202 



IMPORTANT FAMILIES OF PLANTS 



the nitrogen which they have gathered and stored in their 

 leaves, stems and roots is added to the soil. This may soon be 

 changed to forms which corn, potatoes, or other crops may use 

 while growing in that soil. 



Beans. The term " bean " is applied to many plants of 

 this family; the broad bean (Vicia faba) is of Asiatic origin 



FIG. 127. AKalfa and clover. 



and is extensively grown in Europe for the feeding of live stock ; 

 the kidney bean (PJiaseolus vulgaris) probably originated in 

 tropical America and is represented by many species and 

 varieties of garden and field beans which are so extensively 

 grown throughout the world; the Lima bean (P. lunatus) (Fig. 

 126) is a native of South America, the soy or soja bean 

 (Glycine hispida) is of Asiatic origin and is grown extensively 

 for stock feed ; the so-called cowpea or bean ( Vigna simensis) is 



