Chap. II. HTBEID PEIMULAS. 55 



CHAPTEE II. 



Hybrid Pbimulas. 



The Oxlip a hybrid naturally produced between Primula verig and 

 vulgaris — The differences in structure and function between the 

 two paient-species — Effects of crossing long-styled and short-styled 

 Oxlips with one another and with the two forms of both parent- 

 species — Character of the offspring from Oxlips artificially self- 

 fertilised and cross-fertilised in a state of nature — Primula elatior 

 shown to be a distinct species — Hybrids between other heterostyled 

 species of Primula — Supplementary note on spontaneously produced 

 hybrids in the genus Verbasoum. 



The various species of Primula have produced in a 

 state of nature throughout Europe an extraordinary 

 number of hybrid forms. For instance, Professor 

 Kemer has found no less than twenty-flve such forms 

 in the Alps.* The frequent occurrence of hybrids in 

 this genus no doubt has been favoured by most of the 

 species being heterostyled, and consequently requiring 

 cross-fertilisation by insects ; yet in some other genera, 

 species which are not heterostyled and which in some 

 respects appear not well adapted for hybrid-ferti- 

 lisation, have likewise been largely hybridised. In 

 certain districts of England, the common oxlip — a 

 hybrid between the cowslip (P. veris, vel officinalis) 

 and the primrose (P. vulgaris, vel acaulis) — is fre- 

 quently found, and it occurs occasionally almost every- 



* " Die Primulaceen-Bastarten," ' Bull. Soc. Bot. de France,' torn. x. 



' Oesterr. Bot. Zeitschriit,' Jahr 1853, p. 178. Also in ' Revue des 



1875, Nos. 3, 4, and 5. See also Sciences Nat.' 1875, p. 331. 

 Oodron on hybrid Primulas in 



