1 34 i W. C. Areschoug. 



On cultivated specimens of R. Arrhenii, raised from seeds in the Botanical 

 Garden at Lund, the leaves, however, become more in accordance with those 

 of R. scanicus, and this, in size as well as in shape. Although these species 

 are well separated from one anothér, I still consider, that R. Arrhenii 

 approaches R. scanicus in a greater degree than either R. sciaphilus or 

 chlorothyrsos. 



In my attempts to discover the origin of the blackfruited brambles endemic 

 fco the scandinavian peninsula, I have started from the assumption, that all 

 such forms descend from species still growing on the continent. It seems to 

 me, indeed, very probable, that the numerous blackfruited brambles, which at 

 present grow in Western Europé, have arisen after the glacial period, and have 

 immigrated from the south, or as regards R. subérectus, perhaps, from the 

 east, to the scaiidinavian peninsula (pag. 22). It is also very probable, that 

 the species which require a warmer climate and therefore, in common with R. 

 scanicus, only appear in the southernmost part of our country, have immi- 

 grated last. Should this not have been the case, it will then be necessary to 

 assume, that the species in question has descended from some form that has 

 become extinct. But then one must almost assume. that R. scanicus grew 

 before the glacial period, and that its parent species became extinct during that 

 lime. Hut in this case it is difficult to see the cause for the absence of this 

 Bpecies on the continent. For, as it is restricted to the most southern part ot 

 Sweden, and, therefore seems to require a mild climate, it can be taken for 

 certain ihai on the irruption of the ice, it should draw itself towards the 

 south, and afterwards wander back liere, when the climatic conditions bad 

 again assumed such a character that it could live here. 



I do not think, therefore, that I am mistaken, when I assume. that the 

 brambles, peculiar to the Scaiidinavian Hora, directly, or indirectly derive their 

 origin Innu forms, that still grow on the continent. But in regard to R. 

 scanicus, the peculiar circumstance meets as, that this species cannot easily 

 be considered as descended from any Continental species that lives also in our 

 country. None ut' the other Scaiidinavian species is, for instance, so closely 

 related in Et. scanicus, as iis descent from such a species must presuppose. 

 And of the species living outside our country, there are in truth, only the 

 three forms, above uamed, that have any resemblance with our species 

 worthy of remark. Among these, 11. Arrhenii is without doubt the nearest. 

 1 have therefore also, in the introduetion (pag. 34), expressed my conviction, 

 that It. scanicus is descended from this species. In the Botanical Garden at 



