THE GENUS ROSA 259 



indistinguishable from our Durham and Northern Scottish 

 forms as I have satisfied myself by direct comparison, in the 

 Faroe Islands* it is replaced by a very curious variety 

 approaching the Villosa. This plant Almquist terms a 

 half- Villosan and regards as a mwisint oi R. pitnpine lit folm in 

 that direction. Very likely in that view he is correct. In my 

 mind, however, we are encountering a further step from the 

 "juvenile" species R. pimpinellifolia to the adult R. ?nollts. 

 Nevertheless, let me hasten to explain, this does not exclude 

 the possibility of mutation in any way. 



In the ontogeny of R. mollis it cannot be denied that the 

 species evolves from its seedling stage to its final condition in 

 a determinate direction. R. pimpinellifolia a.x\di R.faroensis (as 

 well as R. orientalis), as has been pointed out, represent 

 halts in this ontogeny, so that their phylogeny recapitulates 

 the ontogeny of the CanincB. Hence, along vastly different lines, 

 these microgenes conform to the usual orthogenetic develop- 

 ment of the species within the genus. 



Only one point remains and this portion of my work is 

 finished ; it must not be overlooked that in the species-types 

 common to the sections, we may be dealing with similar 

 segregates rendered possible by crosses made ages ago 

 between forms carrying the same sets of coupled unit 

 characters. 



III.— POLLEN CONDITIONS IN THE ROS^ WITH 

 SOME CONSIDERATION OF OTHER FEATURES 

 IN THEIR REPRODUCTION. 



Pollen Abortion in the Roses. 



As I have just observed in the previous portion of this paper, 

 the persistence of species-types common to all the sections 

 may arise through segregation from previous crosses — a con- 

 tingency demanding, amongst other considerations, special 

 investigations as to possible hybridity. The first of these to 



* Rostrup in his Flora of the Faroes was completely baffled by this 

 form ; instead of naming it he simply says " perhaps canina "! 



