Cnapter 4 



■ THE VARIETY OF PLANT UFE 



At first sight, the vegetation which makes up our grasslands 

 and forests, our fields and gardens appears to be a bewildering 

 variety of millions of plants. A little observation, however, re- 

 veals the fact that many of these plants look much alike even 

 though no two plants are exactly the same. Almost uncon- 

 sciously we think of a plant as belonging to a certain "kind," 

 which is what the botanist means when he says that it belongs to a 

 definite species. A species is a group of individuals which re- 

 semble each other so closely that their similarities far outnumber 

 any minor differences which may exist. Once we have seen one or 

 two individuals of a species, we have a fair idea of what all the 

 individuals of that species will look like, wherever we meet them. 

 In referring to a species, we use a double name to designate it; 

 a tree is a sugar maple or a white pine, and a flower is a New Eng- 

 land aster or a swamp buttercup. 



The plant kingdom consists of some two hundred and fifty 

 thousand species, but the great majority of these rarely enter into 

 our daily lives. Only a thousand or two, at most, constitute the 

 dominant part of our native plant life, or are used by man. The 

 more common of these species will be described in Chapters 16, 

 17, 26, and 27. 



Since science implies an orderly arrangement of facts, a 

 scientific study of plants must include some systematic method of 

 classifying these species. This is done by grouping species with 

 numerous characteristics in common into an assemblage which is 

 based upon relationship. For example, the white pine, red pine 

 and pitch pine are three distinct species each with its particular 

 characteristics; the white pine has five leaves in a cluster, the 

 pitch pine has three, and the red pine has two. On the other hand, 



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