Sonic Observations on the Genus Kubus. 14/ 



insularis and approaches the former in just those respects, in which that form 

 recedes from R. insularis. And when R. Lindebergii belongs to a southern 

 type, which is modih'ed by a northern elimate, it can be assumed that R. 

 Langii also is a northern form of a southern type. As far as I know, R. 

 Langii only appears on the Jutlandic peninsula, and is not found in the danish 

 islands, while R. Lindebergii is rare on the Jutlandic peninsula, but pretty 

 common in the danish islands, particularly those, the nearest to Sweden. 1 

 consider therefore, that both these species spring from R. insula ris, either in 

 this maiiner, that that species produccd R. Langii, and tliis in its turn R. 

 Lindebergii, or, that both these species are parallel descendents. of R insu- 

 laris. R. Langii arose within a more southern, R. Lindebergii within a 

 more northern district. In each case, R. Lindebergii must have arisen from 

 R. insularis. 



As to the three species, belonging to Discolores, R. polyanthemos, 

 insularis, and Lindebergii, the whole of their external organisation shows, 

 that they or their ancestor have their origin in southern tracts. It 

 appears to me even probable, that they originate from sonie form, which in 

 some still more southern tracts developed itself from R. tomentosus, Borckh. 

 and during its wandering towards the north, has given rise to the type in 

 queßtion. But also there is a possibility, that this group in southern Europé 

 developed itself from some form of R. corylifolius, which in the south, 

 particularly in low situated tracts, approaches Candicantes, as well as Disco- 

 lores. However, I, for my part, cannot embrace this opinion. For it a 

 southern form, which has arisen from R. corylifolius, wanders towards the 

 north, it ^eems very probable that it will in such a degree be inodified by the 

 influence of the northern climate, that its exteriör organisation could not main- 

 tain its southern charaefcer so perfectly, asis the case with the Discolores. If, on 

 the contrary, aform of the R. tomentosus-type wanders towards the north, it is 

 highly probable that it there will retain considerably more of its original type, 

 than can be the case with even a southern form of R. corylifolius. It eeems 

 to me, therefore, almost certain, that R. polyanthemos, insularis, and Linde- 

 bergii have arisen from eome form of the R. tomentosus-type. It has been 

 propounded, in treating of R. pol vant hemos, that in our country this form 

 springs from R. insularis; and that a variety of R. Lindebergii, described as 

 the variety sericeus, is a form that arose under the same conditions, and is 

 analogous to R. polyanthemos. This species bears clear marks of baving 



