36 HETEROSTYLED DIMORPHIC PLANTS. Chap. I. 



flowers from each lot were measured, but there was no 

 sensible difference between them in size. Nine long- 

 styled and eight short-styled plants growing together 

 in a state of nature were marked, and their capsules 

 collected after they had been naturally fertilised; and 

 the seeds from the short-styled weighed exactly twice 

 as much as those from an equal number of long-styled 

 plants. So that the primrose resembles the cowslip in 

 the short-styled plants, being the more productive of 

 the two forms. The results of my trials on the fer- 

 tility of the two forms, when legitimately and illegiti- 

 mately fertilised, are given in the following table : — 



Table 9. 

 Primula vulgaris. 



* This average is perhaps rather too low. 



We may infer from this table that the fertility of 

 the two illegitimate unions taken together, is to that of 



