OUR CULTIVATED PLANTS 279 



Root crops. Most of our plants with edible roots are little 

 changed from the originals. This is quite natural, since the 

 only improvement desired has been the increased size of the 

 roots and a greater storage of food. The beet is a native of 

 the Mediterranean region and still grows wild there and as 

 far east as Persia. The carrot, turnip, parsnip, and radish are 

 found in southern and central Europe, and, all but the turnip, 

 having escaped from cultivation in this country, have shown 

 themselves able to maintain an existence in the wild state. 

 Salsify, or vegetable oyster, like the beet, still grows wild in the 

 Mediterranean region. From the garden beet the field -or sugar 

 beet has arisen, and from the turnip comes the rutabaga. The 

 potato, though in no sense a root, is usually classed with the 

 root crops. It is a native of western South America, where 

 its relatives still abound. It was cultivated by the natives of 

 the region before the discovery of America, but does not seem 

 to have been known to the North American Indians. The sweet 

 potato is a true root, the product of a plant belonging to the 

 morning-glory family. It is regarded as a native of South 

 America, but has long been in cultivation in China and is 

 thought by some to have had a separate origin in each country. 

 The Jerusalem artichoke is a species of sunflower, which grows 

 wild in the Northern states and Canada, and was occasionally 

 cultivated by the Indians before the advent of the whites. 



Leaf crops. Chief of the plants grown for their leaves is the 

 cabbage, which is still found in the wild state in the south of 

 England, the Channel Islands, and on the shores of the North 

 Sea. The wild plant has thickish leaves, but it is quite unlike 

 the hard-headed specimens of our gardens. From this same 

 plant has come a long list of varieties that are valued in cul- 

 tivation, such as kale, cauliflower, Brussels sprouts, kohl-rabi, 

 and the like. Lettuce came originally from the Mediterranean 

 region, but is now widely distributed in both the Old World 

 and the New as a pernicious weed. It is not easy to realize 



