274 CONCLUDING RBMAKKS Chap. VL 



flowers legitimately fertilised. With P. auricula and 

 farinosa the stamens resemble those of the short-styled 

 form in length, but those of the long-styled 'in the 

 size of their pollen-grains ; the pistil also resembles that 

 of the long-styled, so that although the stamens and 

 pistil are of nearly equal length, and consequently 

 pollen is spontaneously deposited on the stigma, yet 

 the flowers are not legitimately fertilised and yield 

 only a very moderate supply of seed. We thus see, 

 firstly, that equal-styled varieties have originated in 

 various ways, and, secondly, that the combination of 

 the two forms in the same flower differs in complete- 

 ness. With P. elatior 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 varia- 

 tion 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 induce reversion, and 

 it is chiefly the cultivated species of Primula which be- 

 come equal-styled. Illegitimate 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 sub- 

 sequent stages of this variation. With some other plants 

 of P. Sinensis of similar parentage the flowers ap- 

 peared to have reverted to their original wild con- 

 dition. 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 



