18 HETEROSTYLED DIMORPHIC PLANTS. CHAP. L 



never found on the same individual plant. I marked 

 many Cowslips and Primroses, and on the following 

 year all retained the same character, as did some in my 

 garden which flowered out of their proper season in the 

 autumn. Mr. W. Wooler, of Darlington, however, in- 

 forms us that he has seen early blossoms on the Polyan- 

 thus,* which were not long-styled, but became so later 

 in the season. Possibly in this case the pistils may not 

 have been fully developed during the early spring. An 

 excellent proof of the permanence of the two forms may 

 be seen in nursery-gardens, where choice varieties of 

 tiie Polyanthus are propagated by division ; and I found 

 whole beds of several varieties, each consisting exclu- 

 sively of the one or the other form. The two forms exist 

 in the wild state in about equal numbers : I collected 

 522 umbels from plants growing in several stations, 

 taking a single umbel from each plant ; and 241 were 

 long-styled, and 281 short-styled. No difference in 

 tint or size could be perceived in the two great masses 

 of flowers. 



We shall presently see that most of the species of 

 Primula exist under two analogous forms ; and it may 

 be asked what is the meaning of the above-described 

 important differences in their structure? The ques- 

 tion seems well worthy of careful investigation, and I 

 will give my observations on the cowslip in detail. 

 The first idea which naturally occurred to me was, 

 that this species was tending towards a dioacious 

 condition; that the long-styled plants, with their 

 longer pistils, rougher stigmas, and smaller pollen- 

 grains, were more feminine in nature, and would pro- 

 duce more seed; that the short-styled plants, with 

 their shorter pistils, longer stamens and larger pol- 



* I have proved by numerous that the Polyanthus is a variety 

 experiments, hereafter to bo given, of Primula verr*. 



