TUBER CROPS 109 



but in many parts of Europe. To-day Europe leads the world in 

 the production of this vegetable. Germany alone produces at least 

 one fourth of the world's crop. We grow several hundred million 

 bushels annually in the United States. Our most productive 

 States are New York, Minnesota, Wisconsin, Michigan, Pennsyl- 

 vania, Oklahoma, Colorado, Utah, and California. 



Several important commercial articles are now manufactured 

 from potatoes, among which may be mentioned alcohol, starch, 

 glucose, and artificial ivory. . 



Jerusalem Artichoke. This is really a species of sunflower 

 which has been known and cultivated in both Europe and America 



Gathering the potato crop. 



for the past two hundred years. This species produces tubers 

 which look very much like potatoes. Farmers may cultivate and 

 handle this crop in the same way as for potatoes, but the tubers 

 are usually plowed up and left on the ground as feed for hogs. 



Chinese Yam. These plants have a food value similar to sweet 

 potatoes. They have large, thick roots which make them hard to 

 dig. They are propagated by means of small tubers. The Chinese 

 yam makes a valuable winter food for hogs. 



Chufa. This plant produces an abundance of small tubers and 

 grows best on sandy soils. It is grown chiefly for hogs. 



