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THE AMERICAN NATURALIST [Vol. XLIV 



both Y x and Y 2 . The remaining ears are clearly mono- 

 hybrids with reference to yellow endosperm. 



Table II. 



.me Cross as S 



Aght Yellow Seeds He 



for Planted 



In a second case the female parent possessed the yellow 

 endosperm. No. 11, a twelve-rowed yellow flint, was 

 crossed with No. 8, a white dent. The F 2 kernels in part 

 showed clearly a mono-hybrid ratio, and in part blended 

 gradually into white. Two of these indefinite ears proved 

 in the F z generation to have had the 15 : 1 ratio in the F 2 

 generation. Ear 7 of the F 2 generation calculated from 

 the results of the entire F z crop must have had about 547 

 yellow to 52 white kernels, the theoretical number being 

 561 to 31. The hand-pollinated ears of the F z generation 

 (yellow seeds) gave the results shown in Table III. 



The F z generation grown from the other ear, Ear No. 8, 

 showed that the ratio of yellows to whites in the F 2 gen- 

 eration was about 227 to 47. As the theoretical ratio is 

 257 to 17, the ratio obtained is somewhat inconclusive. A 

 classification of the open field crop could not be made 

 accurately on account of the light color of the yellows and 



