OENOTHERA LAMARCKIANA MUT. VELUTINA. 



179 



figures of 0. Lamarckiana. This splitting may be considered, there- 

 fore, as amphiclinous 1 ), 73 per cent of the hybrids belonging to the 

 one and 27 per cent belonging to the other parental type. The 

 splitting is analogous to that of the cross 0. Lamarckiana x nanella, 

 which gives, under ordinary circumstances, in the first generation 

 about 78 per cent tall and 22 per cent dwarfish specimens. It must 

 be pointed out, however, that here the germs, which belong to the 

 next generation, are dealt with as a mark of the first generation. 

 In this respect they may be compared with the rudimentary ovules 

 of Geerts, which are not fertilized. 



I tried also the blandina plants of the same crosses, but had fer- 

 tilized only two specimens of each, which is too few to study this 

 phenomenon. I found 77 and 69 per cent, 67 and 60 per cent, and 

 71 and 70 per cent of good grains among their seeds. It is remarkable 

 that all of these plants had about the same figure, which is far less 

 than that of the specimens of the race of 0. blandina (about 95 per 

 cent), but a splitting did not show itself. 



The same difference as between the laeta and extracted velutina 

 was shown by the subrobusta and the velutina from the crosses with 

 0. rubrinervis. I found the figures as given in table V. 



Table V 



It is possible, however, that this difference is only an effect of 

 the higher exigencies of the plants of the type of blandina, since we 

 have already seen that their amount of good grains is easily dimin- 

 ished by an unfavorable culture. Moreover, this character is not 

 a constant one, for in trying the blandina plants of the second gen- 

 eration I found their contents of normal embryos complete, no 

 single empty grain being found in lots of 200 seeds of two such 

 plants. 



It is necessary, of course, to study the progeny of the laeta plants 

 with a high and of those with a low percentage figure. Until now, 

 however, I have had only an opportunity to study the offspring 



*) Ueber amphikline Bastarde. Ber. Deutsch. Bot. Gesells. 33:461 — 468. 

 1915. Opera VII, p. 48. 



