HETEROSTYLISM. 205 



The first observation is that in twelve cases the short- 

 styled are in excess of the long-styled, and in four cases (1) this 

 is reversed. Hence Mr. Darwin's conclusion is not absolute ; 

 and it is a somewhat remarkable fact that Primula veris (the 

 Cowslip) is the identical species from which he deduced the 

 conclusion that the short-styled was the more feminine of 

 the two forms. The conclusion now arrived at from this 

 species would be, that Avhen it is left to itself the short-styled 

 form sets most seed ; but when artificially crossed it is the 

 long-styled form which bears best. The cause of the former 

 result is that some pollen in the short-styled form can fall 

 upon the stigma and so secure self-fertilisation, which is 

 impossible in the latter case. The same results occurred with 

 Mr. Scott.* 



Hence Mr. Darwin's first conclusion, that the short-styled 

 was the more feminine, was drawn from a wrong premise ; 

 as it was not a question of sex so much as of union. When 

 the results of self-fertilisation are compared, as given in the 

 table on next page, it appears that the long-styled form of 

 the Cowslip is the more feminine of the two, in the pro- 

 portion of 42 to 30. 



Of that table, three cases of Primula sp. (|) only show the 

 short-styled bearing more seed than the long-styled when 

 illegitimately fertilised; viz., with Mr. Scott, P. vulgaris, var. 

 alba, and P. Auricula (i.e. forms more or less modified by 

 cultivation) ; and with Hildebrand, P. Sinensis, when crossed 



* Journ. Linn. Soc. Bot., vol. viii., 1864. This case may be taken to 

 illustrate one of the disadvantages often accruing through groat differenti- 

 ation and adaptation to insect visitors. Tliough it appears proved that 

 legitimate crossing sets most seed when carefully and artificially 

 effected; yet, when the process is left to the capricious visits of insects, 

 Mr. Darwin's experiments show how nature fails to derive the full 

 benefit of intercrossing ; so that the Cowslip has to be contented with the 

 results of the illegitiniate union of the least fertile of the two forms. 



