CHAPTER IX 

 CROPS GROWN FOR FRUIT OR SEED PARTS 



THREE families of plants furnish most of the vegetable crops 

 grown for fruit or seed parts the legumes, nightshade family, 

 and cucurbits. 



177. The legumes. The pea and bean are members of a 

 large group of plants called legumes which bear their seed in 

 pods. Other examples are the peanut, locust, clover, alfalfa, 

 lupine, vetch, and acacia. The flowers of most of the genera 

 possess the peculiar structure so familiar in the sweet pea. 

 On the roots of legumes are tubercles containing bacteria 

 which take the nitrogen from the air and fix it in the form of 

 compounds available for plant use. On this account, the 

 legumes can be grown in soil deficient in nitrogen. For the 

 same reason, they are valuable crops for building up the soil, 

 and should occupy an important place in plans for rotation. 

 There are many different species in the family, yielding diverse 

 and important products, as forage, hay, dye-stuffs, balsam, 

 rubber, and oils; but the two garden plants of most impor- 

 tance are the pea and bean. 



178. The bean was supposed to have come originally from 

 Egypt, for there is mention of it in the early records of the 

 Egyptian priests; but it grows wild in the tropics of both the 

 Old and the New World, and forms differing from one another 

 but little have been obtained from countries widely separated 

 geographically. Since it is tropical, it will endure very little 

 frost; and must be planted and harvested between the times 

 of spring and autumn cold. The " bush " or dwarf forms have 

 resulted from breeding and selection; the wild kinds are of 

 the trailing or climbing type. 



109 



