224 ILLEGITIMATE OFFSPRING OF CHAP. V 



that the short-styled form is not rendered qtiite sterile by a 

 long course of fertilisation with pollen of the same form : but as 

 there would always be some liability to an occasional cross with 

 the other form, we cannot tell how long self-fertilisation has 

 been continued. 



PRIMULA FABINOSA. 



Mr. Scott says * that it is not at all uncommon to find equal- 

 styled plants of this heterostyled species. Judging from the 

 size of the pollen-grains, these plants owe their structure, as in 

 the case of P. auricula, to the abnormal elongation of the 

 stamens of the long-styled form. In accordance with this view, 

 they yield less seed when crossed with the long-styled form 

 than with the short-styled. But they differ in an anomalous 

 manner from the equal-styled plants of P. auricula in being 

 extremely sterile with their own pollen. 



PBIMULA ELATIOB. 



It was shown in the first chapter, on the authority of 

 Herr Breitenbach, that equal-styled flowers are occasionally 

 found on this species whilst growing in a state of nature ; and 

 this is the only instance of such an occurrence known to me, 

 with the exception of some wild plants of the Oxlip a hybrid 

 between P. veris and vulgaris which were equal-styled. Herr 

 Breitenbach's case is remarkable in another way; for equal- 

 styled flowers were found in two instances on plants which bore 

 both long-styled and short-styled flowers. In every other 

 instance these two forms and the equal-styled variety have been 

 produced by distinct plants. 



PKIMULA VULGARIS, Brit. FL 

 Var. acaulis of Linn, and P. acaulis of Jacq. 



Var. ruhra. Mr. Scott states! that this variety, which 

 grew in the Botanic Garden in Edinburgh, was quite 

 sterile when fertilised with pollen from the common 

 primrose, as well as from a white variety of the same 



* ' Journal Proc. Linn. Soc.' viii. (1864), p. 115. 

 t ibid. p. 98. 



