an
hour being long enough to show quite a change in position. Now
mount a few filaments in water and examine under a high power.
They will be seen to sway from side to side, and to move quite rap-
idly across tbe field of the microscope.
(d)	In midsummer scrape off one of the small jelly-like masses of
Rivularia, so common on the submerged stems of water-plants, mount
in water, crushing or cutting the mass so as to show the individual
filaments. Each filament tapers from the centre of tbe mass out-
ward, and at its larger end there is generally a larger cell (a hetero-
cyst).
(e)	Some protophytes may be preserved as herbarium specimens for
future study. The Slime Moulds should be kept dry in little pill-
boxes. The filamentous Green Slimes may be floated out upon sheets
of paper as described in (j) on page 129.
(/) It is always desirable to preserve some of the aquatic proto-
phytes in weak alcohol for future study. Reduce the alcohol to one
fourth or one fifth strength.CHAPTER VHI.
BRANCH II. ZYGOPHYTA.
THE UNISEXUAL PLANTS.
236.	This is an assemblage of quite diverse plants, rang-
ing from minute unicellular species, on the one hand, to
large seaweeds of considerable complexity, on the other.
237.	In this branch we find the first examples of un-
doubted sexuality. The sexual organs all have this in
common, that between the male and the female there is no
appreciable difference as to form, size (with a few excep-
tions), color, origin, etc. The result of the union of the
two sexual cells is the production of a new cell, the resting
spore or zygospore, possessing very different characteristics
from either. While the sexual cells have only ordinary
walls, or none at all, the resting spores are covered with
thick, firm walls.
238.	The resting spore is so called because under certain
circumstances it remains quiescent, while retaining its vi-
tality, often for long periods of time. Thus at the close
of the growing season, as upon the advent of the summer
drought, or of winter, the resting spores fall to the bottom
of the pools (in the fresh-water forms), and in the dried or
frozen mud remain uninjured until the return of favorable
conditions, when they germinate and give rise to a new
generation of plants.116
BOTANY.
239.	Nearly all the plants of this group contain chloro-
phyll, only one order being destitute of it. The green
forms are all aquatic, and inhabit either fresh or salt water.
Those which have no chlorophyll are mostly saprophytes,
and live upon dead organic matter. They are doubtless to
he regarded as modified forms of some of the types of the
chlorophyll-bearing portion of the group.
240.	Two classes of Unisexual plants have been distin-
guished, as follows:
1.	Sexual cells locomotive—Zoosporece.
2.	Sexual cells fixed—Conjugate.
Class I. Zoospoee^e.
241.	In this large class the protoplasm is quite in the
habit of escaping from the plant and taking on a locomo-
tive state, in which it is called a zoospore, a word which
means an animal-like spore (from the Greek zoon, an ani-
mal). Under the microscope a zoospore looks very much
like a monad, and this resemblance is made still greater
when we observe the cilia by which it darts rapidly through
the water. All the plants of this class contain chlorophyll.
242.	Pandorina is the pretty name given to a fresh-water
plant of this class. It consists of a globular colony of green
cells, each cell provided with two cilia, which project out-
ward from the ball, and by rapid vibration give it a rotary
motion (Fig. 50). At a certain stage of its development
some of the cells of the colony escape and swim about in
the water; finally two come in contact with one another
and unite, forming a resting spore (F, F, G, H, Fig. 50).
After a period of rest, the resting spore bursts its wall, the
protoplasm escapes, swims about for a time by means of
two ciliq with which it is provided; at last it comes to restZYGOPHYTA.
117
and divides itself into sixteen cells, which then constitute
a new colony similar to that with which we started (A,
Fig. 50).
243.	The Water-Net (Hydrodictyon) is one of the most
curious of the common plants of pools and slow streams in
midsummer. Well-grown specimens are from 20 to 30
centimetres long (8-12 inches), and consist of an actual net
made of cylindrical cells joined at their ends. The whole
Fig. 50.—A, a colony of Pandorina morum; C, sexual cells escaping; E, F, G,
union of sexual cells; H, resting spore. All highly magnified.
net is a colony, and the general mode of reproduction re-
sembles that of Pandorina.
244.	New colonies are formed also directly by the proto-
plasm of a cell first breaking up into a great number of
small ones (by internal cell-formation), and then these soon
arrange themselves into a miniature net inside of the old
cell-wall. The old wall eventually decays and sets free the
new colony.
245.	In the common Water-Flannel (Cladophora) of our118
BOTANY.
creeks and rivers we have an example of a filamentous plant
of the class Zoosporeae. It is a large, dark-green, much-
branched plant, which attaches itself to stones and timbers
in the water. It grows so vigorously that it soon forms long
matted masses, often several metres in length, which float
and wave back and forth in the currents of water. It pro-
duces myriads of zoospores.
246. The Sea-Lettuce (Ulva), which is common along the
coast and in brackish waters, grow-
ing upon stones, wharf-timbers, etc.,
and resembling small lettuce-leaves,
reproduces by zoospores. The
plant is composed of a couple of
layers of cells, and in some of these,
by internal cell-formation, zoospores
are produced; these escape into the
water, where they swim about by
means of their two cilia.
247. Kelp and its Allies (Phseo-
sporese) make up a large group of
zoospore-bearing plants. They are all marine, often attain
a great size, and are of an olive-brown color. They con-
stitute the Kelp which is often so abundant on the sea-
shore after a storm.
248.	The large, flat, leaf-like kelp (Laminaria, commonly
called Devil’s Apron) may be taken to illustrate the larger
forms. The “ leaf ” portion is sometimes from one to six.
metres long and nearly a metre in breadth, while its stalk
sometimes attains a length of two to four metres. It is
held to rocks and stones at or below low-water mark by
means of root-like processes.
249,	The zoospores, which have two cilia, are producedZYGOPHYTA.
119
in certain specialized cells. These occupy particular por-
tions of the plant-body, and compose the “fruit,” so called.
In Devil’s Apron these fruits occur as bands or spots in
the central part of the leaf. The union of zoospores to
form a resting-spore (zygospore) has been observed in but
few cases, and not at all in the larger and more common
species.
Practical Studies.—(a) In midsummer search quiet pools for water-
nets. With a fine scissors cut out a piece of one and mount care-
fully in water. Study with a low power of the microscope. Some
of the cells will be found producing zoOspores. Search for young
nets forming within the old cells.
(b)	Collect a quantity of water-flannel, and put it in a large dish of
water, leaving it over night. Next morning the side of the dish
which is nearest the light will show a green band at the water’s edge,
due to the myriads of zoOspores which escaped during the night.
Mount a drop of water and search for zoOspores. Occasionally the
escape of zoOspores may he seen by mounting a number of filaments
and searching carefully,
(c)	Collect sea-lettuce and study in the same way.
(d)	Study the tissues of Devil’s Apron (Laminaria) in cross and
longitudinal sections.
Class II. Conjugates.
250.	Here the sexual cells which unite are fixed; that
is, they are not locomotive. The sexual act always takes
place in the mature plant. No zoospores' are produced.
This class includes many plants of great beauty and scien-
tific interest. Of the four orders here noticed the first
three are composed of chlorophyll-bearing plants, while in
the fourth they are destitute of chlorophyll.
251.	The Desmids (Desmidiacece) are minute unicellular
fresh-water plants. The cells are of very various forms,
usually more or less constricted in the middle, and divided
into two symmetrical half-cells. The cell-wall is more or
less firm, but never silicious.120
BOTANY.
252.	The reproduction of desmids takes place by fission
and by union; that is, asexually and sexually. In the first,
the neck uniting the two halves of the cell
elongates and becomes divided by a trans-
verse partition, so that instead of the original
symmetrical cell there are now two exceed-
ingly unsymmetrieal ones (Fig. 52); these
grow by the rapid enlargement of the new
and small halves; eventually the two cells become sym-
metrical, by which time they have separated. This pro-
cess may be repeated again and again.
253.	In the sexual process each of two cells which are
Fig. 52.—A des-
midin process of
fission. Highly
magnified.
Fig. 53.—Sexual reproduction of a desmid (Cosmarium menenghinii). a, front;
ft, end; c, side view of the adult plants; d. two cells conjugating; e, young rest-
ing spore formed; /. ripe resting spore, with spiny wall—the four halves of the
parent cells are empty; g, the resting spore germinating after a period of rest;
n, the young cell escaped from resting spore; i, young cell dividing, showing
two new plants, similar to a, placed crosswise in the interior of the cell. Magni-
fied 475 times.
near one another sends out from its centre a tube, which
meets the corresponding one from the other (d, Fig. 53).
Fig. 54.—A common
desmid, Closlerium.
Highly magnified.
At the point of meeting the two tubes
swell up hemispherically, and finally, by
the disappearance of the separating wall,
the contents unite and form a rounded
resting spore (e), which soon becomes
coated with a thick wall (f). After a
longer or shorter time the resting spore may geminate,ZYGOPUYTA.
121
which it does by bursting its wall and dividing its con-
tents into two parts, each of which finally becomes a new
desmid (g, h, i).
254.	The Diatoms (Diatomaceee) are microscopic uni-
cellular water-plants, resembling the Desmids, but differ-
ing from them in having walls which are silicified, and
in the chlorophyll being hidden by the presence of a
yellow coloring matter (phycoxanthine). Each cell is
usually composed of two similar portions, called the
valves. Each valve may be described as a disk whose edge
is turned down all around, so
as to stand at right angles to
the remainder of the surface,
making the valve have the
general plan of a pill-box
cover. The two valves are
generally slightly different in
size, so that one slips within
the other (A, Fig. 55), thus
forming a box with double
sides. In other cases the
valves are simply opposed
and do not overlap.
255.	The individuals may
exist singly or in loose fami-
lies; they are free, or attached
to other objects by little
stalks, and they are frequently
imbedded in a mucous secretion. The free forms are loco-
motive, and may be seen in constant motion under the
microscope: the mechanism of the motion is not certainly
known.
Fig. 55.—A, front view of a diatom,
showing the overlapping walls; B,
same view of a diatom undergoing fis-
sion ; C, side or top view of a diatom
(Navicula viridis), showing markings.
Highly magnified.122
BO VAST.
256.	In their reproduction diatoms resemble the desmids,
the only differences being those made necessary by their
rigid walls.
257.	Diatoms are .exceedingly abundant; they occur in
both salt and fresh water, usually forming a yellowish
layer at the bottom of the water, or they are attached to
the submerged parts of other plants, and to sticks, stones,
and other objects; they have been dredged from the ocean
at great depths, and appear to exist there in enormous
quantities. They are also found among mosses and other
plants on moist ground. Great numbers occur as fossils,
forming in many instances vast beds composed of their
empty shells. The varied and frequently very beautiful
markings of their valves have long made diatoms objects
of much interest to the microscopist. The great regularity
and the extreme fineness of the lines and points upon some
have caused them to be used as microscopic tests.
258.	The Pond Scums (Zygnemace.ee). The plants of this
order, which are all aquatic, are elongated unbranched fila-
ments, composed of cylindrical cells arranged in single
rows. The cells are all alike, and each one appears to be
independent, or nearly so, of its associates. The filament
is thus, in one sense, rather a composite body than an indi-
vidual. The chlorophyll is generally arranged in bands or
plates.
259.	The vegetative increase of the number of cells takes
place by the fission of the previously formed cells. The
protoplasm in a cell divides, and a plate of cellulose forms
in the plane of division. This is repeated again and again,
and by it the filament becomes greatly elongated. It is
interesting to note that this increase of cells, which here
constitutes the growth of the plant-body, is that which inZYQOPEYTA.
m
simpler plants is called the asexual mode of reproduction.
In the plants under consideration there is harely enough
coherence of the cells to enable them to constitute a plant-
body, and one can readily see that
the same fission of the cells which
here increases the size of the plant
would, if the cells cohered less, sim-
ply increase the number of individ-
uals.
260. As might he expected, the
filaments occasionally separate
Fig. 56.—A, beginning of the sexual reproduction of a Pond Scum (Spirogyra
longata): a, beginning of the formation of lateral tubes; 6, c, the tubes in con-
tact B, the protoplasm passing from one cell to the other at a; b, the mass of
protoplasm formed by the union of the protoplasmic contents of the two cells.
C. two young resting spores (c), each with a cell-wall. They contain numerous
oil-drops, and are still enclosed by the walls of the parent-cell. Magnified 550
times.
spontaneously into several parts of a considerable length,
and the parts floating away give rise to new filaments.
The separation takes place'by the cells first rounding off
slightly at the ends, so that their union is weakened at124
BOTANY.
their comers; finally only the centres of the rounded ends
are left in slight contact, which soon breaks.
261.	The sexual reproduction is well illustrated in Spi-
rogyra, one of the principal genera. At the close of
their growth in the spring, the cells push out short tubes
from their sides, which extend until they come in contact
with similar tubes from parallel filaments (A, Fig. 56).
Upon meeting, the ends of the tubes flatten upon each
other, the walls fuse together and soon afterwards become
absorbed, thus making a channel leading from one cell to
the other (_B, Fig. 56). Through this channel the proto-
plasm of one cell passes into the other, and the two unite
into one mass, which becomes rounded and in a short time
secretes a wall of cellulose around itself (Fig. 56, JB and C).
The resting spore thus formed is set free by the decay of
the dead cell-walls of the old filament surrounding it; it
then falls to the bottom of the water, and remains there
until the proper conditions for its growth appear.
262.	The germination of the resting spore is a simple
process. The inner mass enlarges and bursts the outer hard
coat; it then extends into a columnar or club-shaped mass,
gradually enlarging upward from its point of beginning;
after a while a transverse partition forms in it, and this is fol-
lowed by another and another, until an extended filament
is formed.
'263. The Black Moulds (Mucorini) are saprophytic and
some times parasitic plants; they are composed of long
branching filaments (hyphce), which always form a more
or less felted mass, the mycelium; when first formed the
hyphse are continuous, but afterwards septa are formed in
them at irregular intervals. The protoplasmic contents of
the hyphae are more or less granular, but they never de-ZYGOPUYTA.
125
velop chloropnyll. The cell-walls are colorless, except in
the fruiting hyphse, which are usually dark-colored or
smoky (fuliginous); hence the name of Black Moulds.
264. The mycelium sometimes develops exclusively in
the interior of the nutrient medium; in other cases, it de-
velops partly in the medium and partly in the air. In
some species the mycelium may occasionally attach itself
to the hyphse of other plants of the same order, and even
Fig. 57.—Diagram showing the mode of growth of Mucor mucedo. to, the
mycelium; s, single spore-case, borne on an aerial erect hypha.
to nearly related species, and derive nourishment parasiti-
cally from them. It is doubtful, however, whether any
species are entirely parasitic, and so far as parasitism oc-
curs it appears to he confined to narrow limits; none, so
far as known, are parasitic upon higher plants.
265. The reproduction of Black Moulds is asexual and
sexual. In the asexual reproduction the mycelium sends
up erect hyphae (Fig. 57), which produce few or many sepa-
rable reproductive cells—the spores. The method of for-
mation of the spores in the Black Mould of decaying fruits,126
BOTANY.
pastry, etc. (Mucor mucedo), is as follows: The vertical
hyphse, which are filled with protoplasm, become enlarged
at the top, and in each a transverse partition forms (A, a,
Fig. 58), the portion above the partition (5) becomes larger,
and, at the same time, the transverse partition arches up
(B, a), finally appearing like an extension of the hypha,
then called the columella (C, a). The protoplasm in the
enlarged terminal cell (b) divides into a large number of
minute masses, each of which surrounds itself with a cell-
Fig. 58.—Diagrams showing mode of growth of the spore-ca6e of Mucor mu-
cedo. A, very young stage; B, somewhat later; C, spore-case with ripe spores.
a in all the figures represents the partition-wall between the last cell of the fila-
ment and the spore-case, b.
wall; these little cells are the spores, and the large mother-
cell is now a spore-case, or sporangium.
266.	The spores are set free in different ways: in some
cases the wall of the spore-case is entirely absorbed by the
time the spores are mature; in other cases only portions of
the wall are absorbed, producing fissures of various kinds.
The spores germinate readily when on or in a substance
capable of nourishing them, by sending out one or two
hyphse, which soon branch and give rise to a mycelium.
Spores may, if kept dry, retain their vitality for months.
267.	Sexual reproduction takes place after the produc-
tion of asexual spores. Two hyphse, in the air or withinZYGOPHYTA.
127 '
the nutritive medium, come near each otner, and send out
small branches, which come in contact with each other (a,
Fig. 59); these elongate and become club-shaped, and at
the same time they become more closely united to each
other at their larger extremities (b); a little later a trans-
verse partition forms in each at a little distance from their
place of union (c); the wall separating the new terminal
Fig. 59.—Conjugation of a Black Mould, a. two hyphae near each other, and
sending out short lateral tubes or branches, which come in contact; 6, the
branches grown larger; c, the formation of a partition near the end of each
branch; d, absorption of the wall between the two branches, and the consequent
union of the protoplasm of the end cells; e, resting spore fully formed, e mag-
nified 90 times, the others nearly the same.
cells is now absorbed, and their protoplasmic contents unite
into one common mass (d); the last stage of the process is
the secretion of a thick wall around the new mass, thus
forming a zygospore (e).
268. The resting spore does not germinate until it has
undergone desiccation, and has experienced a certain period
of rest, when, if placed in a moist atmosphere, it sends out
hyphae which bear spore-cases. Resting spores appear neverBOTANY.
128
to form a mycelium: that s always the result of the growth
of the spores from the spore-cases.
Practical Studies.—(a) Collect a quantity of Pond Scum and other
aquatic vegetation, and preserve in a dish of water. Mount portions
of this material and search for desmids, using a i-inch objective.
Two-lobed or star-shaped desmids of a bright-green color may fre-
quently be found. A large lunate desmid (Closlerium, Fig. 54) is
often still more common. In the latter the clear protoplasm at each
end is always streaming rapidly.
(b)	Collect a little of the brownish-yellow scum which in early
spring gathers on the top of the water of brooks, ditches, and pools.
Mount in water and examine with a high power. Hundreds of dia-
toms may be seen moving rapidly across the field in every direction.
In any such preparation many species of various shapes will be
found. The prevailing form, however, is generally elongated and
somewhat diamond-shaped.
(c)	Study in like manner the slimy coating upon dead leaves and
twigs in water in the summer for diatoms. On some of these, very
fine markings may be found.
(d)	Collect a quantity of bright-green Pond Scum which always
abounds in shallow ponds and pools, and preserve in a dish of water.
Collect, also, some of the same which has begun to turn yellow and
brown. Upon mounting a bit of the first in water and examining
with a high power, it will be found to consist of threads of cylindri-
cal cells, each containing one or more spiral chlorophyll-bands (Spi-
rogyra, Fig. 56) or star-shaped chloropliyll-budies (Zygnema). Upon
mounting some of the second collecting, here and there the formation
of resting spores may be observed. In all cases care must be taken
not to mount loo great u, quantity of the material, nor to injure the
plants by rough handling.
(e)	In the study of Black Moulds it is mostly necessary to make
use of alcohol for freeing the specimens of air; afterwards they usu-
ally require to be treated with a dilute alkali, as a weak solution of
ammonia or potassic hydrate, which causes the hypbse to swell up to
their original proportions.
(/) Cut a lemon in two, and, squeezing out most of the juice, ex-
pose the two halves to the air of an ordinary living-room or school-
room for a few days, when various moulds will begin to develop.
Under favorable circumstances Black Mould will predominate. It
can be told by its dark color and the minute round black spore-
cases on the ends of the erect hyphse. Mount a few hyphas (as di-
rected in e above) and examine liyphse. spore-cases, and spores.Z7Q0PII7TA.
129
(g) Moisten a piece of perfectly fresh bread, and then sow here and
there on its surface a few spores of Black Mould; cover with a tum-
bler or bell-glass. In a few hours a new crop of Black Mould will
begin developing.
(/t) The most common Black Moulds are species of the genus Mucor.
M mucedo and M. stolonifer are common on many decaying sub-
stances. M. syzygites occurs on decaying toadstools and other large
fungi. Pilobolus crystallinus, Piptocephalis freseniana, and Cbaeto-
cladium jonesii occur on animal excrement Phycomyces nitens
grows on oily or greasy substances, as old bones, oil-casks, etc.
(i)	Place several clean glass slides in conlact with a culture of
Black Mould, as described in (g). By removing these at different
times the various stages of growth of the mould may be easily
studied.
(j)	Good specimens of Pond Scums may be made for preservation
in the herbarium as follows: Place a tuft of the Pond Scum in a dish
of clean water, and then by agitating the water for a few seconds the
filaments may be made to spread out iu the water; now pass under
the floating mass a sheet of heavy white paper, and slowly raise it in
such a manner as to lift out the plants with the least disturbance of
their filaments. Allow the surplus water to drain off, then press the
paper and specimens between sheets of heavy blotting-paper, first,
however, laying a moist cotton or linen cloth over the specimen. By
care such specimens will be found to adhere quite lightly to the
sheets of paper.
(k)	Black Moulds may be obtained for herbarium specimens by
placing cards or slips of paper in contact with cultures, and then re-
moving them when the proper amount of mould lias run over them;
or portions of the mass as it grows upon a piece of bread—as in (g)—
may be pressed lightly, and then glued to a sheet of paper.
(il) For future study in the laboratory the aquatic zygophvtes
should be preserved in bottles of water containing just enough alcohol,
glycerine, or carbolic acid to prevent their decay. One fourth or fifth
of the first and second, and enough of the last to give a decided
odor, will usually do well enough.CHAPTER IX.
BRANCH III. OOPHYTA.
THE EGG-SPORE PLANTS.
269.	The distinguishing feature of the plants belonging
to this division is that they develop a large cell (the oogone,
or oogonium), differing from those about it in size and
general appearance, which contains one or more rounded
masses of protoplasm (the germ-cells), which are subse-
quently fertilized by the contents of a second kind of spe-
cial cell of much smaller size (the antherid, or antheridium).
The oogone is the female reproductive organ, and the am
therid the male. The protoplasm of the latter is in some
cases transferred by direct contact to the germ-cell; in
other cases it first breaks up into motile bodies (the anther-
ozoids), which then come to and unite with the germ-cell.
270.	The germ-cell itself is never motile, and in most
cases it remains within the parent-plant until long after it
is fertilized. The result of fertilization is the production
of a resting spore (here called an oospore) which differs
from the germ-cell structurally in having a hard and gen-
erally colored coating, and physiologically in having the
power of germination and growth after a period of rest of
greater or less duration.
271.	The plants of this division vary greatly as to the
development of the plant-body. In some cases it is a feebly
united colony, while in its highest forms it is a well-devel-
oped thallus, with even the beginning of a differentiation
into Caulome, Phyllome, and Root. Most of them areO'dPHYTA.
131
chlorophyll-bearing, but a few are colorless saprophytes
and parasites.
272.	Four classes have been distinguished:
1.	Zoosporece, analogous and related to the ZoSsporete of Branch II.
2.	CEdogoniem; plant body a cellular filament.
3.	Caloilastem ; plant-body a tubular filament.
4.	Fucacece; plant-body large and complex; color olive-green.
Class I. Zoospores.
273.	The little spherical Volvox of the pools and ditches
may be taken as an illustration of the first class. It resem-
bles Pandorina in many respects,
and without doubt is closely re-
lated to. it. Volvox is a colony of
very many little cells, each of
which projects its two cilia out-
ward, giving the ball a hairy ap-
pearance. By the lashing of the
cilia the ball rolls about in the
water.
274.	At a certain stage some of
the cells enlarge and slip into the
interior of the colony, becoming free oogones, each con-
taining one germ-cell. At the same time other cells break
up their protoplasm into motile antherozoids, which escape
into the same cavity of the colony. At length the anthero-
zoids unite with the germ-cell, when as a result the latter
secretes a thick wall, and thus becomes a resting spore.
Upon germination the resting spore divides its protoplasm
into several hundred small cells, which then arrange them-
selves into a new colony.
275.	The asexual reproduction takes place by certain
cells breaking into great numbers of little cells, which then
Fig. 60.—A Volvox colony,
magnified about 45 times,
showing young colonies with-
in.132
BOTANY.
unite themselves directly into a new colony in the interior
of the parent-colony (Fig. 60).
Class II. CEdogonie^e.
276. The plants constituting this class are composed of
articulated, simple, or branched
filaments, which are attached to
sticks, stones, earth, or other ob-
jects by root-like projections of
the basal cells. The chlorophyll
in the cells is always dense and
uniform. They inhabit ponds and
slow streams, and form green
or brownish masses which fringe
the sticks and other objects in the
water.
277. The asexual reproduction
of (Edogoniete is very curious.
During the early and active
growth of the plants the proto-
plasm of certain cells escapes as a
large zoospore (Fig. 61, A and B);
it is provided with a crown of
cilia about its smaller hyaline
end, by means of which it swims
rapidly hither and thither in the
water (C). After a time it comes
Fig. 61. —Asexual reproduc-	.....
tion of CEdogonium. A. fracture to rest, clothes itself With a Cell-
of a filament; B, escape of pro-
toplasm and formation of a zoo- wall, and sends out from its small-
spore; C, swimming zoospore;	7
er end root-like prolongations (B),
ptent comfmsed'o'f oa\y onecelt which attach it to Some object;
CMr escapi"s- it now elongates, and at lengthO'dPHYTA.
133
forms partitions, taking on eventually the form of the adult
filament. It sometimes happens that before the new plant
resulting from the growth of a zoospore has formed its
Fig. 62 —Showing the sexual state of an CEdogonium. A, part of a filament
with three oogones. og\ m, m, small filaments (dwarf males) which produce an-
therozoids in this species; B, an oogone at time of fertilization; D, part of fila-
ment of another species, showing escape of antherozoids. Highly magnified.
first partition, the protoplasm again abandons its cell, to be
for a second time a zoospore (E).
278. In the sexual reproduction of the plants of this class134
BOTANY.
the female organ consists of a rounded germ-cell situated
within a cavity—the oogone; it is developed from one of
the cells (sometimes two) of the filament by a condensing
and rounding off of the protoplasmic contents; when the
germ-cell is fully mature, an opening is formed in the
oogone-wall for the ingress of the antherozoids (A and B,
Fig. 62). One or more antherozoids are produced in cer-
tain small cells of the same or another filament; in shape
they resemble the zoospores mentioned above. Upon es-
caping into the water they swim about vigorously, eventu-
ally making their way through the opening in the oogone,
and then burying themselves in the substance of the germ-
cell (B, z, Fig. 62). After fertilization, the germ-cell be-
comes covered with a thick and colored (brown or red)
coat, and it then becomes a resting spore.
279. After a period of rest, the resting spore germinates
by rupturing its thick coat and permitting the escape of
the contents, enclosed in a thin envelope; by this time the
protoplasm has divided into four portions, which take on
an oval form and develop a crown of cilia. They soon
escape from the investing membrane, and after a brief
period of activity grow into an ordinary filament in exactly
the same manner as the zoospores.
Practical Studies.—(a) In midsummer collect a few quarts of the
surface-water of weedy ponds, together with the Pond Scums grow-
ing therein; put it into a shallow dish, and after an hour or so look
carefully (with the naked eye) for Yolvox. It will be seen as a minute
green ball (from .5 to 1 millimetre in diameter) rolling slowly through
the water. Now carefully transfer it to a slide along with enough
Pond Scum to prevent crushing. Under even a low power many of
the details of structure may be made out, and one or more young
colonies in the interior may almost invariably be seen.
(4) Specimens of (Edogonium may be obtained by examining the
small sticks and stems of aquatic plants from quiet waters. They
may be recognized by the enlarged cells (obgones).OUPHTTA.
135
Class III. Cceloblaste^e.
280.	The plant-body in this important and interesting
class is a branched filament, in which the protoplasm is
continuous. These plants are, however, not to be consid-
ered single-celled, but rather rows of cells which have not
become separated from one another by partitions.
281.	The Green Felts (Vaucheriacece) are good repre-
sentatives of the first order under this class. They are
coarse, green, tubular plants which grow in abundance on
the moist earth in the vicinity of springs, and in shallow
running water, forming dense felted masses.
282.	The asexual reproduction consists of a separation of
a part of the plant-body, sometimes a swollen lateral
branch, sometimes only the protoplasm of such a branch.
In the latter case the protoplasm may escape as a zoospore
(A, Fig. 63) which eventually forms a wall around itself,
and then proceeds to elongate into a new plant-body.
283.	Sexual reproduction takes place in lateral branches
also. Both antherids and oogones develop as lateral pro-
tuberances upon the main stem (og, og, h, Fig. 63). The
male organ (antherid) is long and rather narrow, and soon
much curved; its upper portion becomes cut off by a par-
tition, and in it very small biciliate antherozoids are de-
veloped in great numbers. The female organ (oogone) is
short and ovoid in outline, and usually stands near the
male organs. In it a partition forms near its point of
union with the main stem; the upper portion becomes an
oogone, and its protoplasm condenses into a rounded body,
the germ-cell: at this time the wall of the oogone opens,
and permits the entrance of the antherozoids which were
set free by the rupture of the antherid-wall.136
BOTANT.
284. Upon coming into contact with the germ-cell the
antherozoids mingle with it and disappear; the germ-cell
immediately begins to secrete a wall of cellulose about
itself, and it thus becomes a resting spore. After a period
of rest the thick wall of the resting spore splits, and through
Fig. 63.—Reproduction of Green Felt (Vaucheria sessilis). A. formation of a
zoospore; B, zoospore come to rest; C. zoospore germinating; D, E, young
plants; w, root-like holdfasts; F, plant with sexual organs. Magnified about 30
times.
the opening a tube grows out which eventually assumes
the form and dimensions of the full-grown plant.
285. The Water-Moulds (Saprolegniacece) are colorless
saprophytes or parasites, more frequently the latter; they
are generally to be found in the water, attached to the
bodies of living or dead fishes, crayfishes, etc., or occasion-
ally in the moist tissues of animals out of the water, TheOOPIIYTA.
137
plant-body is greatly elongated and branched, and all its
vegetative portion is continuous; the reproductive portions
only are separated from the rest of the plant-body by
partitions.
286.	The asexual reproduction is very much the same as
in Green Felt. It may be briefly described as follows:
The protoplasm in the end of a branch becomes somewhat
condensed, a partition forms, cutting off this portion from
the remainder of the filament, and the whole of its contents
becomes converted by internal cell-division into zoospores
provided with one or two cilia (Fig. 64, 1). These soon
escape from a fissure in the wall and are active for a few
minutes, after which they come to rest and their cilia dis-
appear (2 and 3). In one or two hours they germinate by
sending out a filament (4), from which a new plant is
quickly produced.
287.	The sexual organs also bear a close resemblance to
those of Green Felt. The oogones are spherical, or nearly
so (in most of the species), and contain from two to many
germ-cells, which are fertilized by means of antherids,
which usually develop as lateral branches just below the
oogones. In some species the antherids and oogones are *
upon the same plants, and in such cases the fertilization
takes place by the direct contact of the antherid and the
passage of its contents into the oogone by means of a tubu-
lar process from the former; in other species the plants
are dioecious, and in them the antherids produce motile an-
therozoids, by means of which the fertilization is effected.
After fertilization each germ-cell becomes covered with a
wall of cellulose and is thus transformed into a resting
spore.
388. What is given above may be taken to illustrate the138
BOTANY.
general mode of reproduction in the order. It presents
much variation in the different genera and species. The
resting spores of the Water-moulds possess, when mature,
Fig. 64.—Showing reproduction in Water-moulds. 1, 2, 3, 4, asexual reproduc-
tion; 5 to 10, sexual reproduction. 6 to 9 show development of oogones and an*
therids. Highly magnified,00P1IYTA.
m
a thick integument, which is double—that is, formed of an
outer thicker coat (epispore) and an inner thinner one (en-
dospore). After a considerable period of repose the rest-
ing spores germinate by sending out a tube, as in Green
Felt.
289.	The Fly-Fungus (Entomophthora muscse), which in
the autumn is so destructive to house-flies, is a member of
a small order (Entomophthorece) apparently related to the
Water-moulds. It consists of small cells which grow in
the moist tissues of the fly, and at last pierce the skin, pro-
ducing minute terminal spores, which give the fly a pow-
dery appearance. These spores (called, also, conidia) may
he seen as a whitish halo surrounding the spot to which the
fly, now dead, has attached itself.
Resting spores have been observed
in some species. They are round
and thick-walled.
290.	The Mildews and White
Rusts (Peronosporeoe) live parasiti-
cally in the interior of higher plants.
They are composed of long branch-
ing tubes, whose cavities are con-
tinuous throughout. They grow
between the cells of their hosts,*
and draw nourishment from them
by means of little branches (haus-
toria), which thrust themselves
through the walls (Fig. 65).
291.	1 he asexual spores (conidia) into the ceils (z, z) of its hcwj
Magnified 300 times.
are produced upon branches of the
* In speaking of a parasite, the plant or animal upon which it feeds is called
its host.140
boTANY.
fungus which protrude through the epidermis of the tost.
In the Mildews (species of Peronospora) these branches
Fig. 66.—Showing tips of two conidia-beaiing branches of Potato-mildew
(Peronospora infestans). Highly magnified.
find their way through the breathing-pores, and bear their
spores singly upon lateral branchlets (-Fig. 66); in the
White Rusts (species of Cystopus) the
conidia-bearing branches collect under the
epidermis and rupture it. Here the coni-
dia are borne in chains or bead-like rows
(Fig. 67).
292. In some species the conidia germi-
nate by forming a tube; in others they
divide internally and finally emit many
zoospores. The latter eventually protrude
a tube and bore their way into the cells of
Fig. 67. — Showing the host (Fig. 68, a to i).
d^a-b'ear?nK^ranc<hes 293. The sexual reproduction always
of the White Rust of ,	,	.
Peppergrass. Magni- takes place in the intercellular spaces of
fled 400 times.	...
the host. Lateral branches of two kinds
appear upon the hyphse; those of one kind (the youngOOPEYTA.
141
odgones) become greatly thickened and finally assume a
globular shape (Fig. 69, o); the other branches (the young
antherids) become elongated and club-shaped (Fig. 69, n).
Fig. 68.—Germination of the conidia of Potato-mildew, a, &, c, formation of
zoospores; d, growth of zoospores; sp, a zoospore growing into the cells of the
plant, e, i. Magnified about 400 times.
The antherids bend and come in contact with the oogonea,
and soon each thrusts out a small tube which penetrates
the oogone, reaching the germ-cell. The protoplasm of the
Fig. 69.—Sexual organs of a Mildew, o, odgones; n, antherids. A, youngest
stage; B and C, older stages. Magnified 350 tunes.
antherid is thus transferred directly to the germ-cell (Fig.
69, A, B, C). After fertilization the germ-cell secretes a
thick double wall, and so becomes a resting spore. -
294. The resting spores remain in the tissues of the host
until the latter decay, which is generally in the spring.142
POTANt.
Germination then takes place, in some species by the pro-
duction of a tube, in others by the division of the proto-
Fig. 70.—Resting spores of White Rust of Peppergrass; at A, still surrounded
by odgone. By C, formation of zoospores; Dt free zoospores. Magnified 400
times.
plasm into zoospores (Fig. 10, B, 0, D) whose subsequent
development is like that described above in case of the
conidia.
Practical Studies.—(a) Collect a quantity o-f Green Pelt and pre-
serve it in a dish of water. After a few hours a large number of zob-
spores may be observed collected at the edge of the water nearest to
the light.
(6) Examine carefully mounted specimens of the bright-green fila-
ments, and look for the thickened lateral branches which produce
the zobspores.
(c)	Select some of the oldest, yellowish filaments. Mount and ex-
amine with a low power for the sexual organs. In collecting speci-
mens for the study of the sexual organs it is necessary always to
lake those masses which are yellowish and appear to be dying or
dead.
(d)	Throw a dead fish into a pool of water in the summer, and ex-
amine it after a few days, when it will probably be found covered
with a mould-like growth. Remove a few filaments and look for
the formation of zobspores. The same Water mould (Saprolegnia
ferax) may often be found upon the bodies of young fishes, especially
in fish-hatching houses.
(e)	In the latter part of summer and in the autumn, examine the
dead flies which adhere to window-panes, door-casings, and especiallyOOPHYTA.
143
to wires and strings hanging from the ceiling. The whitish powder
around the fly will indicate the presence of the Fly-fungus. Mount
some of this white powder in water and study under a high power
to see spores. Examine some of the tissue of the fly (by tearing out
small bits of the distended abdomen) for the internal portion of the
parasite.
(/) In the spring the leaves of shepherd’s purse and peppergrass
may often be found covered underneath with a white mould-like
growth (Peronospora parasitica). Carefully scrape off a little of this
growth and mount first in alcohol, afterwards adding a little potassic
hydrate. The irregularly branching hyph® will be seen to bear here
and there their white, broadly ellipsoidal conidia. Similar studies
may be made of the Grape-mildew (Peronospora viticola) on grape-
leaves in autumn, and the Lettuce-mildew (Peronospora gangliformis)
on cultivated and wild lettuce from spring to autumn.
(g)	Make very thin cross-sections of a leaf affected with a Mildew,
when the latter has passed the period of its greatest vegetative ac-
tivity. Mount in alcohol (to drive out air-bubbles), then add potassic
hydrate, and look for the resting spores, which in some species are
of a dark-brown color.
(h)	White Rusts occur on many plants: one (Cystopus candidus)
on shepherd’s purse, peppergrass, radish, etc.; another (C. bliti) on
amarantus; and another (C. portulacae) on purslane. For conidia,
make very thin cross-sections of leaves, through a white-rust spot, and
mount as above. The resting spores (which are dark brown) are
easily obtained in the leaves of amarantus and purslane.
Class IY. Fucaceje (the Mockweeds).
295.	The plants of this class are entirely marine. In
many cases the development of the plant-body is unusually
perfect, showing a differentiation into parts which have a
considerable resemblance to roots, stems, and leaves. In
size they approach the flowering plants. Their tissues, too,
show a high degree of differentiation; the cells are arranged
in cell-masses, and these are differentiated into several va-
rieties of parenchyma, approaching, in some instances, to
the condition which prevails in the Mosses and their allies.
296.	With the foregoing there is found a marked differ-144
BOTANY.
entiation of portions of the plant-body into general repro-
ductive organs, analogous to the floral branches of higher
plants. The sexual organs are developed upon modified
branches, which differ more or less in
shape and appearance from the ordi-
nary ones.
29V. In Rockweed (Fucus) the sex-
ual organs are found in the thickened
ends of the lateral branches (A, Fig.
V2). They occur on the walls of
cavities termed conceptacles, which
are spherical, with a small opening at
the top (B, Fig. 72). The concepta-
cles are at first portions of the general
surface, and afterward become de-
pressed and walled in by the over-
growth of the surrounding tissues;
they are thus in reality portions of the
general surface.
298. The walls of the conceptacles
are clothed with pointed hairs, which
in some species project through the
opening, and among these are found
the sexual organs, which are them-
selves, as Sachs has pointed out,
modified hairs. The antherids are
produced as lateral branches of hairs (A, Fig. 73); each
antherid is a thin-walled cell, whose protoplasm breaks up
into a large number of biciliate antherozoids, which escape
by the rupture of the surrounding wall (JB). Before rup-
turing, however, the antherids detach themselves and float
in the water with their contained antherozoids.
Fig. 71. Part of a plant of
knotted Rockweed (Asco-
phyllum nodosum), show-
ing the air-bladders. Nat-
ural size.OOPHttA.
145
299. The oogone is a globular or ovoid short-stalked
body containing eight germ-cells. The germ-cells escape
from the oogone surrounded by an investing membrane,
which floats out through the opening of the conceptacle,
Fig. 72.—A, end of branch of a Rockweed (Fucus evanescens), natural size;
/, /, conceptacles. B. magnified section through a conceptacle, showing hairs,
a, b; oogones, c; an the rids, e.
where it finally ruptures and sets the germ-cells free (IT,
Fig. 73). The antherozoids, which are liberated at about
the same time, gather around the inactive germ-cells in
great numbers, and by the vigor of their movements some-
times actually give them a rotary motion {III). The re-146
BOTANY.
suit of their coming together is the fertilization of the germ-
cells, and their transformation into resting spores by the
secretion of a wall of cellulose on each one.
300. In germination the resting spore lengthens and un-
Fig. 73.—Sexual organs of Rockweed (F. vesiculosis). A, antherids; B, an-
therozoids; I, oogone and hairs; II, escape of germ-cells; III, germ-cell sur-
rounded by antherozoids; IV, V, germination of resting spore. Magnified 160
times; B, 360.
dergoes division into numerous cells; at the same time it
elongates below into root-like processes, which serve to
hold fast the new plant (V, IV).
Practical Studies.—(a) Secure specimens of Rockweeds, fresh or
dry. Fresh ones may easily be found along the beach of the ocean
after a storm. Dry specimens can easily be procured by purchase or
exchange. Make thin cross-sections through the conceptacles in the
thickened ends of the branchlets. When mounted in water, even
the sections from the dry specimens will frequently show the sexual
organs quite well. It must be remembered that some species are
dioecious, i.e., have the antherids on one plant and the oOgones on
another.OOPHTTA.
147
(ft) Make very tliin cross and longitudinal sections of different por-
tions of tlie plant-body, and study the tissues. Note particularly the
boundary tissue (epidermis), and the cells constituting the midribs
and harder portions of the stems and leaves.
(c)	The following key to the genera of American Fucacese will be
helpful in their study.
I.	Plant branched:
1.	Leafy; air-bladders stalked, separate......Sargassum.
In addition to half a dozen species of both coasts, the
Gulfweed (Sargassum bacciferum) may be mentioned,
which floats in great quantity in mid-Atlantic, consti-
tuting the so-called Sargasso Sea. Its proper home is in
the West Indian region, where it grows attached to rocks.
2.	Leaves spirally inserted, bearing air-bladders on their
blades (Southern)..........................Turbinaria.
3.	Leaves 2-ranked, bearing air-bladders on their petioles
(Western).................................Phyllospora.
4.	Plant pinnatifid; air-bladders several celled, terminal on
the branclilets (Western)....................Halidrys.
5.	Plant dichotomous, the parts flat and provided with a mid-
rib (both coasts)...............................Fucus.
This contains the proper Rockweeds of the seaside.
Eight species occur in the United States.
6.	Plant irregularly dichotomous, the linear parts destitute
of a midrib (Eastern).....................Ascophyllum.
7.	Plant much branched, bushy, the branches filiform (West-
ern).......................................Cystoseira.
II.	Plant reduced to a top-shaped or cup-shaped vesicle (doubt-
fully American).......................... Himanthalia.
(d)	The filamentous oophytes may be preserved for herbarium
specimens by floating out as described on page 129 (j). The Mildews
and White Rusts may be preserved by simply drying the affected
leaves and stems (of the hosts) under pressure.
(e)	Preserve specimens in weak alcohol for future study.CHAPTER X.
BRANCH IY. CARPOPHYTA.
THE SPORE-FBUIT PLANTS.
301.	The distinguishing characteristic of the plants
which constitute this vast division is the formation of a
spore-fruit (sporocarp) as a result of fertilization. The
spore-fruit consists essentially of two different parts; viz.,
(1) a fertile part, which either directly or indirectly pro-
duces spores, sometimes a few, or even one, or a very great
number; (2) a sterile part, consisting of cells or tissues de-
veloped from the cells adjacent to the fertile part, and so
formed as to envelop it.
302.	This immense group includes plants with chloro-
phyll, and a large number of species which are parasitic
or saprophytic, and which, as a consequence, are destitute
of chlorophyll. In the former, the spore-fruit is small in
proportion to the size of the vegetative parts of the plant;
hut in the latter, where the vegetative parts are greatly
reduced, the spore-fruit is proportionately large. In this
the parasites and saprophytes of the Carpophyta are like
those of the flowering plants, in which the vegetative or
assimilative organs are smaller than in those which contain
chlorophyll; thus the very large spore-fruits of many of
the larger fungi, and their relatively small mycelium, may
be compared to the large reproductive organs and the re-GARPOPHTTA.
149
duced stems and leaves of the Vine-rape of Sumatra
(Rafflesia).
303.	The female organ in this division is called a car-
pogone, and consists of a single enlarged cell, or of several
cells of a special form. In some cases a projection, called
the trichogyne, is attached to the carpogone; its function
appears to he the conveyance to the carpogone of the fer-
tilizing matter received from the antherid.
304.	The antherid is much more variable in structure
than the female organ. In some cases it is applied directly
to the carpogone in fertilization, while in others it produces
antherozoids.
305.	The plant-body shows in general a more perfect
development in the Carpophyta than in the preceding divi-
sions. While it is hut little developed in the parasitic and
saprophytic species, it is well developed in many of the
Red Seaweeds and the Stoneworts, in which there is often
a considerable amount of differentiation of the plant-body
into caulome and phyllome.
306.	Five classes may he readily distinguished, as follows:
1.	Green fresh-water plants; fruit-spores few..............Coleochatece.
2.	Red or purple mostly marine plants; fruit-spores many. .Floridece.
3.	Parasites; fruit-spores many, enclosed in sacs..........Ascomycetes.
4.	Parasites; fruit-spores many, on stalks..............Basidiomycetes.
5.	Green fresh-water plants; fruit-spore one................. .Oharacece.
Class I. Coleoch^etejs.
307.	The genus Coleochsete shows us the simplest form
of sexual reproduction among the Carpophytes. The spe-
cies are all small green fresh-water plants, composed of
branching filaments, which are arranged radially; the diam-
eter of each cushion-like mass is from 1 to 2 mm. (.04 to
,08 in.).150
BOTANT.
308.	Asexual reproduction is by means of ciliated zoo-
spores, one of which may form in each cell and escape
through a round hole in the cell-wall (D, Fig. 74).
309.	In the sexual process the female organ, the carpo-
gone, is a single cell, wide below and tapering above into
a long slender canal, the trichogyne, which is open at its
apex (A, og, Fig. 74). In the swollen basal portion there
Fig. 74.—Coleochsete. an, antherids; og, carpogones, each with a trichogyne;
z, z, antherozoids; B, fertilized carpogone, surrounded by the covering, r(“ peri-
carp”), the whole forming the spore-fruit; C. spore-fruits burst open, showing
interior tissues; D, zoospores from C. Magnified 350 times.
is a considerable mass of protoplasm, which is the essential
part to be fertilized. The male organs, the antherids, are
formed as flask-shaped protuberances which grow out of
adjoining cells. In each antherid a single oval biciliate
antherozoid is formed (A, z, z, Fig. 74).
310.	Fertilization is doubtless effected by these anthero-
zoids coming in contact with the protoplasm of the carpo-CAUPOPHYTA.
151
gone, but the actual entrance of the former has not yet
been seen. After fertilization the protoplasm in the car-
pogone increases considerably in size, and forms a cellulose
coat of its own. The cells which support the carpogone
send out lateral branches, which grow up and closely sur-
round it, finally covering it entirely (excepting the tricho-
gyne) with a cellular thick-walled “pericarp” (B, r). The
whole mass, including the fertilized carpogone and its in-
vesting pericarp, constitutes the simplest form of spore-
fruit (the sporocarp).
311.	The further growth of the spore-fruit takes place
the next spring by the swelling of the protoplasmic con-
tents, and the consequent rupture of the pericarp; the
inner portion divides into several cells, C (the proper fruit-
spores), which give rise to zoospores closely resembling
those developed from the vegetative cells. From each
zoospore a new plant eventually arises.
Practical Studies.—(a) These little plants occur in fresh-water pools
as little green masses adhering to leaves, sticks, etc. According to
Wood, we have probably two species.
(b) The sexual process and the development of the sexual organs
occur in May, June, and July.
Class II. Floride^e (the Red Seaweeds).
312.	The plants of this class, which are almost without
an exception marine, are among the most beautiful and in-
teresting members of the vegetable kingdom. All have
some shade of red or purple which sometimes becomes ex-
ceedingly rich; while for beauty of outline and delicacy of
branching they stand unrivalled among plants.
313.	To a great extent they grow in the deep water
below low-water mark, far beyond the reach of the ordi*152
BOTANY.
nary collector. There is therefore a good deal of diffi-
culty involved in their study. The greater part of the
material which the student secures for study is that which
the storms have washed ashore from the deeper waters.
314. The plant-body varies from small branching fila-
ments, on the one hand, to expanded leaf-like growths
showing a considerable degree of complexity, with the be-
ginning of a differentiation of the cells into several kinds
of tissues. All contain chlorophyll, which, however, is
Fig. 75.	Fig. 76.
Fig. 75.—A Red Seaweed (Plocamium coccineum). About natural size.
Fig. 76.—Tetraspores of Red Seaweeds. A, of Lejolisia mediterranea; f, tetra-
spores. B, of Corallina officinalis; t, tetraspores iu a cup-sliaped extremity of a
branch.
generally hidden by the presence of a red or purple color-
ing matter.
315. The asexual reproduction takes place by means of
spores, which, from almost always forming in fours, are
known as tetraspores (A and B, t, t, Fig. 76). These appear
to replace the swarm-spores of other seaweeds, and may
also be compared to the conidia of certain fungi; they are
destitute of cilia, and are, as a consequence, not locomotive.CARPOPHYTA.
153
316.	The sexual organs consist of earpogones and anther-
ids. The latter are situated singly or in groups on the
ends of branches (A and B, a, a, Fig. 77). The anthero-
zoids are small round bodies which are destitute of cilia
Fig. 77.—Sexual reproduction of Red Seaweeds A (Lejolisia): a, antherid;
x, antherozoids; b, carpogone, with antherozoids attached to the trichogyne; s,
section of ripe spore-fruit, from which a spore (fruit-spore) is escaping. B
(Nemalion): a, antherid, and antherozoids; o, carpogone. D and E, develop-
ment of spore-fruit. Magnified 150 times.
(A, x, Fig. 77), and are carried about by currents of water,
and in this way brought to the earpogones.
317.	The earpogones are somewhat variable as to their
complexity, being much more simple in the lower orders
than in the higher. In some cases (Nemalion) the carpo-
gone (B, b, Fig. 77) is thickened below, and elongated
above into the trichogyne, which differs from that in Co-
leochsete in not being open at the top.
318.	When the antherozoids are set free from the anther-154
BOTANY,
ids they attach themselves to the trichogyne, as shown in
Fig. 11. The result of this contact of the antherozoids with
the trichogyne is the fertilization of the carpogone, which
immediately enlarges and at the same time undergoes
division into many cells, which grow into short, crowded
branches, hearing a spore at the end of each (D and E, Fig.
11). This growth, which includes the spores and the short
branches which hear them, and which resulted from the
fertilization of the carpogone, is the spore-fruit (sporocarp)
of these plants. In the genus under consideration the
spore-fruit is a comparatively simple growth, as compared
with the degree of complexity it reaches in some other
orders of this class.
319. In some other cases (Lejolisia, etc.), the carpogone,
before fertilization, consists of several cells (A, b, Fig. 11).
Upon fertilization taking place, the outer cells of the carpo-
gone divide, and develop into articulated branches which
lie side by side and form a more or less spherical envelope,
the so-called “ pericarp.” In the mean time the central cell
of the carpogone produces outgrowths or short branches
which eventually hear spores, occupying the cavity of the
pericarp (A, s, Fig. 11). The spore-fruit here consists
of a fertile part which hears spores, and a sterile part
which serves as a protection or covering. In technical
works the spore-fruit is called a “cystocarp.”
Practical Studies.—There are many orders of the Red Seaweeds,
but it is unnecessary to notice them here particularly. About one
hundred species occur along the New England coast, and the number
is greatly increased as we pass to the southward.
It is difficult for the student to study the plants of this class away
from the seashore, and as a rule it is perhaps as well for the begipner
to content himself with only a general examination of such specimens
as may be accessible.
Specimens for the study of the structure should be preserved inCARPOPHTTA
155
alcohol or glycerine. However, much may be made out by the care-
ful examination of dried specimens.
Red Seaweeds may often be obtained “ in the rough” which can
be slightly moistened and then pressed out and dried for study.
Such material will often yield quite good specimens.
Good mounted microscopic specimens may sometimes be obtained
showing the structure of the plant as well as of the sexual and asex-
ual reproductive organs.
Class HI. Ascomycetes {the Sac-Fungi).
320.	This large class includes chlorophyll-less plants
which differ much in size and appearance, hut which agree
in producing their fruit-spores (sac-spores, or ascospores)
in sacs (asci).
321.	The sexual organs consist of carpogones and anther-
ids, and, after fertilization, produce a spore-fruit (sporo-
carp) which includes the sacs and their contained sac-spores.
The most common number of sac-spores is eight in each
sac; but it sometimes exceeds, and frequently falls short, of
this number, there being often no more than one or two.
The sacs are in many cases arranged side by side in a com-
pact mass, forming a spore-bearing surface (the hymenium).
322.	In addition to the sac-spores there are generally one
or more other kinds of spores which are developed asexu-
ally. Some of these are doubtless to be regarded as the
equivalents of the conidia of the lower groups, and will
accordingly be so named here.
Of the Sac-fungi there are a number of well-marked
orders, all but one of which are popularly known as fungi.
323.	The Blights and their Allies {Order Perisporia-
cece).—These plants, which are mainly parasitic, are com-
posed of branching jointed filaments (hyphce) which form
a white web-like film upon the surface of the leaves and
stems of their hosts. There are both sexual and asexual166
BOTANY.
spores, and of the latter there are in most cases two or three
different kinds, which are produced earlier than those that
result from a fertilization.
324. The sexual organs and the spore-fruit resulting from
the act of fertilization bear a striking resemblance to those
of Coleochsete, the difference being such as may be ac-
counted for by taking into consideration the aquatic habits
Fig. 76.- Orape-blight (Erysiphe). a, a piece of a vegetative. hypha, m, m,
upon, a fragment of the epidermis of the leaf of the grape, and to which it is fas-
tened by the suckers, h\ o, hypha, with the suckers, h, seen in side view. Mag
nified 3<0 times.
Fig. 79.—Grass-blight (Erysiphe communis), o, vegetative filaments, with a
few suckers; 6, branches bearing conidia; c, separated conidia. Magnified 135
times.
of the one and the aerial and parasitic or saprophytic habits
of the other.
325. In the Blights, which are all parasitic, the jointed
filaments closely cover the leaves and other tender parts of
their hosts, and draw nourishment from them by means of
suckers, whioh project as irregular outgrowths from the
side next to the epidermis (Fig. 78). These suckers apply
themselves closely to the epidermal cells, and, in some
cases, appear to penetrate them.
a
Fia. 78.
Fio. 79.CARPOPHTTA.
157
326.	The crossing and branching filaments soon send up
many vertical branches, in which partitions form at regular
intervals. The cells thus formed are at first oblong and
cylindrical, with flattened ends; but the topmost one soon
becomes rounded at its extremities, and the others follow
in quick succession, thus giving rise to a row of cells, the
spores, or conidia (Fig. 79). These fall off and germinate
at once by pushing out a tube, which gives rise to a new
plant.
327.	The sexual process in most species takes place late in
the season. Two filaments crossing each other or coming
Fig. 80.—The sexual process in a Blight (Erysiphe). o, jointed threads; b,
antherid; c. carpogone; d, young spore-fruit; e, older spore-fruit. Magnified.
Fig 81.—Ripe spore-fruit of Willow-blight (Uncinula adunca). The append-
ages are curved or hooked. Magnified.
into close contact swell slightly and send out from each a
short branch; one of these becomes the carpogone (c, Fig.
80). From the swollen part of the other filament a corre-
sponding branch is given off, which grows up in contact
with the carpogone and becomes the antherid (b, Fig. 80).
328.	Fertilization at once takes place, by the direct union
of protoplasm. Eight or ten branches grow out just below
the carpogone, and growing upward soon completely cover
it with a cellular coat which eventually becomes hardened
and turns brownish in color, constituting the pericarp of
the spore-fruit (Fig. 81).158
BOTANY,
329. The carpogone inside of the pericarp gives rise, by
branching, to one or more large cells filled at first with
granular protoplasm, which soon forms two to eight spores
spores? "Magnified""about contained spores, to escape.
270 times.	330. The Herbarium-mould (Euro-
tium) is a near relative of the Blights. It is common on
poorly dried specimens in the herbarium, and also on de-
caying fruits, wood, etc. It sends up vertical branches,
which swell at the top and bear a great number of small
protuberances (the sterigmata, A, c, st, Fig. 83), each of
which produces a chain of conidia.
331.	The sexual organs appear a little later than the
conidia. The end of a branch of the plant becomes coiled
into a hollow spiral (A, as, Fig. 83), which constitutes the
carpogone. From below the spiral an antherid grows up-
ward, and brings its apex in contact with the upper cells
of the carpogone (B, Fig. 83).
332.	After fertilization, other branches grow up around
the carpogone, and finally completely enclose it, as in the
Blights described above (0,1), Fig. 83). In the mean
time, from the cells of the enclosed carpogone branchesCARPOPHYTA.
159
bud out, and finally produce many eight-spored sacs on
their extremities; after a time the sacs are dissolved, and
the spore-fruit, now of a sulphur-yellow color, contains a
multitude of loose spores.
Fig. 83.— Eurotium. A, a portion of the plant, with erect hypha, c, bearing at
its top a radiating cluster of sterigmata, st, from which the conidia have fallen;
us, young carpogone—below it a younger branch is beginning to coil spirally to
form another carpogone. B, the carpogone, as, and the antherid, p. C, the
same beginning to be surrounded by the enveloping branches which grow out
from its base. D, spore-fruit. Highly magnified.
Pi'actical Studies.—(a) Collect in the autumn a quantity of leaves
of the lilac -which are covered with a whitish mould-like growth,
the Lilac-blight (Microsphaera friesii). Scrape off a bit of this Blight,
after moistening with a drop of alcohol; mount carefully, adding a160
BOTANY.
little potassic hydrate. Look tor conidia and suckers (haustoria)
Look also for spore-fruits, which appear like minute dark dots to the
naked eye. Carefully crush the spore-fruits and observe the sacs
(4 to 7) with their contained spores (6). Notice the beautifully
branched tips of the appendages.
(b) Collect aud study the blights to be found on hops (Spbterotheca
castagnei), on cherry- and apple-leaves (Podosphasra tridaetyla), on
hazel- and ironwood-leaves (Phyllactinia suffulta), on willow-leaves
(Uncinula adunca), on leaves and fruit of grapes (U. americana), on
wild sunflowers, verbenas, etc. (Erysiplie laroprocarpa), on peas (E.
martii), on grass, anemones, buttercups, etc. (E. communis).
(c) Place a few slips of green twigs in an
ordinary plant-press, allowing them to remain
until they become (1st) mouldy (conidial state),
aud (2d) covered with minute yellow globular
bodies (the spore-fruits). These are known as
the Herbarium-mould (Eurotium herbariorum).
Study as in case of the blights.
333.	The Truffles (Order Tuberacece)
are well known from their large under-
ground spore-fruits, which are edible.
Internally there are narrow tortuous
channels on whose walls sacs develop,
each containing a number of spores (Fig.
84). Little is known of their round of
life, and the sexual organs have not been
discovered.
334.	The Blue Moulds (species of Peni-
cillium) are members of this order, and
are in reality minute truffles. The coni-
dial stage is the common Blue Mould on
decaying fruit and pastry (Fig. 85). The
sexual organs resemble those of the herbarium-mould, and
the spore-fruit is a minute truffle-like body as large as a
coarse sand-grain.
Practical Studies.—(a) Truffles are natives of Europe, but they may
he obtained for study in our markets.
Fig. St.—A, a small
slice of the spore-fruit
of a truffle (Tuber me-
lanosporum), showing
sacs and spores; B, a
sac and its spores, more
enlarged.CARPOPHYTA.
161
(b) Blue Mould may be obtained from decaying fruit, pastry, and
frequently upon ink.
335.	The Cup-Fungi and their Allies
(Order Helvellacece).— The common
Cup-fungus of the woods is a good
representative of this order. The fa-
miliar cup- or saucer-shaped growth is in
reality the spore-fruit, while the plant
itself generally grows underground.
The plant consists of whitish, jointed
filaments which grow on or in the
ground, drawing their nourishment from
decaying sticks, roots, etc.
336.	But little is known as to the
asexual reproduction, but in some spe-
cies conidia much like those in the pre-
ceding orders have been observed.
337.	The sexual organs are pro-
duced by the swelling up of the
ends of certain of the white filaments
of the plant into globular or ovoid
cells, the carpogones, each having a
projection (trichogyne). From be-
low each carpogone a slender branch
grows out, and becomes the antherid
(Fig. 86).
338.	Fertilization takes place by
the antherids coming in contact
with the trichogyne. As a result,
numerous branches start out from
below the carpogone, and growing
upward form a dense felted mass which gradually takes on
Fig. 85.—A filament of
Blue Mould (Penicillium
chartarum), bearing co-
nidia. At the side is
shown an isolated chain
of conidia.
Fig. 86.—Sexual organs of
a Cup-fungus (Peziza ompha-
lodes). The two carpogones
are globular; each has a
curved trichogyne. The an-
therids are curved branches
from below the carpogones.
Much magnified.162
BOTANY.
the size and form of the spore-fruit. Some of the filaments
of the spore-fruit become enlarged into sacs in which spores
are developed (Fig. 88), while the others make up the sterile
Fig. 87.
Fig. 87.—Diagrammatic vertical section of a Cup-fungus, showing position of
the spore-sacs.
Fig. 88.—A few spore-sacs of a Cup-fungus (Peziza convexula). in various stages
of development, a, youngest, to/, oldest. The slender filaments (paraphyses)
belong to the sterile tissue. Magnified 550 times.
or protective tissue. The spore-sacs grow so that all reach
the same height, and make up the inner surface of the cup
(Fig. 87).CAEP0PI1YTA.
163
Practical Studies.—(q) Search for cup-shaped fungi, in the spring,
about old hot-beds and upon well-rotted barnyard-refuse. The com-
mon Cup-fungus of an amber color (Peziza vulgaris) often to be met
with in such localities is one of the best for the study of spores and
spore-sacs. Make very thin sections at right angles to the inner sur-
face. This species may be readily preserved in alcohol for future
study.
(b) Collect the bright-red saucer-shaped plants growing in the
woods upon decaying sticks and having a diameter of 1 to 4 cm.
Make similar sections.
(«) Collect a few Morels (Morchella esculenta), and make sections at
right angles to the surface of the pits which cover its upper portion,
for spores and spore-sacs. The Morel, which grows in the woods, is
an amber- or straw-colored fungus 10 to 15 cm. high and having an
egg-shaped pitted top, B to 6 cm. in diameter, borne upon a thick
stalk, both stalk and top being usually hollow. The whole growth
above ground (which is edible) is to be regarded as a spore-fruit.
339.	The Black Fungi (Order Pyrenomycetes).—The
plants of this order are parasitic or saprophytic in habit;
their tissues are usually hard and somewhat coriaceous, dif-
fering in this respect from the Cup-fungi,w'hich are generally
fleshy. In many respects the Black Fungi are much like
the Cup-fungi, to which they are doubtless closely related.
340.	A good illustration of the plants of this order is
the Black Knot (Plowrightia morbosa) which attacks the
plum and cherry. In the spring the parasitic filaments,
which the previous year penetrated the young bark, mul-
tiply greatly, and finally break through the bark and form
a dense tissue. The knot-like mass grows rapidly, and when
full-sized is usually from two or three to ten or fifteen cen-
timetres long (.8 or 1.2 to 4. or 6. in.), and from one to three
centimetres in thickness (.4 to 1.2 in.); it is solid and but
slightly yielding, and is composed of filaments intermin-
gled with an abnormal development of the bark-tissues of
the host-plant.
341.	The knot at this time is dark-colored, and has a164
BOTANY.
velvety appearance, which is due to the fact that its sur-
face is covered with myriads of short, jointed, vertical fila-
ments, each of which hears one or more conidia (Fig. 89, 1).
The conidia, which fall off readily, are produced until the
latter part of summer, when the filaments which hear them
shrivel up and disappear.
342.	During the latter part of summer spore-sacs are
produced, but require the greater part of winter to come
to perfection. The spore-sacs grow in the cavities of mi-
Fig. 89.—Structure of Black Knot. 1, filaments bearing conidia; 2, stylo-
spores; 3, a hollow papilla(perithecium) containing spore-sacs; 4. spore-sacs and
spores, with three slender filaments (paraphyses); 5, a spore; 6, spores germi-
nating. All much magnified.
nute papillae (perithecia), and are intermingled with slender
filaments (paraphyses, 3 and 4, Fig. 89). Each spore-sac
contains eight spores, which eventually escape through a
pore in the top of the sac. These spores germinate by
sending out a small filament, or sometimes two (Fig. 89, 6).
343.	Besides the perithecia, there are other cavities
found which much resemble them and contain other sup-
posed reproductive bodies.
344.	No sexual organs have as yet been observed.OARPOPIIYTA.
165
Possibly they exist in the dense tissues of the knot, and
fertilization probably occurs in the spring or early summer,
while the conidia are being produced on the surface of the
young knot.
345.	The parasitic filaments of each year’s knot gener-
ally penetrate downward some centimetres into the unin-
jured bark, and remain dormant there until the following
spring, when they begin the growth which results in the
production of a new knot, as described above.
346.	The Black Fungi include a large number of exceed-
ingly injurious species; they often attack and destroy not
only plants, but also insects, upon which their ravages are
in many cases very great.
347.	To this order belongs the Ergot (a common para-
site upon heads of rye), and also many of the black growths
upon the bark and wood of trees. Many species produce
black spots upon living leaves, while many others occur
upon dead leaves and twigs.
Practical Studies.—(a) In early summer examine the Choke-cherry
and Plum trees (wild and cultivated) for the young stages of Black
Knot. Watch the development until the knot becomes velvety in ap-
pearance (about midsummer). Now make very thin cross-sections
of the knot and examine for conidia.
(b) Late in autumn and in early winter examine the knots on the
same trees. Note the young peritbecia, i.e. hollow papillae. Make
very thin vertical sections through some of these. No perfect spores
can be found at this time.
(e) Collect fresh knots in midwinter and make similar examina-
tions, when the sacs and spores will be found.
Note.—The several stages may be readily preserved in alcohol for future
study.
348.	The Lichens (Order Lichenes) are among the most
interesting plants of the vegetable kingdom. They are not
only often of exceeding beauty, but their structure and
their mode of life are in some respects very wonderful.166
BOTANY.
They abound almost everywhere—on tree-trunks, rocks, old
roofs, and in many regions upon the ground. They are
for the most part of a greenish-gray color, and hence are
often called Gray-mosses. Other colors, as black, purple,
yellow, and white, are also common.
349. They are all of rather small size, varying from a
millimetre or so to 20 or 30 cm. in length. For the greater
Fig. 90.—A, a flat-growing1 (foliaceous) Lichen (Sticta pulmonaria); B, a
stemmed (fruticose) Lichen (Usnea barbata); a, a, fruit-discs (apothecia). Nat-
ural size.
part the plant-body is flattish, and adherent to the surface
upon which it grows (A, Fig. 90), but some species have
more or less elongated branching stems (H).
350. The plant-body of a lichen is composed of jointed,
branching, colorless filaments similar to those in the pre-
ceding orders. They obtain their nourishment from little
green protophytes, to which they attach themselves parasi-VAltPO Pll YTA.
167
tically. These protophytes, which
live in the midst of the moist tis-
sues of the lichens, were until re-
cently supposed to be parts of the
lichen itself, and were called go-
nidia, a term which it is still con-
venient to use. A few lichens are
parasitic in this way upon plants a
little higher than protophytes.
351. The spores of lichens are
produced in sacs, which are either
in discs (similar to those of Cup-
fungi) or in cavities (similar to
these of the Black Fungi). In
many common species the spore-
bearing discs (called apothecia)
are large and readily seen (Fig. 90,
A and JB), while in others they are
small and not easily made out. In
other species the spore-sacs are im-
Fig. 92.
Fig. 91.—Gonidia of different Lichens, showing attachment of the parasitic
filaments: several are dividing. All highly magnified.
Fig. 92.—A vertical section of a common Lichen (Ph.yscia stellaris) through a
fruit-disc, showing spore-sacs at th, intermingled with slender filaments (para-
physes), t\ gonidia at g, g'\ cm, the interlacing branching filaments, becoming
harder and denser at cc and h. Much magnified.168
BOTANY.
mersed in cavities which show only as blackish lines or
dots on the surface of the lichen-body.
352. The spores germinate by sending out one or more
tubes which develop directly into the ordinary filaments of
the lichen-body. Experiments have shown that these fila-
ments will not grow for any great length of time unless
they can come into contact with a protophyte of the proper
species to which they can become attached. The lichen-
filaments then grow rapidly and surround the protophytes,
and in the moist tissues thus formed the latter find protec-
tion and ample opportunity for growing. There-is thus an
Fig. 93.—Sections of gelatinous Lichens (Collema), showing (in A) a carpogone,
c, with its projection, d. and (in B) a cavity (spermogone) emitting sperm-cells
(spermatia). The gonidia here (6, b) are species of Nostoc. Highly magnified.
association between these plants which is mutually bene-
ficial. The lichen lives parasitically upon the protophytes,
to which it in return furnishes shelter and moisture.
353. We know very little as to the sexual organs of
lichens. A few years ago Stahl discovered them in Colle-
ma, a low form of gelatinous lichens. The carpogone is a
tightly coiled spiral filament, which sends up a prolonga-
tion to the surface (Fig. 93, A, c, <i). Fertilization takesCARPOPHYTA.
169
place by means of minute cells (sperm-cells, or spermatid),
which are produced in countless numbers in cavities (sper-
mogones) in the lichen-body. The sperm-cells come in
contact with the projecting filament (trichogyne), doubtless
by means of winds, the result of which is the rapid upward
growth of filaments which ultimately produce spore-sacs
and spores in discs, as above described.
Practical Studies.—(a) Collect fruiting specimens of the common
fruticose lichen shown in Fig. 90, B, which grows upon branches of
trees in forests. Make thin cross-sections of the stem, mount in alco-
hol, afterwards adding dilute potassic hydrate. Study the filaments,
and their relation to the gonida. Isolate some of the gonidia by
tapping on the cover-glass, and note their resemblance to Green
Slime.
(b)	Make thin vertical sections through one of the fruiting discs,
mount as above, and study spore-sacs, spores, and paraphyses.
(c)	Collect some of the small, flat, many-lobed lichens which grow
on the bark of apple-, maple-, and oak-trees, and having small blackish
fruit-discs. Make careful sections of the plant-body through the
fruit-discs, and study the whole structure, spores, spore-sacs, para-
physes, filaments, and gonidia. (Compare with Fig. 92.) Here also
the gonidia closely resemble Green Slime.
354.	The Rusts (Order Uredinece) are minute parasitic
plants, which grow in the tissues of higher plants. Their
life-history is only imperfectly known; nothing as yet being
known as to their sexual organs, if indeed they have any.
355.	The common Wheat-rust (Puccinia graminis) may
be taken as an illustration of the order. It is common
wherever wheat is grown, and often greatly injures and
sometimes entirely destroys the crop. Its round of life
shows four well-marked stages, as follows: (I) In the spring
clusters of minute yellowish cups break through the tissues
of the leaves of the Barberry. These cups are at first
rounded masses of gonidia which develop on the internal170
BOTANY.
parasite, and at length burst through the epidermis (Fig.
94, A and I). The conidia quickly drop out and are car-
Fig. 94 —Wheat-rust (Puccinia graminis). I, a cross-section of a Barberry-
leaf through a mass of Cluster-cups; a, a, a, cups opened and shedding their
conidia; p, and A, above, cups not yet opened; sp, sp, sperinogones which pro-
duce spermatia, whose function is not known. U, three Red-rust spores, ur, on
stalks; £, a Black-rust spore. Ill, a mass of Black-rust spores bursting through
the epidermis, e, of a leaf. All highly magnified.
ried away by the winds. This stage is known as the
cluster-cup stage,CAliPOPllYTA.
171
§56. (II) The conidia falling upon a wheat-leaf germi-
nate there and penetrate its tissues, sending parasitic fila-
tnents into the Cells, After a few days, if the weather has
Fig. 95.—Wheat-rust, A and B, a Black-rust spore germinating, and pro-
ducing sporids, sp\ C, fragment of a Barberry-leaf with a sporid, sp, germi-
nating and penetrating the epidermis; D, showing manner of germination of
Red-rust spore. All highly magnified.
been favorable, the parasite has grown sufficiently to begin
the formation of large reddish spores (stylospores) just be-BOTANY.
\1%
neath the epidermis, which is soon ruptured, exposing the
spores (Fig. 94, II) in reddish lines or spots upon the leaves
and stems. This is the Red-rust stage, so common before
wheat-harvest. These red spores fall easily, and quickly
germinate, producing more Red-rust (Fig. 95, D), and so
rapidly increasing the parasite.
357. (Ill) Somewhat later in the season the same para-
sitic filaments which have been producing Red-rust spores
begin to produce lines or spots of dark-colored, thick-walled,
two-celled bodies (teleutospores), the so-called spores of
the Black-rust (Fig. 94, III). Being thick-walled,
they endure the winter without injury, and when spring
comes (IV) they germinate on the rotting straw and pro-
duce several minute spores, called sporids (Fig. 95, A and
I). This is the fourth and last stage of the rust. The
sporids fall upon Barberry-leaves and germinate (Fig. 95,
C), giving rise to cluster-cups again.
These stages are so different in appearance that for a long time they
were regarded as distinct plants, and received different names. Thus
the first stage was classified as a species of iEcidium, the second as a
species of Uredo, and the third as a Puccinia. We still preserve
these names by sometimes calling the spores of the first aeeidiospores,
and of the second uredospores, while the third name is retained as
the scientific name of the genus.
The sporids cannot ordinarily produce rust directly upon wheat,
probably because of the toughness of the epidermis; but it has re-
cently been discovered that when sporids germinate upon very young
leaves of wheat-seedlings, they penetrate the epidermis and then soon
give rise to a red-rust stage. In such cases the cluster-cup stage is
omitted. This is no doubt the mode of propagation of rust on the
spring wheat so largely grown in the Mississippi Valley, and also
upon oats and barley (sown in the spring), which are affected by the
same species.
There are many kinds of rusts, distinguished mainly by their te-
leutngpores, which are one-celled (Uromyces and Melampsora), two
celled (Puccinia and Gymnosporangium), or many-celled (Pliragmidi-CARPOPllTTA.
173
um). In many species the round of life is like that in Wheat-rust,
but in others there appears to be a constant omission of certain stages.
Moreover, in many species all the stages develop upon the same host-
plant.
A teleutospore is here regarded as one or more spores contained in
a thin-walled and tightly fitting spore-sac. It is therefore to be com-
pared with the spore sacs of the previous orders (Figs. 88, 89, 92), and
its simplicity is to be regarded as due to the excessive parasitism of the
rusts. The Black-rust stage is thus a degraded spore fruit, iu which
the spore-sacs are not compacted into a well-defined fruit-like body.
Practical Studies.—(a) Collect specimens of cluster-cups (from bar-
berry, buttercups, or evening primrose, etc.); examine first under a
low power without making sections. Note the cups filled with yel-
lowish or orange conidia (aecidiospores). Note spermogones (minute
dark spots) generally on the opposite side of the leaf.
(b)	Make very thin cross sections through a mass of cups so as to
obtain vertical sections of the cups and the spermogones. (Compare
with Fig. 94, A and I.)
(c)	In June and July collect leaves of wheat, oats, or barley, bear-
ing lines or spots of Red-rust. First examine a few of the spores
mounted iu alcohol, with the subsequent addition of a little potassic
hydrate. Then make very thin cross-sections through a rust-spot,
and mount as before, so as to see parasitic filaments in the leaf, bear-
ing the Red-rust spores upon little stalks. (Compare with Fig. 94,
II, ur.)
(d)	In July, August, or September collect stems of wheat, oats, or
barley bearing lines or spots of Black-rust. Study the spores as
above, and afterwards make sections of the leaf also (Fig. 94, III).
(e)	In early spring collect and examine the Black-rust on wet stems
of rotting straw. Look for germinating teleutospores and sporids
(Fig. 95, A and B).
(/) Examine microscopically the gelatinous prolongations on “ce-
dar-apples,” and observe the teleutospores, which resemble those of
Wheat-rust. “ Cedar-apples,” which are common in the spring on
Red-cedar twigs, are in reality species of rust. Their cluster-cups
occur on apple-leaves.
358. The Smuts ( Order JJstilagineae). The plants which
compose this order are all parasites living in the tissues of
flowering plants. Like the Rusts, they send their parasitic
threads through the tissues of their hosts, and afterwards174
BOTANY.
produce spores in great abundance, which burst through
the epidermis. There is a still greater simplicity of struc-
ture in the plants of the present order than in the Rusts,
probably due to a greater degradation through excessive
parasitism.
359.	The parasitic threads of the Smuts are well defined,
and consist of thick-walled, jointed, and branching fila-
ments, which are generally of very irregular shape. They
grow in the intercellular spaces and cell-cavities of their
hosts, and send out suckers (haustoria), which penetrate
the adjacent cells much as in the Mildews. The para-
site generally begins its growth when the host-plant is
quite young, and grows with it, spreading into its branches
as they form, until it reaches the place of spore-formation.
In perennial plants the parasite is perennial, reappearing
year after year upon the same stems, or upon the new
stems grown from the same roots; in annuals it must ob-
tain a foothold in the young plants as they grow in the
spring.
360.	The life-history of the Smuts has not yet been com-
pletely made out. Two kinds of spores have been observed
in certain species, but neither the sexual organs (if any
exist) nor the mode of entrance of any of the species into
their hosts has yet been discovered.
361.	The Smut of Indian corn (Ustilago maidis) is very
common in autumn. The parasitic filaments are found in
various parts of the host, and at last those which reach the
young kernels become semi-gelatinous and form spores in-
ternally. There is much crowding and distortion of these
spore-bearing filaments, but here and there their resem-
blance to spore-sacs is quite evident (Fig. 96). When the
spores are ripe, the gelatinous walls of the spore-sacs dis-CARP0PH7TA.	if5
solve and, the watery portions evaporating, leave a. dusty
mass of black spores.
The spores germinate by sending out a short filament
much as in the wheat-rust (Fig. 95, A and
B), upon which minute sporids are
formed. The subsequent history of the
sporids is not known.
362. Other Smuts, as Grain-smut or
Black Blast (Ustilago segetum) of wheat,
oats, and barley, and the Bunt or Stinking-
smut (Tilletia tritici) of wheat have a
structure and mode of development close-
ly resembling the foregoing.
Comparing the spores of the Smuts with those
of the preceding orders, we here consider them as
sac-spores (ascospores), and the mass of tissues
in which they are produced, as a degraded spore-
fruit. The orderly arrangement of spore-sacs so
evident in the Cup-fungi is less marked in the
more parasitic Black Fungi; it is scarcely notice-
able in the Rusts, while in the Smuts it has en-
tirely disappeared. As the parasitism increases the structural degra
dation also increases.
Fig. 96. — Ends of
three spore - bearing
filaments (spore-sacs?)
of Indian-corn Smut,
showing, a, b, young
spores; c, a spore
nearly ripe. Magni-
fied 1800 times.
Practical Studies.—(a) Collect several smutted ears of Indian corn.
Mount a little of the black internal mass in water and observe the
spores.
(ib) Make very thin slices of young fresh specimens and examine
for parasitic and spore-bearing filaments. The outer tissues of the
distorted kernels are generally best.
(c) Make similar studies of the Grain-smut, which may be readily
collected in June or a few days after the “heading” of the grain
(wheat, oats, or barley).
Class IY. Basidiomycetes (the Puff-balls and Toadstools).
363. The'plants of this class are among the largest and
finest of the fungi. They are mostly saprophytes whose176
Botany.
abundant vegetative filaments (mycelium) ramify through
the nourishing substance, and afterwards give rise to the
spore-fruit. The spores are produced upon slender out-
growths from the ends of enlarged cells (basidia), usually
arranged parallel to each other so as to form a spore-bearing
surface (hymenium), which may be external (in Toadstools)
or internal (in Puff-balls). Two orders may be readily
separated in this class, the Gasteromycetes and the Hy-
menomycetes.
364.	The Puff-Balls (Order Gasteromycetes).—The plants
of this order are saprophytes, whose spore-fruits are often
of large size and usually more or less globular in form.
The spores are always borne in the interior of more or less
regular cavities, and from these they escape by the drying
and rupture of the surrounding tissues.
365.	The vegetative filaments of Puff-balls penetrate the
substance of decaying wood, and the soil filled with de-
caying organic matter. They are colorless and jointed,
and usually aggregate themselves into cylindrical root-like
masses. After an extended vegetative period, the fila-
ments produce upon their root-like portions small rounded
bodies, the young spore-fruits, which increase rapidly in
size and assume the forms characteristic of the different
genera.
366.	No sexual organs have yet been discovered, but
analogy points to their probable existence upon the vege-
tative filaments just previous to the first appearance of the
spore-fruits. The spore-fruits are composed of interlaced
filaments loosely arranged in the interior, and an external
more compact limitary tissue forming a rind (peridium).
367.	The Puff-balls proper belong to the genus Lyco-
perdon, of which there are a good many species, the mostGAiiPopjiri'A.
ill
Striking being the Giant Puff-ball (L. giganteum), whose
spore-fruit sometimes is 30 cm. or more (one foot) in diam-
eter. The proper plant, that is, the vegetative
portion, lives underground, obtaining its food
from decaying vegetable matter. The great
ball is a spore-fruit composed of innumerable
filaments whose swollen extremities (basidia)
bear spores (basidiospores).
368.	There are other genera, as the Earth- pungu's^Cya4
stars (Geaster), whose outer coat splits into a sus)S veNatu-
star-shaped form, the curious little Bird’s-nest ra bl2e'
Fungus (Crucibulumand Cyathus, Fig. 97), fetid Stink-horn
(Phallus), etc.
Practical Studies.—(a) Collect specimens of puff-balls in various
stages of growth. Make very thin sections of the young spore-fruit,
and look for the cavities lined with spore-bearing cells (basidia).
(b) Mount in alcohol some of the dust which escapes from a dry
puff-ball. Examine with a high power, and note the spores and frag-
ments of broken-up filaments.
(e) Dig up the earth under a cluster of young puff-balls, and ob-
serve the vegetative filaments. Examine some of these filaments
under the microscope.
369.	The Toadstools (Order Hymenomycetes).—These
plants are doubtless to be regarded as the highest of the
chlorophyll-less Carpophytes. They are not only of consid-
erable size (ranging from one to twenty centimetres, or
more, in height), but their structural complexity is so much
greater than that of the other orders that they must be
regarded as the highest of the fungi. Like the Puff-balls,
they produce an abundance of vegetative filaments (myce-
lium) underground or in the substance of decaying wood.
These filaments are loosely interwoven, becoming in some
cases densely felted into tough masses or compacted into
Fig. 97. —178
BOTANY.
root-like forms (Fig. 98, A, m). Sooner or later these un-
derground filaments produce the spore-fruits, which are
Fig. 98.—Development and structure of a Toadstool. A, vegetative filaments
producing young spore-fruits; I, II, III, IV, V, sections of successive stages of
spore-fruits, from very young to maturity; l, the gills; v, veil; VI, magnified
section of a gill, showing layer of spore-bearing cells, hy\ VII, greatly magnified
section of part of a gill, showing layer of spore-bearing cells, with spores of dif-
ferent ages.
mostly umbrella-shaped, as in common Toadstools and
Mushrooms, or of various more or less irregular shapes, as
in the Ear-fungi, Club-fungi, etc.CARPOPHYTA.
179
3TO. The Mushroom (Agaricus campestris) so commonly-
cultivated may be taken to illustrate the mode of develop-
ment of the Toadstools. The vegetative filaments com-
pose the so-called “ spawn” which grows through the de-
caying matter from which it derives its nourishment. Upon
this at length little rounded masses of filaments arise, which
become larger and larger and gradually assume the size
and shape of the mature spore-fruit, the Mushroom of the
markets.
3VI. At maturity the spore-fruit of the Mushroom con-
sists of a short thick stalk, bearing an expanded umbrella-
shaped cap, beneath which are many thin radiating plates,
the gills. Each gill is a mass of filaments whose enlarged
end-cells (basidia) come to, and completely cover, both of
its surfaces (Fig. 98, VIand VII). The basidia produce
spores in the usual manner for plants of this class, that is,
upon slender stalks.
3V2. In the Pore-fungi (Polyporus) the spore-bearing
cells line the sides of pores; in the Prickly Fungi (Hydnum)
they cover the surface of spines; while in the Ear-fungi
(Stereum, etc.) they form a smooth surface.
3V3. But little is known as to the sexual organs. Several
botanists have described such supposed organs upon the
vegetative filaments before the formation of the spore-
fruit, but there are still some doubts as to the correctness
of the observations.
3V4. The vegetative filaments (mycelium) of some species
of this order (as Polyporus fomentarius, etc.) often form
thick, tough, whitish masses of considerable extent in
trees and logs, and constitute the Amadou, or German tin-
der of the shops.
3V5. We know but little as to the germination of theBOTANY.
180
spores and the subsequent development of the vegetative
filaments.
Practical Studies.—(a) Collect a few toadstools in various stages
of development, securing at the same time some of the subterranean
vegetative filaments. Note the appearance of the young spore-
fruits, and how they develop into the mature toadstool.
(b)	Select a mature (but not old) spore-fruit with dark-colored
spores, cut away the stem, and place the top (pileus) on a sheet of
white paper, witli the gills down. In a few hours many spores will
be found to have dropped from the gills upon the paper.
(c)	Examine the minute structure of various parts of the spore-
fruit and the vegetative filaments, and observe that they are com-
posed of rows of cylindrical colorless cells joined end to end.
(d)	Make very thin cross-sections of several of the gills and care-
fully mount in water or alcohol. Note the layer of spore-bearing
cells (hymenium), with spores borne upon little stalks, as in Fig. 98,
VI and VII.
Class V. Characeas (the Stoneworts).
376.	The plants of this class are small green aquatics
with jointed stems bearing whorls of leaves (Fig. 99). Both
stems and leaves are very simple, being often no more than
a row of cells, but sometimes a cylindrical mass of cells.
The sexual organs occur upon the leaves. They consist of
an ovoid earpogone and a globular antherid, which are
barely visible to the naked eye.
377.	The earpogone (Fig. 100, s) is a single cell, as in
Coleochaete (p. 150), which soon becomes covered by the
growth of a layer of cells from below. This covering,
which here develops before fertilization, is homologous with
the protective covering which in Coleochsete, Red Sea-
weeds, Blights, etc., forms after fertilization has taken
place.
378.	The antherids (Fig. 100, a) are globular many-celled
bodies, in the interior of which certain cells produce an-CAHPOPIIYTA.
181
therozoids. Each antherozoid is a long spiral thread of
protoplasm, provided with two long cilia at one end, by
means of which they swim rapidly through the water.
Fig. 99.—A Stonewort (Chara crinita). One half the natural size. (From Allen.)
379. Fertilization takes place by the antherozoids swim-
ming down the opening at the top of the covering cells
(Fig. 100, c). The carpogone and its covering now become
Fig. 100.—Sexual organs of a Stonewort (Chara fragilis). a, an antherid; s,
spore-fruit; c, its crown of five cells; 6, fragment of the leaf which be^rs the
sexual organs; brtvpteqles. Magnified about 53 times.182
BOTANY.
thicker-walled and constitute the proper spore-fruit. The
latter soon drops off and falls to the bottom of the water,
where it remains at rest for a time.
380.	The spore-fruit of the Stoneworts contains, thus,
but one spore. This in germination sends out a jointed
filament, which eventually gives rise to a branching plant
again (Fig. 99).
381.	Two orders (Nitellece and Charece) may be sepa-
rated in this class. The principal genus of the first is Ni-
tella, and of the latter Chara; each contains a dozen or
more widely distributed species in this country.
Practical Studies.—(a) Search the saDdy margins of ponds, lakes,
and slow streams for Stoneworts. They are generally found in water
from a few centimetres to one or two metres in depth. Preserve
such specimens temporarily in water which is frequently changed,
but for future use preserve in alcohol.
(b)	Mount carefully a considerable portion of a plant, and examine
its structure under a low power. Note that in some species the stem
(and leaves) is composed of a row of large cells surrounded by a coat
of smaller ones. Look for the rapid movement of protoplasm which
is so marked in these plants.
(c)	Mount several spore-fruits in various stages of development.
Note the covering layer of spirally coiled cells surrounding the car-
pogone (in young specimens) or the spore (in older specimens).
(d)	Mount several full grown antherids. Carefully crush them and
look for antherozoids, which are produced in chains of cells.
(«) Preserve the aquatic carpopliytes by floating out of water as
described on page 139 (j). In Classes III and IY the fleshy species
are best preserved in alcohol, while most of the remaining ones may
be pressed and mounted very nearly as if they were ordinary flower-
ing plants.CHAPTER XI.
BRANCH Y. BRYOPHYTA.
THE MOSSWORTS.
382.	This Branch includes plants of much greater com-
plexity than any of the preceding. In very many cases
they have distinct stems and leaves, whose tissues often
show a differentiation into several varieties. In the sexual
organs the cell to he fertilized (the germ-cell) is from the
first enclosed in a protective layer of cells, and after fer-
tilization it, develops into a complex spore-fruit.
383.	Mossworts are all chlorophyll-bearing plants, and
none are parasitic or saprophytic. They are of small size,
rarely exceeding ten or fifteen centimetres in height. They
generally prefer moist situations upon the ground, or on
the sides of trees or rocks. A few are aquatic.
384.	Two classes of Bryophytes may be distinguished, as
follows:
1.	Mostly thalloid creeping plants with splitting spore-fruits, and
having elaters...................Hepatic.®. Liverworts.
2.	Leafy stems, mostly erect, with spore-fruit opening by a lid, and
having no elaters........................Musci. Mosses.
Class I. Hepatic.® (the liverworts).
385.	In the Liverworts, the plant-body is for the most
part either a true thallus or a thalloid structure. When
there is a differentiation into stem and leaves, in most cases
the plant-body has two distinct and well-marked surfaces,184
BOTANY.
an upper and an under one, the latter bearing the root-
hairs (rhizoids), by means of which the plant is fixed to
the ground. In this class breathing-pores are found for
the first time in the vegetable kingdom. They are of very
simple structure (Fig. 101).
386. The leaves, when present, are usually in two rows
(sometimes three), and are either opposite or alternate.
The tissues of the plant-body show a little differentiation;
Fig. 101.—J, a thalloid Liverwort; B and C, showing bud-cups, natural size; D,
enlarged to show breathing-pores. II, a leafy-stemmed Liverwort; a, unripe,
and b, ripened and split, spore-fruit.
the leaves, however, have no midrib or other veins, and
consist of a single layer of cells. The development of the
stem is always from a single apical cell, which repeatedly
divides.
387. The asexual reproduction of Liverworts takes place
by means of peculiar bodies, the buds (or gemmse) so fre-
quently to be seen in the Common Liverwort (Marchantia
polymorpha). In the latter plant they are little stalkedBRYOPHYTA.
185
masses of cells in small cups 4 to 6 millimetres inch) in
diameter (2? and C, Fig. 101). They are in reality hairs
(trichomes) whose upper cells have repeatedly divided so
as to form flattish masses. When these fall off they grow
directly into new plants.
388. The antherids of Liverworts are more or less globu-
lar, stalked bodies (Fig. 102, C), usually immersed in little
depressions in the plant-body. They are to be regarded as
hairs (trichomes) whose end cells have become greatly in-
Fig. 102.—A, a portion of Common Liverwort (Marchantia polymorpha) with
two male branches;, hu, in which antherids are borne; C, an antherid, magnified;
D, two antherozoids, greatly magnified.
creased in number. There is an outer layer of cells sur-
rounding a great number of interior thin-walled cells, the
sperm-cells, each of which contains an antherozoid.
In the Common Liverwort (Marchantia polymorpha) the
antherids are produced in the broadly expanded discs of
special branches (Fig. 102, A). The antherozoids are spiral
threads of protoplasm, each provided with two cilia (Fig.
102, D).
389. The female organ of Liverworts is called an arehe-186
BOTANY.
gonium, or archegone. It bears some resemblance to the
corresponding organ in the Stoneworts (p. 181), and, like
Fig. 103—Archegones of the Common Liverwort ift various stages of develop-
ment, I to F; e, germ-cell. VI, fertilized germ-cell, /, divided once. VII and
VIII, further development of germ-cell; pp, the perianth in various stages. IX,
germ-cell now developed into a spore-fruit, /, filled with spores and elaters; a,
the greatly distended wall of the archegone. X, immature and mature elaters
and spores. All magnified.
it, has an internal cell (the germ-cell) to be fertilized, sur-
rounded by an envelope of protective cells (Fig. 103,1- V).PRYOPIIYTA.
187
The archegones of the common Liverwort are clustered
upon special branches, a few centimetres in height. These
branches expand into lobed discs at the top, and beneath
these the archegones appear. They grow out as trichomes,
and finally consist of a rounded cell (germ-cell) enclosed
in a flask-shaped vessel (Fig. 103).
390.	Fertilization takes place in wet weather by the
antherozoids swimming to and down the open neck of the
archegone. As a consequence, the germ-cell begins divid-
ing, and finally develops into a spore-fruit containing many
spores, intermixed with spiral threads called elaters. The
use of the latter appears to he to aid in the dispersion of
the spores (Fig. 103, X).
391.	In most cases the spore-fruits split open to permit
the escape of the spores, which soon germinate and pro-
duce a thalloid mass; this develops directly into a new
plant in the lower forms, and in the higher soon begins the
development of a stem and leaves.
392.	There are four or five orders of Liverworts, includ-
ing (1) the Crystalworts (Order Ricci-
aceae), which are terrestrial or aquatic
thalloid plants; (2) the Horned Liver-
worts (Order Anthocerotese), which are
terrestrial thalloid plants with slender
spore-fruits (Fig. 104); (3) the Liver-
worts proper (Order Marchantiacese),
terrestrial thalloid plants, including, the
Common Liverwort (Marchantia poly-
morpha) and the Great Liverwort (Co-
nocephalus conicus), both large, flat, branching plants grow-
ing in moist places about springs, brooks, ditches, etc.; (4)
the Scale-mosses (Order Jungermanniaceae, Fig. 101, IT),
Fig. 104. — A Horned
Liverwort (Anthoceros
laevis), natural size, with
spore-fruits, K, K, split-
ting open.188
BOTANY.
mostly leafy creeping plants growing on moist earth, rocks,
and tree-trunks.
Practical Studies.—(a) Collect specimens of the Common Liverwort,
which may be found in fruit in midsummer. Note that one plant
produces the male branches, which have flat discs, and another pro-
duces the female branches, which have lobed discs. Note the bud-
cups, with contained buds (gemmae).
(4) Examine the upper surface of a plant with a low power of the
microscope, and note the round breathing-pores. Next strip off some
of the epidermis, mount in alcohol, and study with high power.
(c)	Make longitudinal sections of the plant through its thickened
central rib, and observe the elongated cells, which foreshadow fibro-
vascular bundles.
(d)	Make vertical sections of the male disc, mount in water, and
study the antherids (Fig. 102, 0). By repeated trials, antherozoids
may be seen.
(<?) Make similar sections of the female disc, and study archegones.
By taking older specimens, the spore-fruits, spores, andelatersmaybe
studied. For the latter, mount in alcohol and afterwards add a little
potassic hydrate.
(/) Examine the bark of trees for small brownish Scale-mosses.
Mount a bit of one in alcohol, afterwards adding potassic hydrate,
and study as a specimen of a leafy Liverwort. In the spring the
minute splitting spore-fruits may readily be found.
Class II. Musci {the Mosses).
393.	The adult plant-body in this class is always a leafy
stem, which is rarely bilateral. It is fixed to the soil or
other support by root-hairs (rhizoids) which grow out from
the sides of the stem, but there are no true roots. The
leaves are usually composed of a single layer of cells, and
sometimes have a midrib.
394.	The tissues of the Mosses present a considerable
advance upon those of the Liverworts. In the stem there
is frequently a bundle of very narrow thin-walled cells,
which in some species become considerably thickened. In
a few cases there have been observed bundles of thin-walledBRTOPIITTA.
189
Hmr
) b
cells extending from the leaves to the bundle in the stem.
It cannot be doubted, then, that the Mosses possess rudi-
mentary fibro-vascular bundles. As in liverworts, the tis-
sues of mosses develop from a single apical cell. Breathing-
pores resembling those of the higher plants occur on the
spore-fruits; they are not found upon the leaves or stems.
395.	Mosses, for the most part, grow upon moist earth
or rocks, or upon the sides of trees;
comparatively few are aquatic.
They range in size from less than a
millimetre to many centimetres in
length, the most common height
being from two to four centimetres.
They are all chlorophyll-bearing
plants, and are generally of a bright-
green color; occasionally, however,
they are whitish or brownish.
396.	The reproduction of mosses
is mainly sexual, but occasionally
buds are found resembling those of
the liverworts. The sexual organs
develop either upon the end of the
stem, within flower-like rosettes of
leaves, or in the axils of the leaves.
The antherids are club-shaped or
globose trichomes (Fig. 105), whose
interior cells (sperm-cells) produce
antherozoids. The sperm-cells, when
mature, escape from the antherid
through a rent in its wall. Each sperm-cell contains one
spirally coiled antherozoid, which, when set free, swims by
means of its two long cilia (Fig. 105, c).
Fig. 105.—A, an antherid of
a Moss ruptured, showing
the mass of sperm-cells, a—-
magnified 350 times; b, a
sperm - cell, magnified 800
times, showing antherozoid,
which at c is free.190
BOTANY
397. The archegoneB are elongated flask-shaped bodies
with a swelling base and a long, slender neck. At ma-
turity the neck has an open channel from its apex to the
Fig. 106.— A, several archegones at the apex of a Moss-stem; B, an archegone
more enlarged, showing germ-cell at 6; C, apex of archegone at maturity; D, a
Moss-plant with young spore-fruit; E, the same with mature spore-fruit, show-
ing its stalk, s, spore-case, /, and the remains of the old archegone, c (the calyp-
tra); F, vertical section of the spore-case, showing structure; s, the spore-bear-
ing layer; d, the lid; (?, a ripe spore-case; H, spore-case after the lid has fallen
off, showing the teeth. All magnified.
base, where there is a rounded germ-cell (Fig. 106). In
some mosses the antherids and archegones are intermixed
in the same “ flower,” but in other cases they occur uponBRT0PE7TA
191
different parts of the same plant (monoecious) or even
upon different plants (dioecious).
398.	The act of fertilization requires water; hut as the
antherozoids are so minute, a dew-drop may be sufficient.
The antherozoids swim to the open neck of the archegone,
down which they pass to the germ-cell. The germ-cell
now begins to divide rapidly, growing upward and eventu-
ally forming the spore-fruit. In most mosses the spore-
fruit is narrow and elongated below, forming a stalk which
supports its upper spore-bearing part (the capsule or spore-
case).
399.	The spore-case, when ripe, usually opens by a lid
which falls off, leaving a round opening, generally fringed
with many teeth (Fig. 106, G and H). In most species, as the
spore-fruit elongates it carries up the remains of the dis-
tended archegone as a little cap (calyptra) (Fig. 106, E, c).
400.	The spores, which are round or angular cells con-
taining protoplasm, chlorophyll-granules, oil-drops, etc.,
germinate quickly upon moist soil. Each spore protrudes
a tubular filament, which develops into a conferva-like
branching growth of green cells, called the protonema (Fig.
107). Upon this there finally are produced buds from
which spring up the leafy stems, thus completing the round
of life.
401.	There are four orders of Mosses, as follows: (l) the
Peat-mosses (Order Sphagnacese), composed of large, soft,
and usually pale-colored plants, with clustered lateral
branches; they inhabit bogs and swampy places, where
they form dense moist cushions, often of great extent. On
account of peculiarities in the structure of their leaves they
are enabled to absorb and hold large quantities of water,
and for this reason they are extensively used for “ packing”192
B01ANY
in the transportation of living plants. They all belong to
the genus Sphagnum. (2) Order Andrseacese, composed of
a few small and rare mosses. (3) Order Phascaceae, small
mosses with but little development of a leafy stem, and a
persistent protonema.
402. (4) The True Mosses (Order Bryaceae) include the
great majority of the mosses of the country. They are
usually bright-green (in a few genera brownish), and in
most instances live upon moist ground and rocks, or upon
the bark of trees; in a comparatively small number of
cases the species live in the water. They are undoubtedly
the highest of the class, and show a greater differentiation
of tissues than any of the preceding orders. Among the
more common mosses are species of Dicranum, Fissi-
dens, Polytrichum, including the well-known Hair-cap
Moss (P. commune), Timmia, Bryum (Fig. 106, G and II),
Mnium, Funaria (F. hygrometrica, Figs. 105, 106, A to F,BRY0PI1YTA.
193
and 107); Fontinalis, large floating mosses, common in
brooks and rivulets; Cylindrothecium; Climacium (C.
americanum is a large tree-shaped moss); Hypnum, the
bog-mosses, etc.
Practical Studies.—(a) Collect several kinds of mosses in fruit: some
of these should be of large species. Note the brownish root-hairs,
the stem and leaves, the spore-fruit composed of a slender stalk bear-
ing a spore-case, the latter in some species covered by a membranous
or hairy cap (calyptra).
(A) Select a broad-leaved species. Mount a single leaf in water,
and examine with a low power. Note that the leaf is (generally) a
single layer of cells, and that the midrib (if present) is composed of
elongated cells. Make cross and longitudiual sections of stems of
the larger species, and note that some of the cells are elongated and
fibre-like.
(c)	Place a spore-case under the microscope and examine with a
low power, noting the lid (Fig. 106, G). Now remove the lid and
observe the teeth (Fig. 106, II). The teeth may be studied still better
by splitting the spore-case from base to apex and then mounting in
alcohol, and afterwards adding potassic hydrate. In this specimen
spores may be studied also.
(d)	Split a young spore-case and examine the external surface of
the lower part for breathing-pores.
(«) Collect a number of mosses not in fruit, showing at the apex of
their stems little cup-shaped whorls of leaves. Make several vertical
sections of one of these cups, and mount in water. Examine for
autherids and arcliegones (Figs. 105 and 106). Antlrerozoids may
sometimes be seen with a high power.
(/) The first stage (protonema) of a moss may be found by scrap-
ing off some of the greenish growth from a wall or cliff where young
mosses are just springing up. By mounting some of this in water
and washing away the dirt the branching green growth may generally
be seen.
(g) Collect fruitiDg specimens of bryophytes, dry them under
pressure, and then glue them upon white paper for herbarium speci-
mens.
(7i) For the identification of the species of bryophytes of this coun-
try the student may profitably use L. M. Underwood’s “ Descriptive
Catalogue of the North American Hepatic* north of Mexico” and
the “Manual of the Mosses of North America,” by Leo Lesquereux
and T. P. James.CHAPTER XH.
BRANCH VI. PTERIDOPHYTA.
THE FERNWORTS.
403.	The Fernworts are for the most part leafy-stemmed,
root-bearing plants of considerable size, whose leaves bear
spores. All are chlorophyll-bearing, and they are mostly
terrestrial in habit, comparatively few being aquatic.
404.	Their tissues show a high degree of development.
The epidermis is distinct, and contains breathing-pores sim-
ilar in form and position to those of the flowering plants.
The fibro-vascular bundles are generally of the concentric
type, although collateral and radial bundles occur also.
The bundles generally possess tracheary and sieve tissues;
the former is usually well developed, but the latter not.
Fibrous tissue occurs only to a limited extent within the
bundles, but it is common in the stems as thick strength-
ening masses. These tissues generally develop from a
single cell at the apex of the stem, but in the higher orders
there are groups of apical cells, as in the flowering plants.
405.	The round of life of a fernwort shows a curious al-
ternation of generations. When a spore of a fernwort
germinates, it produces a small, flat, green liverwort-like
plant upon which sexual organs arise. This is the first
stage, or sexual generation. After fertilization has taken
place in the sexual organs, a leafy-stemmed, long-lived
plant is produced directly. This is the second stage, orPTERIDOPHYTA.
195
asexual generation, and upon it the spores are produced
from which new individuals of the first generation may be
developed.
406.	The first stage (called the prothallium) is composed
throughout of a few layers of soft tissue (parenchyma)
richly supplied with chlorophyll. From its under surface
root-hairs grow out into the soil. The sexual organs re-
semble those of the liverworts, and are antherids (producing
antherozoids) and archegones. They are generally pro-
duced upon the under side of the plant, and project slightly
from the surface.
407.	The fernworts are divisible into three classes, viz.:
1.	Stems hollow, jointed; leaves small. Equisetin^b. Horsetails.
2.	Stems solid; leaves mostly broad. Filicin^b. Ferns.
3.	Stems solid; leaves small or narrow. Lycopodin.<e. Lycopods.
Class I. Equisetevab {the Horsetails).
408.	In the plants of this class the plant-body consists of
a hollow elongated and jointed stem, hearing whorls of
narrow united leaves, which form close sheaths (.s, Fig.
108); the stem is grooved, and is usually rough and hard
from the large amount of silica deposited in the epidermis.
409.	The branches, when present, are in whorls. Both
the main axis and the branches are in most cases richly
supplied with chlorophyll-hearing tissue; in some of the
species the stems which bear the spores are destitute of
chlorophyll. All the species have underground stems,
which bear roots and rudimentary sheaths, and which each
year send up the vegetating and spore-hearing stems.
410.	The Horsetails are perennial plants. In some species
the underground portions only persist, the aerial stems196
BOTANY.
dying at the end of each year: these are called the annual
stemmed species. In other species the aerial stems also
persist; the latter are hence known as perennial-stemmed.
411. The epidermal cells
are mostly narrow and elon-
gated. The breathing-pores,
which are present in all the
chlorophyll-bearing parts of
the plant, are arranged with
more or less regularity in
longitudinal rows; on the
stem they occur in the chan-
nels between the numerous
ridges.
Fig. 108.	Fig. 109.
Fig. 108.—Part of a green stem of the Great Horsetail (Equisetum telmateia),
showing its structure; and a whorl of united leaves, with part of a whorl of
branches. Natural size.
Fig 109.—^4, part of an old cone of the Great Horsetail, showing three sepa-
rated whorls of shield-shaped leaves; B, three shield-shaped leaves, slightly
magnified; st, stalk, and s, expanded part of leaf; sg, the spore-cases.
412. The fibro-vascular bundles of the stem are disposed
in a circle, and run parallel with each other from node toPTERIDOPIIT TA.
197
node, where they join with one another. They contain
tracheary, sieve, and fibrous tissues, arranged somewhat as
they are in the bundles of flowering plants.
413. The spores of Horsetails are produced in cones at
the summit of the stems. The cones are composed of
crowded whorls of shield-shaped leaves, each of which
bears upon its under surface five to ten spore-cases (Fig.
109, B). The spores are spherical, and at maturity the
outer wall splits spirally into four narrow filaments (elaters)
which unroll when dry, and roll up around the spore again
when moistened. Their office seems to be to aid in setting
the spores free .from the spore-cases.
414. The spores germinate soon after falling upon watei198
BOTANY.
or moist earth, enlarging and successively dividing until a
flattish irregular plant (the first stage, or prothallium) a
few millimetres in breadth is produced. This stage is
short-lived. It hears sexual organs upon its edges or lobes;
in some cases both kinds of organs are on the same plant,
while very commonly they are upon separate plants.
415.	The antherids consist of one or more cells, sur-
rounded by a layer of cells. The inner cells divide inter-
nally into many sperm-cells, each of which contains a large
spirally twisted antherozoid.
416.	The archegones are flask-shaped organs sunken into
the tissues of the plant. At maturity the neck is open
down to the roundish germ-cell. Fertilization takes place
in water, the antherozoids swimming by means of their
many cilia to and down the neck of the archegone, where
they unite with the germ-cell.
417.	After fertilization the germ-cell begins to divide
again and again, soon giving rise to a new plant of the
second stage. The latter is at first a small and quite sim-
ple stem with minute leaves, hut the successive joints be-
come larger and larger until full size is reached. At the
same time roots develop which push downwards into the
soil, absorbing moisture and nutritious solutions.
This class contains but one order (Equisetacese) of living plants,
including a single genus and twenty-five species. Among the more
well known are the Common Horsetail (Equisetum arvense), which
sends up short-lived, pale or brownish cone-bearing stems in spring,
and profusely branching green stems in summer (E. telmateia, the
Great Horsetail of Europe and our own Northwestern region, re-
sembles, but is larger than, the Common Horsetail); the Woodland
Horsetail (E. sylvaticum), whose green cone-bearing stems branch
profusely after fruiting, and persist all summer; and the Scouring
Rush, called also Dutch Rush (E. hiemale), with harsh green branch-
less stems which produce cones, and survive the winter.PTERTBOPETTA.
199
In ancient geological times the Calamites and their allies consti-
tuted a distinct order (Calamariese) of tree-like plants f metre in thick-
ness and ten metres in height.
Practical Studies.—(a) Collect in early spring a number of cone-
bearing stems of the Common Horsetail. Note the joints (nodes),
bearing whorls of united flat leaves, and the cone, composed of whorls
of shield-shaped leaves. Split the cone and stem and note that the
latter is hollow, with closed nodes.
(b)	Carefully dissect out a single shield shaped leaf from the cone,
and examine it, using a low power. Note the sac shaped spore-cases
upon the under side of the leaf. Mount some of the spores dry, using
no cover-glass, and examine with the -J-inch objective. Breathe upon
the spores very gently to moisten them, and notice the coiling of the
elaters; observe the quick uncoiling which takes place upon the
evaporation of the moisture.
(c)	Sow a quantity of the fresh spores upon moist earth or porous
pottery, covering with a bell-jar and taking every precaution to secure
constant moisture. The spores will begin to germinate in a few days,
when studies of successive stages of growth may be taken up. By
care the mature plants of the first stage (protliallia) may be grown,
and the antlierids and archegones studied.
(d)	Make very thin cross-sections of the stem of the Common Horse-
tail. Note the position of the fibro vascular bundles. Now make
vertical sections of the bundles and study the tissues, using high
powers.
(e)	Study the breathing-pores on the green stems of the Common
Horsetail. Compare these with those of the Scouring Rush. Study
also the disposition of the chlorophyll-bearing tissue in cross-sections
of both stems.
(/) Examine underground stems of Horsetails, and compare the
structure with that of the aerial stems. Make cross-sections of the
roots which are attached to these underground stems.
Class II. Filicin^e (the Ferns).
418. Here the plant-body consists of a solid stem, bearing
roots and broadly expanded leaves, the latter usually long-
stalked. The stems are mostly horizontal and under-
ground, but in some cases they rise to a considerable height
vertically in the air.200
BOTANY.
419.	The leaves are in nearly all cases supplied with
fibro-vascular bundles, which run as veins through the soft
tissue; there is usually a prominent midrib, upon each side
of which are small veins, which are free (i.e., running more
or less parallel from the midrib to the margin) or reticu-
lated. Some or all of the leaves at maturity bear spore-
cases containing spores.
420.	The ferns are all richly supplied with chlorophyll,
and none are in any degree parasitic. Nearly all the species
Fjg. 111.—A, the first stage of a Fern, under side; b, root-hairs; an, antherids;
ar, archegones. B, the same after fertilization, showing the growth of the fern-
let; b, its leaf; w', its first root. Magnified a few times.
are perennial; in some cases, however, dying down to the
ground at the end of the summer, the underground por-
tions alone surviving the winter.
421.	The first stage in the ferns is frequently somewhat
heart-shaped, and is generally provided with root-hairs on
its under surface, by means of which it secures nourishment
for its independent growth (Fig. Ill, A). In the Pepper-
worts the first stage is so reduced as to be only a small
outgrowth of the germinating spore.PTERID OPE YTA.
201
422.	The antherids and archegones resemble those of the
Horsetails; however, in the highest order (Pepperworts)
the antherids become greatly reduced.
423.	The ferns are classified mainly upon the structure
Fig. 112.—A common Fern (Polypodium vulgare) showing the underground
root-bearing stem, and the leaves, one with round spore-dots on its lower sur-
face. Natural size.
of their spore-hearing parts. Four orders may thus be
separated.
424.	The True Ferns (Order Filices) include very nearly
all the common fern-like plants of our woodlands and hill-202
BOTANY.
sides. They are among the most beautiful of our land-
plants, and their leaves furnish examples of a gracefulness
of bearing and outline scarcely excelled in the vegetable
kingdom. In temperate climates ferns are herbaceous, but
in the tropics many possess a perennial woody stem which
bears a crown of leaves upon its summit.
425. The tissues of the True Ferns are well developed.
The epidermis resembles that of the flowering plants.
Fig. 113.—Spore-case clusters (spore-dots, or sori) of various Ferns. A, round
and naked (Polypodium); B, round and covered (Aspidium); C, elongated and
covered (Asplemum); D. elongated, and covered by folding of the leaf (Adian-
tum). All magnified. (The covering is known as the indusium.)
Complicated fibro-vascular bundles run through the stems
and extend into the leaves, where they branch extensively,
forming the delicate veins which are so characteristic „of
fern-leaves.
426. The young leaves before expanding are coiled or
rolled, so that as they grow up and open they unroll from
below upwards (i.e., circinately). Upon the lower surface
of some of the leaves little clusters of club-shaped hairs
(trichomes) grow out, generally in connection with a fibro-
vascular bundle. The internal cells of the larger end of
these hairs undergo subdivision and thus give rise to a
A
BpteridophytA.
203
number of spores. The hairs are thus spore-cases. In
some ferns these clusters of spore-cases are naked (Fig. 113,
A), while in others they are covered by a special outgrowth
of the epidermis (Fig. 113, JB, C), or by a folding of a
part of the leaf (Fig. 113, D), etc.
427.	The mature spore-case in most common ferns has a
ring of thicker cells extending around it. When these
become dry, they contract in such a way as to break open
the spore-case and thus set the spores free.
428.	The spores soon germinate, upon moist earth. The
first stage thus produced is generally a little heart-shaped,
flat, green plant, adhering closely to the earth by its root-
hairs. After some weeks or months little “ seedling” ferns
may be found, with one or two minute leaves. Under
favorable conditions every such fernlet will give rise to a
strong and long-lived fern.
Among our common ferns are the Common Polypody (Polypodium
vulgare, Fig. 113), the Golden Fern (Gymnogramme triangularis) of
California, the Maidenhair of the North (Adiantum pedatum) and of
the Soutli (A. capillus-veneris), the Common Brake (Pteris aquilina),
the Spleenworts (Asplenium) of many species, the Shield-ferns (Aspi-
dium), also of many species, the curious little Walking leaf (Campto-
sorus rliizophyllus), the Bladder-fern (Cystopteris fragilis), the large
Ostrich-fern (Onoclea strutkiopteris), the Flowering Ferns (Osmun-
da) of several species, and, most beautiful of all, the Climbing Fern
(Lygodium palmatum) of the Appalachian region.
In the Coal Period the ferns were much more numerous than at
the present. Many families which flourished then are now extinct.
The ferns of that period were often tree-like and of large size.
429.	The Ringless Ferns (Order Marattiacece) constitute
an interesting transitional group, all exotics. Some are
cultivated in fern-houses.
430.	The Adder-Tongues (Order Ophioglossaceaz) include
a few species of fern-like plants, which differ from the true204
BOTANY.
'ferns mainly in the mode of development of the large ring-
less spore-cases, and in the leaves being straight or folded
•(not rolled) before expansion. The first stage is much
Fig. 114.—Moonwort (Botrychium lunaria), one of the Adder-tongyes. st, the
-short stem bearing the divided leaf, bs, of which b is the sterile, and / the fertile,
-part.
Fig. 115.—A Pepperwort (Marsilia salvatrix, from Australia), k. the creeping
stem, bearing the divided leaves, of which 6, b. are the sterile, and/,/, the fer-
, tile, parts (the so-called fruits). One half the natural size.PTKlilDOPll 1'TA.
205
smaller than it is in the true ferns, indicating a tendency
towards its disappearance.
Two genera, Ophioglossum, Adder-tongues proper, and Botrychi-
um, tlie Moonworts, are represented in the United States by ten or
eleven species..
431.	The PepperWotts (Order Rhittocarpece) are small
aquatic or semi-aquatic plants, producing spores of two
kinds, viz., small ones (microspores) which are very numer-
ous, and large ones (macrospores) which are less numerous.
The spore- cases are enclosed in rounded “ fruits” or recep-
tacles which are modified parts of leaves.
432.	The small spores, upon germinating, produce a
slight outgrowth of a few cells (some of which develop
antherids and spiral antherozoids), which is the extent of
the first stage. The large spores likewise produce a few*
celled growth, which is barely large enough to burst and
protrude beyond the spore-wall. Archegones are devel-
oped upon these, and from them, after fertilization, the
leafy stage of the plants is produced.
A few species of Pepperworts are sparingly found in the United
States. Some have four-lobed leaves, as in the genus Marsilia (Fig.
115), of which M quadrifolia occurs in New England, M. vestita and
others in the Mississippi valley and westward; Pilularia, with filiform
leaves, is represented by P. americana of the Southwest; it is 2 to 4
centimetres high, and grows in muddy places; Azolla, containing
minute, moss-like, floating plants, is represented throughout the
United States by A. caroliniana. These interesting plants, which
should be sought for more than they have been hitherto, are doubt-
less much more common than we now consider them to be.
Practical Studies.—(a) Collect several different kinds of ferns, in-
cluding the underground portions as well as the leaves. Study the
fibro-vascular bundles, stony tissue, and fibrous tissue in the under-
ground stem (Fig. 116).206
BOTANY.
(b) Examine the disposition of the small fibro-vascular bundles in
the leaves, whether free or reticulated. Peel off a bit of epidermis
from both surfaces, and study the breathing-pores.
power study the spore-dots, using top light only.
The spore-cases may be easily seen and their at-
tachment made out in this way, in those cases
where there is no covering to the spore-dot.
(d) Make a vertical section through the cluster of
spore-cases, and study carefully, looking for the
ring of darker cells on the spore-cases.
(«) The first stage of ferns may often be found in
plant-houses on or in flower pots near ferns. They
may be found also by carefully examining the
moist earth among mosses, etc., in shady ravines.
Collect a few of these of various sizes, and keep
them in water in a watch-glass. Carefully wash
off the dirt from the under side, and then mount in
water, and examine the under surface for antherids
and archegones (Fig. Ill, A). By careful search-
ing, young fernlets may be found still attached
to the first stage (prothallium), as in Fig. Ill, B).
(/) Collect specimens of Adder tongue or Moonwort, and compare
the structure of the spore-bearing organs with the foregoing.
(g) Search the borders of lakes, ponds, and slow streams for Pepper-
worts. They may probably be found in every part of the country,
although they have rarely been collected.
(c) With a low
Fig. 116. — Cross-
section of under-
ground stem of a
Brake (Pteris aqui-
lina). og, outer ring
of fibro - vascular
bundles; ig. inner
fibro-vascular bun-
dles; pr, two bands
of fibrous tissue
(shown in black); p,
soft tissue (paren-
chyma) ; r, rind' of
stony tissue.
Class HI. Lycopodinae (the lycopods).'
433.	The plant-body consists of a solid, dichotomously
branched, leafy, and generally erect stem. The leaves are
small, simple, sessile, and imbricated, and usually bear a
considerable resemblance to those of Mosses. The roots
are mostly slender and dichotomously branched.
434.	The Lycopods are for the most part terrestrial per-
ennials. They are usually of small size, rarely exceeding
a height of 15 or 20 centimetres (6 or 8 inches).
435.	The spores of the Lycopods are pi-oduced in-spore-
cases on the upper side of the leaves. In some of thePTERID OPH 7 TA.
207
genera the spores are of one kind; while in others they are
of two kinds, large ones (macrospores) and small ones
(microspores).
436. The first stage (prothallium) is but little known in
the genera with one kind of spore only; it appears, how-
ever, to be a thickish mass of tissue, which develops under-
Fig. 117.—Part of a Club-moss (Lycopodium clavatum), the running, horizon-
tal rooting stem below, with the spore-bearing cones, s, above. One half natural
size.
ground, and bears both kinds of sexual organs. In the
genera with two kinds of spores, the macrospores produce
small cellular growths, which project slightly through the
ruptured spore-wall, and upon these several or many arche-
gones are formed; the microspores produce very small, few-
celled growths, each of which bears a single antherid, in
which there are developed a few antherozoids.208
BOTANY.
There are three orders of Lyeopods, viz.:
437. The Club-Mosses {Order Lycopodiacece) are terres-
trial plants with many small, generally moss-like leaves
Fig. 118.—A, part of branch of a Little Club-moss (Selaginellainsequifolia),
bearing a cone. Natural size. B, enlarged vertical section of a cone, showing
spore-cases, with large and small spores.
covering the stems. The spore-oearing leaves are often
crowded towards the summits of certain branches, in some
cases forming well-marked cones (Fig. 117, «). The spoTesPTlOtWoPHYTA.
209
are all of one kind, and are borne in roundish spore-cases,
Which are generally single on each leaf.
The Club-mosses are common in the Appalachian region, Canada,
and northwestward, and all but one of our species belong to the
genus Lycopodium. Of these may be mentioned the Common Club-
mosses (L. clavatum and L. complanatum) and the Ground-pine (L.
dendroideum), all extensively used in Christmas decorations.
438.	The Little Club-Mosses (Order Selaginellaceoe) re-
semble the foregoing, but are generally smaller and more
Moss-like, and have (with few exceptions) four-ranked
leaves. Their spore-cases occur singly on certain more or
less modified leaves, which are clustered into terminal
spikes. The spores are of two
kinds; the small ones, which are
very numerous, are generally
borne in spore-cases in the upper
part of the spike, while the
larger ones (macrospores) are
mostly four in each spore-case in
the lower part of the spike (Fig.
118).
n . Club-moss (Selaginella martensii),
439.	Ihe nrst stage OI the showing cotyledons. /, twoplant-
°	lets growing from one spore; p,
Little Club-mosses is almost ob- the first stage (prothallium). II, a
plantlet separated from the spore;
literated. When a small spore r^robtj A ^structure called the
germinates, it becomes divided
internally into a considerable number of cells, one of which
appears to represent the first stage (prothallium), while all
the rest form one large antherid, each cell of which pro-
duces an antherozoid.
440.	The large spore likewise produces a very small
growth, which in this case, however, protrudes a little from
the ruptured spore-wall. Upon this several archegones de-BOTANY.
210
velop. After fertilization the germ-cell gives rise directly
to a leafy plant, which emerges from the spore-wall in a
way to remind one very forcibly of the growth of a plantlet
from a seed. This resemblance is made greater by the
likeness the first leaves hear to cotyledons (Fig. 119).
But one genus, Selaginella, is known in this order. It contains
about three hundred species, most of which are tropical. Two only
(viz., S. rupestris and S. apus) are common throughout the United
States, although five others are indigenous. Several exotic species
are commonly cultivated in plant-houses.
441.	The Quillworts (Order Isoetacem) are small grass-
like plants, with narrow leaves growing from short, thick,
tuber-like stems. They grow in water or muddy places.
442.	Their spores, which are of two kinds, are produced
in spore-cases on the upper surfaces of the leaf-bases. In
their germination and development of the sexual organs
they resemble the plants of the previous order.
The Quillworts are all of one genus, Isoetes, of which
there are in the United States fourteen species.
Fossil Lycopods.—Two orders of Lycopods once existed, containing
large trees, which appear to have been very abundant. The Lepido-
dendrids (Order Lepidodendracese were a metre (2 to 4 feet) thick
and 15 to 20 metres (45 to 60 feet) high, and seem to have had the
general appearance of the Club-mosses. The Sigillarids (Order Sigil-
lariacese) appear to have been trees 30 or more metres (100 feet) in
height and 14 metres (4 or 5 feet) in diameter. Both produced two
kinds of spores, showing their relationship to the Little Club-mosses
and the Quillworts. Although very abundant in the Coal Period,
they have long since become entirely extinct.
Practical Studies.—(a) Secure a few fresh or alcoholic specimens
of various kinds of Lycopods in fruit. The Little Club-mosses may
be readily obtained in plant-houses. Make cross-sections of the stems
and study the fibro-vascular bundles, which in Lycopodium are im-
bedded in a thick mass of fibrous tissue. Examine the leaves, notingPTERID OPll TTA.
211
the small fibro-vascular bundle in the midrib. Study the epidermic
which contains numerous breathing-pores.
(b)	Carefully dissect out from the fruiting cone of a Little Club-
moss several spore-cases, the lower ones with four large spores, the
upper with many small spores. Examine in like manner a cone of
Lycopodium, iu which but one kind of spore will be found.
(c)	Search the borders of lakes, ponds, ditches, and slow streams
for Quillworts, which may be at once distinguished from grasses,
rushes, etc., by the spore-cases on the bases of the leaves. Although
they are rarely collected, they may doubtless be found in almost
every locality in the United States.
(d)	Collect pteridophytes in fruit and dry them under pressure,
afterwards gluing them to sheets of heavy white papei;for herbarium
specimens. The best size is 43 centimetres (16| inches) long, by
30 centimetres (114 inches); this is the size adopted by the botanists of
this country and used in the large herbariums.
(e)	For the identification of the species of pteridophytes of this
country the student may profitably use “Our Native Ferns and
their Allies,” by L. M. Underwood.CHAPTER Xm.
BRANCH VII. PH ANEROG AMI A.
THE FLOWERING PLANTS.
443.	In this great group we find the highest development
of the plant-body, its tissues, and organs of reproduction.
They are tire most complex in structure, and most difficult
to fully understand, of all the plants in the vegetable king-
dom.
444.	The plant-body is composed of roots, stems, and
leaves, generally well developed. Frequently these mem-
bers of the plant-body are more or less branched, giving
rise to extensive branching root-systems, branching stems,
and branching leaves. Hairs (trichomes) of various forms
may occur upon all parts of the plant.
445.	By far the greater number of flowering plants are
chlorophyll-bearing, comparatively few only being para-
sitic or saprophytic. They range from minute plants one
or two centimetres in height, and living but a few days or
weeks, to enormous trees, which continue to grow for many
hundred years, and attain a height of a hundred metres or
more.
446.	The tissues are generally well developed in flower-
ing plants. The epidermis, which is copiously supplied with
breathing-pores, consists of one or (rarely) more layers of
cells, whose external walls are generally somewhat thick-
ened, and whose cell-contents rarely contain chlorophyll.PI1 A NER OQ AMI A.
218
447.	The fibro-vascular bundles are of the collateral form,
the only exception being the first-formed bundle in the
root, which is of the radial type. The bundles are sym-
metrically arranged in the stem, through which they run
nearly parallel to each other, and extend into the leaves;
a few, however, have no connection with the leaves.
448.	All the kinds of tissues, with the exception of thick-
angled tissue, may occur in the bundles; but they are
mainly made up of tracheary, sieve, and fibrous tissues. In
the larger perennials, as the trees, the great mass of tissue
in the woody stems is principally made up of the tracheary
and fibrous tissues of the fibro-vascular bundles. In succu-
lent plants, especially those growing in water, the bundles
are usually smaller and more simple, being sometimes re-
duced to a thread of tracheary or sieve tissue.
449.	Of the remaining tissues, soft tissue, in its various
forms, is by far the most common. The hypodermal por-
tions are frequently composed of thick-angled or stony
tissue. Milk-tissue is common in certain orders.
450.	The organs of reproduction in all flowering plants
are modifications of the type found in the higher Fern-
worts. The leafy plant produces two kinds of cells, an-
swering to the two kinds of spores we have lately studied.
Moreover, these reproductive cells are produced, as in
Fernworts, upon more or less modified leaves.
451.	The small reproductive cells, which are here called
pollen-cells instead of spores, develop in great numbers
within sac-like enlargements upon certain modified leaves.
They are set free by the breaking of the sac, and then
mostly fall out and are borne away by the winds, by in-
sects, or other means.
452.	The larger reproductive cells are likewise produced214
BOTANY.
within outgrowths of certain modified leaves. Only a few
are produced in each outgrowth, and of these rarely more
than one become fully developed. Moreover, these larger
cells (here called embryo-sacs instead of spores) never be-
come free, but always remain within the outgrowth.
453.	We have seen that in the higher Fernworts the
parts of the plant-body bearing the reproductive cells are
considerably modified, often forming cones. In the flow-
ering plants this modification is carried still further, giving
us in the lower orders such structures as the cones of pines,
etc., and in the higher orders the many varied and beauti-
ful forms of flowers.
454.	The modified leaves upon which the pollen-cells are
produced are known by the name of stamens, and the sac-
like enlargements (corresponding to spore-cases) are com-
monly called anthers. The outgrowths in which the em-
bryo-sacs develop are known as ovules, and the leaves
bearing these are the fruiting leaves, or carpophylls.
455.	The embryo-sac soon undergoes a few changes,
somewhat similar to but much less than those in the large
spores of the Lycopods, resulting in a germ-cell similar to
the germ-cell of an archegone. About this time a mass of
cells, corresponding to the first stage of a Lycopod, devel-
ops in the embryo-sac. It is a belated growth; having lost
nearly all its former usefulness as a supporting and nour-
ishing tissue for the sexual organs, its development is more
or less retarded.
456.	Fertilization of the germ-cell takes place essentially
as in plants of a lower grade. When the pollen-cell germi-
nates, it forms in a few cases a several-celled first stage
(prothallium), reminding us again of the higher Lycopods.
More commonly even this feeble growth of a first stagePHANER 0 OAMIA.
215
has not been detected. In either case the pollen-cell de-
velops a tubular filament, sometimes of great length. If,
now, such a germinating pollen-cell happens to he favora-
bly placed near to an ovule, the pollen-tube may penetrate
it and come in contact with the germ-cell. The protoplasm
of the tube then unites with that of the germ-cell, and fer-
tilization is complete.
457.	The fertilized germ-cell soon begins growing and
dividing, producing in a short time a many-celled body—
the embryo-plant. The embryo during its growth is nour-
ished by the surrounding cells of the first stage, here called
the endosperm. While the embryo has been growing, the
covering of the ovule (one or two cellular coats) becomes
gradually harder and firmer; finally the growth of the em-
bryo stops, and the ovule containing it separates from its
supporting fruit-leaf as a ripe seed.
458.	After a longer or shorter period of rest, the little
plant in the seed resumes its growth, the necessary condi-
tions being the proper heat and moisture. It is at first
quite simple, consisting of a little root and stem and a few
small leaves, but with the development of each succeeding
leaf it becomes more like the adult plant.
459.	The flowering plants are separated into two classes,
viz.:
1.	Ovules on an open fruit-leaf—Gymnosperjle.
2.	Ovules enclosed within a closed fruit-leaf—Angiosperm.e.
f
Class I. Gtmnosper m /E (the Gymnosperms).
460.	These are plants with solid stems, which bear in
most cases small, simple, narrow leaves with parallel veins.
Most of them are large trees, and all are terrestrial and216
BOTANY.
chlorophyll-bearing, none being in any wise parasitic.
Common examples are the pines, spruces, firs, etc.
461. The general structure of the reproductive organs
Fig. 120.—A cluster of staminate cones or flowers. A, of a Pine (Pinus sylves-
tris), with a detached stamen. Natural size. B, showing the two pollen-sacs.
Considerably magnified.
may be understood from a study of those of the pines.
The pollen-bearing flowers—staminate flowers, as they are
Fig. 121.—Pollen-cells of Gymnosperms. A, of a Cycad; y, rudimentary first
stage (prothallium), one pollen-cell germinating. B, pollen-cells of a Pine, side
and top views, showing bladder-like enlargements of outer cell-wall, blx the
rudimentary prothallium is shown here also. Much magnified.PEA NEBOOAMIA.
217
generally called—are loose cones generally crowded into
considerable clusters. Each cone consists of a stem upon
which are many flattish stamens, each bearing two pollen-
sacs (Fig. 120).
462. The pollen-cells are roundish, and covered by a
Fig. 122.— A ripe cone of a Pine, partly cut away to abow the position of the
seeds, g\ A, a scale from a young cone, upper side showing two ovules (enlarged);
B, the same when mature, showing two winged seeds, ch. Each seed-coat has a
small pore, M, through which the first root will grow in germination.
double wall, the outer being thick and hard, and in some
cases swollen out into bladder-like enlargements, appar-
ently for the purpose of enabling the oell to be carried in
the air (Fig. 121, B). One or more cells of the rudiment-
ary first stage are always present (Fig. 121, y).218
BOTANY.
463. The ovule-bearing flowers consist of the well-known
cones which, when mature, bear the seeds (Fig. 122). The
cone consists of a stem bearing many leaf-like scales
closely crowded together, and upon these the ovules are
produced. Each ovule has one coat which grows up from
below, almost covering it; but as the ovules grow they bend
Ftg. 123—Pan of a Pine-ovule, ov, the body of the ovule; w, embryo-sac filled
with endosperm, en, which contains two large cells (rudimentary archegones);
n, neck of archegone; pt, pollen-tubes growing upward into necks of archegones.
Magnified 30 times.
down, so that the opening through the coat comes to be
below (Fig. 122, A and S).
464. The embryo-sac appears in the body of the ovule,
when the cone is quite small, as an enlarged cell. It soon
forms a mass of cells (the endosperm, or rudimentary first
stage) within itself, and in this are developed one, two, or
more rudimentary archegones, each with its germ-cell.PUANEllO&AMlA.
219
Thus we see that the development which takes place here
inside of the ovule (which corresponds to the spore-case) is
similar to that which in the Lycopods takes place only after
the large spore has separated itself from the parent-plant.
465.	Fertilization takes place as follows: The scales of
the cone open slightly, permitting the pollen, which has
been carried in the wind, to roll down to their bases where
the ovules are. Here the pollen-cells germinate, and their
tubes enter the opening in the ovule-coat and push through
the tissues to the archegones, where the pollen-protoplasm
is fused with that of the germ-cell (Fig. 123).
466.	As a result of the fertilization, there is first a
growth of a row of cells (called the suspensor, erroneously),
upon the end of which the embryo begins to form. The
root-end of the embryo is always in contact with the sus-
pensor, so that, taking the whole embryo at maturity, the
suspensor is at one end and the little leaves at the other.
Moreover, the root-end of the embryo is always directed
towards the opening in the ovule- or seed-coats. The em-
bryo proper is composed of a little stem ending in a short
root below and bearing a number of little leaves (cotyle-
dons) above. The stem ends in a bud, above and within
the whorl of leaves. During the growth of the embryo
the ovule enlarges, and its coat becomes thicker and harder,
and at last, when growth within has ceased,it separates from
the parent-plant as a seed (Fig. 124, I).
467.	In germinating, the seed first absorbs water and
swells so as to burst its thick coat, the root elongates and
pushes out into the soil (Fig. 124, A), soon sending out
little branches. The leaves (cotyledons) are in contact with
the endosperm, which is rich in starchy and sugary mat-
ters, which afford the plantlet food for its growth. Finally,220
BOTANY.
by the elongation of the leaves, the whole plant is pushed
out of the now empty seed-coat (Fig. 124, III).
Fig. 124.—Seeds of a Pine in different stages of germination. 7, ripe seed in
longitudinal section; s, seed-coat; e, endosperm; w, axis of embryo; c, leaves;
y, opening in seed-coat. 77, 77, four views of the beginning of germination: A,
external view; B, with half of the seed-coat removed; C, in longitudinal section:
D, in transverse section; s, seed-coat; e, endosperm; c, leaves; w>, root. III.
germination completed.PHANEROGAMIA.
221
468. The tissues of the Gymnosperms are individually
hut little higher than those of the Fernworts, hut in their
Fig. 125.—Diagrammatic cross-sections of stems, showing the fibro-vascular
bundles, /c, of which x is the woody side and p the softer or bark side; 6, b, 6,
bast-fibres; R, M, the fundamental tissues of the stem, of which R (the rind) is
the cortical and M the medullary portion, or pith; ic. a belt of cambium which
extends from bundle to bundle.
arrangement they show great and
important differences. The fibro-
vascular bundles are of the col-
lateral form, and are so placed in
the stem that the harder and more
woody side is nearer the centre of
the stem, while the softer side is
always nearer to the surface (Fig.
125, A). The inner part of the
bundles is composed mostly of long,
large cells, the trachelds, which
have the well-known characteristic
bordered pits (Fig. 126). The outer
part contains, besides other tissues,
a little fibrous tissue (bast-fibres).
Between these two halves of the
bundles there is a thin layer of
growing cells (cambium) which is
continuous with a layer between the bundles (Fig. 125,
A and H). At this stage the stem is composed of an inner
Fig. 126.—Longitudinal sec-
tion of wood of a Pine (Pinus
sylvestris). Bordered pits, t',t\
t"; o-e, parts of six trachelds;
sZ, large pits, where medullary
rays touch trachelds. Magni-
fied 325 times.222
BOTANY.
mass of cells, the pith (Jf), and an outer, the rind, or cor-
tex (H), connected with one another by the broad rays
between the bundles (Fig. 125).
469.	As the stem grows older, the cambium of the bundles
keeps on forming tissues similar to those already found in
the bundle; in other words, the woody part of each bundle
is increased on its outer side, and the bark part on its inner
side. In the mean time the cambium between the bundles
gives rise to new bundles, which then increase in size in
the manner described above. The woody part of the stem
soon comes to have the shape of a cylinder, surrounded by
a softer bark portion as a sort cf sheath.
470.	The stem grows in thickness in the warm part of
the year, but stops its growth as cold weather comes on.
The first growth in each year is most vigorous, the cells
being larger, while those formed towards the end of the
season are .regularly smaller and ^smaller until activity
ceases. This manner of growth produces the well-known
growth-rings, so readily seen in a cross-section of any pine
or spruce stem. As there is generally but one period of
growth each year in the cooler climates, every growth-ring
represents a year of the tree’s life; but it appears that oc-
casionally there may be two periods of growth in a year,
and consequently two growth-rings.
471.	Many members of this class have canals running
through the tissues of their stems and leaves, in which a
resinous turpentine is found.
Practical Studies—(a) In the spring of the year collect a quantity
of the staminate cones of a pine (Scotch or Austrian are very goodj,
and preserve such as are not wanted for immediate use in alcohol.
Collect at the same time the young ovule-hearing cones which are
to be found upon the ends of the new shoots as ovoid bodies, 8 to 10
mm. long by 5 to 6 broad.PHANEROGAMlA.
223
(b)	Split a staminate and an ovule-bearing cone vertically, and
study their structure, comparing the one with the other. Dissect
out a stamen and an ovule-bearing scale, and compare. In the
former note the pollen-sacs, and in the latter the ovules (Figs. 120
and 122).
(c)	Study pollen-cells from young and mature staminate cones. In
the young pollen look for the cells representing the first stage (pro-
thallium); in the ripe pollen note the bladder-like enlargements of the
outer coat (Fig. 121, B).
(d)	Note that the ovule-bearing cones of Scotch and Austrian pines
are two years in coming to maturity. Make vertical sections of cones
of various ages, and note the growth of the seed. Note the thin
wing (useful in their dispersion) on the seeds. Make longitudinal
sectioDSjof seeds, and note the little plantlet with its several leaves
(cotyledons).
(e)	Make cross-sections of leaves, and note the turpentine-canals,
one near each angle, with others symmetrically arranged between.
Make cross-sections of the young twigs, and note the canals in the
rind or bark. Make similar sections of the wood of the trunk; and
note similar canals at intervals.
(/) Make very thin cross-sections of the mature wood of the stem,
and note shape and size of the cells; note also the gradual decrease
in the size in passing from the inner to the outer side of a growth-
ring. Now make a very thin longitudinal-radial section, and observe
the bordered pits (Fig. 126). A longitudinal section at right angles
to the last (longitudinal-tangential) will show no bordered pits. In
all these sections note that the wood is made up of but one kind of
cells, viz., trachei'ds.
(g) In a cross-section of a stem, note the thin radiating plates of
tissue (medullary rays), in many cases extending from pith to bark.
In longitudinal tangential section of the stem these rays are seen in
cross section to be made of thick-walled cells (stony tissue). In longi-
tudinal-radial sections the rays are seen split lengthwise (Fig. 126, si).
(/t) Make very thin cross-sections of the stem through bark and
wood, and note the layers of very soft thin-walled tissue (cambium)
between wood and bark. This may be made more evident by soak-
ing the section for a few hours in carmine, by which the cambium
will be stained.
There are three orders of Gymnosperms, viz.:
472. The Cycads (Order Cycadacece) are large or small
trees, with much the general appearance of the palms and224
BOTANY.
tree-ferns. They are of slow growth and are long-lived;
the stem elongates by a slowly unfolding terminal hud,
which gives rise to a crown of widely spreading pinnate
leaves, which are constantly renewed above as they die and
fall away below. About seventy-five species are now
known, all confined to tropical or sub-tropical climates. In
geologic times (Triassic and Jurassic) they were very abun-
dant.
473.	The Conifers (Order Coniferce) are mostly trees of
a considerable size, with branching, spreading, or spiry
tops, as the pines, spruces, firs, etc. etc. They are gener-
ally of rapid growth, and in many cases attain a great
height and diameter. In the greater number of species the
leaves are persistent, and the trees, consequently, evergreen.
474.	The order contains thirty-two genera and about
three hundred species, which are distributed mainly in the
cooler climates of the globe. Seventy or more species
occur within the limits of the United States, and constitute
in many places enormous forests hundreds of miles in ex-
tent.
The pines (Pinus) include the most important trees of the order.
The White pine (P. strobus), formerly very abundant from the Great
Lakes eastward, furnishes the greater part of the “pine lumber” so
largely used in the Northern States for building and other purposes.
The Sugar-pine (P. lambertiana) of California resembles the White
pine but is much larger, being often 60 to 90 metres (200 to 300 feel)
in height, with a trunk 3 to 6 metres (10 to 20 feet) in diameter. The
Southern pine (P. australis), abundant from the Carolines to Texas, is
a tree ol' moderate dimensions, whose hard wood is “superior to that
of any other North American pine,” and is known in the markets as
Yellow or Georgia pine. Scotch pine (P. sylvestris) and Austrian
pine (P. laricio), both natives of Europe, are extensively planted in
this country. Besides the spruces, firs, larches, cedars, and many
other well-known trees, the order contains the two species of great
Redwoods. The most remarkable is called the Big Tree (SequoiaPhanerogamia.
225
gigantea), and grows in a few valleys on the western slope of the
Sierra Nevada Mountains in California. It attains a height of more
than 100 metres (300 feet) and a diameter of 6 to 10 metres (20 to
30 feet). The other species is the common Redwood (S. semper-
virens), confined to the coast-range mountains of California. It is
but little inferior to the preceding in size, and its wood is extensively
used for building and other purposes.
In the Southern Hemisphere the Kauri pine (Agathis australis) of
New Zealand, the Norfolk Island pine (Araucaria excelsa) of the
South Pacific Ocean, and others represent a group of conifers closely
related to those which were abundant in ancient geological times.
475.	The Joint-Firs (Order Gnetacece) include a few
undershrubs or small trees, mostly natives of the warmer
parts of the world. Their curious structure is far too diffi-
cult to be taken up here.
Class II. Angiosperms (the Angiosperms).
476.	The plants of this class have, in most cases, more
or less elongated stems; these are solid at first, and in the
great majority of cases they remain so. They usually bear
ample leaves, with parallel or netted veins.
477.	Their reproductive organs are mostly collected into
definite and distinct flowers, which often show great beauty
of form and color. The pollen-bearing leaves (stamens)
resemble those of the Gymnosperms, but the ovule-bearing
leaves (carpophylls) are folded into a closed vessel (ovary).
478.	Most Angiosperms are terrestrial and chlorophyll-
bearing plants; there are, however, many aquatic and aerial
species and a considerable number of parasites. They
range, also, in size and duration, from minute annuals, a
millimetre in extent, to enormous trees, 50 to 150 metres
high and many centuries old.
479.	We have seen (pp. 216-218) that in the Gymnosperms
the flower consists of a stem upon which are the leaves220
BOTANT.
which bear reproductive cells. The flower of the Angio-
sperms is likewise a stem, bearing leaves which have to do
with reproduction. In this class, however, there is, as a
rule, a division of labor, as we may say: instead of all the
leaves bearing reproductive cells, some of them are modi-
fied in form, color, or structure, so as to make the flower
Fig. 127.—Diagrammatic section of a flower. Ke, calyx; K, corolla; /, the fila-
ment, and a, the anther, of the stamen; p, pollen-cells, some in the anther,
others on the stigma; F, the ovary, surmounted by the style, g, and the stigma,
n (this ovary contains one ovule, which has a single coat, i, enclosing the ovule-
body, S); em, the embryo-sac; E, germ-cell; ps, a pollen-tube penetrating the
style, and reaching the germ-cell through the micropyle of the ovule.
more conspicuous, which is, as we shall see, to the advan-
tage of the plant.
480. There are so many particular forms of flowers that
it would be impossible to notice or describe them all in this
place. In some cases the flower is a little stem (axis) upon
which are pollen-bearing or ovule-bearing leaves (stamens
or ovaries); these clusters of reproductive organs may have
a number of sterile leaves below them on the stem, the
floral leaves, or perianth. In other cases both kinds of re-PHANEROGAMIA.
227
productive organs are in one flower, when the ovaries are
highest on the stem, the stamens being next, and the sterile
leaves (if any) lowest of all (Fig. 127). There is, more-
over, great diversity in the development of the sterile
leaves, varying from a few small green or pale leaves to
two or more distinct whorls of sepals (the outer) and petals
(the inner) which may show great differences in size, shape,
texture, and color.
481. The stamens of Angiosperms often bear so little
resemblance to leaves that their real nature would not be
Fig. 128.—Pollen-cells with roughened walls. A, of Chicory; B, of Flowering
Mallow (Lavatera). Highly magnified.
suspected. There is usually a slender stalk, the filament,
at the top of which are from one to four pollen-sacs, the
latter forming the anther. We may regard the filament
and its extension (the so-called connective) between the
pollen-sacs as representing a very narrow leaf upon which
the pollen-sacs develop as outgrowths. Sometimes the
stamen is broad, showing at once its leafy nature.
482. The development of the pollen-cells is like that of
the spores of Fernworts and the pollen of Gymnosperms.
Certain internal cells (called pollen mother-cells) in the228
BOTANY.
young pollen-sacs undergo division into four parts, which
become rounded and covered with a double coat or wall.
The outer coat is often much thickened, and may be rough-
ened by ridges or prickles (Fig. 128).
483.	The pollen-cells germinate in moisture, by sending
out a tube which is a prolongation of the inner coat. In
some cases there are cells or nuclei in the cell or tube, evi-
dently representing the first stage (prothallium) in its last
stages of suppression. The protoplasm of the cell passes
freely down the tube to its extremity.
484.	The ovule-bearing leaves of Angiosperms bear still
less resemblance to ordinary leaves than do the stamens.
In the simpler cases the young leaf becomes curved so that
its edges touch and finally grow together, forming the
ovary, which usually tapers above into a style or stalk sup-
porting a gland ular structure, the sti gma (Fi g. 12 7,n). The
whole ovule-bearing organ, com-
posed of ovary, style, and stigma,
is usually known as the pistil. In
many plants several pistils grow
together, and thus form a com-
pound pistil.
485.	The ovules grow upon the
inner (i.e., upper) surface of the
leaf which forms the ovary, or at
its base (Fig. 127), or more frequently upon its margins.
At first it is a simple rounded outgrowth of a few cells; as
it grows older a circular ridge arises upon it, which often
is soon followed by another (Fig. 129, A and B). These
ridges grow out and upwards so rapidly that they overtake
and enclose the ovule-body, leaving but a small opening or
A	B
Fig. 129.—Very young ovules,
nc, ovule-body; sc, inner, and pf,
outer, coats just beginning to
grow; fn, ovule-stalk. Magnified
140 times.PEANEROGAMIA.
229
486. The embryo-sac is an enlarged cell, at maturity con-
taining several rounded masses of protoplasm, one of which
is the germ-cell. As the tissues of the ovule-body can suf-
Fig. 130.—Diagrammatic longitudinal sections of ovules, fc, the body of the
ovule, with its embryo-sac, em; ai, the outer, and ii'jfne inner, coat; m, the
opening in ovule-coat (micropyle); c, the base of the ovule; /, the ovule-stalk;
A, a straight ovule; B, an inverted ovule; the long stalk, /, has fused with the
outer coat of one side of the ovule.
ficiently nourish the germ-cell, there is little or no develop-
ment of the first stage (prothallium) at this time, and there
is an almost complete suppression of the archegone-walls.
Fig. 131.—JTTa longitudinal section of an ovule of the Pansy, after fertilization;
a and i, coats of the ovule; p, pollen-tube; e, embryo-sac, with the very young
embryo at one end and free endosperm-cells at the other. B, apex of embryo-
sac, e; eb, very young embryo of four cells.
487. Fertilization takes place as follows: The pollen-
cell, resting upon the moist surface of the stigma, germi-
nates, and its tube penetrates the soft tissues of the stigma
and style, finally reaching the cavity of the ovary, where230
BOTANY.
it enters the ovule through the opening in the coats (Fig.
131, A). Here it comes in contact with the apex of the
ovule-body, and soon reaches the embryo-sac. The contents
Fig. 132.—Embryo of Shepherd’s Purse (Capsella), in various stages, u, the
suspensor. In V the root-cells, w, first appear, the rudimentary leaves, c, c, and
stem, s, already formed. Highly magnified.
of the pollen-tube unite with the germ-cell, which then
forms a wall about itself; it then divides transversely one
or more times, forming a row of cells (the suspensor), at thePI1ANER OG A MIA.
231
end of which an embryo soon begins to form by the fission
of cells in three planes (Figs. 131, JB, and 132, I to IV).
488. At first the embryo is a minute rounded cell-mass
attached to the end of the row of cells, and in some plants
it passes but little beyond this stage until after the ripen-
ing of the seed. In most cases, however, the cell-mass con-
tinues its growth until it has formed a little stem bearing
Fig. 133.—Magnified sections of seeds, showing embryos and endosperms. A.
Oat; B. Sedge; C, Coffee; D, Marsh-marigold; E, Bitter-sweet; F. Goosefoot;
G, Nettle; H, Oak; I, Sweet Pea; J, a Mustard. In A to D, small or minute
embryo in large endosperm; E to (?, larger embryo and smaller endosperm;
H to •/, large embryo and no endosperm.
rudimentary leaves above and a root below. There are to
be found all degrees of simplicity in the embryos of An-
giosperms, from the rounded cell-mass (thallus) to the well-
formed plantlet provided with distinct root, stem, and
leaves.
489. While these changes are going on, cells arise in the
basal part of the embryo-sac and increase rapidly, generally
filling up a considerable part of its cavity. These cells232
BOTANY.
constitute the endosperm, and serve somewhat later to
nourish the growing embryo, This nourishing tissue is
considered to be the homologue of the first stage (prothal-
lium) of the Fernworts, here greatly belated.
490.	The emhryo in its growth gradually absorbs the en-
dosperm. In many cases growth is checked in the ripening
of the seed, before much of the endosperm is used up (Fig.
133, A to D); in such seeds the emhryo is small and poorly
developed. In other cases more (Fig. 133, E to G), or in
still others all (Fig. 133, Hto J), of the endosperm is ab-
sorbed; in these the embryos are much larger and better
developed. Where endosperm remains in a seed, its cells
are generally filled with starch, or less frequently with
oily matters; where no endosperm remains, there is always
a storage of starch or oily matter in some part of the em-
hryo. While the emhryo is growing inside of the ovule,
the outer ovule-coat generally becomes thicker and harder,
all the ovule-tissues become drier, and at last the hard,
dry ovule, now called a seed, separates at its base and falls
to the ground.
491.	The seed in germinating absorbs moisture, swells
up, and generally hursts its coat. The emhryo resumes its
growth, sending out its root into the soil, and its stem and
leaves upward into the air. Where there is endosperm,
the emhryo grows by absorbing food from it; where there
is no endosperm, the large embryo is strong enough to grow
for a time by using the store of food contained within itself.
In some cases (e.g., bean, squash, melon, etc.) all the leaves
•withdraw from the seed-coat and appear above ground,
while in others the first one or two leaves (cotyledons) re-
main in the seed in the ground, only the succeeding leaves
coming up into the light and air, as in peas, wheat, etc,PHANEROGAMIA.
233
492.	We have seen that fertilization of the germ-cell
not only caused the latter to develop into a plantlet, but
excited the tissues of the ovule to a growth which they
would not have made otherwise. This excitation of growth
extends much further than the ovule; it commonly causes
the ovary to undergo considerable changes, and in some
cases even parts of the perianth or the stem which bears
the organs of the flower. These changes give rise to the
fruit of Angiosperms.
493.	The changes which most frequently take place in
the growth of the fruit are such as (1) an increase in the
number of ovule-chambers by the formation of false par-
titions, or (2) a decrease in their number by the oblitera-
tion of some; (3) the growth of wings or prickles upon the
exterior of the fruit; (4) the thickening and formation of
a soft and juicy pulp; (5) the hardening of some portions
of the wall by the development of stony tissue; (6) the
thickening and growth of the calyx or receptacle.
494.	In cases where the walls remain thin and eventu-
ally become dry, the fruits are said to be dry—e.g., in the
bean; where the walls become thickened and more or less
pulpy, they are fleshy—e.g., the peach.
495.	It is unnecessary here to describe the various kinds
of fruits. It is enough to point out that they all appear
to have to do with the protection or dispersion of the seeds
they contain. Thus the hard walls (as of nuts, achenes,
etc.) or the bitter pulp of some (as of certain berries) are
protective, while the sweet pulp (many berries, drupes, etc.)
and explosive capsules of others serve to distribute the
seeds.
496.	The particular structure of the flower, its position
on the plant, and its relation to other flowers in forming234
BOTANY.
flower-clusters of tfhis or that shape, all have reference to
pollination (i.e., the placing of the proper pollen upon the
stigma). The pollen-cells are dependent for transportation
to the stigma upon (1) the wind (anemophilous flowers);
(2) certain contrivances by means of which insects (or
rarely birds) are made to carry the pollen from anther to
stigma (entomophilous flowers); (3) the favorable position
of the anthers and stigmas, bringing the pollen in the
opening anther into contact with the stigmatic surface
(1autogamous flowers).
497.	The grasses and sedges, and the oats, beeches,
chestnuts, walnuts, birches, and their allies, and a few
others, have wind-pollinated flowers. In these the pollen
is produced in great abundance, and the flowers are mostly
small, regular in form, simple in structure, uncolored, and
destitute of nectar (honey). The pollen-hearing flowers
are always in clusters which are exposed to the wind, as
in grasses at the top of the plant.
498.	A great number of plants have insect-pollinated
flowers; these are, as a rule, large, colored, sweet-scented,
and provided with nectar-glands; the nectar acts as a bait,
and the showiness and scent as guides, to honey-loving in-
sects, which, by various contrivances in the flowers, are
made to come in contact with the anthers of one flower
and the stigmas of another, in the first dusting their bodies
with pollen, which in the second adheres to the stigmas.
499.	Large flowers are frequently solitary, but smaller
ones are, as a rule, massed in clusters which thus become
conspicuous. In the golden-rods we have a good illustra-
tion of an extreme case of this kind, the individual flowers
being very small and inconspicuous, while the flower-clus-
ters of hundreds of massed flowers may be seen for a longphanerogamiA.
S35
distance. In sunflowers, in addition, the marginal flowers
in the cluster develop an especially showy perianth, sur-
rounding the whole with conspicuous rays.
500.	Many showy flowers have no nectar (honey) glands,
but in general some part of the flower secretes a sweet,
sugary fluid which is attractive to insects and some birds.
The nectar is always situated in the back part of the flower,
so that in securing it the insect is obliged to come near to
the pollen-sacs or stigma.
501.	In this connection the various irregularities of size
and form in the parts of the perianth, as well as of stamens
and pistils, have a meaning. Thus the perianth-leaves may
grow together ifito a tube, in which case the nectar is at
its bottom; or they may be of different sizes, as in orchids,
beans, peas,' etc., where they are so placed as to admit of
access to the nectar from one direction only. In some
tubular flowers there are two forms in the same species,
those of some plants having long stamens and short styles,
while in others the structure is exactly the reverse. Insects
in getting honey from these will pollinate the long-styled
flowers with pollen from the long stamens of other flowers,
and vice versa. There is also very often a greater or less
difference in the time of maturity of the stamens and pis-
tils. In some the pollen is set free before the stigma is
ready for pollination; in others it is the reverse. This (and
the preceding) arrangement prevents pollination of a pistil
by pollen from the stamens of the same flower; i.e., close
fertilization is prevented.
502.	Self-pollinated (autogamous) flowers are much less
numerous than those which are wind- or insect-pollinated,
and it is doubtful whether there are any species of plants
all of whose flowers exhibit constant self-pollination (au-236
&OTAN ?.
togamy). There are a good many plants, however, which
have two forms of flowers, viz., large, showy, nectar-hear-
ing, insect-pollinated ones, and small, inconspicuous self-
pollinated ones, generally with a rudimentary perianth.
Flowers exhibiting this form of autogamy are said to he
cleistogamous.
503.	Examples are to he met with-in some violets, wild
touch-me-not, etc.: early in the season these have large
flowers, which are pollinated by insects, hut later only small
cleistogamous ones appear, and in some violets these are
subterranean. Without doubt it frequently happens that
the pollen of wind- and insect-pollinated flowers falls upon
their stigmas, resulting in accidental self-pollination; but
too frequent a recurrence of this is guarded against by
various structural devices.
504.	The foregoing are but a few of the general modifi-
cations for securing proper pollination which flowers show;
they must serve to direct the student’s attention to this
interesting part of the study of plants, which can be taken
up in connection with the writings of Darwin, Muller,
Gray, and others.
Practical Studies.—(a) Collect a few wild buttercup flowers. Begin
at the lower side of the flower and carefully remove the five green
sepals constituting the so-called calyx, next the five yellow petals
constituting the so-called corolla, next the many stamens, and last
the numerous small pistils which cover the rounded end of the floral
stem. Make a careful drawing of a representative of each part.
(6) Mount in water (after moistening with alcohol) a little of the
pollen of the morning-glory, sunflower, mallow, and Indian corn.
Note the surface markings. Crush the cells and test with iodine.
Pollen-grains may he germinated by placing them in a five-per-cent
solution of common sugar in water. The pollen-tubes may also be
found by carefully mounting stigmas or longitudinal sections of stig-
mas. Many grasses are good subjects for such studies.
(<•) Kemove the pistil from a fresh pea-flower. Split it longitudi-
nally, and observe that the ovules are in a row along one seam (suture).PHANEROGAM!A.
237
Make many cross-sections of another pistil, so as to secure sections of
ovules, in which note the ovule-body and the coats. Make cross-
sections of younger and younger unopened flowers of the pea, and
study the development of the ovary and ovules. It is very easy to
get specimens showing the ovary not yet closed, and the ovules as
very small outgrowths from its margins.
(d)	Make longitudinal sections of several young pea-pods in such
manner as to secure thin sections of the ovules. By selecting pods
of different ages, the large embryo sac, with the youug embryo in
various stages of growth, may he observed.
(e)	Carefully dissect and examine a pea after soaking over night in
water. Note the short curved stem, tipped by a root, the two thick
starch-gorged leaves (cotyledons) with smaller leaves between them.
Examine in like manner a bean, seeds of the apple, squash, buck-
wheat, oat, Indian corn. Note the endosperm when present.
(/) Examine in succession ripened fruits as follows: 1, marsh-mari-
gold (follicle); 2, pea (legume); 3, mustard (capsule); 4, parsnip (cre-
mocarp); 5, oak (nut); 6, sunflower (achene); 7, Indian corn (cary-
opsis); 8, melon or cucumber (pepo); 9, gooseberry (berry); 10, cherry
(drupe); 11, apple (pome). Numbers 6 and 7, which are popularly
called seeds, are composed of a large seed enclosed in a tightly fitting
ovary-wall.
(g) Study the Indian corn as an example of a wind-pollinated (ane-
mophilous) plant. Note the position of staminate (in the tassel) and
pistillate (in the ear) flowers. Estimate the relative number of pollen-
cells, and ovules (one in each ovary).
(li) Study the position of the nectar in clover (at the bottom of the
corolla), columbine (in deep sacs of the petals), and buttercup (on
glands at the base of the petals).
(i) Examine flowers from several different plants of eyebrights
(Houstonia), puccoon (Lithospermum), and cultivated primrose. Ob-
serve that on some plants the flowers have long stamens and short
styles, while in others they are the reverse. By measurements the
anthers of the one form will be found to have exactly the height of
the stigmas of the other. Many other flowers show this dimorphism;
a few show trimorphism, i.e., three forms.
(J) Observe the flowering of spring-beauty (Claytonia), and notice
that the stamens mature, before the stigmas are ready for pollination.
Observe in like manner thistles and sunflowers in which proterandry,
as it is called, takes place also. Now observe the flowering of the
strawberry and the apple, in which the pistils mature before the
stamens. This is known as proterogyny. Both proterandry and
proterogyny are included under the general term.of dichogamy.238
BOTANY.
(lc) Observe the large early flowers of violets, which are dependent
upon insects for pollination. Notice that after a while none of these
appear, but only small ones destitute of petals. In the common yel-
low violet these are borne on the stem above the ground, but in blue
violets they are often underground. These small flowers are self-
pollinated (cleistogamous).
505.	The fibro-vascular bundles of the stems of Angio-
sperms are entirely of De Bary’s “collateral” class; that
is, each bundle in cross-section is more or less distinctly
two-sided, viz., wood and bark. Each of these sides gen-
erally contains soft, fibrous, and vascular tissues.
506.	The disposition of the bundles in the Angiosperms
is for the most part dependent upon the position of the
leaves. Nearly all the first-formed bundles are of the kind
termed “common bundles;” that is, they extend on the
one hand into the leaf, and on the other down into the
stem.
507.	The general arrangement may be illustrated by Fig.
134, in which there pass down from each leaf three bun-
dles; at the lower internode these are, on the left, a, b, c,
and, on the right, d, e, f At the next internode, where
the leaves stand at right angles to the lower ones, there
are three bundles again, g, h, i, and k, l, m; these are
largest at their points of curvature, and they dwindle in
size as they pass downward and finally unite with the bun-
dles from the lower pair of leaves. The bundles from the
third internode pass downward, and in like manner join
those from the second pair of leaves, and so on. Thus in
such a stem every bundle passes downward through one
internode before joining another, and in any internode all
the bundles are derived from the leaves at its summit.
508.	In some Angiosperms the bundles in a cross-section
of a stem are separate from one another, while in othersPEANEROQAMIA.
239
Fig. 134.—Tho fibro-ynacular system ot the stem of a Virgin’s-bower (Clematis).240
BOTANY.
they soon become connected by a cambium-ring as in the
Gymnosperms. In the perennial species this gives rise to
a marked difference in the structure of the stem (Fig. 135,
A and JB).
509. The tissues of Angiosperms are the most varied
and highly developed of any in the vegetable kingdom.
Not only is every tissue abundantly represented, but each
one shows almost numberless more or less well-marked va-
Fig. 135.—Cross-sections of tree-trunks. A, of a Palm; B, of an Oak; Ig,
woody, and ec, cortical (bark), portion; m, pith; m, medullary rays.
rieties. Moreover, the structures which they form, as the
solid (woody) parts of the stems, are of a higher order and
far more complex than those in any other groups of plants.
Practical Studies.—(a) Make cross-sections of young stems of the
asparagus and hickory. Note the difference in arrangement of the
bundles. In like manner compare cross-sections of young stems of
virgin’s-bower (Clematis) and green-brier (Smilax).
(b)	Make vertical sections of the foregoing, and note the relation
of the bundles to the leaves.
(c)	Make cross and longitudinal sections of the solid (woody) part
of a bamboo or green-brier stem, and compare with similar sections
of oak or hickory. In the latter note the pith, medullary rays, and
distinct bark, not present in the former.
(d)	In the sections of oak and hickory note the cambium-zonePEA NER 00 AM I A.
241
Which lies between the inner solid (woody) mass and the outer softer
portion.
510. The Angiosperms are readily separated into two
sub-classes, as follows:
Sub-Class I. Monocotyledones (the Monocotyledons).—
The first leaves produced by the embryo are alternate;
the endosperm is usually large and the embryo small.
Sub-Class II. Dicotyledones (the Dicotyledons).—The
first leaves of the embryo (cotyledons) are opposite; the
endosperm is very often rudimentary or entirely wanting,
and the embryo is generally large.
Fig. 136.—Longitudinal section of the seed of Indian Corn, c, adherent wall
of the ovary; n, remains of the style; sf, base of the ovary (all the remainder
of the figure is the true seed); eg, ew, endosperm; sc, ss, cotyledon; e, its epi-
dermis; k, young.leaves; w, the main root; w', roots springing from the stem.
Magnified 6 times.
Sub-Class I. The Monocotyledons (Monocotyledones).
511. The first leaves of the embryo are alternate; hence
we say that they have one cotyledon. The#venation of the242
BOTANY.
Fig. 137.—Germination of In-
dian Corn. /, II, III. succes-
sive stages. A and B, front and
side views of a separated em-
bryo; w, root; e, part of seed
filled with endosperm: sc, co-
tyledon; r, its open margins;
b, bb", leaves or young plant;
l, fragment of wall of ovary.
Natural size. «
leaves is for the most part such that
the veins run more or less parallel
to one another, and when they
join each other enclose four-sided
spaces; rarely, however, their veins
are irregularly distributed and
form an irregular network.
512.	The germination of Mono-
cotyledons may he illustrated by
the Indian corn. Here the embryo
lies partly imbedded in one side of
the large endosperm (Fig. 136).
The first leaf of the young plant
(the cotyledon, or scutellum), sc,
has its broad dorsal surface in con-
tact with the endosperm; anteriorly
it is curved entirely around the re-
mainder of the embryo.
513.	Under proper conditions
the main root pushes through the
root-sheath (ws, Figs. 136, 137).
The plumule, consisting of a mi-
nute stem and a few rudimentary
leaves, next pushes out through
the upper end of the curved co-
tyledon (II, Fig. 137). The co-
tyledon remains in contact with
the endosperm and absorbs nour-
ishment from it for the sustenance
of the growing parts. Lateral
roots soon appear upon the main
root, and adventitious ones arisePHANEROGAMIA.
243
from the first internodes of the stem (w"', to", to'). The
first leaf above the cotyledon is quite small (b), and each
succeeding one becomes larger and larger until the full size
is reached.
514. Monocotyledons include about 18,000 known species
which are by the latest authorities arranged under thirty-
four orders. These orders, moreover, are brought together
in seven groups (series). In the following tabular presen-
tation only the more obvious characters are given.
Series I. Glumacese.—Perianth chaff-like or none. Ovary single,
one-ovuled. Seeds with endosperm.
Order 1. The Grasses (Gramme®).—Herbaceous or rarely woody
plants with round, jointed, and mostly hollow stems, hearing alter-
nate two-ranked leaves with split sheaths. Species 3100 to 3200,
distributed in all climates.
Order 2. The Sedges (Cyperaceae).—Herbaceous plants with three-
angled solid stems bearing three-ranked leaves with entire sheaths.
The 2200 species are distributed throughout the world.
Orders 3 to 5 (Restiacete, Centrolepide®, Eriocaulonaceae) include
five or six hundred grass-like or rush like, mostly tropical plants.
Series II. Apocarpeae.—Perianth in one or two series or none. Ova-
ries single, or many always distinct. Seeds without endosperm.
Order 6, the Pondweeds (Naiadace®), Order 7, the Water-plan-
tains (Alismace®), Order 8 (Triuride®), mostly common water-
plants, aggregating about 200 species.
Series III. Nvidiflorae.—Perianth none. Ovaries single, or many
united. Seeds mostly with endosperm.
Order 9. The Duckweeds (Lemnacese).—These are the smallest of
flowering plants, and consist of floating discs generally bearing one
or a few roots beneath. About twenty species are known, half of
which occur in the United States.
Order 10. The Aroids (Aroides).—Herbs often large and palm-like
in appearance, with large leaves having reticulated venation. There
are about 900 species, distributed mostly in tropical countries, where
they sometimes attain a height of several metres (6-12 feet); in tern
perate climates they are much smaller.
Order 11. The Cat-tails (Typhace®).—This small order is well rep-
resented by the well-known Cat-tail Flag of our ponds,244
BOTANY.
Order 12 (Oyclanthacese), of a few herbs, and Order 13, the Screw-
pines (Pandanacere), of eighty shrubs or trees, are both tropical.
Series IV. Calycinae.—Perianth small, calyx-like. Ovary free (i.e.,
not united to the perianth). Endosperm copious.
Order 14. The Palms (Palmace®).—Trees, shrubs, or woody climb-
ers; natives almost exclusively of the torrid zone, or the adjacent
hotter portions of the temperate zones, being rarely found beyond
40° north and 35° south latitude. Eleven hundred species of palms
have been enumerated.
Order 15. The Rushes (Juncacese), of which there are 200 species,
are widely distributed, while the very small Order 16 (Plagellarieae)
is confined to the tropics.
Series V. Coronariese.—Perianth more or less corolla-like. Ovary
free, or rarely attached at the base. Endosperm copious.
Order 17 (Rapateacese) contains a few South American herbs.
Order 18, the Spider-worts (Commelinacese), includes about 300
mostly tropical herbaceous species.
Order 19 (Mayacese), Order 20, the Yellow-eyed Grasses (Xyri-
dacese), Order 21 (Philydraceae,) and Order 22, the Pickerel-weeds
(Pontederiacem), are all small orders and consist of herbaceous species.
Order 23. The Lilies (Liliacese).—These are mostly perennial, her-
baceous, rarely shrubby or tree-like plants, with entire leaves, and
generally showy flowers. The species, of which there are about
2100, are distributed in all climates.
Order 24 (Roxburghincese).
Series VI. Epigynse.—Perianth more or less corolla-like. Ovary
inferior (i.e., united to the perianth so that the latter appears to be
on the ovary). Endosperm copious.
Order 25, the Yams (Dioscoreacese), and Order 26 (Taccacese),
small orders of mostly tropical plants.
Order 27. The Amaryllids (Amaryllidaceae) are mostly perennial
herbs, widely distributed. About 650 species are known.
Order 28. The Irids (Iridacese) are perennial herbs numbering 700
species, very generally distributed throughout all regions.
Order 29. The Bloodworts (Haemodoracoffi), a small order, natives
mostly of the Southern Hemisphere.
Order 30. The Pine-apples and their allies (Bromeliacese), about
350 species of warm climates.
Order 31. The Bananas and their allies (Scitaminese), perennial
herbs, sometimes almost tree-like, numbering about 450 species,
mostly tropical.
Series VII. Microspermae.—Perianth more or less corolla-like. Ova-
ry inferior, §eeds minute, without endosperm,PH A NEllOQAMIA.
245
Order 32. The Orchids (Orchidacese) constitute an immense group
of 4500 to 5000 species of perennial herbs. Some of these are terres-
trial, while very many are epiphytic (i.e., grow upon trees: not para-
sitically, however).
Order 33 (Burmanniacea) and Order 34, the Frog’s-bits (Hydro-
charidese), include about 100 species of small herbs.
515.	The Monocotyledons include many of the most in-
teresting plants botanically to be found in the vegetable
kingdom. While the flowers in the lower orders are sim-
ple and unattractive, those in the higher series are often
exceedingly complex and of great beauty. If, for exam-
ple, we compare the flower of a grass with that of an Orchid,
the differences are so great that at first we can scarcely see
any resemblance. However, the two stand at opposite ex-
tremes, and, as may be seen by a study of the foregoing
synopsis, there is a pretty regular gradation from the one
to the other. From the Grasses through the Aroids to the
Palms the gradation is an easy one, while from the Orchids
through the Irids the passage is equally easy to the Lilies.
We may, perhaps, regard the Palms and the Lilies as typi-
cal Monocotyledons between which lie a number of small
connecting orders, and from which on either hand the
orders diverge to specialized forms.
516.	While the flowers of most grasses are wind-pol-
linated (anemophilous), those of the Orchids are almost
entirely dependent upon insects for pollination. In the
grasses we find a great amount of dry powdery pollen,
but in the Orchids, on the contrary, the pollen is in small
quantity and usually held together by sticky threads. The
stigmas of grasses are large, prominent, and generally
feathery, so as to easily catch and retain the pollen; in the
Orchids, however, they are mostly sticky surfaces, rarely
projecting, often much depressed,246
BOTANY.
517.	These differences in the sexual organs are accom-
panied by similar ones in the surrounding parts. Thus
the stamens and pistils in grass-flowers are surrounded by
chaffy scales pale or green in color. Such flowers are
therefore not conspicuous, although generally clustered at
the summit of the stem. Moreover, they possess little or
no nectar, and, with few exceptions, are scentless. In the
Orchids there is a well-developed perianth which shows
high specialization of form and color. Most are provided
also with nectar-glands and an attractive odor.
518.	In Orchid-flowers the stamens and styles are fused
together into a “column” which occupies the centre of the
perianth. In the great majority of cases there is but one
anther (representing one stamen), and this is on or near the
end of the column, so placed as to he readily touched by
an insect entering the flower. The pollen-cells cohere in
little sticky masses, which easily adhere to the head, an-
tennae, or hack of an insect.
519.	It is an interesting fact that in the ordinary terres-
trial Orchids the flower develops in such a way that it must
twist upon its ovary in order to attain its proper position
when open (Fig. 138). Thus, without twisting, the lip (l)
with its spur would be uppermost, while the anther would
be below.
520.	When a long-tongued insect is attracted to an
Orchid-flower by the color and odor, it thrusts its tongue
down into the spur (sp) in search of nectar or sweet juices,
in the mean time perhaps resting its feet upon the lip (Z).
Its head comes in contact with the sticky discs (at A), which
adhere tenaciously. When the insect withdraws its tongue,
it at the same time carries away the pollen-masses adhering
to its head. When the insect visits another Orchid-flowerPIIANEROGAMIA.
247
of the same species, the pollen-masses are thrust against the
sticky stigma (si) and all or a part adheres to it. Thus, as
the insect passes from flower to flower, it unconsciously
pollinates them, always, however, carrying the pollen of
one flower to the stigma of some other.
521. The Lady’s Slippers are examples of Orchids with
Fig. 138.—An Orchid-flower (Orchis mascula). A, vertical section of a flower-
bud (magnified) before it has twisted upon its ovary,/; gs, the column, bearing a
pollen-mass, pi; h, its sticky disc, below which is the stigma. B, an open flower;
/, its twisted ovary; l, lip; st, stigma; a, anther; h, its sticky disc; sp, spur.
two anthers; these are upon the sides of the curved column
which hears the stigma higher up. The lip is here shaped
like a slipper (whence the common name), into the opening
of which the column bends. The lip and the other parts
of the perianth are colored, often showing striking con-
trasts, and these doubtless serve to attract the notice of
insects. When an insect enters the slipper (lip), it does so248
BOTANY.
from the top; but once inside, it finds it difficult to escape
by that route on account of the incurved margins of the
opening, as well as the smooth sides of the slipper. It ac-
cordingly passes backward under the dependent stigma,
and escapes by squeezing between the column and base of
the slipper: in doing this it covers its back with sticky
pollen from the anther on the column. When it visits
another flower this experience is repeated; and as it passes
under the stigma in its endeavor to find an exit, some of
the pollen is left on its surface.
522.	Among the tropical Orchids there are some marvel-
lous flowers. One of the most remarkable of these is a
large flowered species of Catasetum, native of South
America. The flowers are diclinous, i.e., the pollen and
the ovules are produced in different flowers. The column
of the staminate flower is furnished with a pair of slender
horns, one or both of which are sensitive. The pollen-
masses are curved and in a state of tension, like a curved
whalebone spring. Now, when an insect alights on the lip
of the flower and comes in contact with one of the sensitive
horns, the pollen-mass is instantly set free with a jerk suf-
ficient to throw it nearly a metre, and in such a direction
as to strike and adhere to the head of the insect. When
the insect visits a pistillate flower, the pollen-mass is in the
proper position to be brought in contact with the stigma,
thus effecting pollination.
523.	Much might be written about these truly wonderful
plants, but what has been said must suffice to call the at-
tention of the student to them. Our native species will
well repay a careful examination, while the exotic ones, of
which hundreds are now grown in conservatories, show a
greater variety in form and color of flower than can bePHANEROGAMIA.
249
found in any other order of plants. The student may
profitably read in this connection Mr. Darwin’s work, “ The
Various Contrivances by which Orchids are Fertilized by
Insects.”
524.	The Monocotyledons include many of our finest
ornamental plants. Thus some of the grasses and sedges
are grown for the beauty of their foliage and flower-clus-
ters, and many aroids find places in greenhouses, one of the
most common being the so-called Calla-lily from South
Africa. In the Lilies, however, we find the greatest num-
ber of plants grown for the beauty and attractiveness of
their flowers, possibly excepting the Orchids. Of the
Lilies proper there are many species from America, Europe,
Asia Minor, China, and Japan which have long been in
cultivation in gardens. Closely allied to these are the Day-
lilies and the stately Crown-imperial, the Hyacinth, now
of many forms and colors, and the Tulips, which under
cultivation have been made to vary still more. The Ama-
ryllids have given us the Snowdrop and Snowflake, the
Daffodils, Jonquils, and the delightfully sweet-scented
Tuberose. From the Irids we have many species of Iris
and Crocus and Gladiolus, the last from South Africa.
The use of the Orchids as ornamental plants has already
been referred to; but while, doubtless, more species of
them are grown, they are for the most part confined to
special greenhouses and conservatories called orchid-houses,
and are not found in common cultivation among the peo-
ple at large.
525.	The rank of the Monocotyledons economically is
high. The seeds of the grasses have a copious starchy en-
dosperm which has for ages been used as food for man and
his domestic animals, Thus wheat, rye, barley, oats, and250
BOTANY.
rice, all natives of the old world, have been in cultivation
from time immemorial. Indian Corn, being a native of
America, has but recently come under general cultivation.
The stems of most grasses are nutritious, and constitute the
greater part of the pasturage and fodder for domestic ani-
mals. In several of the larger species, as the Sugar-canes,
Fio. 139.—Part of a flowering plant of the Banana, showing the unfolding
flower-bud and the young fruits.
this nutritious matter is so abundant as a sweet juice that
they furnish the greater part of the sugar of the world.
526. The Palms, while of little value to the people of
cooler climates, furnish in tropical regions most of the
necessaries of life. In some countries every want of man
is supplied by one or another of the palms. The Cocoa-
nut-palm, now grown in all hot climates, is one of the most
useful of the species, furnishing material for huts, fences,PHANEROGAMIA.
351
baskets, buckets, ropes, mats, cups, food, wine, and many
other purposes. The Date-palm of the Mediterranean
region, the Palmyra Palm of Southern Asia, and the Sago-
palms of Siam and the Indian Archipelago are all food-
producing trees of great importance to the people of these
countries.
527.	The Bananas likewise furnish great quantities of
food to the natives of tropical countries. There are sev-
eral species and many varieties; all are large herbs with a
palm-like aspect, often 3 to 5 metres (10-15 feet) high.
Their fruits are borne at the summit of the stem, a large
flowering bud gradually unfolding and exposing clusters
of small flowers which produce the well-known fruits
(Fig. 139)
Sub-Class II. The Dicotyledons (Dicotyledones).
528.	The first leaves of the embryo are two and oppo-
site; hence they are said to have two cotyledons. The
venation of the leaves is for the most part such that the
veins are rarely parallel, and in joining one another they
form an irregular network.
529.	The germination of Dicotyledons may be illustrated
by the following examples. In the seed of the Windsor
Bean (Fig. 140) the embryo entirely fills up the seed-
cavity, the endosperm having all been absorbed. The
thick cotyledons lie face to face, and are attached below to
the small stem of the embryo-plant. The stem extends
upward a short distance between the cotyledons, bearing
a few rudimentary leaves and itself ending in a growing
point, the whole constituting the plumule. The downward
prolongation of the stem (commonly but erroneously called262
BOTANT.
the radicle, for it is not a little root) ends in a very short
root which is continuous with the stem.
530. Under the proper conditions of heat and moisture,
the root elongates and pushes out through the pore (micro-
Fig. 140.	Fib. 141.
Fig. 140.—Windsor Bean (Vicia faba). A, seed with one cotyledon removed;
c, cotyledon; kn, plumule; iv, root; s, seed-coat B, germinating seed ; s, seed-
coat, partly torn away at l; st, stalk of one of the cotyledons; k, curved stem
above, and he, short stem below, the cotyledons; h, ws, root.
Fig. 141.—Castor-oil Plant (Ricinus communis). I, longitudinal section of the
ripe seed. II, germinating seed with the cotyledons still inside of the seed-coat
(shown more distinctly in A and B). s, seed-coat; e, endosperm; c, cotyledon;
he, stem; w, root.
pyle) of the seed-coat; at the same time the stalks of the
cotyledons elongate and thus bring the plumule outside of
the seed-coat, the cotyledons alone remaining within. Dur-
ing the first few days of its growth the young plant isPIIANEROGAMIA.
253
nourished by the starch in the cotyledons, which in this
species remain during the whole process of germination
beneath the ground enclosed in the seed-coat. In the com-
mon Field-bean (Phaseolus) the germination is the same
excepting that the stem elongates below the cotyledons
and brings the latter above the ground.
531.	The seed of the Castor-oil Plant contains a large
embryo surrounded by a thin
layer of endosperm (Fig. 141,
I). In its germination the
root and stem below the coty-
ledons elongate, and thus bring
the seed-coat with the con-
tained cotyledons above the
ground (Fig. 141, II). The
cotyledons remain within the
seed-coat until they have ab-
sorbed all of the endosperm;
when this is accomplished the
empty seed-coat falls away, and
the freed cotyledons expand
and assume to some extent the function of ordinary foliage-
leaves.
532.	The venation of the leaves of Dicotyledons is easily
studied by macerating them so as to remove the soft tissue,
leaving only the fibro-vascular bundles. While there is as
a rule a general likeness between them, there is yet an
almost infinite diversity in the details of structure. The
general disposition of the smaller veins is well illustrated
by Fig. 142.
533.	There are now known upwards of 78,000 Dicotyle-
dons, showing every degree of development from minute
Fig. 142—Magnified fragment of
a leaf of a Dicotyledon, showing re-
ticulated venation.254
BOTANY.
herbaceous annuals to large woody perennials. It is a most
difficult matter to arrange so great a number of species
satisfactorily, so as to show their mutual relationship.
They have been grouped into about one hundred and sixty
orders. The orders, again, have been grouped as far as
possible in such a way as to bring together those which
bear the closest resemblance to one another. The disposi-
tion of these groups is as yet partly artificial, in many
cases resulting in the separation of orders which are evi-
dently related.
534. The following synopsis will show the latest arrange-
ment, as generally adopted in'this country. For conven-
ience three artificial groups are made, viz., Apetalae, Gamo-
petalse, and Choripetalse.
I. Apetal-e. Apetalous Dicotyledons.
Plants whose flowers generally have but a single floral envelope
(calyx) this even, in some cases, wanting.
Many of the orders here brought together are related to those to be
noticed further on. Their flowers are in many cases to be regarded
as simplified Choripetalse, or less commonly Gamopetalae. The
grouping given below is almost entirely artificial.
Series I.------. —Flowers mostly unisexual. Perianth none or
small. A group of anomalous orders of doubtful relationship.
Order 1. The Horn worts (Ceratopliyllacese) are a few small aquatics,
widely distributed. The seeds contain a well-developed embryo and
no endosperm.
Order 2. The Crowberries (Empetracese).—These are four small
Heath-like shrubs producing berry-like fruits whose seeds contain a
small embryo in copious albumen.
Order 3 (Lacistemacem), shrubby plants (16 species) of tropical
America, producing dry fruits whose seeds contain a copious endo-
sperm.
Order 4. The Willows (Salicacese) are trees and shrubs common in
the Northern Hemisphere. They include also the Poplars, there being
150 or more species of true willows and 18 poplars now known.
The flowers are unisexual, and the staminate and pistillate forms
always occur on different plants (i.e., they are dioecious); they arePH A NER 00 A MIA.
255
destitute of a perianth and are clustered into weak spikes or catkins.
The seeds contain a well-developed embryo and no endosperm.
Series II. TJnisexuales.—Flowers unisexual. Perianth none or
small. Seeds few or one, with little or no endosperm (excepting in
Orders 12 and 13).
Order 5, the Oaks (Cupuliferse), trees and shrubs mostly of the
Northern Hemisphere, including, in addition to the oaks proper, the
Beeches, Chestnuts, Ironwoods, Hazels, Birches, and Alders. Four
hundred species are known.
Order 6, the Beef woods (Casuarinese), a few leafless trees and shrubs
with green jointed branches having much the aspect of the horsetails
(Equisetum).
Order 7, the Galeworts (Myricacese), a few aromatic shrubs produc-
ing drupe-like fruits.
Order 8, the Walnuts (Juglandaceae), generally large trees bearing
drupe-like fruits enclosing a stony shell. About 30 species are known,
widely distributed throughout the Northern Hemisphere.
Order 9 (Leitneriese), and Order 10, the Plane-trees (Platanacese),
each of a few species.
Order 11, the Nettleworts (Urticacese), a large group of herbs,
shrubs, and trees (1500 species), often separated into several distinct
orders. It includes the Elms, Hackberries, Figs, Mulberries, and in
the tropics many other trees. The hop and hemp and many species
of nettles are common representatives of the herbs of this order.
Order 12 (Balanopseae), a few Australian woody plants.
Order 13. The Spurgeworts (Euphorbiaceae) include 3000 or more
species of herbs, shrubs, and trees, mostly rich in latex (contained in
milk-tissue). The order is mostly tropical, where it abounds in large
trees; but the few species found in colder climates are almost entirely
small and herbaceous.
Series III. Achlamydosporese.—Perianth generally calyx- or corolla-
like. Ovules few. Ovule-body without coals, the seeds therefore
naked. Endosperm mostly present.
Order 14 (Balanophorete), Order 15, the Sandalworts (Santalacese),
and Order 16, the Loranths, or Mistletoe Family (Loranthaceae), are
all more or less parasitic herbs or shrubs.
Series IV. Daphnales.—Perianth generally calyx-like. Ovules few.
Endosperm wanting (with few exceptions). Mostly trees and shrubs
witli perfect flowers (i.e., with both stamens and pistils in the same
flower).
Order 17, the Oleasters (Elseagnacece), a few scurfy-leaved shrubs
and trees, widely distributed.
Order 18 (Penseacese), a few South African evergreen shrubs.256
BOTANY
Order 19. The Daphnads (Thymelaeaceae) include about 360 tough,
barked trees and shrubs (with a few herbs), mostly of the Southern
Hemisphere.
Order 20. The Proteads (Proteace®) are strange-looking evergreen
shrubs and trees (about 950 species), mostly natives of Aostralia and
South Africa.
Order 21. The Laurels (Laurace®) are aromatic trees and shrubs of
tropical and temperate climates. About 900 species are known.
Series V. Micrembryeae.—Perianth mostly wanting. Ovules few.
Emhryo minute, in copious endosperm.
Order 22 (Monimiace®), Order 23, the Nutmegs (Myristicacese), and
Order 24 (Cbloranthacese) are aromatic trees and shrubs of hot
climates, about 250 species in all.
Order 24a. The Peppers (Piperace®) are herbs, shrubs, or small
trees, almost confined to the tropics; generally with a pungent and
aromatic principle. About 1000 species are known.
Series VI. Multiovulatse terrestres.—Perianth calyx-like. Ovary
mostly inferior. Ovules numerous. Endosperm present. Terres-
trial or parasitic plants.
Order 25, the Birthworts (Aristolochiacese), Order 26, the Vine-
rapes (Cytinace®), curious parasites, and Order 27, the Pitcher,
leaves (Nepenthace®). with curiously formed pitcher-shaped leaves.
Series VII. Multiovulatse aquatic®.—Perianth small or none.
Ovary superior (i.e., not united with the perianth). Ovules numerous.
Endosperm wanting. Aquatic herbs.
Order 28, the Podostemads (Podostemace®), a small order, mostly
tropical.
Series VIII. Curvembrye®.—Perianth green or colored. Ovary
superior. Ovules few. Seeds with endosperm, containing a curved
embryo.
Order 29, the Buckwheats (Polvgonacese), including 600 species,
Order 30 (Batidea;), and Order 30a (Phytolaccace®) are mostly herba-
ceous, and mainly tropical.
Order 31, the Clienopods (Cheuopodiacete), 520 species of all
climates; Order 32, the Amaranths (Amarautace®'), nearly 500species
of wide distribution; Order 33 (Illecebrace®) and Order 34 (Nyctagi-
nace®), 200 or more species, mostly tropical. All the orders of this
series (excepting No. 80) contain many weedy plants,
II. Gamopetalae. Gamopetai.otis Dicotyledons.
Plants whose flowers generally have both sepals and petals, the
latter more or less united.
Here are grouped the orders containing plants showing the highestPHANEROOAMIA.
257
development in the vegetable kingdom. They are naturally ar-
ranged under ten cohorts, and these fall into three series.
Series IX. Bioarpellatse,—Ovary mostly superior. Pistil generally
composed of two carpophylls (leaves).
Lamiale Cohort (with irregular flowers).
Order 35, the Mints (Labiatae); 2500, herbs or shrubs; temperate and
warm climates.
Order 36, the Vervains (Verbenacese); 700, herbs, shrubs, or trees,
mostly tropical.
Order 37 (Selaginese); 140, shrubs or herbs, mostly South African.
Order 38 (Myoporinese); 80, shrubs or small trees, mostly Austra-
lian.
Personate Cohort (with irregular flowers).
Order 39, the Acantbs (Acanthaceee); 1500, herbs, mostly tropical.
Order 40 (Pedaliacese); 40, herbs, mostly tropical.
Order 41, the Bignoniads (Bignoniace®); 500, mostly woody, and
generally tropical.
Order 42 (Gesneracese); 700, herbs, shrubs, and rarely trees, of the
tropics.
Order 43 (Columelliace®); 2, small evergreen trees, of tropical
America.
Order 44, the Biadderworts <Lentibulariacese); 180, mostly marsh
herbs of temperate and tropical climates.
Order 45, the Broom-rapes (Orobanchacea); 150, parasitic herbs,
widely distributed.
Order 46, the Figworts (Scrophulariacese); 2000, herbs, shrubs,
rarely trees, of all parts of the world.
Polemoniale Cohort.
Order 47, the Nightshades (Solanacea); 1250, herbs or woody plants,
chiefly tropical.
Order 48, the Bindweeds (Convolvulacese); 800, mostly herbaceous
climbers, chiefly tropical.
Order 49, the Borageworts (Boraginacese); 1200, herbs, shrubs, and
trees, widely distributed.
Order 50, the Hydrophylls (Hydrophyllacese); 150, mostly Ameri-
can herbs.
Order 51, the Phloxes (Polemoniacese); 150, mostly American herbs.
Oentianale Cohort.
Order 52, the Gentians (Gentianacea); 520, herbs, common in
mountain regions.258
BOTANY.
Order 53 (Loganiacese); 350, mostly shrubs and trees of the tropics.
Order 54, the Milkweeds (Asclepiadaceae); 1300, mostly herbaceous,
chiefly tropical.
Order 55, the Dogbanes (Apocynacese); 900, mostly trees and
shrubs, rarely herbaceous, chiefly tropical.
Order 56 (Sal vadoracese); 8, woody plants of hot climates.
Order 57, the Olives (Oleaceae); 280, shrubs and trees, rarely herbs,
of temperate and tropical climates.
Series X. Heteromerae.—Ovary mostly superior. Pistil composed
of more than two carpopliylls (leaves).
Ebenale Cohort.
Order 58, the Storaxworts (Styracacete); 220, shrubs and trees of
hot climates.
Order 59, the Ebonyworts (Ebenacese); 250, shrubs and trees of
hot climates.
Order 60, the Star-apples (Sapotaceae); 300, shrubs and trees of hot
climates.
Primulale Cohort.
Order 61 (Myrsinaceae); 500, shrubs and trees of hot climates.
Order 62, the Primroses (Primulaceae); 250, herbs, mostly of the
north temperate zone.
Order 63, the Plantains (Plantaginace®); 200, herbs, widely dis-
tributed. An anomalous order, probably to be placed here.
Order 64, the Lead worts (Plumbaginacese); 200, mostly herbs of
temperate climates.
Ericale Cohort.
Order 65 (Lennoacese); 4 or 5, herbaceous root-parasites of Califor-
nia and Mexico.
Order 66 (Diapensiacese); 6 to 8, low plants, of cold regions.
Order 67, the Heaths (Ericacete); 1700, mostly shrubs and small
trees, a few herbs, of wide distribution.
Series XI, Inferae.—Ovary inferior.
Campanale Cohort.
Order 68, the Bell worts (Campanulacese); 1000, herbs, rarely shrubs,
widely distributed.
Order 69 (Goodeniacese); 200, mostly herbaceous plants of the
Southern Hemisphere.
Order 70 (Stylidiacece); 100, mostly herbaceous plants of the South-
ern Hemisphere.PIIANEROGA MIA.
259
Asterale Cohort.
Order 71, the Composites (Composite); 10,000 or more, mostly
herbs, some shrubs, a few trees, of all parts of the world.
Order 72 (Calycerace®); 20, herbs of South America.
Order 73, the Teaselworts (Dipsacese); 120, mostly herbs, chiefly of
the north temperate zone.
Order 74 (Yalerianacese); 300, mostly herbs, chiefly of the north
temperate zone.
Rubiale Cohort.
Order 75, the Madderworts (Rubiacese); 4100, trees, shrubs, and
herbs, mostly tropical.
Order 76, the Honeysuckles (Caprifoliacese); 200, mostly woody
plants of the Northern Hemisphere.
HI. CHORIPETALzE (Polypetal,e). Choripetalotjs
Dicotyledons.
Plants whose flowers generally have both calyx and corolla, the
latter of separate petals.
Although this group is here placed last, it is composed of plants
which must rank as structurally lower than those of the Gamopetal®.
Series XII. Calyciflorse.—Calyx generally of united sepals. Sta-
mens on the calyx-cup. Ovary frequently inferior.
Umbellate Cohort.
Order 77, the Cornels (Cornaceee); 75, shrubs and trees, rarely herbs,
mostly of the north temperate zone.
Order 78, the Ivy worts (Araliacese); 340, trees and shrubs, rarely
herbs, mostly tropical.
Order 79, the ITmbellifers (Umbelliferae); 1300, herbs, rarely shrubs
or trees, mostly of the north temperate zone.
Ficoidale Cohort.
Order 80, the Ficoids (Ficoide®); 450, mostly fleshy herbs, chiefly
of the tropics.
Order 81, the Cactuses (Cactacese); 1000, succulent herb9, shrubs,
and trees, generally leafless, all American.
Pamjlorale Cohort.
Order 82 (Datiscace®); 4, herbs and trees, of the Northern Hemi-
sphere.
Order 83, the Begonias (Begoniace®); 350, herbs, mostly of tropi-
cal America.260
BOTANT.
Order 84, the Cucurbits (Cucurbitacese); 470, herbs or undershrubs,
mostly tropical.
Order 85, the Passion-flowers (Passifloracese); 250, trees, shrubs,
and herbs, mostly of the tropics.
Order 86 (Turueracese); 76, herbs and shrubs, mostly tropical.
Order 87 (Loasacese); 100, mostly herbaceous tropical plants.
Order 88 (Sarny daceae); 150, trees and shrubs of the tropics.
Myrtale Cohort.
Order 89, the Onagrads (Onagracese); 300, herbs, shrubs, and trees
of temperate climates.
Order 90, the Lythrads (Lythracese); 250, herbs, shrubs, and trees,
mostly tropical.
Order 91, the Melastomads(Melastomaceae); 1800, trees, shrubs, and
a few herbs, almost entirely tropical.
Order 92, the Myrtles (Myrtacese); 1800, trees, shrubs, and a few
herbs, mostly tropical.
Order 93 (Combretacese); 240, trees and shrubs, mostly tropical.
Order 94, the Mangroves (Rhizophoraceae); 50, trees and shrubs,
mostly tropical.
Bosale Cohort.
Order 95, the Hippurids (Haloragese); 80, mostly aquatic herbs of
wide distribution.
Order 96 (Bruniacete); 40, Heath-like plants of South Africa.
Order 97, the Witch-hazels (Hamamelacese); 30, shrubs and trees,
mostly of warm climates.
Order 98, the Sundews (Droseraceae); 110, mostly bog-herbs, widely
distributed.
Order 99, the Crassulas (Crassulacese); 400, usually succulent herbs
or shrubs, of temperate and warm climates.
Order 100, the Saxifrages (Saxifragaceae); 450, trees, shrubs, and
herbs, of temperate and cool climates.
Order 101, the Roseworts (Rosaceae); 1000, herbs, shrubs, and trees,
distributed throughout the world.
Order 102, the Leguminous Plants (Leguminosae); 6500, herbs,
shrubs, and trees, distributed throughout the world.
Order 103 (Connaracese); 140, trees and shrubs of the tropics.
Series XIII. Disciflorse.—Calyx of distinct or united sepals. Flow-
ers usually with a conspicuous disc (i.e., broadened and thickened
receptacle). Stamens on or at the base of the disc. Ovary supe.
rior.PHANEROGAMIA.
261
Sapindale Cohort.
Order 104 (Moringese), and Order 105 (Coriariese); each with 3-4
species of woody plants, mostly of the old world.
Order 105, the Anacards (Anacardiacete); 450, trees and shrubs, -
mostly tropical.
Order 106 (Sabiaceae); 32, trees and shrubs, mostly tropical.
Order 107, the Soapworts (Sapindacese); 600 to 700, trees and
shrubs, rarely herbs, widely distributed.
Celastrale Cohort.
Order 108, the Vines (Ampelidece); 250, mostly climbing shrubs of
temperate and hot climates.
Order 109, the Rhamnads (Rhamnacete); 430, trees, shrubs, rarely
herbs, of temperate and hot climates.
Order 110 (Stackhousieaj); 20, small herbs, mostly Australian.
Order 111, the Spindle-trees (Celastrace®); 400, small trees and
shrubs of temperate and hot climates.
Olacale Cohort.
Order 112 (Cyrillace*); 8, trees and shrubs of the hotter parts of
America.
Order 113, the Hollies (Ilicine*); 150, trees and shrubs of temper-
ate and hot climates.
Order 114, the Olacads (Olacine*); 170, trees and shrubs, mostly
of the tropics.
Oeraniale Cohort.
Order 115 (Chailletiaceae); 38, trees and shrubs of the tropics.
Order 116, the Mcliads (Meliace®); 270, trees and shrubs of the
tropics.
Order 117 (Burseracete); 145, trees and shrubs of the tropics.
Order 118 (Oclinacese); 140, trees and shrubs, mostly of the tropics.
Order 119, the Quassiads (Simarubacese); 112, trees and shrubs of
the tropics.
Order 120, the Rueworts (Rutace*); 650, trees, shrubs, rarely herbs,
of tropical and temperate climates.
Order 121, the Cranesbills (Geraniacese); 750, mostly herbaceous
plants of temperate and warm climates.
Order 122 (Zygophyllacese); 100, shrubs and herbs, rarely trees, of
the tropics.
Order 123 (Malpighiace*); 580, trees and shrubs, mostly of the
tropics.
Order 124 (Humiriace®); 20, balsamic trees and shrubs of the
tropics.262
BOTANY.
Order 125, the FI ax worts (Linaceae); 135, herbs, shrubs, and a few
trees, in temperate and tropical climates.
Series XIV, Thalamiflorae,—Calyx usually of distinct sepals. Pet-
als and stamens usually growing on the.flower-receptacle. Ovary
superior.
Malvale Cohort.
Order 126, the Lindens (Tiliace®); 330, trees, shrubs, rarely herbs,
mostly tropical.
Order 127, the Stercuiiads (Sterculiace®); 520, herbs, shrubs, and
trees, almost entirely tropical.
Order 128, the Mallow-worts (Mai vacete); 700, herbs, shrubs, and
trees, widely distributed.
Outtiferale Cohort.
Order 129 (Chlsenacete); 8, shrubs and trees of Madagascar.
Order 130 (Dipterocarpe®); 112, resinous trees, rarely shrubs, of
the tropics.
Order 131, the Theads (Ternstrcemiace®); 260, trees and shrubs,
mostly tropical.
Order 132, the Guttifers (Guttifer®); 230, resinous trees and shrubs
of the tropics.
Order 133, the St.-John’sworts (Hypericacese); 210, herbs, shrubs,
rarely trees, of warm temperate climates.
Order 134 (Elatinacese); 20, marsh-herbs, widely distributed.
Caryophyllale Cohort.
Order 135, the Tamarisks (Tamariscineae); 40, mostly shrubs of the
warm temperate zone.
Order 136, the Purslanes (Portulacaceae); 125, herbs and a few
small shrubs, widely distributed.
Order 137, the Pinkworts (Caryophyllacese); 800, herbs, widely
distributed.
Order 138 (Frankeniacese); 12, maritime herbs and shrubs of warm
temperate climates.
Polygalale Cohort.
Order 139 (Yocbysiacese); 100, resinous trees and shrubs of tropi-
cal America.
Order 140, the Milkworts (Polygalace®); 400, mostly herbs of warm
temperate climates.
Order 141 (Tremandrese); 24, Australian shrublets.
Order 142 (Pittosporacese); 90, shrubs of hot climates.PHANEROGAMIA.
263
Parielale Cohort.
Order 143 (Bixinefe); 160, trees and shrubs of the tropics.
Order 144 (Canellacese); 4, trees of tropical America.
Order 145, the Violets (Violacete), 240, herbs, shrubs, and a few
trees of temperate and tropical climates.
Order 146, the Rock-roses (Cistacese); 60, herbs and shrubs of tem-
perate climates.
Order 147, the Resedads (Resedacete); 30 to 40, herbs aDd a few
shrubs, mostly of the Mediterranean region.
Order 148, the Capparids (Capparidacese); 300, herbs, shrubs, rarely
trees, of tropical or subtropical regions.
Order 149, the Crucifers (Cruciferae); 1200, herbs and a few low
shrubs, widely distributed.
Order 150, the Fumeworts (Fumariacete); 100, herbs of warm tem-
perate regions.
Order 151, the Poppyworts (Papaveracese); 60, herbs and a few low
shrubs, mostly of the north temperate zone.
Order 152, the Pitcher-plants (Sarraceniacese); 8, American herbs.
Ranale Cohoi't.
Order 153, the Water-lilies (Nymphseaceae); 35, aquatic herbs,
widely distributed.
Order 154, the Berberids (Berberidaceae); 100, herbs and shrubs of
temperate climates.
Order 155, the Moonseeds (Menispermacese); 80, woody twining
plants, mostly tropical.
Order 156, the Anonads (Anonacese); 400, trees and shrubs, mostly
tropical.
Order 157, the Magnoliads (Magnoliacete); 70, trees and shrubs,
mostly of warm climates.
Order 158 (Calycanthaceas); 3, shrubs of North America and Japan.
Order 159 (Dilleniacese); 180, mostly shrubs, which are chiefly
tropical.
Order 160, the Crowfoots (Ranunculacete); 540, herbs and a few
shrubs of temperate and cool climates.
535. If we glance over the foregoing assemblage of
plants, we are at once struck with their great diversity of
structure, both as regards the flowers and the general plant-
body. The extreme of simplicity is reached, perhaps, in
the Podostemads; and these small aquatics, almost desti-264
BOTANY.
tute of fibro-vascular bundles and with minute flowers of
simple structure, may be contrasted with the Heaths, Com-
posites, and Madderworts. The highest development, all
things considered, is undoubtedly reached in the Compos-
ites: this is indicated by the number and variety of their
tissues, the high differentiation of the epidermal structures,
the aggregation of their flowers into heads, and these
Fig. 143.—Marsh-marigold (Caltha palustris), with showy yellow perianth.
often into secondary clusters; by the union of the parts
of the flower; by its inferior ovary with its single ovule;
its well-developed embryo; as well as by many other
things which we have not space to explain here.
536. As to the arrangement of the Dicotyledons, it is
probable that a natural disposition of the orders would
place the Choripetalse below the Gamopetalse, the latter ex-PHANEROGAMTA.
265
hibiting several divergent groups, the one containing the
Asterale Cohort rising highest. In such an arrangement
the orders of the Apetalae would be placed as degraded or
simplified offshoots mainly from the Choripetalae, while a
few would doubtless be regarded as directly lower than
and preceding the latter group.
537.	A great many Dicotyledons show adaptations for
pollination by insect
agency, and it is safe to
say that more than half
the species are more or
less dependent upon the
visits of insects in order
that their ovules may be
fertilized. In a general
way it may be said that
the showy flowers with
a bright calyx or corol- Fig. 144.—1The Cherry (Primus cerasus), with
1 i	1V ,	1 clustered flowers.
la, or both, are pollinated
by insects, while those without showiness are wind-polli-
nated, or close-fertilized. The plants of the Apetalous
orders are for the most part not visited by insects; few of
them have bright colors, and few produce nectar.
538.	The simpler Choripetalse, as the Crowfoots (Fig.
143) and their near allies, attract insects by their showy
perianth, and the nectar they secrete. Cross-fertilization
is generally secured by a difference in the time of maturity
of stamens and pistils (i.e., by dichogamy), apparently,
however, often permitting close fertilization. The same
is true in general of most of the regular flowered Chori-
petalae. Thus in the Roseworts (Fig. 144), while nectar is
usually abundant and the flowers are generally sweet-266
BOTANY.
scented as well as showy, their regularity of form prevents
perfect cross-pollination. H'owever, as the flowers are
generally in clusters, it usually happens that the pollen
from one flower is carried to the stigmas of another. The
attractiveness of the flowers is such that through the visits
of great numbers of insects the large amount of pollen is
pretty well distributed upon other stigmas.
539. In the nearly related Leguminous Plants, as beans,
peas, clover, lupines, etc., the perianth is not regular.
There are three forms of petals in each flower, viz., one
Fig. 145.—Flower of Dead-nettle, side view and vertical section. Magnified.
large broad one, the “banner,” two lateral ones, the
“wings,” and two anterior ones which together form the
“keel.” These all together form a structure enclosing the
stamens and pistil in such a way that an insect cannot get
any of the nectar at the base of the corolla without setting
free some of the pollen, which adheres to the hairs of its
body and is thus carried to the stigma of some other flower.
540. In the Gamopetalae the union of petals into a tube
serves to compel insects to visit the flower in one way only.
In the Mints (Fig. 145) the flower is two-lipped? the broaderPHANEROGAM!A.
267
lip usually serving as a resting-place for the insect while it
thrusts its head or tongue into the corolla. The upper lip
is frequently arched so as to contain the stamens and style.
In the Dead-nettle the stigma projects beyond the stamens
(Fig. 145), so that upon visiting successive flowers the in-
insect always first pollinates the stigma with pollen from
Fig. 146—Flowers of Composites. A, of Dandelion, showing style protruding
through ring of anthers; B, of Thoroughwort; C, ditto, vertical section showing
style surrounded by anthers; D, style showing two stigmas. All magnified.
preceding flowers, and then coming in contact with the
stamens secures more pollen. In many plants with a sim-
ilar structure the stamens mature before the stigmas are
ready for pollination, so that in these, while the means for
cross-pollination are perfect, self-fertilization is rendered
impossible.268
BOTANY.
541.	In the Composites (Fig. 146) the five anthers are
united into a ring or tube around the style. The pollen
escapes from the inner side of the anthers into the anther-
tube, and at this time the immature style is short. As the
latter grows it pushes up thrpugh the anther-ring, carrying
the mass of pollen with it. Insects visiting the flowers for
nectar at this stage rub off the little piles of pollen from
the top of the stamen-tubes, and coming in contact after-
wards with the expanded stigmas of other flowers, some of
the pollen is left upon them.
542.	After the pollen is set free the style elongates still
more, and finally the two lobes of the stigma open out and
are ready for pollination. This development takes place
beginning at the outer rows of flowers in each flower-head
and proceeds towards the centre. Thus at any time in
any blooming flower-head, as of the Sunflower, there may
be seen a ring of pollen-bearing flowers and outside of it
a ring of flowers with expanded stigmas. In some Com-
posites, in addition to these structural peculiarities, the
stamens are sensitive, and when touched will suddenly
contract, drawing the anther-tube down and ejecting pol-
len. This may easily be seen by passing the finger quickly
across the top of a thistle-head when in full bloom.
543.	The foregoing must serve to direct the student to
the careful observation of the flowers of Dicotyledons.
He should remember Lubbock’s remark that “ it is probable
that all flowers which have an irregular corolla are polli-
nated by insects,” and to this he may well add that it is
equally probable that all tubular flowers are likewise polli-
nated by insects.
544.	Among the interesting things to which attention
has been directed during the past few years is that of thePPLANER 00 AMI A.
269
Insectivorous habits of certain plants. Here again no more
than a fragment can be given, barely enough to introduce
the student to the subject.
545. Many plants catch insects by means of their sticky
Fig. 147.—A Sundew plant. Natural size.
glandular hairs, or glandular surfaces upon their stems or
leaves. This may he readily seen by examining a petunia
or tomato stem, or the sticky belts on the stems of various
species of Catchfly, or the sticky spots on the bracts sur-270
BOTANY.
rounding the flower-heads of some thistles. Whether the
small insects thus caught are made use of by the plants in
any way is as yet uncertain.
Fig. 148.—The Carolina Fly-trap (Dionsea muscipula). About natural size.PBANEROOAMIA.
271
546.	In the Sundews (Fig. 147), which are common little
hog-plants, the leaves have many stalked glands which
secrete a sticky substance. These glands are sensitive, and
when an insect comes in contact with one or more of them
and is held fast, the others slowly bend towards the insect,
and the leaf itself rolls up, completely surrounding the un-
fortunate victim. An acid fluid is produced by the glands,
and by this the insect is dissolved and afterwards absorbed
by the leaf-tissues. In midsummer it is no uncommon
thing to find several of these leaves with insects upon
them.
547.	The Carolina Fly-trap (Fig. 148), or Venus’s Fly-
trap as it is frequently called, is one of the most remarka-
ble plants known. It is a native of a small district near
Wilmington, North Carolina, hut is now grown considera-
bly as a curiosity in conservatories. Each leaf has a
rounded blade fringed on the sides with a row of stiff
points or spikes. Upon each half of the leaf there are
generally three sensitive hairs, and when these are touched
the sides quickly close together, and the stiff marginal
spikes interlock like the teeth of a rat-trap. “ The upper
surface of the leaf is thickly studded with minute glands
of a reddish or purplish color” (Darwin). These secrete
an acid fluid which has the power of digesting insects and
other nitrogenous matters. When an insect happens to
alight upon a leaf and touches one of the sensitive hairs
the trap closes so quickly upon it that it is almost invaria-
bly caught and securely held, its struggles only serving to
increase the vigor of the grasp in which it is held. After
a while the digestive fluid is poured out by the glands, and
in this the insect is gradually dissolved. In this way the
leaf-tissues absorb the insect, and are doubtless nourished272
BOTANY.
by it. After a time a leaf which has caught and digested
an insect opens again and is ready for another. In this
connection the student may profitably read Mr. Darwin’s
interesting hook, “ Insectivorous Plants,” published in 1875.
548. A quite different class of insect-catching plants is
Fig. 149.—Common Pitcher-plant (Sarracenia purpurea), showing leaves and
flower; one leaf cut across so as to show the cavity. Half natural size.
represented by the Pitcher-plants of various kinds. In the
Common Pitcher-plant, which grows in marshes in the
Northern and Eastern United States, the leaves are dilated
into tubular or pitcher-shaped cavities (Fig. 149), contain-
ing a watery fluid. The upper part of the leaf is reddishphaneiiogamia.
273
in color, and doubtless this attracts insects. Moreover this
upper part is covered with minute stiff hairs, which point
downward; they also cover the upper part of the inner
surface of the cavity, and probably have not a little to do
with the entrance of insects into the fatal pitcher. How-
ever this may be, many insects are found drowned, and in
all stages of decomposition, in the
fluid in the pitchers. Other spe-
cies in the Southern States have
a lid-like cover which prevents
the entrance of rain, and in some
species drops of nectar have been
found upon the outside of the
pitcher, forming a trail to lure
insects to its edge.
549.	The California Pitcher-
plant (Fig. 150) resembles the
foregoing, but its arched leaves
have a curious forked appendage
hanging down from the edge of
the orifice, which is here on the
under side of the arch. This ap-
pendage is more or less covered
with a sweet secretion which lures
insects. Probably this is made more effective by the red-
dish or purplish color of the appendage, giving it at a dis-
tance no little resemblance to a flower. The watery fluid
inside of the leaf always contains the remains of many
insects.
550.	Various species of Nepenthes (Fig. 151) occur in
the East Indies. The leaves are prolonged into a slender
tendril-like organ, upon whose extremity there develops a
Fig. 150.—The California Pitch-
er-plant (Darlingtonia calif orni-
ca), showing leaves and a flower.
About one seventh natural size.274
BOTANY.
hollow closed body, which finally becomes open by the
separation of a hinged lid (Fig. 151, d, e,f). In the cavi-
ties of these pitchers a watery, slightly acid fluid is secreted;
Fig. 151.—Two leaves of Nepenthes, the Indian Pitcher-leaf. /,.the lid, which
is still closed in the younger leaf. Reduced.
upon their borders are secreted honey or nectar drops,
which attract insects, and these falling into the fluid, withinP1IANEROOAMIA.
275
are soon dissolved by it, and then absorbed by the plant
for its nourishment.
551.	An Australian plant related to the Saxifrages pro-
duces remarkable pitchers. It is a low plant with a rosette
of leaves upon the ground; some of these resemble the
covered pipes used by many Frenchmen (Fig. 152). The
border of the pitcher is incurved and presents an obstacle
to the egress of insects, which are no doubt thus captured.
Fig. 152.—Leaves of Australian Pitcher-plant (Cephalotus). Natural size.
552.	There is a close connection between the ornamental
value of a plant and the perfection of its flower as a mech-
anism to secure pollination by means of insects. In other
words, those things in a flower which are attractive to in-
sects are, as a rule, attractive to us also. Thus the large,
brightly-colored perianth and the sweet scent of the wild
rose, which serve to secure the visits of insects, are like-
wise attractive to us.
553.	The Apetalse are thus of low ornamental value in
go far as their flowers are concerned. The Ghmopetalae276
BOTANY.
and Choripetal®, however, furnish many fine flowers which
have long been favorite ornaments in gardens and con-
servatories. Thus the Verbenas, Phloxes, Heliotropes,
Primroses, Azaleas, Rhododendrons, Heaths, Bellflowers,
Honeysuckles, and great numbers of Composites may be
taken to represent the ornamental members of the Gamo-
petalse. And so the Passion-flowers, Roses, Lupines, Wis-
tarias, Mallows, Camellias, Pinks, Violets, Mignonettes,
Poppies, Water-lilies Buttercups, and Columbines may be
taken as representatives of the ornamental Choripetalse.
Fig. 153.—A Water-lily (Nelumbium luteum). One third natural size.
554. Economically the Apetalas, Gamopetalse, and the
Choripetalse are of very different rank. Thus while the
first supplies us with very little food aside from the floury
seeds of Buckwheat and the oily nuts of the Hickories,
Walnuts, Hazels, Chestnuts, and a few others, it furnishes
us the great bulk of our hard-wood timber in the wood of
the Elms, Hackberries, Walnuts, Hickories, Oaks, Beeches,
Chestnuts, Birches, Willows, Poplars, and Plane-frees. ToPI IA NEIi OG A MIA.
277
the Apetalae also the world is indebted for that exceedingly
valuable substance, India-rubber, which is obtained from
Fig. 154.—Potato.
Fig. 155.—Flax.
the milky juice of several tropical trees related to the
Nettles and the Spurges.278
BOTANY.
555.	The Gamopetal* are of higher value as food-fur-
nishers, supplying us with the Potato, Tomato, Sweet-
potato, Artichokes, Olives, Huckleberries, Cranberries,
Coffee. Of timber, the Catalpa, Ebony, and Ash are the
more important of those in common use.
556.	The Choripetalae contain more plants which supply
us with food than either of the preceding. Thus we have
from these Parsnips, Carrots, Cucumbers, Melons, Squashes,
Pumpkins, Apples, Pears, Strawberries, Blackberries,
Fig. 156.—Flower-cluster of the Pear (Pirns communis).
Raspberries, Plums, Peaches, Cherries, Beans, Peas, Grapes,
Cabbage, Turnips, Radishes, and Tea. From this group
we get flax and cotton, two of the most important fibres
in the world. The timber-trees of most importance are
the Maples and the Lindens, the Magnolias and the Tulip-
trees.
557.	The two drugs of greatest value medicinally, viz.,
opium and quinine, are furnished respectively by the
Choripetalae and Gamopetalse.
For the identification of the species of phanerogams of this country
the student may profitably use Asa Gray’s “Manual of the Botany
of the Northern United States” or A. W. Chapman’s “Flora of the
Southern States,”INDEX.
Acaothace^:, 257
Acauths, 257
Achlamydosporete, 255
Acids, 83
Acids in Cell-sap, 14
Acorus, bundle, 44 (fig.)
Adder-longues, 203
Adiantum, 203
Adiantum, 202 (fig.)
ALcidios pores, 172
iEcidium, 172
Agaricus, 179
Agnlliis, 225
Ailanthus, tissue, 53 (fig.)
Aiders, 255
Aleurone, 11
Alismace®, 243
Alkaloids, 83
Alternation of Generations, 194
Amadou, 179
Amarantace®, 256
Amaranths, 256
Amaryllidaceae, 244
Amaryllids, 244
Ampelideae, 261
Anacardiace®, 261
Anacards, 261
Andr®ace®, 192
Anemophilous Flowers, 234
Angiosperm®, 225
Angiosperms, 225
Anonace®, 263
Anonads, 263
Antherid, 130
Antheridium, 130
Antherozoids, 130
Anthers, 214
Anthoceros, 187 (fig.)
Anthocerote®, 187
Apetalae (orders of), 254
Apetalous Dicotyledons, 254
Apical Cell, 30
Apocarpe®, 243
Apocynace®, 258
Apothecia, 167
Appendages, 158
Apple-blight, 160
Apples, 278
Araliace®, 259
Araucaria, 225
Archegone, 186
Archegonium, 186
Aristolochiacese, 256
Aristolocliia, vessels, 24 (fig.)
Aroideae, 243
Aroids, 243
Arrangement of Dicotyledons,
264
Artichokes, 278
Asci, 155
Asclepiadacese, 258
Ascomycetes, 155
Ascophyllum, 147
Ascospores, 155
Ash, 278
Aspidium, 203
Aspidium, 202 (fig.)
Asplenium, 203
Asplenium, 202 (fig.)
Assimilation, 79
Assimilation and Metastasis, re.
suits of, 84
Asterale Cohort, 259
Austrian Pine, 223, 224
Autogamous Flowers, 234, 235
Autogamy, 236
Azaleas, 276
Azolla, 205	-280
INDEX.
Bacillus, 110
Bacillus, 109 (fig.)
Bacteria, 6, 108
Bacteria of diseases, 110
Bacterium, 110
Bacterium, 109 (fig.)
Balanophores, 255
Balanopsese, 255
Balsam, tissues, 4, 23 (figs.)
Bauanas, 244, 251
Bark, 240
Barley, 249
Basidia, 175
Basidiomycetes, 175
Basidiospores, 177
Bast, 18
Batidese, 256
Beans, 278
Bean, field, 253
Bean, Windsor, 251
Beeches, 255, 276
Beefwoods, 255
Beet-crystals. 12 (fig.)
Begoniaceae, 259
Begonia, tissue, 16 (fig.)
Begonias, 259
Bellflowers, 276
Bellworts, 258
Berberidaceae. 263
Berberids, 263
Bicarpellatae, 257
Bignouiacese, 257
Biguoniads, 257
Big-tree, 224
Big-tree of California, sieve-tube,
22 (fig.)
Bindweeds, 257
Birches, 255, 276
Birch, lenlicel, 54 (fig.)
Birds’-nest Fungus, 177
Birthworts, 256
Bittersweet, embryo, 231 (fig.)
Bixineae, 263
Blackberries, 278
Black Blast, 175
Black Fungi, 163
Black Knot, 163
Black Moulds, 124
Black Rust, 172
Bladder-fern, 203
Bladderworts, 257
Blights, 155
Bloodworts, 244
Bloom, 35
Blue Moulds, 160
Bog-mosses, 193
Borageworts, 257
Boraginacese, 257
Botrychium, 205
Botrychium, 204 (fig.
Bracts, 62
Brake, 203
Brake-fern, bundle, 47
Brake, tissue, 17, 24, 48 (figs.)
Branches of the Vegetable King-
dom, 98, 99
Branching, modes of, 65
Breathing-pores, 37
Bristles, 63
Bromeliacete, 244
Broom rapes, 257
Bruuiace*. 260
Bryacete, 192
Bryophyta, 183
Bryophytes, 183
Bryum, 192
Buckwheat, 276
Buckwheats, 256
Bud-cups, 184
Buds, 184
Bulb axes, 62
Bundle-sheath, 45
Bunt, 175
Burmanniaceae, 245
Burseracese, 261
Buttercup, study of, 236
Buttercups, 276
Cabbage, 278
Cactacese, 259
Cactuses, 259
Caffeine, 83
Calamariete, 199
Calamites, 199
California Pitcher-plant, 273
Calla-lily, 249
Caltha, flower, 264 (fig.)
Calycanthacete, 263
Calyceracete, 259
Calyciflonju, 259
Calycinse, 244
Calyptra, 191INDEX.
281
Calyx, 2S6
Cambium, 44, 49
Campanale Cohort, 258
Campanulace®, 258
Camptosorus, 203
Canellace®, 263
Cane-sugar, 13, 81
Capparidacese, 263
Capparids, 263
Capri foliace®. 259
Capsella, embryos, 230 (flg.)
Capsule, 191
Carolina Fly-trap, 271
Carpels, 62
Carpogone, 149
Carpogonium, 149
Carpophylls, 214
Carpophyta, 148
Carpopbytes, 148
Carrots, 278
Caryopliyllacese, 262
Caryophyllale Cohort, 262
Castor-oil Plant, bundle, 42
Castor-oil Plant, bundle, 42, 43
(figs.)
Castor-oil Plant, 253
Casuarinese, 255
Catalpa, 278
Catchfly, 269
Cat-tail Flag, 243
Cat tails, 243
Caulome, 60, 61
Cedar-apples, 173
Cedars, 224
Celastracese, 261
Celastrale Cohort, 261
Cell-division,- 7
Cell-fission, 7
Cell sap, 13
Cellulose, 4
Cell-union, 7
Cell-wall, 4
Centrolepide®, 243
Cepbalotus, 275
Cephalotus, 275 (fig.)
Ceratophyllacese, 254
Chaetocladium, 129
Chailletiace®, 261
Chara, 182
Chara, 181 (figs.)
Characeae, 180
Chare®, 182
Chart showing distribution of
plants in Geological Time, 103
Chemistry and Physios of Plants,
68
Chenopodiaceae, 256
Chenopods, 256
Cherries, 278
Cherry-blight, 160
Chestnuts, 255, 276
Chlaenacete, 262
Chloranthace®, 256
Chlorophyll, 8
Choripetal®, 259
Choripetalous Dicotyledons, 259
ChroOcoccus, 112
Oinchonin, 83
Circinately, 202
Circulation of Sap, 75
Circumnutation, 91
Cistace®, 263
Citric Acid, 83
Cladophora, 117
Classes of Plants, 98
Classification and Distribution,
97
Claytonia, 237
Cleistogamous Flowers, 236
Clematis, 240
Clematis, bundles, 239 (fig.)
Climacium, 193
Climbing Fern, 203
Closed Bundles, 49
Close Fertilization, prevention of,
235
Closterium, 128
Closterium, 120 (fig.)
Club-fungi, 178
Club-moss, bundle, 46
Club-moss, bundle, 46 (fig.)
Club-mosses, 208
Cluster-cup, 170
Cocoanut-palm, 250
Coffee, 278
Coffee, embryo, 231 (fig.)
Coeloblaste®, 135
Coleocheete, 149
Coleochmte, 150 (fig.)
Coleochsetese, 149
Collateral Bundles, 49
Collema, 168282	INDEX.
Collema, 168 (6g.)
Collenchyma, 16
Columbiues, 276
Colamella, 126
Columelliaceae, 257
Combretaceae, 260
Commelinace®. 244
Common Bundles, 238
Composit®, 259
Composites, 259
Concentric Bundles, 49
Conceptacles, 144
Conidia, 139
Coni ferae, 224
Conifers, 224
Conjugatae, 119
Conuaraceae, 260
Connective, 227
Convolvulaceae, 257
Corallina, 152 (fig.)
Coriarieae, 259
Cork, 53
Cork-cambium, 54
Corms, 62
Cornace®, 259
Cornels, 259
Corolla, 226
Coro narieae, 244
Cosmarium, 120 (fig.)
Cotton, 278
Cotyledons, 210, 219
Cranberries, 278
Cranesbills, 261
Crassulaceae. 260
Crassulas, 260
Crocus, 249
Crowberries, 254
Crowfoots, 263
Crown-imperial, 249
Crown-imperial Cells, 1 (fig.)
Crucibulum, 177
Cruci ferae, 263
Crucifers, 263
Crystals, 12
Crystalworts, 187
Cucumbers, 278
Cucurbitaceae, 260
Cucurbits, 260
Cup-fungi, 161
Cups, 63
Cupulifer®, 255
Curvembryeae, 256
Cuticle, 35
Cyanophyceae, 112
Cyathus, 177
Cyatlius, 177 (fig.)
Cycadace®, 223
Cycads, 223
Cyclanthace®, 244
Cylindrothecium, 193
Cyperace®, 243
Cyrillace®, 261
Cystopteris, 203
Cystopus, 140
Cystoseira, 147
Cytinaceae, 256
Daffodils, 249
Dapbnads, 256
Dapbnales, 255
Darlingtonia, 273 (fig.)
Darwin’s book cited, 249, 272
Darwin quoted, 271
Date-palm, 251
Daliscaceae, 259
Day-lilies, 249
Dead nettle, 267
De Bary’s Classification of Bun-
dles, 49
Desmidiaceae, 119
Desmids, 119
Devil's Apron, 118
Diagram of Classification, 99
Diapensiacetc, 258
Diatomaceae, 121
Diatoms, 121
Dichogamy, 287
Dichotomous Branching, 65, 66
Dichotomy, forms of, 66
Dicotyledones, 251
Dicotyledons, 251
Dicotyledons, number of species,
253
Dicranum, 192
Diffusion of Fond, 79
Digestion and Use of Starch, 81
Dilleniaceae, 263
Dimorphism of Flowers, 237
Dioecious, 191
Dionaea, 270 (fig.)
Dioseoreaceae, 244
Dipsace®, 259INDEX.
283
Dipterocarpeae, 262
Discitlorae, 260
Dispersion of Seeds, 233
Distribution of Plants, 100
Districts of Vegetation, 100
Division of Cells, 7
Dogbanes, 258
Droseracese, 260
Duckweeds, 243
Duration of Plants, 102
Dutchman's Pipe,vessels, 24(fig.)
Dutch Rush, 198
Ear-fungi, 179
Earth-stars, 177
Ebenaceae, 258
Ebenale Cohort, 258
Ebony, 278
Ebonyworts, 258
Economic value of Dicotyledons,
276
Economic value of Monocoty-
ledons, 249
Echinocystis, epidermis, 38 (fig.)
Egg-spore Plants, 130
Elaeagnaceae, 255
Elaters, 187, 197
Elatinaceae, 262
Elms, 255. 276
Embryo, 215
Embryo-sacs, 63, 214
Empetraceae, 254
Endosperm, 215
Entomophilous Flowers, 234
Entomoplithora, 139
Entomophthoreae, 139
Epidermal System of Tissues,
33
Epidermis, 34
Epigynae, 214
Equilibrium of Water, disturb-
ance of, 70
Equilibrium of Water in Plants,
69
Equisetacese, 198
Equisetinae, 195
Equisetum, 198
Equisetum, 196 (fig.)
Ergot, 165
Ericaceae, 258
Ericale Cohort, 258
Eriocaulonaceae, 243
Erysiphe, 160
Erysiphe, 156, 157 (figs.)
Euphorbiaceae, 255
Euphorbia, milk-tubes, 19 (fig.)
Eurotium, 158
Eurotium, 159 (fig.)
Evaporation of Water, 71
FERN-BUNDLE, 47
Ferns, 199
Ferns, True, 201
Fern worts, 194
Fertilization in—
Angiosperms, 229
Bryophytes, 187-191
Carpophytes, 148
Gymnosperms, 219
OOphytes, 130
Phanerogams, 215
Pteridophytes, 198
Fibrous Tissue, 17, 27
Fibro-vascular Bundles, 40
Fibro-vascular System of Tissues,
40
Ficoidnle Cohort, 259
Ficoideae, 259
Ficoids, 259
Field-bean, 253
Figs, 255
Figworts, 257
Filament of Stamen, 227
Filices, 201
Filicinae, 199
Firs, 224
Fissidens, 192
Fission of Cells, 7
Flagellarieae, 244
Flax, 278
Flax, 277 (fig.)
Flaxworts, 262
Flora, 100
Floral Envelopes, 62
Florideae, 151
Flower-axes, 62
Flowering-fern, 203
Flowering Plants, 212
Flower, plan of, 226
Flowers, 214
Flow of Water (Sap), 75
Fly-fungus, 139284	index.
Fly-trap, 271
Fontinalis, 193
Foutinulis, tissue, 30 (fig.)
Food, imbibition of, 2
Forage-grasses, 250
Fossil Plants, 102
Fraukeuiaceae, 262
Free Veins, 200
Freezing of Plants, 88
Frog’s-bits, 245
Frui ting-leaves, 214
Fruits, 233
Fucacese, 143
Fucus, 144, 147
Fuligo, 108
Fuligo, 107 (fig.)
Fumariaceae, 263
Fumeworts, 263
Funaria, 192
Fundamental System of Tissues,
Fungi, 148, 155
Galeworts, 255
Gamopetalae, 256
Gamopetalous Dicotyledons, 256
Gasteromyeetes, 176
Geaster, 177
Gemmae, 184
Generalized Forms, 59
Geutianaceae, 257
Gentianale Cohort, 257
Gentians, 257
Geological Distribution of Plants,
102
Georgia Pine, 224
Geotropism, 93, 94
Geraniaceae, 261
Geraniale Cohort, 261
German Tinder, 179
Germ-cell, 130
Germination of—
Angiosperms, 232
Dicotyledons, 251
Gymnosperms, 219
Indian Corn, 242
Monocotyledons, 242
Gesneraceae, 257
Giant Puff ball, 177
Gladiolus, 249
Glands, 63
Glandular Hairs, 37
Giceocapsa, 112
Glceocapsa, 112 (fig.)
Glucose, 13, 81
Glumaceae, 243
Gnetaceae, 225
Golden Fern, 203
Goodeniaceae, 258
Goosefoot, embryo, 231 (fig.)
Grain-smut, 175
Graminese, 243
Grape blight, 160
Grape-mildew, 143
Grapes, 278
Grape-sugar, 13
Grass-blight, 160
Grasses, 243
Gray Mosses, 166
Green Felt, 135
Green Felt, 136 (fig.)
Green Slime, 6, 113, 169
Green Slimes, 112
Ground-pine, 209
Grouping of Plants, 97
Groups of Tissues, 32
Growing-point, 31
Guard-cells, 37
Gulf-weed, 147
Gum-canals, 58
Guttiferse, 262
Gultiferale Cohort, 262
Guttifers, 262
Gymnogramme, 203
Gymnospermte, 215
Gymnosperms, 215
Gymnosporangium, 172
Hackberries, 255, 276
Haemodoracete, 244
Hair-cap Moss, 192
Hairs, 36, 63
Halidrys, 147
Haloragem, 260
Hamamelaceae, 260
Haustoria, 139
Hazels, 255, 276
Heaths, 258, 276
Hedera, tissue, 57 (fig.)
Heliotropes, 276	,
Heliotropism, 92, 94
Helvellacese, 161INDEX.
285
Hemp, 255
Hepatic®, 183
Herbarium-mould, 158
Heteromer®, 258
Hickories, 276
Hickory-nut, tissue, 17 (fig-)
Himanthalia, 147
Hippurids, 260
Hollies, 261
Honey, 235
Honeysuckles, 259, 276
Hops, 255
Hop-blight, 160
Horned Liverworts, 187
Hornworts, 254
Horsetails, 195
Host, 139
Houstonia, 237
Huckleberries, 278
Humiriace®, 261
Hyacinth, 249
Hydnum, 179
Hydrocbaridea, 245
Hydrodictyon, 117
Hydropliyllace®, 257
Hydrophylls, 257
Hymenium, 155
Hymenomycetes, 177
Hypericace®, 262
Hypli®, 124
Hypnum, 193
Hypoderma, 53
Ilicine.e, 261
Hlecebrace®, 256
Indian Corn, 250
Indian Corn, bundle, 40
Indian Corn, embryo, 241, 242
(figs.)
Indian-corn Smut, 174
Indian-corn, tissues, 3, 41, 56
(figs.)
India-rubber, 277
Indusium. 202
Infer®, 258
Insectivorous Plants, 269
Insect-pollinated Flowers, 234
Intercellular Spaces, 55
Internal Cell formation, 7
Inulin, 13, 81
Iridace®, 244
Irids, 244
Iris, 249
Ironwoods, 255
Isoetace®, 210
IsoStes, 210
Ivy, tissue, 57 (fig.)
Ivyworts, 259
Joint-fibs, 225
Jonquils, 249
Juglandace®, 255
Juncace®, 244
Jungermanniace®, 187
Kauki Pinb, 225
Kelp, 118
Labiat.-e, 257
Laburnum, traclields, 25 (fig.)
Lacistemace®, 254
Lamiale Cohort, 257
Laminaria, 118
Larch, 224
Latex, 18, 27
Laticiferous Tissue, 18
Latticed Cells, 20
Laurace®, 256
Laurels, 256
Lavatera, 227 (fig.)
Leadworts, 258
Leaf, 62
Leguminous Plants, 260
Leguminos®, 260
Leitneries, 255
Lejolisia, 154
Lejolisia, 152, 153 (figs.)
Lemnace®, 243
Lennoace®, 258
Lentibulariace®, 257
Lenticels, 55
Lepidodendrace®, 210
Lepidodendrids, 210
Lettuce mildew, 143
Lichenes, 165
Lichens, 165
Light as affecting plants, 89
Lilac-blight, 159
Liliace®, 244
Lilies, 244, 249
Linace®, 262
I Lindens, 262, 278INDEX.
286
Lithospermum, 237
Little Club-mosses, 209
Liverworts, 183
Liverworts, proper, 187
Loasace®, 260
Loganiace®, 258
Loranthacese, 255
Lorantlis, 255
Lubbock’s remark, 268
Lycoperdon, 176
Lycopodiace®, 208
Lycopodia®, 206
Lycopodium, 209
Lycopodium, 207 (fig.)
Lycopodium, bundle, 46 (fig.)
Lycopods, 206
Lygodium, 203
Lytlrrace®, 260
Lytkrads, 260
Macrospores, 205
Madderworts, 259
Magnoliace®, 263
Magnoliads, 263
Magnolias, 278
Maidenhair-fern, 203
Malic Acid, 83
Mallow-worts, 262
Malpighiace®, 261
Malvaceae, 262
Malvale Cohort, 262
Mangroves, 260
Maples, 278
Map of Botanical Regions,101
Marattiace®, 203
Marcliantia, 184
Marchantia, 185, 186 (figs.)
Marchantiace®. 187
Marsh marigold,embryo,231 (fig.'
Marsilia, 205
Marsilia, 204(fig.)
Maximum Temperature, 87
Mayace®, 244
Meconic Acid, 83
Medullary rays, 240
Melampsora, 172
Melastomace®, 260
Melastomads, 260
Meliace®, 261
Meliads, 261
Melons, 278
Menispermaces, 263
Meristem, 29
Metabolism, 83
Metastasis, 83
Micrembrye®, 256
Micrococcus, 110
Micrococcus, 109 (fig.)
Micropyle, 252
Microscope, need of, 2
Microsperms, 244
Microsphffira, 159
Microspores, 205
Mignonettes, 276
Mildews, 139
Milk-tissue, 18, 27
Milkweeds, 258
Milkworts, 262
Minimum Temperature, 87
Mints, 257
Mistletoe Family, 255
Mnium, 192
Monimiace®, 256
Monocotyledones, 241
Monocotyledons, 241
Monocotyledons, number of
species, 243
Monoecious, 191
Monopodial Branching, 65, 66
Monopodium, forms of, 66
Moonseeds, 263
Moon worts, 205
Morchella, 163
Morel, 163
Moringe®, 261
Morphia, 83
Moss, tissue, 30 (fig.)
Mosses, 188
Mosses, True, 192
Mossworts, 183
Movement of Protoplasm, 2
Movement of Water in Plants, 74
Movements of Plants, 91
Mucor, 125, 129
Mucor, 125, 126, 127 (figs.)
Mucorini, 124
Mulberries, 255
Multiovulat®, 256
Musci, 188
Mushrooms, 178
Mustard, embryo, 231 (fig.)
Mustard, seedling, 36 (fig.)TNDEX.
287
Mycelium, 124
Myoporinese, 257
Myricaeese, 255
Myristicacese, 256
Myrsiuace®, 258
Myrtacese, 260
Myrtale Cohort, 260
Myrtles, 260
Myxomycetes, 106
Naiadace.®, 243
Nageli’s terms, Xylem and
PliloSm, 45
Navicula, 121 (fig.)
Nectar, 234
Nelumbium, 276 (fig.)
Nemalion, 153
Nemalion, 153 (fig.)
Nepenthace®, 256
Nepenthes, 273
Nepenthes, 274 (fig.)
Nettle, embryo, 231 (fig.)
Nettles, 255
Nettleworts, 255
Nicotine, 83
Nightshades, 257
Nitella, 182
Nitelle®, 182
Norfolk Island Pine, 225
Nostoc, 112
Nostoc, 112 (fig.)
Nucleus, 5
Nudiflor®, 243
Number of Dicotyledons, 253
Number of Monocotyledons, 243
Number of Species of Plants, 97
Nutmegs, 256
Nutrition of Parasites and Sapro-
phytes, 82
Nyctaginace®, 256
Nymphseaceae, 263
Oak, embryo, 231 (fig.)
Oaks, 255, 276
Oat, embryo, 231 (fig.)
Oats, 249
Ochnace®. 261
Odor of Flowers, 234
CEdogoniese, 132
(Edogonium, 132
(Edogonium, 132, 133 (figs.)
Oil-receptacles, 58
Olacads, 261
Olacale Cohort, 261
Olacine®, 261
Oleace®, 258
Oleasters, 255
Olives, 258, 278
Ouagrace®, 260
Onagrads, 260
Onoclea, 203
OOgone, 130
OOgonium, 130
OOphyta, 130
Obphytes, 130
Obspore, 130
Open Bundles, 49
Ophioglossace®, 203
Ophioglossum, 205
Opium, 278
Optimum Temperature, 87
Orchids, 249
Orchidace®, 245
Orchids, 245
Orchis, flower, 247 (fig.)
Orders of Plants, 98
Ornamental Dicotyledons, 275
Ornamental Monocotyledons, 249
Orobanehace®, 257
Oscillaria, 112
Oscillaria, 112 (fig.)
Osmunda, 203
Ostrich.fern, 203
Ovary, 225
Ovules, 62, 63, 214
Ovules, development of 228
Oxalic Acid, 83
Packing, 191
Palmate®, 244
Palms, 244
Palms, economic value of, 250
Palmyra Palm, 251
Pandanacese, 244
Pandorina, 116
Pandorina, 117 (fig.)
Papaveracese. 263
Paraphyses, 162
Parasites, 78, 82
Parenchyma, 15
Parietale Cohort, 263
Parsnips, 278INDUS.
288
Passifloracese, 260
Passiflorale Cohort, 259
Passion flowers, 260, 276
Pea-blight, 160
Peaches, 268
Pears, 278
Peas, 268
Pea-starch, 10 (fig.)
Peat-mosses, 191
Pedal iaceae, 257
Penteaceae, 255
Penicillium, 160
Penicillium, 161 (fig.)
Peppers, 256
Pepperworts, 200, 205
Pericambium, 45
Pericarp, 151
Peridium, 176
Perisporiacese, 155
Perithecia, 164
Peronospora, 140
Peronospore®, 139
Personale Cohort, 257
Petals, 227
Peziza, 163
Peziza, 161, 162 (figs.)
Phallus, 177
Phaeosporeae, 118
Plianerogamia, 212
Phanerogams, 212
Pliascace®, 192
Phaseolus, 253
Phellogen, 54
Pliilydrace®, 244
Phloem, 45
Phloxes, 257, 276
Phragmidium, 172
Phycomyces, 129
Phycoxanthine, 121
Phyllome, 60, 62
Phyllospora, 147
Physarum. 106 (fig.)
Physcia, 167 (fig.)
Phytolaccace®, 256
Pickerel-weeds, 244
Pileus, 180
Pilobolus, 129
Pilularia, 205
Pine-apples, 244
Pines, 224
Pine, trachelds, 25 (fig.)
Pinkworts, 262
Pinus, 224
Pinus, 216, 221 (figs.)
Piperace®, 256
Piptocephalis, 129
Pirus, 278 (fig.)
Pistil, 228
Pitcher-leaves, 256
Pitcher-plant, Australian, 275
Pitcher-plant, Californian, 273
Pitcher-plants, 263, 272
Pitchers. 63
Pitted Vessels, 23
Pittosporace®, 262
Plane-trees, 255, 276
Plantains, 258
Plantaginaceae, 258
Plant-body, 59
Plant cell, 4
Plant-food, 10, 77
Plant-food, Compounds used, 77
Plant-food, Elements of, 77
Plant-food, how obtained, 78
Plant-food, how transported in
the plant, 79
Platanace®, 255
Plocamium, 152 (fig.)
Plowrightia, 163
Plumbaginace®, 258
Plums, 278
Plumule, 242, 251
Podosphsera, 160
Podostemace®, 256
Podostemads, 256
Polemoaiace®, 257
Polemoniale Cohort, 257
Pollen, 62
Pollen-cells, 213
Pollen Mother-cells, 227
Pollen-tube, 215
Pollination, 234
Pollination of Dicotyledons, 265
Pollination of Monocotyledons,
245-8
Pollination of Orchids, 246-8
Polygalace®, 262
Polygalale Cohort, 262
Polygonace®, 256
Polypetal®, 259
Polypodium, 203
Polypodium, 201, 202 (figs.)ZtsbEX.
289
Polypody, 203
Polyporus, 179
Polytrichum, 192
Pond-scum, 11, 124 (figs.)
Pond-scums, 122
Pond-weeds, 243
Pontcderiace®, 244
Poplars, 254, 276
Poppies, 276
Poppyworts, 263
Pore-fungi, 179
Portulacace®, 262
Potato, 278
Potato, 277 (fig-)
Potato-mildew, 140
Potato mildew, 140, 141 (figs.)
Prickles, 63
Prickly Fungi, 179
Primary Meristem, 29
Primrose, linirs, 37 (fig.)
Primroses, 258, 276
Primulace®, 258
Primulale Cohort, 258
Procambium, 49
Proteace®. 256
Proteads, 256
Protein Matter, 11
Proterandry, 237
Proterogyny, 237
Prothallium, 195
Protococcus, 113
Protonema, 191
Protophyta, 105
Protophytes, 105
Protoplasm, 1
Protoplasmic Activity, 2
Prunus, flower, 265 (fig.)
Pteridophyta, 194
Pteridophytes, 194
Pteris, 203
Pleris, tissue, 24, 48, 206 (figs.)
Puccinia, 169
Puccinia, 170, 171 (figs.)
Puff-balls, 175, 176
Pumpkins, 278
Pumpkin stem, sieve-tissue, 21
(fig.)
Punctum vegetationis, 31
Purslanes, 262
Pyrenomycetes, 163
Quassiads, 261
Quillworts, 210
Quinic Acid, 83
Quinine, 278
Radial Bundles, 49
Radicle, 252
Radishes, 278
Ranale Cohort, 263
Ranunculace®, 263
Rapateace®, 244
Raspberries, 278
Red Rust, 172
Red Seaweeds, 151
Red-snow Plant, 113
Redwoods, 224
Regions of Vegetation, 100
Resedace®, 263
Resedads, 263
Restiace®. 243
Reserve Material, storing of, 81
Reserve Material, use of, 82
Resin-canals, 58
Resting Spore. 115, 130
Reticulated Veins, 200
Reticulated Vessels, 23
Rhamnace®, 261
Rhamnads, 261
Rhizoids, 183
Rhizocarpe®, 205
Rhizophorace®, 260
Rhododendrons, 276
Rhubarb crystals, 12 (fig.)
Ricciace®, i87
Rice, 250
Ricimis. embryo, 252 (fig.)
Ringed Vessels, 23
Ringless Ferns, 203
Rivularia, 113
Rock-roses, 263
Rockweeds, 143
Rockweeds, 144, 145, 146 (figs.)
Root, 60, 63
Root-liairs, 37, 63
Root-pressure, 75
Root stocks, 62
Rosace®, 260
Rosale Cohort, 260
Roses, 276
Roseworts, 260
Roxburghiace®, 244290	INDEX.
Rubiace®, 259
Rubiale Cohort, 259
Rueworts, 261
Runners, 61
Rushes, 244
Rush, tissue, 57 (fig.)
Rusts, 169
Rutace®, 261
Rye, 249
Sabiace.®, 261
Saccharomyces, 110
Sac-fungi, 155
Sacs, 155
Sac-spores, 155
Sago-palm, 251
Salicace®, 254
Salvadorace®, 258
Samydaceae, 260
Sandalworts, 255
Santalace®, 255
Sap (Cell sap), 13
Sap, flow of, 75
Sapindace®, 261
Sapindale Cohort, 261
Sapotace®, 258
Sap, no circulation of, 75
Saprolegnia, 142
Saprolegniace®, 136
Saprophytes, 78, 82
Sargasso Sea, 147
Sargassum, 147
Sarracenia, 272 (fig.)
Sarraceniace®, 263
Saxifragace®, 260
Saxifrages, 260
Scalariform Vessels, 23
Scale-mosses, 187
Scales, 62, 63
Scliizomycetes, 108
Scitamine®, 244
Sclercnchyma. 17
Scorzonera, milk-vessels, 19 (fig.)
Scotch Pine, 223, 224
Scouring Rush, 198
Screw-pines, 244
Serophulariace®, 257
Scutellum, 242
Sea-lettuce, 118
Sea-lettuce, 118 (fig.)
Sedge, embryo, 231 (fig.)
• Sedges, 243
Seed, 215
Seeds, germination of, 219, 242,
251
Selaginese, 257
Selaginella, 210
Selaginella, 208, 209 (figs.)
Selaginella, bundle, 47 (fig.)
Selaginellace®, 209
Sepals, 227
Sequoia, 224
Sequoia, sieve-tube, 22 (fig.)
Sexless Plants, 105
Sexuality, first appearance of 115
Shield-ferns, 203
Sieve-tissue, 20, 27
Sigil lariaceae, 210
Sigillarids, 210
Silver-maple, tissue, 18 (fig.)
Simarubacese, 261
Sleep of Plants, 93
Slime-moulds, 5, 106
Smilax, 240
Smuts, 173
Snowdrop, 249
Snowflake, 249
Soapworts, 261
Soft Bast, 44
Soft Tissue, 15, 26
Solanace®, 257
Southern Pine, 224
Spawn, 179
Spermatia, 169
Sperm-cells, 169
Spermogones, 169
Sphaerotheca, 160
Spbagnace®, 191
Sphagnum, 192
Spiderworts, 244
Spindle trees, 261
Spines, 63
Spiral Vessels, 23
Spirillum. 109 (fig.)
Spirochsete, 109 (fig.)
Spirogyra, 124, 128
Spirogyra, 124 (fig.)
Spleen worts, 203
Sporangia, 63
Sporangium 126
Spore, 126
Spore-case, 126, 1INDEX.
291
Spore-fruit, 148
Spore-fruit Plants, 148
Spores. 63
Sporids, 173
Sporocarp, 148
Spruces, 324
Spurge, milk-tubes, 19 (fig.)
Spurgeworts, 255
Squashes, 278
Squash, hairs, 36 (fig.)
Stackhousiese, 261
Stahl’s discovery of the sexual
organs of Lichens, 168
Stamens, 62, 214
Star apples, 258
Starch, 9, 79
Starch, digestion of, 81
Starch-making, 79
Starch, storing of, 81
Stem, 61
Sterculiaceae, 262
Sterculiads. 262
Stereum, 179
Sterigmata, 158
Sticta, 166 (fig.)
Stigma, 228
Stinkhorn, 177
Stinking Smut, 175
St.-Jolmsworts, 262
Stomata, 37
Stoneworts, 180
Stony Tissue, 17, 26
Storaxworts, 258
Storing of reserve material, 81
Strawberries, 278
Strychnia, 83
Style, 228
Stylidiaceae, 258
Siylospores, 164
Styracaceae, 258
Sucrose, 13
Sugar, 13, 81
Sugar canes, 250
Sugar, origin of, 250
Sugar-pine, 224
Sundews, 260, 271
Suspensor, 219
Sweet-flag, bundle, 44 (fig.)
Sweet-flag root, bundle, 45
Sweet-pea, embryo, 231 (fig.)
Sweet-potato, 278
TAMAHISCINEiE, 262
Tamarisks, 262
Tannic Acid, 83
Tartaric Acid, 83
Tea, 278
Teaselworts, 259
Teleutospores, 172
Temperature as affecting plants.
86
Tendrils, 62, 63
Ternstroemiace®, 262
Thalamifloree, 262
Thallome, 61
Theads, 262
Thick-angled Tissue, 16, 26
Thorns, 62
Thymelaeaceae, 256
Tiliaceae, 262
Tilletia, 175
Timmia, 192
Tissues of Plants, 15
Tissue-systems, 32
Toadstools, 175, 177
Tomato, 278
Tracheary Tissue, 22, 28
Trachelds, 24, 29
Tremandreae, 262
Trichogyne, 149
Trichome, 60, 63
Trimorphism of Flowers, 237
Triurideae, 243
Truffles, 160
Tuber, 160 (fig.)
Tuberaceae, 160
Tuberose, 249
Tubers, 62
Tulips, 249
Tulip-trees, 278
Turbinaria, 147
Turneraceae, 260
Turnips, 278
Turpentine canals, 58
Typkacese, 243
Ulva, 118
Ulva, 118 (fig.)
Umbellale Cohort, 259
Umbelliferae, 259
Umbellifers, 259
Uncinula, 160
Uncinula, 157 (fig.)INDEX.
292
Union of Cells, 7
Unisexuales, 255
Unisexual Plants, 115
Uredinese, 169
Uredo, 172
Uredospores, 172
Uromyces, 172
Urticaceae, 255
Usiilaginete, 173
Ustilago, 174
Usnea, 166
Usnea, 166 (fig.)
Vacuoles, 2
Valerianaceae, 259
Vascular Bundles, 40
Vaucheria, 136
Vaucheria, 136 (fig.)
Vaucheriaceae, 135
Vegetative Cone, 31
Vegetative Point, 31
Venation of Dicotyledons, 253
Venation of Monocotyledons, 241
Venus’s Fly-trap, 271
Verbena blight, 160
Verbenacete, 257
Verbenas, 276
Vervains, 257
Vicia, embryo, 252 (fig.)
Vines, 261
Vine-rapes, 256
Violaceae, 263
Violets, 263, 276
Vocliysiaceae, 262
Volvox, 131
Volvox, 131 (fig.)
Walking-leap, 203
Wall of Cell, 4
Walnuts, 255, 276
Water-culture Experiments, 85
Water-flannel, 117
Water in Cell-walls, 69
Water, imbibition of, 2
Water in Protoplasm, 68
Water in the Plant, 68
Water-lilies, 263, 276
Water-lily, tissue, 57 (fig.)
Water-mould, 138 (fig.)
Water-moulds, 136
Water-net, 117
Water-plantains, 243
Wheat, 249
Wheat-rust 169
Wheat-smut, 175
White Pine, 224
White Rust, 142 (fig.)
White Rusts, 139
Wild Cucumber, epidermis, 38
(fig-)
Willow-blight, 160
Willows, 254, 276
Wind-pollinated Flowers, 234
Windsor Bean, 251
Witch hazels, 260
Wood, 18
Woody Bundles, 40
Xylem, 45
Xyridacese, 244
Yams, 244
Yeast-plants, 108. 110
Yeast plants, 8, 111 (figs.)
Yellow eyed Grasses, 244
Yellow Pine, 224
ZoSspoke, 116
ZoSsporeae, 116, 131
Zygnema, 128
Zygnemacese, 122
Zygophyllacese, 261
Zygophyta, 115
Zygopliytes, 115
Zygospore, 115THE AMERICAN SCIENCE SERIES.
The principal objects of the series are to supply the lack—in
some subjects very great—of authoritative books whose princi-
ples are, so far as practicable, illustrated by familiar American
facts, and also to supply the other lack that the advance of Sci-
ence perennially creates, of text-books which at least do not
contradict the latest generalizations. The scheme systemati-
cally outlines the field of Science, as the term is usually em-
ployed with reference to general education, and includes
Advanced Courses for maturer college students, Briefer
Courses for beginners in school or college, and Elementary
Courses for the youngest classes. The Briefer Courses are not
mere abridgments of the larger works, but, with perhaps a
single exception, are much less technical in style and more
elementary in method. While somewhat narrower in range
of topics, they give equal emphasis to controlling principles.
The following books in this series are already published:
THE HUMAN BODY. By H. Newell Martin, Professor in
the Johns Hopkins University.
Advanced Course. Large 121110, Pp. 655.	$2 75.
Designed to impart the kind and amount of knowledge every
educated person should possess of the structure and activities
and the conditions of healthy working of the human body.
While intelligible to the general reader, it is accurate and suffi-
ciently minute in details to meet the requirements of students
who are not making human anatomy and physiology subjects of
special advanced study. Tdie regular editions of the book contain
an appendix on Reproduction and Development. Copies without
this will be sent when specially ordered.
From the Chicago Tribune : “The reader who follows him through
to the end of the book will be better informed on the subject of
modern physiology in its general features than most of the medical
practitioners who rest on the knowledge gained in comparatively an-
tiquated text-books, and will, if possessed of average good judgment
and powers of discrimination, not be in any way confused by state-
ments of dubious questions or conflicting views.”THE AMERICAN SCIENCE SERIES.
THE HUMAN BODY—Continued.
Briefer Course. l2mo. Pp. 364. $1.50.
Aims to make the study of this branch of Natural Science a
source of discipline to the observing and reasoning faculties,
and not merely to present a set of facts, useful to know, which
the pupil is to learn by heart, like the multiplication-table.
With this in view,.the author attempts to exhibit, so far as is
practicable in an elementary treatise, the ascertained facts of
Physiology as illustrations of, or deductions from, the two car-
dinal principles by which it, as a depaitment of modern science,
is controlled,—namely, the doctrine of the “Conservation of
Energy” and that of the “ Physiological Division of Labor.” To
the same end he also gives simple, practical directions to assist
the teacher in demonstrating to the class the fundamental facts
of the science. The book includes a chapter on the action ttpon
the body of stimulants and narcotics.
From Henry Sf.wall, Professor of Physiology, University of Michi-
gan : “ The number of poor books meant to serve the purpose of
text books of physiology for schools is so great that it is well to
define clearly the needs of such a work : I. That it shall contain ac-
curate statements of fact. 2. That its facts shall not be too numer-
ous, but chosen so that the important truths are recognized in their
true relation. 3. That the language shall be so lucid as to give no
excuse foi misunderstanding. 4. That the value of the study as a
discipline to the reasoning faculties shall be continually kept in view.
I know of no elementary text book which is the superior, if the
equal, of Prof. Martin’s, as judged by these conditions.”
Elementary Course, i2mo. Pp. 261. 90 cts.
A very earnest attempt to present the subject so that children
may easily understand it, and, whenever possible, to start with
familiar facts and gradually to lead up to less obvious ones.
The action on the body of stimulants and narcotics is fully treated.
From W. S. Perry, Superintendent of Schools, Ann Arbor, Mich.:
“I find in it the same accuracy of statement and scholarly strength
that characterize both the larger editions. The large relative space
given to hygiene is fully in accord with the latest educational opinion
and practice ; while the amount of anatomy and physiology comprised
in the compact treatment of these divisions is quite enough for the
most practical knowledge of the subject. The handling of alcohol
and narcotics is, in my opinion, especially good. The most admira-
ble feature of the book is its fine adaptation to the capacity of younger
pupils. The diction is simple and pure, the style clear and direct and
the manner of presentation bright and attractive.”THE AMERICAN SCIENCE SERIES.
3
ASTRONOMY. By Simon Newcomb, Professor in the Johns
Hopkins University, and Edward S. Holden, Director of
the Lick Observatory.
Advanced Course. Large 12 mo. Pp. 512. $2.50.
To facilitate its use by students of different grades, the sub-
ject-matter is divided into two classes, distinguished by the size
of the type. The portions in large type form a complete course
for the use of those who desire only such a general knowledge
of the subject as can be acquired without the application of ad-
vanced mathematics. The portions in small type comprise ad-
ditions for the use of those students who either desire a more
detailed and precise knowledge of the subject, or who intend to
make astronomy a special study.
From C. A. Young, Professorin Princeton College: “ I conclude
that it is decidedly superior to anything else in the market on the
same subject and designed for the same purpose."
Briefer Course. i2mo. Pp. 352. $1.40.
Aims to furnish a tolerably complete outline of the as-
tronomy of to-day, in as elementary a shape as will yield satis-
factory returns for the learner’s time and labor. It has been
abridged from the larger work, not by compressing the same
matter into less space, but by omitting the details of practical
astronomy, thus giving to the descriptive portions a greater
relative prominence.
From The Critic: “The book is in refreshing contrast to the
productions of the professional schoolbook-makers, who, having only
a superficial knowledge of the matter in hand, gather their material,
without sense or discrimination, from all sorts of authorities, and
present as the result an indigesta moles, a mass of crudities, not un-
mixed with errors. The student of this book may feel secure as to
the correctness of whatever he finds in it. Facts appear as facts, and
theories and speculations stand for what they are, and are worth.”
From W. B. Graves, Master Scientific Department of Phillips
Academy: “ I have used the Briefer Course of Astronomy during the
past year. It is up to the times, the points are put in a way to inter-
est the student, and the size of the book makes it easy to go over the
subject in the time allotted by our schedule.”
From Henry Lefavour, late Teacher of Astronomy, Williston Semi-
nary : “The impression which I formed upon first examination, that
it was in very many respects the best elementary text-book on the
subject, has been confirmed by my experience with it in the class-
room.”4	THE AMERICAN SCIENCE SERIES.
ZOOLOGY. By A. S. Packard, Professor in Brown Univer-
sity.
Advanced Course. Large i2mo. Pp. 719.	$3.00.
Designed to be used either in the recitation-room or in the
laboratory. It will serve as a guide to the student who, with a
desire to get at first-hand a general knowledge of the structure
of leading types of life, examines living animals, watches their
movements and habits, and finally dissects them. He is pre-
sented first with the facts, and led to a thorough knowledge
of a few typical forms, then taught to compare these with
others, and finally led to the principles or inductions growing
out of the facts.
From A. E. Verrili,, Professor of Zoology in Yale College : “The
general treatment of ihe subject is good, and the descriptions of
structure and the definitions of groups are, for the most part, clear,
concise, and not so much overburdened by technical terms as in sev-
eral other manuals of structural zoology notv in use.”
Briefer Course. i2mo. Pp. 334.	$1.40.
The distinctive characteristic of this book is its use of the
object method. The authorwould have the pupils first examine
and roughly dissect a fish, in order to attain some notion of
vertebrate structure as a basis of comparison. Beginning then
with the lowest forms, he leads the pupil through the whole
animal kingdom until - man is reached. As each of its great
divisions comes under observation, he gives detailed instruc-
tions for dissecting some one animal as a type of the class, and
bases the study of other forms on the knowledge thus obtained.
From Herbert Osborn, Proftssor of Zoology, Iowa Agricultural
College: “ I can gladly recommend it to any one desiring a work of
such character. While I strongly insist that students should study
animals from th*, animals themselves,—a point strongly urged by
Prof. Packard in his preface,—I also recognize the necessity of a
reliable text-book as a guide. As such a guide, and covering the
ground it does, I know of nothing better than Packard's.”
From D. M. Fisk, Professor of Natural History, Hillsdale College :
“The ‘ Briefer Courses ’ of Packard and Martin have been adopted,
and for these reasons :	1. They are brief; the lessened mechanical
labor of mastering a text leaves time for more observation and for
comparison of authorities. 2. They are clear; the work of cutting
away needless nomenclature has been done with skill. 3. They are
authoritative ; serious students can have confidence in even brief and
dogmatic statements, knowing they come from a master, and not from
a mere compiler. 4. They arc fresh ; fossils are good in their places,
but a fossil text book in science is a fraud on youth."THE AMERICAN SCIENCE SERIES.	$
ZOOLOGY — Continued.
Elementary Course. (In press.)
In general method this book is the same with those just de-
scribed, but, being meant for quite young pupils, it gives more
attention to the higher organisms, and to such particulars as
can be studied with the naked eye. In everything the aim has
been to make clear the cardinal principles of animal life, rather
than to fill the pupil's mind with a mass of what may appear to
him unrelated facts.
BOTANY. By Charles E. Bessey, Professor in the Univer-
sity of Nebraska.
Advanced Course. Large i2mo. Pp. 611.	$275.
Aims to lead the student to obtain at first-hand his knowl-
edge of the anatomy and physiology of plants. Accordingly,
the presentation of matter is such as to fit the book for con-
stant use in the laboratory, the text supplying the outline sketch
which the student is to fill in by the aid of scalpel and micro-
scope.
From J. C. Arthur, Editor of The Botanical Gazette: “The first
botanical text-book issued in America which treats the most important
departments of the science with anything like due consideration.
This is especially true in reference to the physiology and histology of
plants, and also to special morphology. Structural Botany and clas-
sification have up to the present time monopolized the field, greatly
retarding the diffusion of a more complete knowledge of the science.”
Briefer Course. i2mo. Pp. 292.	$1.35.
A guide to beginners. Its principles are, that the true aim of
botanical study is not so much to seek the family and proper
names of specimens as to ascertain the laws of plant structure
and plant life; that this can be done only by examining and
dissecting the plants themselves ; and that it is best to confine
the attention to a few leading types, and to take up first the
simpler and more easily understood forms, and afterwards those
whose structure and functions are more complex. The latest
editions of the work contain a chapter on the Gross Anatomy
of Flowering Plants.
From J. T. Rothrock, Professor in the University of Pennsylva-
nia : “ There is nothing superficial in it, nothing needless introduced,
nothing essential left out. The language is lucid ; and, as the crown-
ing merit of the book, the author has introduced throughout the vol-
ume ‘ Practical Studies,’ which direct the student in his effort to see
for himself all that the text book leaches.”6
THE AMERICAN SCIENCE SEINES.
CHEMISTRY. By Ira Remsen, Professor in the Johns Hop-
kins University.
Briefer Course, iemo. Pp. 387. $1.40.
An introduction to the study of chemistry, following the
inductive method. To avoid overburdening the student’s mind,
the author has presented a smaller number of facts than is
usual in elementary courses in chemistry, but he has at the same
time taken pains to select for treatment such substances and
such phenomena as seem best suited to give an insight into the
nature of chemical action. In other words, he has aimed to
make the book scientific, to lav stress upon the relations which
exist between the phenomena considered, and not to present
merely a mass of apparently disconnected facts. Another
feature of the work is that principles and laws are treated be-
fore the theories which are proposed to account for them.
The other books arranged for in this series are as follows:
PHYSICS. By Arthur Wright, Professor in Yale College.
{In preparation.)
CEOLOCY. By Raphael Pumpelly, late Professor in Har-
vard University. {In preparation:)
PSYCHOLOGY. By William James, Professor in Harvard
University. {In preparation:)
GOVERNMENT. By Edwin L. Godkin, Editor of the Nation.
{In preparation.)
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