Nos. 620-621] COLOR IN A VENA CROSSES 373 



The percentage of awns was determined by taking a 

 typical head from each plant and counting the total num- 

 ber of spikelets and the number of awned spikelets, and 

 then determining the percentage of awed spikelets. 

 Since there are a number of plants having no awns and 

 also a number having 100 per cent, it seems best to ar- 

 range the classes as has been done in this table ; that is, 

 separate classes have been made for the and 100 per 

 cent, values. 



From this table it is clear that the black oats possessed 

 varying degrees of the awned condition from awnless to 

 fully awned. The grays too showed about the same 

 range of distribution. The yellow types, however, 

 showed a tendency to be grouped in the lower classes. 

 No yellow types were found having more than 30 per 

 cent, of awns. It seems quite evident that there may be 

 some relation between the yellow oat and the lack of 

 awning. 



Xilsson-Ehle 6 has discussed a case of a cross in oats 

 where there was an apparent inhibition of awning pro- 

 duced by a yellow oat. He concludes that there was some 

 inhibitory effect of the yellow color or that the yellow 

 color factor acted also as an inhibitor of awns. The 

 oats Nilsson-Ehle worked with were domestic types and 

 it is a well-known fact that the domestic sorts vary as to 

 the amount of awns with the change in environment. 

 For that reason it is felt that results obtained from wild 

 crosses will be more definite since the wild type produces 

 its fully awned condition under very diverse growth con- 

 ditions. This is all the more evident from a cross of 

 this same Sixty Day type used in these crosses with a 

 black cultivated oat. It was found that the yellow oats 

 segregating from this cross contained fewer awns than 

 did the blacks, whites, and grays but that the percentage 

 of awns on the black parent was so variable that the re- 

 sults obtained are not definite. Such is not the case for 

 the awning of the Arena fatua as stated above. 



e Zeitschrift fur induktive Abstammungs- und Yererbungslehre, Bd. XII, 



