158 ELEMENTS OF AGRICULTURE 



is also an important grain crop, but its growth is lim- 

 ited to a small section of country. By the word corn 

 in the United States is meant Indian corn or maize. 

 In many foreign countries the word corn means the 

 seed of all cereal plants — wheat, rye, oats, barley, and 

 Indian corn. The word corn' as we shall use it always 

 refers to Indian corn. 



The cereal crops are grown for the seed they pro- 

 duce. It is true that both corn and oats are some- 

 times grown for fodder, but their chief value to man 

 lies in their seed. 



Corn, wheat, and oats are found growing in all the 

 temperate regions of the earth, in many different 

 kinds of soil and in many climates. The numerous 

 soils and climates in which the crops grow have pro- 

 duced a number of different varieties; thus we have 

 dent corn, flint corn, popcorn, etc.; red wheat, white 

 wheat, bearded wheat, etc. ; and many varieties of oats. 

 But while these varieties differ somewhat in appear- 

 ance they are very similar in habits of growth and food 

 requirements. 



All the cereals are annuals, and have clustered or 

 crown roots, as shown in Fig. 5, page 40. These roots 

 branch out near the surface and spread through the 

 surface soil. Some of the roots penetrate to consid- 

 erable depths in the subsoil; the roots of winter wheat- 

 plants have been known to penetrate the soil to a 

 depth of four feet or more, but most of the roots 

 draw their supplies of food and water from the upper 

 soil. 



