112 



THE AMEBIC AX XATCKALIST 



[Vol. XLVI 



absence, non-starchiness (s). AYhen S came from the J 1 parent 

 zenia appeared in all cases. All F 1 seeds showing zenia proved 

 to be heterozygous. No extracted recessives of the F 2 generation 

 ever proved to be heterozygous. "From this one may conclude 

 that the second male nucleus that fertilizes the endosperm nu- 

 cleus always bears the same characters as the first male nucleus 

 that fertilizes the embryo nucleus, or egg." A few seeds, all 

 heterozygous, were part starchy and part not; i. e., one side was 

 starchy. The authors consider that this confirms Correns's view 

 that, in such cases, the second male nucleus did not fuse with the 

 endosperm nucleus but that each developed separately. 



One semi-starchy ear occurred, grown from a non-starchy seed. 

 The authors suggest two possible causes for this phenomenon. 

 Either there is an incomplete segregation, resulting in contamin- 

 ation of a gene by its allelomorph, this contamination, by selec- 

 tion, being capable of accumulative effects, or the semi-starchy 

 ear arose as the result of a progressive variation. They point 

 out that the infrequency of this phenomenon is an argument 

 against the theory of partial or incomplete segregation, and 

 incline to the idea that it is a case of progressive variation. The 

 data presented certainly favor this interpretation of the case. 



Yellow and Non- Yellow Endosperm 

 Two independent factors for yellow were found, each capable 

 of producing yellow endosperm. The colors produced by these 

 two factors appear to be the same. The pigments occur in 

 rhombic plates, and are insoluble in water, but soluble in ether, 

 chloroform, etc. They appear to be related to the anthochlorins. 



Some crosses between yellow and white gave the ratio 3:1, due 

 to the presence of only one of the factors for yellow. Others 

 gave the dihybrid ratio. Yellow appeared as xenia in the hybrid 

 seeds (seeds which produced the F 1 plants). 



Yellow was dominant, but imperfectly so under certain con- 

 ditions, so that, in certain crosses in which the grains had soft 

 starch at the tip the heterozygotes could be distinguished from 

 the homozygotes. In other crosses yellow was completely 

 dominant. 



The same original ear of some of the parent stocks had some 

 seeds containing both factors for yellow, while other seeds on the 

 same ear had only one of these factors. 



The two yellow factors together generally gave darker yellow 

 seed than one factor alone. 



