38 FIELD CROP PRODUCTION 



it extends sometimes two-thirds of the distance to the 

 crown, and makes up from 7 to 15 per cent of the kernel. 

 It is divided into two parts, the scutellum and the growing 

 portion. The latter is divided into the plumule and the 

 radicle. 



The color of the grain, in the case of white or yellow 

 corn, is determined by the color of the endosperm and the 

 aleurone layer. In the blue, purple or black, it is due to 

 the color of the aleurone layer only, while in red corn the 

 color pigment is found in the hull, and the endosperm 

 may be either white or yellow. 



33. Ancestors of the corn plant. Some of our culti- 

 vated grains can be traced back to a time when their 

 ancestors were growing wild in uncultivated lands. With 

 the corn plant this has not been possible, since no wild 

 types nor any very close relatives have been found. One 

 of its nearest relatives is a plant called teosinte, a forage 

 plant that grows luxuriantly in the favored sections of 

 Mexico and Central America. This plant produces many 

 branches, sometimes as many as forty or fifty coming 

 from a single seed. At the end of the branches are 

 tassels on which the grains are produced. 



Those of us who have worked in the corn field, in cutting 

 or husking, have seen individual corn plants which show 

 great variation from corn plants in general. It is not 

 uncommon to find a corn plant with grains in the tassel. 

 Less frequently, perhaps, do we find branching corn plants, 

 each branch carrying an ear. If we have been close 

 observers, we have often seen appendages attached to the 

 tip of the husk, closely resembling the blade of a leaf. 

 Why do we find these variations? Might it not be that 

 these plants show a reversion, or a striking back to the 

 original wild type? This is thought to be true by some 



