THE GENUS ROSA 267 



Finally, to prove experimentally that crossing between 

 various members of the supersection Cam'nce was possible, I 

 transplanted several microgenes to the garden where they 

 flourished and blossomed freely. After castrating several of 

 their flowers, I cross-pollinated tliem and enclosed them in 

 strong paper bags. Fertile seeds were obtained in nearly all 

 cases, and their numbers and possible parentages are set out 

 in the table on the next page. 



The seeds thus recorded have been planted and appear to 

 be germinating normally; the resulting plants, if hybrid in 

 nature, will not be available for study for a long time. 



A glance at the table will prove conclusively that hybridity, 

 in spite of its ostensible absence, is at least feasible within the 

 limits of the Caninm, and serves to confirm the idea deduced 

 from the pollen condition and the irregular course of its 

 development, backed up by other weighty facts, that within 

 the RoscE we are dealing with multitudes of Utent hybrids. 

 Thus the production of new forms is rendered possible when- 

 ever cross-pollination brings together gametes of different 

 potentialities. This would account for much of the variability 

 of the genus and would, at first sight, offer some explanation 

 of the segregation and passage of the common species-types 

 throughout the groups. We have only to imagine in the pro- 

 duction of various inter-Canine crosses the interaction of a 

 : series of linked* genes, involving the characters proper to any 

 given species-type, and the whole matter is elucidated. A 

 moment's thought, however, recalls the fact that any special 

 species-type passes through species the purity of which is 



* Although to my mind this does not explain the species-type, it may 

 nevertheless be the correct view. Independently of these possible linked 

 genes others do exist in Rosa. That a detailed analysis of their genetical 

 behaviour has not been made depends on the slow growth of the plants ; 

 at any rate the attempt is being made. The following characters appear 

 to be linked ; glandular leaves are always biserrate ; forms with deep red 

 flowers have hairy foliage ; erect and suberect, persistent and subpersistent 

 sepals always accompany woolly fiat heads of stigmas and early ripening 

 fruit, whilst dilated and broad bracts are correlated with short peduncles. 



