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THE AMEBIC AX XATUEALIST [Vol. LIT 



These results show that the segregation as to color, as 

 mentioned above, produces three types, black, gray and 

 yellow. On the assumption that the wild oat carries 

 genes for black, gray and yellow we would expect a segre- 

 gation of 12 black : 3 gray : 1 yellow. These figures ap- 

 proach this result, but there are too few yellows and too 

 many grays. Instead of the numbers obtained we expect 

 315.00 blacks : 78.75 -rays : 2(125 yellows. It is very diffi- 

 cult to always distinguish between pale grays, yellows 

 and whites, a fact which is well know to those working 

 with oats. This is especially true in unfavorable seasons 

 when oats are likely to weather badly. Xo doubt this 

 difficulty is one of the reasons for the deviation of the 

 gray and yellow classes. When we group the non-blacks 

 together we have a very fair approximation to the 3:1 

 ratio, which ratio would be expected on the above assump- 

 tion. 



The relation between color and pubescence for these 

 same second generation plants is well illustrated by Table 

 II. 



TABLE II 



Certain interesting facts are brought out by this table. 

 It is apparent that all of the black oats are pubescent, 

 some having both kernels pubescent and a larger number 

 having only the <>ne kernel pubescent. It is very sig- 

 nificant that there are no smooth black oats. The gray 

 oats, on the other hand, have a certain .number of which 

 both kernels are pubescent, a larger number with one 



