Mr. WoaDS on the British Species of Rosa. 229 



are R. canina, R. systyla, and R. arvensis ; and from each of these 

 it may perhaps be difficult to give a description which shall accu- 

 rately distinguish it, Avhile in habit it is considerably different 

 from cither. From the first it may however, I think, always be 

 known by the porrect styles, the entire pinna; of the calyx-leafits, 

 the peduncle almost always furnished with hairs or setee, the 

 shape and flatness of the leaflets, and the strong and hooked aculei 

 of the footstalk. These marks seem indeed amply sufficient, but 

 I am afraid they are all more or less uncertain. 1 have never 

 seen the glands of the peduncle extending themselves on the re- 

 ceptacle or calyx ; in R. canina, when glands are found on the pe- 

 duncle, they are also generally to be observed on the fruit, and still 

 more on the calyx ; but this character likewise sometimes fails. 

 A better distinction in the living plant is found in the enormous 

 surculi covered with beautiful blue wax, and bearing great cymes 

 of flowers. In the most favourable circumstances it is only by 

 accident that R. canina has more than four flowers. In this plant 

 if any surculi are produced, and it is rarely without them, the ob- 

 server will not often be disappointed in searching for eight or ten, 

 and he will sometimes find double that number; but even this 

 mark is not very decidedly exhibited in the variety /3, which 

 seems however to unite better with this species than with any 

 other. From R. arvensis it may be known by the styles, which 

 are here hairy and but just protruded, not smooth and collected 

 into a long cylinder, as in that plant. It is also a much more up- 

 right plant, the surculi being rather erect than decumbent. From 

 R. systyla also a due attention to the styles will distinguish it; 

 and the shape and flatness of the leaf give a decidedly different 

 appearance to the present plant. 



25. Rosa 



