No. -332] GEXETK AE SIC DIES ()\ (ENOTHERA 231 



so recently extinct when, as lie well knows, the UHnotheras 

 are established as remarkably successful forms in our 

 flora. The fact that Lamarckiana is not known as a com- 

 ponent of the native American flora stands as the most 

 serious obstacle to the view that this plant is representa- 

 tive of a wild species. The writer believes it very prob- 

 able that plants more or less resembling Lamarckiana 

 will occasionally, or perhaps rarely, be found in parts of 

 America and under circumstances indicating that they 

 are not garden escapes, but it seems to him equally prob- 

 able that these forms when tested in culture will give evi- 

 dence of a heterozygous, or hybrid nature. The mere 

 records of such plants as handed down by the average 

 type of herbarium specimen, unaccompanied by experi- 

 mental cultures, will have little or no value for the pres- 

 ent problem — the origin of (Enothera Lamarckiana. 



Summary 



This paper offers a body of evidence which shows that 

 hybrids resembling (Enothera Lamarckiana may be syn- 

 thesized from certain strains of the American native 

 species 0. biennis and 0. grandiflora. The resemblances 

 of the hybrids to this plant are strongest with respect 

 to the inflorescence, buds and flowers. The differences 

 are chiefly manifest in the basal foliage of the mature 

 plant, in the coloration of the stem, and in the more strag- 

 gling habit of the hybrids. The rosettes of the hybrids 

 present mixed forms of leaves, the younger with points 

 of similarity to Lamarckiana. Bearing in mind that 

 other strains of biennis have characteristics more La- 

 markiana-like than those of strains A and B, herein de- 

 scribed, it is more than probable that the hybrids from 

 certain crosses made this season (1910), when grown 

 in future cultures, will come closer to the desired end— 

 the synthesis of a hybrid so similar to Lamarckiana as 

 to be practical! v indistinguishable bv the usual taxonomic 

 tests. 



Exception is taken to the claim of MacDougal ('07, 



