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ELEMENTS
OF
STRUCTURAL AND SYSTEMATIC BOTANY,
FOR
HIGH SCHOOLS AND ELEMENTARY
COLLEGE COURSES.
BY
DOUGLAS HOUGHTON CAMPBELL, PH.D.,
PROFESSOR OF BOTANY IN THE INDIANA UNIVERSITY.
BOSTON, U.S.A.:
PUBLISHED BY GINN & COMPANY.
1890.
COPYRIGHT, 1890,
BY DOUGLAS HOUGHTON CAMPBELL.
ALL RIGHTS RESERVED.
TYPOGRAPHY BY J. S. CUSHING & CO., BOSTON, U.S.A.
PRESSWORK BY GINN & CO., BOSTON, U.S.A.
PREFACE.
The rapid advances made in the science of botany within the last few
years necessitate changes in the text books in use as well as in
methods of teaching. Having, in his own experience as a teacher, felt
the need of a book different from any now in use, the author has
prepared the present volume with a hope that it may serve the purpose
for which it is intended; viz., an introduction to the study of botany
for use in high schools especially, but sufficiently comprehensive to
serve also as a beginning book in most colleges.
It does not pretend to be a complete treatise of the whole science,
and this, it is hoped, will be sufficient apology for the absence from
its pages of many important subjects, especially physiological topics.
It was found impracticable to compress within the limits of a book of
moderate size anything like a thorough discussion of even the most
important topics of _all_ the departments of botany. As a thorough
understanding of the structure of any organism forms the basis of all
further intelligent study of the same, it has seemed to the author
proper to emphasize this feature in the present work, which is
professedly an _introduction_, only, to the science.
This structural work has been supplemented by so much classification
as will serve to make clear the relationships of different groups, and
the principles upon which the classification is based, as well as
enable the student to recognize the commoner types of the different
groups as they are met with. The aim of this book is not, however,
merely the identification of plants. We wish here to enter a strong
protest against the only too prevalent idea that the chief aim of
botany is the ability to run down a plant by means of an "Analytical
Key," the subject being exhausted as soon as the name of the plant is
discovered. A knowledge of the plant itself is far more important than
its name, however desirable it may be to know the latter.
In selecting the plants employed as examples of the different groups,
such were chosen, as far as possible, as are everywhere common. Of
course this was not always possible, as some important forms, _e.g._
the red and brown seaweeds, are necessarily not always readily
procurable by all students, but it will be found that the great
majority of the forms used, or closely related ones, are within the
reach of nearly all students; and such directions are given for
collecting and preserving them as will make it possible even for those
in the larger cities to supply themselves with the necessary
materials. Such directions, too, for the manipulation and examination
of specimens are given as will make the book, it is hoped, a
laboratory guide as well as a manual of classification. Indeed, it is
primarily intended that the book should so serve as a help in the
study of the actual specimens.
Although much can be done in the study, even of the lowest plants,
without microscopic aid other than a hand lens, for a thorough
understanding of the structure of any plant a good compound microscope
is indispensable, and wherever it is possible the student should be
provided with such an instrument, to use this book to the best
advantage. As, however, many are not able to have the use of a
microscope, the gross anatomy of all the forms described has been
carefully treated for the especial benefit of such students. Such
portions of the text, as well as the general discussions, are printed
in ordinary type, while the minute anatomy, and all points requiring
microscopic aid, are discussed in separate paragraphs printed in
smaller type.
The drawings, with very few exceptions, which are duly credited, were
drawn from nature by the author, and nearly all expressly for this
work.
A list of the most useful books of reference is appended, all of which
have been more or less consulted in the preparation of the following
pages.
The classification adopted is, with slight changes, that given in
Goebel's "Outlines of Morphology and Classification"; while, perhaps,
not in all respects entirely satisfactory, it seems to represent more
nearly than any other our present knowledge of the subject. Certain
groups, like the Diatoms and _Characeæ_, are puzzles to the botanist,
and at present it is impossible to give them more than a provisional
place in the system.
If this volume serves to give the student some comprehension of the
real aims of botanical science, and its claims to be something more
than the "Analysis" of flowers, it will have fulfilled its mission.
DOUGLAS H. CAMPBELL.
BLOOMINGTON, INDIANA,
October, 1889.
TABLE OF CONTENTS.
PAGE
CHAPTER I.--INTRODUCTION 1
Composition of Matter; Biology; Botany; Zoölogy; Departments
of Botany; Implements and Reagents; Collecting
Specimens.
CHAPTER II.--THE CELL 6
Parts of the Cell; Formation of New Cells; Tissues.
CHAPTER III.--CLASSIFICATION OF PLANTS 9
Protophytes; Slime-moulds; Schizophytes; Blue-green Slimes,
_Oscillaria_; Schizomycetes, _Bacteria_; Green Monads,
_Euglena_, _Volvox_.
CHAPTER IV.--ALGÆ 21
Classification of Algæ; Green Algæ; _Protococcaceæ_,
_Protococcus_; _Confervaceæ_, _Cladophora_, _Œdogonium_,
_Coleochæte_.
CHAPTER V.--GREEN ALGÆ (_Continued_) 30
Pond-scums, _Spirogyra_; _Siphoneæ_, _Vaucheria_; _Characeæ_,
_Chara_.
CHAPTER VI.--BROWN SEAWEEDS 41
_Diatomaceæ_; True Brown Algæ, _Fucus_; Classification of
Brown Algæ.
CHAPTER VII.--RED ALGÆ 49
Structure of Red Algæ; _Callithamnion_; Fresh-Water Forms.
CHAPTER VIII.--FUNGI 54
_Phycomycetes_, _Mycomycetes_; _Phycomycetes_, Black Moulds,
_Mucor_; White Rusts and Mildews, _Cystopus_; Water Moulds.
CHAPTER IX.--TRUE FUNGI 63
Yeast; Smuts; _Ascomycetes_; Dandelion Mildew; Cup Fungi,
_Ascobolus_; Lichens; Black Fungi.
CHAPTER X.--TRUE FUNGI (_Continued_) 77
_Basidiomycetes_; Rusts; _Coprinus_; Classification.
CHAPTER XI.--BRYOPHYTES 86
Classification; Liverworts, _Madotheca_; Classification of
Liverworts; Mosses, _Funaria_; Classification of Mosses.
CHAPTER XII.--PTERIDOPHYTES 102
Bryophytes and Pteridophytes; Germination and Prothallium;
Structure of Maiden-hair Fern.
CHAPTER XIII.--CLASSIFICATION OF PTERIDOPHYTES 116
Ferns; Horse-tails; Club Mosses.
CHAPTER XIV.--SPERMAPHYTES 128
General Characteristics; Gymnosperms and Angiosperms,
Scotch-pine; Classification of Gymnosperms.
CHAPTER XV.--SPERMAPHYTES (_Continued_) 143
Angiosperms; Flowers of Angiosperms; Classification of
Angiosperms; Monocotyledons, Structure of _Erythronium_.
CHAPTER XVI.--CLASSIFICATION OF MONOCOTYLEDONS 153
_Liliifloræ_; _Enantioblastæ_; _Spadicifloræ_; _Glumaceæ_;
_Scitamineæ_; _Gynandræ_, _Helobiæ_.
CHAPTER XVII.--DICOTYLEDONS 170
General Characteristics; Structure of Shepherd's-purse.
CHAPTER XVIII.--CLASSIFICATION OF DICOTYLEDONS 181
_Choripetalæ_: _Iulifloræ_; _Centrospermæ_; _Aphanocyclæ_;
_Eucyclæ_; _Tricoccæ_; _Calycifloræ_.
CHAPTER XIX.--CLASSIFICATION OF DICOTYLEDONS
(_Continued_) 210
_Sympetalæ_: _Isocarpæ_, _Bicornes_, _Primulinæ_, _Diospyrinæ_;
_Anisocarpæ_, _Tubifloræ_, _Labiatifloræ_, _Contortæ_,
_Campanulinæ_, _Aggregatæ_.
CHAPTER XX.--FERTILIZATION OF FLOWERS 225
CHAPTER XXI.--HISTOLOGICAL METHODS 230
Nuclear Division in Wild Onion; Methods of Fixing, Staining,
and Mounting Permanent Preparations; Reference Books.
INDEX 237
BOTANY.
CHAPTER I.
INTRODUCTION.
All matter is composed of certain constituents (about seventy are at
present known), which, so far as the chemist is concerned, are
indivisible, and are known as elements.
Of the innumerable combinations of these elements, two general classes
may be recognized, organic and inorganic bodies. While it is
impossible, owing to the dependence of all organized matter upon
inorganic matter, to give an absolute definition, we at once recognize
the peculiarities of organic or living bodies as distinguished from
inorganic or non-living ones. All living bodies feed, grow, and
reproduce, these acts being the result of the action of forces
resident within the organism. Inorganic bodies, on the other hand,
remain, as a rule, unchanged so long as they are not acted upon by
external forces.
All living organisms are dependent for existence upon inorganic
matter, and sooner or later return these elements to the sources
whence they came. Thus, a plant extracts from the earth and air
certain inorganic compounds which are converted by the activity of the
plant into a part of its own substance, becoming thus incorporated
into a living organism. After the plant dies, however, it undergoes
decomposition, and the elements are returned again to the earth and
atmosphere from which they were taken.
Investigation has shown that living bodies contain comparatively few
elements, but these are combined into extraordinarily complex
compounds. The following elements appear to be essential to all living
bodies: carbon, hydrogen, oxygen, nitrogen, sulphur, potassium.
Besides these there are several others usually present, but not
apparently essential to all organisms. These include phosphorus, iron,
calcium, sodium, magnesium, chlorine, silicon.
As we examine more closely the structure and functions of organic
bodies, an extraordinary uniformity is apparent in all of them. This
is disguised in the more specialized forms, but in the simpler ones is
very apparent. Owing to this any attempt to separate absolutely the
animal and vegetable kingdoms proves futile.
The science that treats of living things, irrespective of the
distinction between plant and animal, is called "Biology," but for
many purposes it is desirable to recognize the distinctions, making
two departments of Biology,--Botany, treating of plants; and Zoölogy,
of animals. It is with the first of these only that we shall concern
ourselves here.
When one takes up a plant his attention is naturally first drawn to
its general appearance and structure, whether it is a complicated one
like one of the flowering plants, or some humbler member of the
vegetable kingdom,--a moss, seaweed, toadstool,--or even some still
simpler plant like a mould, or the apparently structureless green scum
that floats on a stagnant pond. In any case the impulse is to
investigate the form and structure as far as the means at one's
disposal will permit. Such a study of structure constitutes
"Morphology," which includes two departments,--gross anatomy, or a
general study of the parts; and minute anatomy, or "Histology," in
which a microscopic examination is made of the structure of the
different parts. A special department of Morphology called
"Embryology" is often recognized. This embraces a study of the
development of the organism from its earliest stage, and also the
development of its different members.
From a study of the structure of organisms we get a clue to their
relationships, and upon the basis of such relationships are enabled to
classify them or unite them into groups so as to indicate the degree
to which they are related. This constitutes the division of Botany
usually known as Classification or "Systematic Botany."
Finally, we may study the functions or workings of an organism: how it
feeds, breathes, moves, reproduces. This is "Physiology," and like
classification must be preceded by a knowledge of the structures
concerned.
For the study of the gross anatomy of plants the following articles
will be found of great assistance: 1. a sharp knife, and for more
delicate tissues, a razor; 2. a pair of small, fine-pointed scissors;
3. a pair of mounted needles (these can be made by forcing ordinary
sewing needles into handles of pine or other soft wood); 4. a hand
lens; 5. drawing-paper and pencil, and a note book.
For the study of the lower plants, as well as the histology of the
higher ones, a compound microscope is indispensable. Instruments with
lenses magnifying from about 20 to 500 diameters can be had at a cost
varying from about $20 to $30, and are sufficient for any ordinary
investigations.
Objects to be studied with the compound microscope are usually
examined by transmitted light, and must be transparent enough to allow
the light to pass through. The objects are placed upon small glass
slips (slides), manufactured for the purpose, and covered with
extremely thin plates of glass, also specially made. If the body to be
examined is a large one, thin slices or sections must be made. This
for most purposes may be done with an ordinary razor. Most plant
tissues are best examined ordinarily in water, though of course
specimens so mounted cannot be preserved for any length of time.[1]
[1] For the mounting of permanent preparations, see Chapter XIX.
In addition to the implements used in studying the gross anatomy, the
following will be found useful in histological work: 1. a small
camel's-hair brush for picking up small sections and putting water in
the slides; 2. small forceps for handling delicate objects; 3.
blotting paper for removing superfluous water from the slides and
drawing fluids under the cover glass; 4. pieces of elder or sunflower
pith, for holding small objects while making sections.
In addition to these implements, a few reagents may be recommended for
the simpler histological work. The most important of these are
alcohol, glycerine, potash (a strong solution of potassium hydrate in
water), iodine (either a little of the commercial tincture of iodine
in water, or, better, a solution of iodine in iodide of potassium),
acetic acid, and some staining fluid. (An aqueous or alcoholic
solution of gentian violet or methyl violet is one of the best.)
A careful record should be kept by the student of all work done, both
by means of written notes and drawings. For most purposes pencil
drawings are most convenient, and these should be made with a
moderately soft pencil on unruled paper. If it is desired to make the
drawings with ink, a careful outline should first be made with a hard
pencil and this inked over with India-ink or black drawing ink. Ink
drawings are best made upon light bristol board with a hard,
smooth-finished surface.
When obtainable, the student will do best to work with freshly
gathered specimens; but as these are not always to be had when wanted,
a few words about gathering and preserving material may be of service.
Most of the lower green plants (_algæ_) may be kept for a long time in
glass jars or other vessels, provided care is taken to remove all
dead specimens at first and to renew the water from time to time. They
usually thrive best in a north window where they get little or no
direct sunshine, and it is well to avoid keeping them too warm.
Numbers of the most valuable fungi--_i.e._ the lower plants that are
not green--grow spontaneously on many organic substances that are kept
warm and moist. Fresh bread kept moist and covered with a glass will
in a short time produce a varied crop of moulds, and fresh horse
manure kept in the same way serves to support a still greater number
of fungi.
Mosses, ferns, etc., can be raised with a little care, and of course
very many flowering plants are readily grown in pots.
Most of the smaller parasitic fungi (rusts, mildews, etc.) may be kept
dry for any length of time, and on moistening with a weak solution of
caustic potash will serve nearly as well as freshly gathered specimens
for most purposes.
When it is desired to preserve as perfectly as possible the more
delicate plant structures for future study, strong alcohol is the best
and most convenient preserving agent. Except for loss of color it
preserves nearly all plant tissues perfectly.