OENOTHERA AND THE MUTATION THEORY 309 



as early as 1902, to suggest tliat O. Lamarckiana 

 might be a liybrid, and that the new types might 

 be simply recombination products. There were 

 very serious difficulties in the way of this hypothesis, 

 and it was not stronglj^ urged by its proponents. 

 The view was, however, strengthened by a study of 

 the history of the species. The members of the 

 group to which it belongs are a])parently all native 

 in America, but several of them have become 

 naturalized in Europe. It is verj?" dou1)tful if 

 0. Lamarckiana occurs in America as a wild plant, 

 so that it may well be suspected of being a hybrid 

 that was first obtained artificially and that then 

 accidentally escai:)ed and became established in 

 Europe. Davis has worked on this hy]^othesis and 

 has tried to synthesize the species by crossing wild 

 American species. The (iiicstion has now lost 

 much of its point, however, through the discovery 



