Chap. V. HETEROSTYLED DIMORPHIC PLANTS. 229 



Primula vekis, Brit. Fl. 



Var. officinalis of Linn., P. officinalis of Jacq. 



Seeds from the short-styled form of the cowslip 

 fertilised with pollen from the same form germinate 

 so badly that I raised from three successive sowings 

 only fourteen plants, which consisted of nine short- 

 styled and five long-styled plants. Hence the short- 

 styled form of the cowslip, when self -fertilised, does not 

 transmit the same form nearly so truly as does that 

 of P. Sinensis. From the long-styled form, always 

 fertilised with its own-form pollen, I raised in the 

 first generation three long-styled plants, — from their 

 seed 53 long-styled grandchildren, — from their seed 

 4 long-styled great-grandchildren, — from their seed 

 20 long-styled great-great-grandchildren, — and lastly, 

 from their seed 8 long-styled and 2 short-styled great- 

 great-great-grandchildren. In this last generation 

 short-styled plants appeared for the first time in the 

 course of the six generations, — the parent long-styled 

 plant which was fertilised with pollen from another 

 plant of the same form being counted as the first 

 generation. Their appearance may be attributed to 

 atavism. From two other long-styled plants, fertilised 

 with their own-form pollen, 72 plants were raised, 

 which consisted of 68 long-styled and 4 short-styled. 

 So that altogether 162 plants were raised from illegiti- 

 mately fertilised long-styled cowslips, and these con- 

 sisted of 156 long-styled and 6 short-styled plants. 



We will now turn to the fertility and powers of 

 growth possessed by the illegitimate plants. From 

 a short-styled plant, fertilised with its own-form 

 pollen, one short-styled and two long-styled plants, 

 and from a long-styled plant similarly fertilised three 

 long-styled plants were at first raised. The fertility 



