CHAPTER XIV 

 ZEA (Cora, Maize) 



Habit of Plant, Roots. — Corn is distinctly a summer 

 annual. 



The root system is fibrous. Corn generally has been con- 

 sidered a shallow-rooted plant. The contrary is the case. 

 At maturity the roots come to fill the upper 3 feet of soil and, 

 under some conditions, may reach to a depth of 4 or 5 feet 

 (Fig. 56). The depth of planting appears to bear no rela- 

 tion to the depth of rooting, for the first whorl of roots usu- 

 ally forms about i inch below the soil surface, no matter how 

 deep the seed is planted. It will be remembered that this 

 is true for the other cereals too. The roots of corn are thrown 

 off in whorls, varying in number from two to ten, one whorl 

 above another. The internodes between whorls are very 

 short. The entire group of whorls constitutes the root 

 crown. 



Two kinds of roots are developed (Ten Eyck): {a) main 

 vertical roots and {h) main lateral roots. Vertical roots 

 curve out slightly from the crown and go directly downward. 

 The laterals curve downward, as they leave the crown, then 

 extend horizontally for a distance, finally taking a downward 

 course. Laterals that leave the crown at about the soil 

 level slope gradually downward, as indicated above. Midway 

 between the rows of planted grain, about 22 inches from the 

 157 



