366 Origin of Each Species Considered Separately. 



individuals of 0. Laniarckiana of the same age in other 

 respects as well. (See Fig. 64 on page 325.) 



I have recorded the young plants in any one of the 

 four stages (Figs. 78 and 79) according to circum- 

 stances. The further apart the seeds are sown the sooner 

 can the recording be done. But even when they are sown 

 thin a few seeds occasionally fall close together ; so that 

 we find groups of seedlings which cannot be identified 

 until long after the others have been recorded and re- 

 moved. It is often from 4 to 6 weeks before the last 

 individuals have fully developed their characteristics. 



Fig. 79. Oenothera nanella. Young rosettes in May and 

 June. A, from seeds sown thin; B, from seeds sown 

 thick ; V. v. the long-stalked leaves of the atavistic period. 



Indeed I have often had to transplant the seedlings be- 

 fore I could be certain about them : when I did this I gave 

 them ample room and grew them for about a month more 

 in the boxes. If I recognized a plant as a dwarf-mutant 

 in a culture of another species I kept it until it had at- 

 tained the stage shown in Fig. 79 A ; and usually trans- 

 planted it to watch its further development. If on the 

 other hand it was merely a question of finding out 

 whether any Lamarckianas occurred in sowings of 0. 

 nanella (as they often did after fertilization in the open) 



