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 usec 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- 
