Botany for Agricultural Students

612 Pages·46.229 MB·English

by  Martin J.N.

BOTANY
FOR
AGRICULTURAL STUDENTS
BY
JOHN MARTIN
N.
Professor of Botany at the Iowa State College of Agriculture
and Mechanic Arts
FIRST EDITION
NEW YORK
JOHN WILEY &
SONS, INC.
LONDON: CHAPMAN & HALL, LIMITED
1919
COPYRIGHT, 1919,
BY
JOHN N. MARTIN
Stanbopcjprcss
F H.GILSON COMPANY
BOSTON, U.S.A.
PREFACE
Although students vary widely in their reasons for studying
Botany, the fundamental facts or principles of the subject are
not thereby altered. One has considerable freedom, however, in
the presentation of the subject to adapt the subject matter to
special aims of different classes of students, and especially is
this true in courses for agricultural students, since much of the
work in Agriculture is based upon the principles of Botany. In
the choice of material to illustrate principles and in the presen-
tation of the applications of principles, there is special oppor-
tunity to relate courses in Botany to courses in Agriculture.
In any elementary course in Botany, regardless of the kind of
education the student desires to obtain, the primary aim should
be to give the student a notion of the fundamental principles of
Botany. This aim should be the guiding one in both recitation
and laboratory, determining the trend of discussions in recita-
tion, and the nature of the material and procedure in the lab-
oratory. The primary aim should be accompanied by a secondary
aim to relate the subject to the student's major line of work.
When the relation of the subject tomajorlines ofwork is obvious,
the student is more likely to appreciate the subject and is thereby
put in a favorable mood to studythe subject. Even for students
who take Botany merely as a part of a general education, it in no
way detracts from the course or makes botanical training less
efficient to present the practical aspects of the subject.
This book is intended for elementary courses in Botany in
colleges and universities. In its preparation the aim has been to
present the fundamental principles of Botany with emphasis
upon the practical application of these principles. The subject
matter is presented in two parts, part I being devoted to the
study of the structures and functions chiefly of Flowering Plants,
and Part II, to the study of the kinds of plants, relationships,
Evolution, Heredity, and Plant Breeding.
In the preparation of the book, I had the following objects in
view: (1) to present the structures and functions of Flowering
iii
iv PREFACE
Plants and relate them to such agricultural subjects as Farm
Crops, Forestry, and Horticulture, and to the more advanced
coursesinBotany; (2) topresentthekindsofplantswithemphasis
upon their evolutionary relationships and their economic im-
portance; and (3) to present Evolution, Heredity, and Plant
Breeding as related to the improvement of plants.
The topics are arranged in the book in the order in which I
usually present them. The presentation of the reproductive
structures and processes of Flowering Plants, followed by
that of the vegetative organs, has fitted in at Iowa State
College with the time of year at which the agricultural students
begin the study of Botany and also with the courses in
Agriculture. In other schools where conditions are different,
other arrangements of the topics are more suitable. In recogni-
tion of this fact, most of the chapters have been written so as to
be separately understandable, the aim being to make the book
adaptable to any arrangement of topics that the teacher may
prefer.
In the discussion of a subject the presentation of the general
features precedes that of the particular features, and the latter
are presented in most cases by the study of type plants chosen on
account of their familiarity and economic importance.
The book is intended for an entire year's work in Botany and
to be accompanied by laboratory work. Where less time is de-
voted to the subject, the organization of the chapters so as to be
separately understandable permits a selection of topics according
to the requirements of the course.
The reproductive structures and processes in Flowering Plants
(Chapters III and IV) are dwelt upon more than is necessary
for students who have had a good course in Botany in a high
school. A large percentage of the students in my elementary
classes have had no Botany and have difficulty in understanding
sexual reproduction in Flowering Plants. In an effort to thor-
oughly acquaint the student with this subject, I have dwelt at
considerable length upon those phases of the subject that are in
my experience difficult for the student to understand. In case
students are familiar with this subject, parts of Chapters III and
IV can be omitted or read hastily in review.
Usually there are some students in the class that are especially
interested in certain topics and desire a more complete discussion