Sweet Potato 313 



of the common foods in all northern cities. They are little known 

 to the people of central Europe. Nearly 50,000,000 bushels is 

 produced annually in the United States. The largest quantities 

 are grown in the Carolinas, Georgia, Texas, Alabama, Missis- 

 sippi, Virginia, New Jersey. As with other crops, every state pro- 

 duces the best quality, depending on where one lives. Certain 

 varieties of sweet potatoes are called yams in the southern states, 

 but the word " yam " properly belongs to a very different kind of 

 plants, the Dioscoreas. 



In the South a soft, sugary sweet potato is desired. In the North 

 a firm, dry tuber is wanted. Spanish, Sugar, Barbadoes, and Hy- 

 man are popular far south. Nansemond and Jersey are prized for 

 the North. The vineless (Fig. 88), a variety with short tops or 

 vines ("vineless" meaning "not running," or "bushy"),, is now a 

 very popular kind. Price gives the alternative of two schemes for 

 classification of varieties of sweet potatoes : 



A. Leaves entire (not lobed). 



AA. Leaves shouldered (lobed or halberd-shape at base). 

 AAA. Leaves deeply cut or lobed. 



The second classification is based on the tuber: 



A. Tubers white -skinned. 

 AA. Tubers dull straw color. 

 AAA. Tubers light red. 

 AAAA. Tubers purple. 



There are several serious fungous diseases of sweet potato v see 

 bulletins N. J. Exp. Sta.). The leaf -blight may be held in check 

 by spraying with Bordeaux mixture, but the tuber diseases are 

 treated to best advantage by rotation of crops and using only 

 healthy tubers for seed. 



There are two special books on sweet potatoes, by Fitz and 

 Price. See list, pp. 251, 259. For history, see Sturtevant, Amer. 

 Nat., August, 1891, pp. 698, 699. 



