358 Origin of Each Species Considered Separately. 



pollinated individual in a parallel culture in the same 

 year. 



It only remains to be stated that in these two cultures 

 the 0. leptocarpa came true to seed. In fact this can be 

 clearly seen from the above two columns of figures; the 

 individuals measured obviously form a definite group, 

 although their curve of individual variability naturally 

 overlaps that of O. Lamarckiana whose mode is at 22-24. 

 The curves are transgressive, as is so often the case in 

 closely allied species.^ The thickest fruits of O. lepto- 

 carpa are thicker than the thinnest of 0. Larnarckiana, 

 so that if we only had this character to go by we should 

 sometimes be unable to distinguish the tw^o species. 



Culture A consisted of 300 and B of 150 plants and 

 all of them, even those which did not ripen their fruits 

 exhibited the characters peculiar to O. leptocarpa with the 

 single exception of two O. nanella. Some of the plants 

 were perfectly pure leptocarpa whilst others approached 

 the characters of the parent species to a certain degree. 

 For, all the characters of the species exhibit individual 

 variability just as we have seen the thickness of the 

 fruits to do. 



In spite of this transgressive variability the constancy 

 of the new species was proved by the cultures. There was 

 no real reversion. 



§ 17. OENOTHERA SEMILATA. 



This species has only appeared thrice in my cultures ; 

 and every time from 0. lata. One appeared in 1894, 

 the other two in two independent cultures in 1895. They 

 looked very much like 0. lata except that the characters 



^ On this point see § 25 of this Part. 



