306 A TEXT-BOOK OF BOTANY 



upon the discovery of America, and were introduced into 

 Europe by the Spanish conquerors, probably from Peru. 

 For nearly two centuries, however, their importance was 

 not appreciated; but now there are ten times as many 

 bushels of potatoes produced in Europe as in the United 

 States, the entire European crop being said to aggregate 

 more bushels than the entire wheat crop of the world. New 

 York is our great potato-producing State. There are hun- 

 dreds of varieties, new ones replacing old ones every year; 

 but they are all derived from a single species (Solanum 

 tuberosum). It should be remembered that these tubers 

 are subterranean stems ( 27) enlarged as depositories of 

 starch, the stem structure being indicated superficially 

 by the eyes (bracts with axillary buds). In planting, the 

 tubers are cut in pieces, each piece containing one or two 

 eyes and as much of the food-supply as possible. 



Tomato. The tomato was once called love-apple, and 

 was thought to be poisonous. It is grown more extensively 

 in North America than elsewhere; and in the United States 

 there is no vegetable so extensively grown for canning, about 

 300,000 acres being required to produce the annual crop. 

 The principal tomato-growing States are Maryland, New 

 Jersey, Indiana, and California. The numerous kinds vary 

 in form and color, all coming from a single species (Lyco- 

 persicum esculentum) , which is native to the Andean region 

 of South America. 



Tobacco. It is well-known that the Indians used tobacco 

 long before the discovery of America, but never excessively 

 (Fig. 208). From America its use was introduced into 

 Europe, gradually extending to the Asiatic nations, until 

 now the Turks and Persians are the greatest smokers in the 

 world. In the United States tobacco culture began in Vir- 

 ginia, at the first settlement of the colony; and it became 

 the leading industry also of Maryland, North Carolina, 

 South Carolina, Georgia, and Kentucky at their first settle- 



