206 THE MENDEL JOURNAL 



reason that even when growing alongside of other " varieties " 

 (species ?) " of Nicotiana in the open it always seeds true," and 

 this suggestion carries with it the implication that all the seed of 

 N. Sanderae are produced parthenogenetically. 



Mendelian segregation is not to be expected in the case of 

 parthenogenetically produced offspring. Thus the evidence on 

 which N . Sanderae is regarded as not a hybrid is, to say the least, 

 somewhat weak. 



FurthermoiC, it is not shown that iV. Forgeiiana exhibits 

 the phenomenon of parthenogenesis, although this is of course 

 possible. If this were shown, greater weight might be attached 

 to the suggested origin of N. Sanderae., but in the absence of this 

 proof the origin of N. Sanderae seems certainly not less " shrouded 

 in mystery " than it was before. 



It is conceivable that a hybrid, such as N . Sanderae is alleged 

 to be. should breed true by producing seed parthenogenetically. 

 Royal Horticultural Society. Feed. J. Chittenden. 



\ Reply to IVIr. Chittenden's Nete. 



Mr. F. J. Chittenden's criticism of the doubt which I expressed 

 respecting the hybrid nature of Nicotiana Sanderae, in a short 

 paper on "Parthenogenesis (Apogamy) " in '" Nicotiana, "t 

 is based upon the supposition that " Mendelian segregation is 

 not to be expected in the case of parthenogenetically produced 

 offspring." But within my experience segregation has occurred 

 among apogamous plants. I will cite the case : 



An F, N. sylvestris x N. afjinis ; white upper surface, 

 coloured under surface, was treated for apogamy, by cutting off 

 the anthers and stigma in the young bud. and ripe capsules were 

 gathered on the 31st of August, 1909. The seed was sown 4th 

 Sept. ; and germinated r2th Sept. 1909. In May, 1910. all these 

 Fg apogamous plants, some sixty in number, flowered under glass, 

 and split into the reds, purples, and whites with coloured under- 

 surface which we would expect in the case of self-pollinated 

 seed ; unfortunately, the ratio of the different colours was not 

 counted before the plants went off flower, but in June fourteen of 

 them were planted in the open border. These flowered again in 

 September, and the colours were counted : — 



White, with coloured under surface. Red. Purple. 



10 3 1 



t" Mendel Journal," October, 1909. 



