CHAPTER III 

 LEARNING TO NAME PLANTS 



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We shall not get very far in the study of plants without studying them 

 in the field and greenhouse. In order to observe and discuss plants in- 

 telligently, we must have appropriate names for them. Many common 

 plants have local names which may suffice for ordinary conversation. 

 But the names applied in one community may be different from those 

 in another. Furthemiore, the same name is often used for quite different 

 plants in other localities. Many other plants lack common names. To 

 overcome these difficulties scientific names have been given to all the 

 known species of plants, and by agreement these names are used and 

 understood by botanists everywhere. 



Botanists have recognized and named more than a quarter of a million 

 species of plants. As a beginning it will be sufficient to know some of the 

 local seed-bearing plants. Many plants can be recognized readily by 

 their leaf and stem characters; recognition of others may require a 

 knowledge of the flowers and fruits in addition. Names of plants may be 

 obtained from others who know them or from published "keys." To make 

 the simplest keys or to use those made by others, it is necessary to ex- 

 amine the external features of leaves and stems and become acquainted 

 with the terms that are applied to their parts, forms, and arrangements. 



The parts of a leaf. If one examines a leaf, such as that of Japanese 

 quince, it is evident that it consists of a broad, thin blade, a narrow 

 cylindrical petiole, and at the base of the petiole a pair of small ap- 

 pendages, the stipules. A leaf consisting of these three parts is frequently 

 called a complete leaf. The primary parts of a complete leaf, then, are 

 the blade, petiole, and stipules (Fig. 14). 



The stipules are usually small structures; but some of them, such as 

 those of pansy, Japanese quince, and garden pea, are large and blade- 

 like. Those of buckwheat and smartweed are sheaths surrounding the 

 stem for some distance above the point of attachment. Stipules of the 

 greenbrier are tendrils, and those of the black locust are spines. 



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