THE PROBABLE ORIGIN OF OENOTHERA LAMARCKIANA SER. 583 



a doubt upon the stability of those forms for which no positive 

 results have as yet been won. In other words, we may say that 

 almost all the nearest allies of 0. Lamarckiana are open to t he- 

 suspicion of sharing at least some degree of the mutability of this 

 species. There is no use, therefore, in trying to produce mutability 

 by crosses of species of the same subgenus {Onagra) in order to 

 show that this phenomenon is only a result of crossing, as is asserted 

 by Davis. 



Moreover, I might point out that the question should be dealt 

 with from a general standpoint and not be limited to the evening 

 primroses. If it should be true that phenomena like those of 0. 

 Lamarckiana could be produced by crossing immutable species, it 

 would, of course, be of much higher scientific value to produce 

 them in other families or genera, or at least in the other subgenera of 

 the evening primroses. The chance of finding immutable parents 

 for a cross would be far greater and the proof could be given as 

 easily and in many cases with less amount of mechanical work 

 and space in the garden. The line of work chosen by Davis seems 

 to me to be necessarily without any chance of success. 



Besides his experimental work Davis has made some historical 

 researches to discover the origin of 0. Lamarckiana.^) Unfortu- 

 nately he has neglected to visit the Museum d'Histoire Naturelle 

 at Paris, where the herbarium of Lamarck is preserved, and where 

 other valuable documents concerning the first appearance of our 

 species are to be found. For myself I visited these collections in 

 1895 and reported on the results of my investigations in my Muta- 

 tion theory (vol. I. pp. 437-444 of the English edition), in Octo- 

 ber 1913 1 repeated my visit and compared the authentic specimens 

 with the remarks made upon them by Davis. 1 regret to say that, 

 through his ignorance of the available evidence, Davis has been 

 led to conclusions which are fully contradicted by the herbarium 

 material, both of the "Herbier de Lamarck" and of the "Herbier 

 general" of the Museum. As we shall see, the origin of 0. Lamarck- 

 iana is the same as I have pointed out in my book. 



In the herbarium of Lamarck, 0. grandiflora (Lam.), which 

 later was renamed by Seringe and called 0. Lamarckiana, the 



i) Davis, B. M., Was Lamarck's evening: primrose [Oenothera Lamarckiana 

 Seringe) a 'form of Oenothera grandiflora Solander? Hull. Torr. Hot. Club 



3Q:5ig c^2,}), pis. 37 — 39. 1912; A much desired Oenothera. Plant 



World 16: 145—153, 1913; The problem of the origin of Oenothera 

 Lamarckiana. New. Phytol. 12:233—241, 1913- 



