DESCRIPTIVE MANUAL 



199 



Chemical Composition. — The chemical composition of vetch {Vicia 

 sativa) according to U. S. Dept. Agr., 1880; p. 152, is as follows : 



FRESH OR AIR DRY MATERIAL. 



Wild Bean {Strophostyles helvola (L.) Britton). 



Description.— An annual, with prostrate stem; compound leaves 

 ovate to oblong-^obovate, with a prominent rounded lobe at the base ; 

 coroUa greenish white and purplish; pod 4:-8-seeded, large, usually 

 pubescent. 



Distribution. — Common in sandy places in northern United 

 States; from Wisconsin, Minnesota, and Texas east to Massachu- 

 setts ; common in gravel pits on Muscatine Island, along Des Moines, 

 Cedar and Iowa rivers. 



Extermination. — Easily exterminated by cultivation. 

 OXALIDACEAE, WOOD SORREL FAMILY. 



This family contains the cultivated yellow and purple-flowered 

 oxalis. Few of the plants are economic. i, 



