UNIONS OF DIMORPHIC AND TBIMOBrillC PLANTS. 



393 



On the Character and Hybrid-like N'ature of the Offspring from 

 the Illegitimate TJnimis of Dimorphic and Trimorphic Plants. 

 By Chaeles Daemz4. M.A.. F.E.S.. VJ^H /to 



[Bead Feb. 20, 1868.] 

 Table of Coxtexts. 



Preliminary explanation. 



Lythrum SaHcaHa, various illegiti- 

 mate unions and character of off- 

 spring. 



Concluding remarks onLythrum, 

 Oxalis rosea, transmission of form. 

 Primula sinensis. 



Summary on the transmission of form," 

 constitution, and fertility of the ille- 

 gitimate offspring of Rjinerisis, 



Equal-styled variety of P. sinensis. 



Primula Auricula, equal-styled var. of. 

 Pri??mla vulgaris, transmission of form 



and fertility of illegitimate offspring. 

 Primula veris, transmission of form 



and fertility of illegitimate ofTspring. 

 Equal-styled red variety of P. veris. 

 Pulnwyiaria, transmission of form. 

 Conclusions in regard to the illegiti- 



mate offspring of trimorphic and 



dimorphic plants. 



Vaeious plants, which I have called dimorphic and trimorphic, 

 have been described by me in papers read before this Society *. 

 But it may be convenient to recall as briefly as possible the 

 meaning of these terms. Dimorphic species consist of two forms, 

 which naturally exist in about equal numbers : in the long-styled 

 form the pistil is always longer, and the stamens (excepting in 

 the case of Linum grandiflorum) are shorter than in the other 

 form. Conversely, in the short-styled form the pistil is shorter 

 and the stamens longer than in the long-styled form. In the 

 latter the pollen -grains are almost always of larger size than in 

 the sbort-styled form. The sexual union of the two distinct forms 

 is necessary for full fertility : such unions I formerly called hete- 

 romorphic ; but, for reasons which will immediately appear, it is 

 more convenient to speak of them as legitimate, and the offspring 

 thus produced, as ordinarily occurs in nature, as legitimate. 

 When long-styled or short-styled plants are impregnated with 

 their own-form pollen, the union is not fully fertile, or is even 

 absolutely barren. Such unions, and the offspring raised from 

 them, may be called illegitimate. Thus two legitimate and two 

 illegitimate unions can be effected. 



With trimorphic species, the case is more complex. There are 

 three forms, which differ greatly in the length of the pistil ; and 

 in each form two sets of stamens exist, differing in length, in the 



Journal of Proceedings, Bot. vol. vi. ( 1 

 (1864) p. 69. '*On Lythrum sdicaria, 



LINN. PKOC. BOTANT, VOL. X. 



in the species of Priynula,'" 

 "On Linum,'* ibid. vol. rii. 



2d 



