THE EAR 49 



Tillers or suckers come from buds developed at the surface of the 

 soil. If conditions are unfavorable, these buds may simply remain 

 dormant, but if the soil is rich, or planting thin, one or more may 

 develop. Some varieties naturally produce more tillers than others. 

 Sweet corns and flint corns produce more tillers than dent varieties. 



The Roots. When a seed of corn germinates a few temporary 

 roots are first developed. These do not grow ve,ry large and appear 

 to function only while the young plant is establishing. When the 

 young plant reaches sunlight with its leaves, it begins at about the 

 same time to develop permanent roots. These are thrown out at the 

 base of the stem, which usually forms at about one inch below the 

 soil surface. No matter at what depth the seed was planted the 

 permanent roots develop at about the same depth below the surface. 



Spread of Roots. Corn roots usually spread out laterally when 

 full grown to a distance of four to six feet on every side of the plant^ 

 and downward to a depth of five feet on friable loam soils ; but on 

 heavy clay or hardpan soils they may penetrate only two feet. Most 

 of the roots are in the upper 12 to 18 inches, this portion of the soil 

 in a corn field being thoroughly filled with roots. The upper roots 

 are usually about three inches below the surface in loose prairie soils, 

 but in a close clay soil they may come within one inch of the surface, 

 necessitating very shallow cultivation. 



Brace roots are strong roots thrown out just above the soil 

 surface. Above ground they are strong and rigid, but entering the 

 soil they become small and branching, and function like other roots. 

 As the name implies, their principal function is to brace the plant 

 against the effect of strong winds. 



Tassel and Ear. The corn tassel produces the pollen for fer- 

 tilizing the ears. The tassel branches bear a great number of pollen 

 sacs, each of which is filled with pollen grains. It has been estimated 

 that one tassel bears twenty million pollen grains. When the silks 

 are ready to be fertilized, the pollen sacs begin to open and shed the 

 pollen. Not all the pollen from a tassel is shed in one day, but from 

 day to day for about one week. The pollen grains are easily carried 

 by wind to the corn silks (Fig. 19). 



The Ear. An ear of corn usually has from 500 to 1000 kernels. 

 The number of rows varies from 8 to 30. The cob and kernels de- 



4 



