170 F. W. C. Areschoug. 



that R. ideeus differs from all the other European brambles, in so many 

 cssential particulars, that it must be referred to quite another type, whose 

 native land is probably the north east of Asia. As I have not had the op- 

 portunity of studying the Asiatic brambles in any other manner than in 

 herbariums, which on such questions leave us completely in the dark, I can 

 with difficulty give any certain opinion on the genealogy of this species. In 

 the article just referred to, I stated tbe supposition, that it arose in Japan or 

 in Northern America from soine form with simple leaves. But it can also be 

 assumed, that it immediatcly or, perhaps, more probably by the mediation of other 

 species, arose from R. saxatilis, or even from R. ceesius. The latter species 

 which in cnlour and form of prickles, & c. reminds one of R. ideeus, can 

 possibly during its wandering towards eastern Asia have produced species that 

 form the transition to R. idaeus. Under such circumstances it is possible that 

 several of the forms, which have been considered as hybrids between theso 

 forms, are real intermediate ones, and not hybrids. The facility, with which 

 both these species hybridise, could on the other side serve to strengthen 

 the supposition of the afhnity of these species, in regard to their origin. 

 The resemblance in the form of the leaves, which, as has been already men- 

 tionetl, is sometimes to be found between R. idseus and suberectus, and as well 

 as the likeness which distinguishes them in so many other respects, gains, by 

 such an assumption, its proper elucidation. For R. suberectus and idseus 

 should then be separated from their common parent species, by only a few 

 links. On the other hand the difference between R. idseus and caesius 

 is, in fact, so great, that, perhaps, it is more probable the former arose indirectly 

 from R. saxatilis. 



