INTEODUCTOEY — PLANTS IN NATURE 3 



The domestication and improvement of plants has been an 

 essential part of the development of many industries, and has 

 advanced until at the present time the greater part of the 

 food of the world is secured from certain kinds of plants 

 which once grew wild and produced little that was of value 

 to men. The plant producing the biggest crop in the world 

 is the potato, which'in 1906 produced 284,000,000,000 pounds 

 of potatoes. But the most important crop in the world from 

 the point of view of the market value of its product is wheat. 

 In each of three great agricultural regions of the United States 

 one plant is dommant in its value. In the central corn belt 

 there are seven states that produce nearly one half the corn 

 used in the whole world, an amount which in 1909 was worth 

 nearly $3,000,000,000. The Southern States produce over 

 three fifths of the cotton of the world, an amount worth 

 nearly |1,000,000,000. The Northwestern States produce 

 wheat, which, while not so large a proportion of the world's 

 crop, is of tremendous importance to the welfare of the 

 nation. 



Plant fibers are extensively used in the manufacture of 

 clothing. Timber is used in the construction of buildings, 

 furniture, vehicles, and implements for use in the industries. 

 Plant extracts compose the most of our medicines. The paper 

 upon which our ideas are recorded is made chiefly from wood 

 pulp, though it is now proposed to make it from cornstalks. 

 The processes by means of which green plants live, as will be 

 shown later, contribute to the purification of the atmosphere 

 that we breathe. 



The farmers' barns, the city feed stores, warehouses, cold- 

 storage establishments, almost every manufactory and sales- 

 room, and many of the railway and steamship transportation 

 lines in some way are illustrations of the important relations 

 which plant life bears to the fundamental industries. 



4. How plants live : the most important phase of botany. 

 In connection with the preceding discussion regarding the 

 place of plants in nature, it must be clearly understood that 



