The Mutations in the Lamarckiana-Fajnily. 233 



features of Oenothera leptocarpa, a new species at that 

 time. 



The existence of the single Laiuarckiana was i)lainly 

 a difficulty, so that I 

 not only continued but 

 repeated the experi- 

 ment. 



For the continua- 

 tion of the experiment 

 I used the seeds saved 

 in 1896. I raised from 

 them, in 1897, 1114 

 plants; every single one 

 of which was a riibri- 

 nervis. 



For the repetition 

 of the experiment I 

 used the self-fertilized 

 seeds of the four plants 

 which had arisen in 

 1896 from the Laniarc- 

 kiana-i^mily and could 

 therefore boast four 

 generations of pure 

 Lamar ckiana ancestry. 

 From these seeds I 

 raised altogether 1862 

 plants, which were 

 without exception riib- 

 ' rinerz'is. 



From these facts I conclude : 



1. That rnbrinervis is an absolutely ci^nstant elemen- 

 tary species. 



Fig. 44. Oenothera ohlonga. Upper 

 part of a plant at the commence- 

 ment of flowering. 



