MUTATIONS, VARIATIONS, AND RELATIONSHIPS OF THE OENOTHERAS. 8 1 



individuals of oblonga and lamarckiana, in addition to an unrecognizable form, 

 the representative of which did not reach maturity. Purely fertilized seeds of 

 this form have also been seen to give rise to lata and nanella. 



0. oblonga was grown directly from its own seeds and also appeared in all 

 of the cultures of the parental type which were spread sufficiently to include 

 its coefficient of mutability. It appears to be constant in its characters and 

 is strikingly differentiated at a very early stage of its development. 



0. albida was also grown directly from its own seed and appeared in the 

 pedigreed cultures of lamarckiana. It appeared to coincide in all of its 

 characters with the descriptions given by De Vries. 



The single test which was made of the effect of crossing the parental type, 

 lamarckiana, with one of its mutants, rubrinerms, gave results in accordance 

 with the conclusions of De Vries in this matter. Rubrinerms is a mutant of 

 supposedly low frequency of occurrence, since it has not been found in any 

 pedigreed culture for several years. It may be regarded as a progressive 

 derivative of the parental type and presumably carries all of the lamarckiana 

 qualities in a latent condition. On the other hand, the strain of lamarckiana 

 with which it was crossed, and from which it was derived several generations 

 back, must bear the characters which gave rise to this form as a mutant. The 

 two plants must therefore carry the same characters, but some are latent in 

 one and some in the other. 



The origin of species by hybridization, which has been a well -recognized 

 phenomenon for half a century, receives further exemplifications in crosses 

 between 0. cruciata and O. lamarckiana. The fixed forms which may be pro- 

 duced by this cross have been cultivated in European gardens for some time 

 under the names of 0. cruciata, 0. cruciata varia, and 0. biennis cruciata. The 

 list of species which have originated by hybridization is a long one and need 

 not be recounted here. Singularly enough, this fact seems to be unknown to 

 workers who carry on extensive operations in plant breeding. In the instances 

 cited in this paragraph, the most remarkable feature is that a fixed form or 

 new species may be produced by the hybridization of two parental types of 

 comparatively high frequency of mutability. It seems also pertinent to again 

 sound a warning against the continued practice of taxonomists of ascribing 

 hybrid origin to species, with characters apparently intermediate between two 

 neighboring and known forms. Numerous hybrids of known origin in the 

 New York Botanical Garden have been submitted to competent taxonomists, 

 and in no single instance has a correct diagnosis of the parentage been made. 



The fertilization of the eggs of lamarckiana from the pollen of rubrinervis 

 resulted in a single observation in a progeny which contained 71 per cent of 

 the latter, or mutant, type. This is not a universal result, however, since the 

 proportion has been found to vary from 19 to 74 per cent. The pollination of 

 0. biennis by the mutant described in this paper gave a progeny in the first 



