Lecture XVIII 



NEW SPECIES OF OENOTHERA 



In our experiments on the origin of peloric 

 varieties and double flowers we were guided in 

 the choice of our material by a survey of the 

 evidence already at hand. We chose the types 

 known to be most commonly produced anew, 

 either in the wild state or under the conditions 

 of cultivation. In both instances our novelty 

 was a variety in the ordinary sense of the word. 

 Our pedigree-culture was mainly an experi- 

 mental demonstration of the validity of conclu- 

 sions, which had previously been deduced from 

 such observations as can be made after the ac- 

 cidental birth of new forms. 

 . From these facts, and even from these pedi- 

 gree-experiments, it is scarcely allowable to 

 draw conclusions as to the origin of real spe- 

 cies. If we want to know how species originate, 

 it is obviously necessary to have recourse to 

 direct observation. The question is of the high- 

 est importance, both for the theory of descent, 

 and for our conception of the real nature of 



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