61 HYBRID PRIMULAS. CHAP. Tt 



species exist or have recently existed ; and this holds 

 good, as far as I can discover, with the oxlip ; but the 

 P. elatior of Jacq., which, as we shall presently see, 

 constitutes a distinct species, must not be confounded 

 with the common oxlip. Secondly, by the supposed 

 hybrid plant being nearly intermediate in character 

 between the two parent-species, and especially by its 

 resembling hybrids artificially made between the same 

 two species. Now the oxlip is intermediate in cha- 

 racter, and resembles in every respect, except in the 

 colour of the corolla, hybrids artificially produced be- 

 tween the primrose and the polyanthus, which latter 

 is a variety of the cowslip. Thirdly, by the supposed 

 hybrids being more or less sterile when crossed inter se: 

 but to try this fairly two distinct plants of the same 

 parentage, and not two flowers on the same plant, 

 should be crossed ; for many pure species are more 

 or less sterile with pollen from the same individual 

 plant ; and in the case of hybrids from heterostyled 

 species the opposite forms should be crossed. Fourthly 

 and lastly, by the supposed hybrids being much more 

 fertile when crossed with either pure parent-species 

 than when crossed inter se, but still not as fully fertile 

 as the parent-species. 



For the sake of ascertaining the two latter points, 

 I transplanted a group of wild oxlips into my 

 garden. They consisted of one long-styled and 

 three short-styled plants, which, except in the co- 

 rolla of one being slightly larger, resembled each 

 other closely. The trials which were made, and the 

 results obtained, are shown in the five following 

 tables. No less than twenty different crosses are 

 necessary in order to ascertain fully the fertility of 

 hybrid heterostyled plants, both inter se and with 

 two parent-species. In this instance 256 flowers 



