CHAP. II. THE COMMON OXLIP. 59 



were I may remind the reader that 90 per cent, of the 

 flowers of the primrose fertilised legitimately with 

 primrose-pollen yielded capsules, containing on an 

 average 66 seeds ; and that 54 per cent, of the flowers 

 fertilised illegitimately yielded capsules containing on 

 an average 35*5 seeds per capsule. The primrose, 

 especially the short-styled form, when fertilised by the 

 cowslip, is less sterile, as Gartner likewise observed, 

 than is the cowslip when fertilised by the primrose. The 

 above experiments also show that a -cross between the 

 same forms of the primrose and cowslip is much more 

 sterile than that between different forms of these two 

 species. 



The seeds from the several foregoing crosses were 

 sown, but none germinated except those from the 

 short-styled primrose fertilised with pollen of the 

 polyanthus ; and these seeds were the finest of the 

 whole lot. I thus raised six plants, and compared 

 them with a group of wild oxlips which I had trans- 

 planted into* my garden. One of these wild oxlips 

 produced slightly larger flowers than the others, and 

 this one was identical in every character (in foliage, 

 flower-peduncle, and flowers) with my six plants, 

 excepting that the flowers of the latter were tinged of 

 a dingy red colour, from being descended from the 

 polyanthus. 



We thus see that the cowslip and primrose can- 

 not be crossed either way except with considerable 

 lifficulty, that they differ conspicuously in external 

 appearance, that they differ in various physiological 



illegitimately with pollen of the 22 '6 seeds. On the other hand, 

 cowslip gave rive c.ipsules, contain- the seeds produced by the poly- 

 ing on an average 32 4 seeds, an th us - pollen were much the 

 whilot 18 flowers bimilarly fertil- finest of the whole lot, and were 

 ised l>y polyanthus-pollen yielded the only ones which germinated, 

 ouly Qve capsules, containing only 



