No. 608] 



WEAK AWN IX AVENA CROSSES 



491 



awnless class, and that the other classes are represented 

 in practically equal numbers. In the case of the yellows, 

 however, there are ahout two and one half times as many 

 in the awnless class as in the fully-awned class. Fifty- 

 seven per cent, of the yellows have less than 20 per cent, 

 of awning, and seventy-three per cent, have less than 30 

 per cent, of awning. Many of the yellows in the 100 per 

 cent, class are doubtless due to the yellow factor con- 

 tained in the Burt parent. This factor does not inhibit 

 awning. 



Strong Aivn X Aivnless.—H\e results of crosses be- 

 tween Avena fatua and the variety Sixty-Day {A. safiva) 

 agree closely with those obtained in the crosses between 

 the weak-awned and awnless tvpes. (See Tables VIII 

 and IX.) 



TABLE YIII 

 F, Total of Series 2516 



In a Similar study on J. rulna A.satini var. Kherson, 

 Surface (1910) obtaiiUMl h'him^ ^^huh am.. .IumIx uith 

 those presented abovl'. Tlie l-', j)linit> were iicarlx- inter- 

 mediate, although ''The inaionty of F, spikolets show 

 no awn whatever" (p. '2(h)). In tlie second generation 

 the following ty]>es apjieared: 



