142 SOUTHERN FIELD CROPS 



closing the young ear-shoot in a paper bag, it is found 

 that among the parts that develop in the absence of 

 pollen are the cob and the hull (or seed-coats) of 

 the grain. These parts (cob and seed-coats) cannot be 

 changed in the current cross (that is, in the generation 

 in which the cross is made) by pollen from a plant having 

 a different character in these parts (see Pars. 90 and 95). 



Now whenever grains of corn are red, the red color is located in 

 the hull. Proof of this is shown by the fact that meal from red 

 corn is white, after the bran has been carefully sifted out. Hence 

 if the female parent has red grains, the grains maturing soon after 

 a cross is made will be red, no matter whether the pollen used 

 be from a plant with yellow, with white, or with bluish grains. 



In the same way if pollen from a red variety be placed on the 

 silks of a white or yellow variety, the grains of the current cross 

 will all be of the same color as that of the silk-bearing parent. 



Very different is the way the yellow color of the corn grain 

 is transmitted. The yellow color resides, not in the hull, but 

 deeper in the structure of the grain ; that is, in the endosperm. 

 Proof of this is shown in the fact that meal from yellow corn is 

 always yellow, even after the most complete removal of the bran. 



Those parts of the kernel inclosed inside of the hull, that is, 

 the germ and the endosperm (including the aleurone layer), may 

 be visibly influenced by the pollen used in the current cross, that 

 is, by "double fertilization"; these inner portions of the grain 

 may display in a few weeks after the cross is made the color 

 derived from the sire or pollen-bearing plant. Now the yellow 

 color is located in the endosperm. The purple color is located in 

 the thin aleurone layer just under the seed-coats. Both the en- 

 dosperm and its aleurone layer are subject to double fertilization 

 by pollen, and thus they are at once influenced in color by the 

 male parent. Hence pollen from a pure yellow variety, falling on 

 silks of a white kind, promptly makes the grains thus fertilized 

 yellow. Likewise pollen from a lead-colored corn, falling on silks 

 of a white variety, promptly makes the hybrid grains lead-colored. 



