THK GI'.NL'S ROSA 25 1 



In the present paper, with hut the barest indications of 

 possible causes, I intend to demonstrate as fully as possible 

 that the development of section-species, microgenes and 

 varieties in the genus Rosa, and more especially in the 

 supersection Canince, proceeds on orthogenetic lines even if of 

 a rather peculiar type ; in doing so I believe that I shall be 

 giving the first illustration of the law deriveii from the 

 phanerogams. However, despite the emphasis on the 

 Cani/i(z, it must not be supposed that the action of the 

 principle is confined to them ; on the contrary the Pimpiiielli- 

 folice and Cinnatiiomece. exhibit the same phenomenon. Thus, 

 as far as possible these latter groups must be dealt with, but 

 owing to the circumstance that they are at best stranded and 

 possibly more primitive groups, badly represented in the 

 North of England and greatly diminished in species through- 

 out thej"ange oi Rosa, very little material remains for study j 

 whatever has survived the vicissitudes of the past falls exactly 

 in line with the Caaince. 



My attention was first drawn to the subject some years ago 

 by the occurrence of a green-leafed form o^ Rosa coriifolia* on 

 the railway banksides near Billingham, South Durham, which 

 ran down to the microgene fnitetoruin. In spite of its 

 proving on examination to possess all of the characters proper 

 to the aggregate R. coriifolia, as I then termed the hairy- 

 leafed members of the Afzeliance, I could not help being 

 struck by its extraordinary resemblance to that segregate of 

 the TomentoscB which I take to be R, totiieiitosa, Smith. In 

 consequence, influenced by its ambiguous appearance which 

 had caused me at first sight to look upon it without question 

 merely as R. tomentosa, I refrained from including it in my 

 " Wild Roses of Durham " but laid it aside for future study. 

 The same season I made a direct comparison between it and 



* It must not be for<jotten that I regard the glabrous K. glauca -f the 

 hairy A', coriifolia as forming the section species A'. Afzeliana. However, 

 in naming microgenes, to remove misunderstandings in the minds of English 

 readeis, the nomenclature of Wolley-Uod's iist is employed tliroughout 

 this paper. 



