BOTANY 
PLANT STUDIES 
CHAPTEE I 
INTRODUCTION 
1. General relations. Plants form the natural covering 
of the earth's surface. So generally is this true that a land 
surface without plants seems remarkable. Not only do 
plants cover the land, but they abound in waters as well, 
both fresh and salt waters. They are wonderfully varied in 
size, ranging from huge trees to forms so minute that the 
microscope must be used to discover them. They are also 
exceedingly variable in form, as may be seen by comparing 
trees, lilies, ferns, mosses, mushrooms, lichens, and the 
green thready growths (algce) found in water. 
2. Plant societies. One of the most noticeable facts in 
reference to plants is that they do not form a monotonous 
covering for the earth's surface, but that there are forests in 
one place, thickets in another, meadows in another, swamp 
growths in another, etc. In this way the general appear- 
ance of vegetation is exceedingly varied, and each appear- 
ance tells of certain conditions of living. These groups of 
plants living together in similar conditions, as trees and 
other plants in a forest, or grasses and other plants in a 
meadoAV, are known as plant societies. These societies are as 
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