444 MR. C. DATIWIN ON SPECIFIC DirFEHENCES IK PBIMULA. 



consi.sted of one long-styled and three short-styled plants, which, 

 except in the corolla of one being slightly larger, resembled each 

 other closely. The trials which were made, and the results which 

 were 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 dimorphic plants, inter se and with their 

 two parent species. In this instance 256 flowers were crossed 

 in the course of four seasons. I may mention, as a mere curio- 

 sity, that if any one were to raise hybrids between two trimor- 

 phic species, he would have, in order to ascertain their fertility 

 in all ways, to make 90 distinct unions ; and as he Avould have to 

 try at least 10 flowers in each case, he would be compelled to fer- 

 tilize 900 flowers and count their seeds. This would probably 

 exhaust the patience of the most patient man. 



Table I. 



Crosses inter se between the two forms of the common Oxlip 



Illegitimate union. 



Short-styled ox- 

 lip, by pollen of 

 short-styled oxlip : 

 20 flowers ferti- 

 lized, did not pro- 

 duce one capsule. 



Legitimate union. 



Short-styled ox- 

 lip, by pollen of 

 long-styled oxlip : 

 10 flowers ferti- 

 lized, did not pro- 

 duce one capsule. 



Illegitim ate un ion . 



Long-styled ox- 

 lip, by pollen of 

 long-styled oxlip : 

 24 flowers ferti- 

 lized, produced five 

 capsules, contain- 

 ing 6, 10, 20, 8, 

 and 14 seeds. Ave- 

 rage 11 "6. 



Legitimate union. 



Long-styled ox- 

 lip. by pollen of 

 short-styled oxlip : 

 10 flowers ferti- 

 lized, did not pro- 

 duce one capsule. 





Table II, 



Both forms of the Oxlip crossed with pollen of both forms of the 



Cowslip, ^ veris. 



Illegitimate union. Legitimate union. 



Short-styled ox- 

 lip, by pollen of 

 short-styled cow- 

 slip : 18 flowers 

 fertilized, did not 

 produce one cap- 

 sule. 



Short-styled ox- 

 lip by pollen of 

 long-styled cow- 

 slip : 18 flowers 

 fertilized,produced 

 three capsules, con- 

 taining 7, 3, and 

 3 wretched seeds, 

 apparently inca- 

 pable of germina- 

 tion. 



Illegitimate union. 



Long-styled ox- 

 lip, by pollen of 

 long-styled cow- 

 slip : 11 flowers 

 fertilized,produced 

 one capsule, con- 

 taining 13 wretched 

 seeds. 



Legitimate union. 



Long-styled ox- 

 lip, by pollen of 

 short-styled cow- 

 slip; 5 flo WOTS fer- 

 tilized, produced 

 two capsules, con- 

 taining 21 and 28 

 verv fine seeds. 





