no 



BOTANICAL GAZETTE [FEBRUARY 



crimson, which gives the stigmas the appearance of being orange 

 colored, unless examined closely. No study has been made of the 

 inheritance of this stigmatal margin, but it seems not unlikely that it 

 too may prove to be a Mendelian character. Although the color of 

 the disk affects several organs of very different morphological value, 

 it proves to be a simple character, showing the same kind of correla- 

 tion that is found in peas and beans which have purple flowers and 

 black seeds, and other plants which have purple flowers associated 

 with more or less purple in the stems. 



The cross made during the summer of 1905 between the purple- 

 disked wild sunflower and the yellow-disked, branched, garden sun- 

 flower, produced in 1906 a progeny (05153) consisting of 26 with purple 

 disks and 27 with yellow disks ; when I would have expected all purple 

 on the assumption that both parents were pure-bred and purple 

 dominant over non-purple, as has been the general experience with 

 the purple color-character in other plants. The conclusion reached 

 was that either the purple disk is not a Mendelian character or the 

 purple parent was a DR instead of a pure-bred purple. As yellow 

 disks have not appeared among my cultures of wild sunflowers during 

 three years, the assumption that the one plant which I used for the 

 cross was itself a hybrid seemed very unlikely, and the probability 

 that this strictly alternative character was not behaving according 

 to Mendelian expectation led me to watch the culture the following 

 season (1907) with great interest. Five F 2 families were raised, two 

 reciprocal families of purple by purple, representing the hypothetical 

 cross DRxDR; two reciprocal families between purple and yellow, 

 representing the cross DR X R ; and one family of yellow by yellow, 

 representing the cross R X R. The results were as follows : 



No. 06359, 64p:2iy 



No. 06760. 64 p : 16 y 



DRXDR 



DRXR 



Total, 



Expected, 

 R ( No. 06358, 

 ( Expected, 



Total, i28p: 3 7y 



Expected, 



No. 06361, 



