A TEXTBOOK OF GENERAL BOTANY 
CHAPTER I 
INTRODUCTION 
Definition. Botany is the science that deals with plants, and 
in its broadest sense may be said to include all the systema- 
tized knowledge of plants. As a more or less systematized sci- 
ence botany began with Aristotle (884—-322 B.c.). Since his 
time knowledge of the subject has increased tremendously, and 
the field it now covers is so extensive that no one man could 
possibly be more than very superficially acquainted with all of 
its branches. As a result this science has been divided into a 
number of subordinate sciences, such as systematic botany, the 
classification of plants according to their relationships; morphol- 
ogy, the structure of the different parts of plants; physiology, 
the functions of plant organs; plant geography, the distribution 
of plants; genetics, which deals with inheritance and variation ; 
and applied botany, which embraces agriculture, horticulture, for- 
estry, pharmacognosy, bacteriology, plant pathology, etc. 
Value of botanical study. The study of botany is useful for its 
practical applications as well as for its general educational value. 
Plants are probably the most conspicuous elements in the 
natural environment of most people, and it is through plants 
that a large part of the human race comes most frequently in 
contact with nature. 
The food of all animals, including man, comes from plants, 
either directly or, indirectly, through other animals. Plants 
furnish us much of the material from which our clothes are 
made. They also supply us with the wood that we use for fuel, 
for making furniture, for building houses, and for many other 
purposes. They furnish us with numberless valuable products, 
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