LEGUMES 



201 



125). The nodules seen on the roots are the homes of the bac- 

 teria. When the bacteria are present on the roots the phints 

 are enabled to gather nitrogen from the air. This power is 

 not found in other families of plants. 



The relationship existing between the plants of the legume 

 family and the bacteria on the roots is a kind of partnership 

 (or symbiosis). The clover plant, for example, furnishes 

 homes for the bacteria and supplies tliem with nourishment. 



Fio. 12tt. — Pod and seeds of lima bean. 



In return for these benefits, the bacteria enable the clover plant 

 to gather nitrogen from the air and use it in its own growth. 



Different kinds of bacteria are found to suit the different 

 legumes. The red clover bacteria do not tlirive on alfalfa or 

 on beans. There are some forms of bacteria that are adapted 

 to several legumes. For example, those on alfalfa are also 

 found on sweet clover and on bur clover. 



Legumes aid other crops grown in the same soil after 

 them. Tf clover or cowpeas, for example, are plowed under, 



