166 



PLANTS AND MAN 



man; and there is little doubt that these easily-secured portions 

 of plants formed a staple part of the diet of prehistoric man. 

 With the coming of civilization, and a knowledge of plant breed- 



FiG. 100. — Distribution of acreage of vegetables grown for market in 1930. 



ing, the original storage organs have been induced to grow in 

 size and to increase their food content. The result is the variety 

 of earth and leafy vegetables which we use today (fig. 100). 



j 



