242 Emerson. 



in this way, were colored on one side and colorless on the other side. 

 In the production of these half-and-half seeds, as well as of the 60000 

 wholly colored ones, the second male nucleus could not have developed 

 independently of the fused polar nuclei, else the seeds would have had 

 wholly colorless aleurone. 



These results of East are accounted for eciually well either hy 

 hypothesis II, fusion of the second male nucleus with one polar nucleus 

 and independent development of the other polar nucleus, or by hypothesis HI, 

 vegetative segregation subsequent to ordinary double fertilization. It 

 was pointed out by East aud Hayes (9) that the vegetative-segregation 

 hypothesis would be indicated if, among Fi seeds of a cross between 

 parents differing in two allelomorpliic character pairs, the parental 

 characters should appear in the half-and-half seeds in different combi- 

 nations from those of the parent races. On this point I wish to submit 

 a bit of evidence. 



For sometime I have been engaged in investigations, the purposes 

 of which are to determine which one of the three factors for aleurone 

 color, C, R or P, is concerned in certain correlations observed between 

 aleurone color and one of the three factors for plant color ^) and also 

 to determine which of the aleurone factors is responsible for the mottled 

 appearance of some seeds that are heterozygous with respect to aleurone 

 color. These investigations have necessitated not only a careful exami- 

 nation of many seeds but also the cultivation of several distinct lots 

 of maize of known composition with respect to aleurone factors and 

 which can therefore be used as "aleurone testers". 



In some crosses the white Fs seeds of every ear have given red- 

 colored plants only and the colored seeds of the same ears have given 

 both red-colored and green plants. In other crosses the white seeds 

 have given both colored and green plants and the colored seeds only 

 colored plants. In still other crosses both white and colored seeds of 

 the same ear have given both colored and green plants. It has there- 

 fore been necessary to cross a considerable number of i)lants, both from 

 white and from colored seeds, with aleurone testers to determine what 

 factors are concerned in each case. 



In one such cross an ear had ajjproximately 9 purple to 7 white 

 F2 seeds. The white seeds must therefore have been of five genoty- 

 pically different sorts. When the plants grown from these white seeds. 



') My account of the inheritance of plant colors in maize is not yet in print. 



