434 PLANTS AND THEIR RELATION TO MAN 



for only a short time; and still others, like the wheat plant,' 

 furnished grain which could be kept for months and used during 

 the long winter when fresh plant food was scarce. 



In order to increase the harvest of the plant which he liked, 

 and to have crops in places convenient to his dwelling, man be- 

 gan the artificial growing of plants. Seeds from the desired 

 plants were sown in definite plots of land. Soon it was learned 

 that the abundance of the crops depended upon rainfall, upon 

 the fertility of the soil, upon plowing, upon weeding, and upon 

 many other factors. As a result, more and more attention was 



given to the cultiva- 

 tion of plants. Richer 

 fields were sought in 

 which to plant seeds, 

 and deeper plowing 

 and more careful 

 weeding were done. 



The wild plants im- 

 proved under the al- 

 tered conditions, but 

 it was many years 

 before they became 

 transformed into the 

 garden plants of to- 

 day. The close ten- 

 der head of cabbage 

 with its many leaves 

 came from a simple wild plant having only a few bitter leaves 

 arranged in a loose cluster ; but it took years to accomplish the 

 change. Soft, sweet, juicy corn came from stalks bearing small 

 ears of hard dry kernels ; but for this, also, years of work were 

 necessary. Artificial pollination, selection of seed, and cultiva- 

 tion enable us to change totally the character of plants, and to 



FIG. 301. The wild pear tree is very hardy 

 and may develop into a valuable tree under 

 cultivation. 



