Mr. "Wood* on the British Species of Rosa. 213 



the manuscript observations of Professor Swartz, communicated 

 by him to Mr. Robertson of Newcastle. 



The setae which are occasionally met with on the peduncle of 

 this tribe of Roses have a very different appearance from those of 

 the straight-thorned Roses and of R. Eglantcria and R. micrantha ; 

 they are extremely feeble, hardly even stiff enough to support the 

 gland by which they are terminated, and frequently passing into 

 mere hairs without any gland : indeed in the former tribe the 

 stt-e seem to indicate an attempt to produce aculei ; and it is 

 sometimes difficult to say whether the latter name would not be 

 more appropriate r in this they have the appearance of an endea- 

 vour to form hairs ; and as they gradually diminish in strength and 

 in the size of the terminating gland, till at last it entirely disap- 

 pears, it is not always easy to decide to which sort of arms they 

 belong. Thus, extraordinary as it may seem, we have in this 

 genus hairs and prickles passing into one another by steps almost 

 insensible. ' 



. The plant most nearly allied to this is undoubtedly R. caninOf 

 from which it is to be distinguished by its double serratures : by 

 the smooth leaflets without either hairs or glands on the under 

 surface, it may be easily known from R. micrantha ; and the want 

 of hairs will readily distinguish it from H. Borreri and R, ceesia ; 

 but as I am always unwilling to rest upon this character alone^ 

 when the difference of habit is supported by any other, I will 

 observe that the shape of the leaflet, and its being always more 

 or less carinate in this species, will be a decided mark of separa- 

 tion from the former of these plants ; and the same character^ 

 though the difference is less distinctly marked, and the pinnae of 

 the calyx leafits^ wiU make it known from the latter. 



18. Rosa 



