274 CONCLUDING BEMAEKS Chap. VI 



ness. With P. datior some of the flowers on the same 

 plant have become equal-styled, instead of all of 

 them as in the other species. 



Mr. Scott has suggested that the equal-styled varie- 

 ties arise through reversion to the former homostyled 

 condition of the genus. This view is supported by 

 the remarkable fidelity with which the equal-styled 

 variation is transmitted after it has once appeared. I 

 have shown in Chapter XIII. of my 'Variation of 

 Animals and Plants under Domestication,' that any 

 cause which disturbs the constitution tends to in- 

 duce reversion, and it is chiefly the cultivated 

 species of Primula which become equal-styled. Ille- 

 gitimate fertilisation, which is an abnormal process, 

 is likewise an exciting cause ; and with illegitimately 

 descended long-styled plants of P. Sinensis, I have 

 observed the first appearance and subsequent stages 

 of this variation. With some other plants of P. Si- 

 nensis of similar parentage the flowers appeared 

 to have reverted to their original wild condition. 

 Again, some hybrids between P. veris and vulgaris 

 were strictly equal-styled, and others made a near 

 approach to this structure. All these facts support 

 the view that this variation results, at least in part, 

 from reversion to the original state of the genus, 

 before the species had become heterostyled. On the 

 other hand, some considerations indicate, as previously 

 remarked, that the aboriginal parent-form of Primula 

 had a pistil which exceeded the stamens in length. 

 The fertility of the equal-styled varieties has been 

 somewhat modified, being sometimes greater and some- 

 times less than that of a legitimate union. Another 

 view, however, may be taken with respect to the origin 

 of the equal-styled varieties, and their appearance 

 may be compared with that of hermaphrodites amongst 



