MAIZE BREEDING 183 



in the endosperm and a correspondingly large proportion of 

 corneous starch. Some seeds may be entirely free from soft 

 starch, but there is generally some soft starch surrounding the 

 germ. The group is characterized by the small size of its seeds 

 and ears. 



Zea mays indentata, the dent corns. Sturtevant, Bulletin 

 Torrey Botanical Club, 1894, page 329. 



The corneous starch in this group is located at the sides of the 

 seed and the soft starch extends to the summit. The soft 

 starch dries more rapidly than the corneous and this produces 

 the shrinkage which causes the characteristic indentation of the 

 seed. 



Zea mays amylacea, the soft or flour corns, Sturtevant, Bulletin 

 Torrey Botanical Club, 1894, page 331. 



This group is recognized by an almost entire absence of cor- 

 neous starch. There is no indentation in some varieties and only 

 a slight one in others. The soft starch content characterizes 

 this group. 



Zea mays saccharata, the sweet corns. Sturtevant, Bulletin 

 Torrey Botanical Club, 1894, page 333. 



"A well-defined species group characterized by the trans- 

 lucent, horny appearance of the kernels and their more or less 

 crinkled, wrinkled, or shriveled condition." East (1910d) pre- 

 sented evidence which shows that the sweet corns are dent, flint, 

 or pop varieties which have not the ability to mature starch nor- 

 mally. The few starch grains produced are small, angular, and 

 imperfect. 



INHERITANCE OF CHARACTERS 



Endosperm Characters. The word xenia was first used by 

 Focke (1881) to denote the effect which was apparently produced 

 by the action of pollen upon the maternal tissue of the seed. 

 The endosperm of maize was cited as a classical example of such 

 an effect. After the discovery by Guignard (1899) and Nawas- 

 chin (1898) that the polar nuclei of the endosperm fuse with the 

 second male nucleus of the pollen grain, De Vries (1899), Correns 

 (1899), Webber (1900), and Guignard (1899, 1901) saw that this 

 furnished an explanation of xenia in maize. From a considera- 

 tion of inheritance of endosperm character the following law of 

 xenia may be formulated : 



