VOLUME LVII NUMBER S 



THE 



Botanical Gazette 



MAY igi4 



THE PROBABLE ORIGIN OF OENOTHERA 

 LAMARCKIANA SER. 



Hugo De Vries 

 (with plates xvii-xrx) 



In a series of most interesting articles, B. M. Davis has recently 

 tried to prove that mutability might be a result of previous crosses. 

 This view was first proposed by Bateson and Saunders, and 

 applies especially to the phenomena which Oenothera Lamarckiana 

 shows when seeds from the pure strain, and even from pure lines 

 within this strain, are sown, as in the experiments I conducted in 

 my experimental garden. Davis expected to be able to offer the 

 desired proof by showing that 0. Lamarckiana might be dupUcated 

 by crossing two other species of the same group. Up to this time, 

 as a matter of fact, he has not succeeded in producing any form 

 which comes sufficiently near 0. Lamarckiana to be compared with 

 it.' But if he had succeeded in doing so, evidently it would not 

 have been a proof for his assertion, unless his hybrid should show 

 the same degree of mutability as does O. Lamarckiana, since we 

 have as yet no means of judging from the morphological characters 

 of a given plant whether its hereditary characters are in a stable 

 or in an unstable condition. 



In starting his experiments to produce a duplication of 

 Lamarck's eveniag primrose, Davis was unfortunate in the choice 

 of the species for his combination. He chose 0. biennis L. and a 



' For a successful duplication of an dementary species by means of crossing, 

 see Oenothera biennisXO. cruciata Nutt. in Gruppenweise Artbildung, p. 311. 



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