I 



VEGETABLE FOODS 



161 



roots, and in addition slender rhizomes (which are true stems) 

 with swollen tips growing into the familiar tubers (fig. 97). 

 White potatoes are therefore stems and not roots; this is evident 

 when we realize that the eyes of a potato are really buds, and that 

 no roots produce buds. Potato plants ar^ usually propagated by 

 these tubers, which will sprout after a short resting period, each 

 eye growing into a shoot with leaves. Each tuber is made up of a 

 thin skin, relatively narrow cortex with some starchy cells, a 

 ring of vascular bundles and an extensive pith containing most 



PHLOEM 



BUD 



CORTEX 

 CAMBIUM 



STORAGE PARENCHYMA 



Fig. 97. — The underground pordon of the potato plant consists of fibrous 

 roots and slender rhizomes with swollen tips which grow into the tubers, or 

 potatoes. 



of the cells gorged with starch. Potatoes have a high water con- 

 tent (78%), and contain about 18% carbohydrates, 2% proteins, 

 less than 1% fat and about 1% potash. The first explorers to the 

 New World found the natives cultivating potatoes, which are 

 indigenous to the tropical Americas and still grow wild in Chile, 

 Peru, Mexico and Central America. A native species occurs in 

 the mountainous regions of New Mexico and Arizona, producing 

 small tubers the size of marbles; this plant was prized by the 

 Navajos and comprised a good share of their diet when other 

 food failed. The white potato was brought to Spain by the early 

 explorers, then found its way to England, Russia and Ireland 

 where the potato soon become an important crop. It was brought 



