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THE AMERICAN NATURALIST [Vol. XLIX 



pubescence, foliage, inflorescence, buds, flowers, and capsules. 

 The rosettes were also Lamarckiana-like. Only in habit was it 

 somewhat difficult to match the symmetry of Lamarckiana. 

 That further selection in later generations is likely still to fur- 

 ther improve on the results of this synthesis seems altogether 

 probable. These studies will shortly be described in full. 



I am well aware that a synthesis of a Laynarckiana-like hybrid 

 even should it throw in successive generations a series of marked 

 variants (mutants) will not be considered by De Vries and his 

 disciples as casting doubt on the validity of the "mutation" of 

 Lamarckiana. They will say that in this case the hybrid took its 

 mutating habit from one or both of the parents. Since in my 

 cross one of the parents is the Dutch 'biennis which Stomps has 

 shown can produce nanella, semi-gigas and sulfurea mutants, it 

 will be claimed that any behavior of my hybrids similar to 

 mutation will be due not to the mixing of diverse germ plasms, 

 i. e., to crossing, but will be merely a further expression of 

 mutating habits inherent in the germ plasm of at least biennis 

 if not also of franciscana. 



This phase of the discussion may rest until we know the future 

 behavior of my hybrids and the possibilities of the Dutch biennis 

 as a form capable of mutation. It is to be expected that Stomps 

 will carry out his very important studies on a scale that will 

 virtually exhaust the mutative possibilities of this species. Such 

 a study on a close-pollinated species of CEnothera so well known 

 as the Dutch biennis will give, it seems to me, the safest data 

 that has yet been published by students of mutation among the 

 CEnotheras. It becomes a matter of great interest to know the 

 range of variants that such a type can produce. Similar studies 

 among some of the wild American species should also be made. 

 The open-pollinated assemblage of forms to which Lamarckiana 

 belongs must always be open to suspicion of hybridization more 

 or less remote in time or distant in relationship. Only prolonged 

 experiment can establish an open-pollinated CEnothera as free 

 from the taint of crossing. 



It is, I trust, clear that one may believe very strongly that 

 CEnothera Ijamarckiana is not safe material on which to base 

 experiments designed to test the mutation theory and yet remain 

 receptive to evidence that may come from other sources. 



Bradley Moore Davis 



University of Pennsylvania, 

 October, 1914 



