THE SWEET POTATO. 33 



II. ECONOMIC I.AIPORTANCE. 



A. Distribution and Comparative Yield. 



The sweet potato is primarily a tropical plant, and 

 it has found its widest distribution in the tropics. 

 As with other tropical products, so with this — we 

 know that it is one of the most important food plants, 

 but we cannot even approximately estimate the 

 amounts produced. Even in a country like Mexico 

 the statistics on agricultural products are so utterly 

 unreliable that they are of no practical value. 



In the tropics the sweet potato is a perennial. 

 The tubers are constantly dug up without removal 

 of the parent plants, until replanting seems advis- 

 able. Since the immature tubers are as good for 

 use as the mature ones, the natives merely dig up 

 the largest potatoes, no matter whether they are 

 ripe or not. The large potatoes can usually be 

 detected by the cracking of the earth above them. 

 There is no part of the tropics now where several 

 varieties of sweet potatoes are not cultivated. 



In Mexico, Central, and South America they are 

 a staple crop in all the states down to Argentine and 

 Chile. 



In Africa they are cultivated largely by the 

 natives of all the European colonies as well as by 

 those of the interior. In Mediterranean Europe 

 they are a well-known crop. In Persia, Hindustan, 

 India, Farther India, China, Japan, and the entire 

 Malay Archipelago they form one of the principal 

 productions, utilized in many ways. In Japan the 



