TJie Endosperm in Tuheritance 



147 



layer of endosperm, while the bulk of the seed consists 

 of the starchy endosperm. Since aleurone is endosj)erm, 

 colors peculiar to it would show xenia in inheritance. 

 This was the case in East's 

 red and purple corn, the 

 colors being located in the 

 aleurone layer. 



There is another phase 

 of the situation to which 

 attention should be called. 

 By pollinating the silks of a 

 white-grained individual 

 with pollen from a red- 

 grained individual, xenia is 

 secured, the resulting grains 



erm 



mbrvo 



Cross-Section of 

 Com-Seed 



Fig. 24. — Diagram of corn seed 



being red like those of the pollen parent. In the reciprocal 

 cross, however, that is, pollinating silks of a red-grained 

 individual with pollen from a white-grained individual, 

 a different result is obtained. The resulting grains are 

 not white like those of the pollen parent, but red like 

 those of the ovule parent. There is no xenia, therefore, 

 for the pollen has no immediate effect upon the develop- 

 ing endosperm. This seeming difliculty, however, is 

 easily explained. When the pollen parent is white and 

 the ovule parent is red, the endosperm gets its characters 

 from both parents, and since red is dominant ()\'er white 

 the resulting endosperm will be red because the female 

 nuclei that entered into the triple fusion carried the 

 factor for red endosperm; and therefore the pollen from 

 the white ])arent seemed to ha\c no cIUh t. 'i1u' mecha- 

 nism works in all cases, but, owing to dominance, xem'a 

 appears only in certain cases. 'Jliere is no need to dis- 



