THE CONTINENTAL FLORA OF SOUTH SWEDEN 273 



Hence the South Swedish flora does not in any way break the uniformity in 

 the flora of the Middle European plain. The northerly, Subarctic species that 

 might perhaps be expected to give it a more isolated position is a very little 

 marked element in the flora. The differences between the South Swedish flora 

 and that of the North German districts depend in a higher degree on the fact 

 that certain North German species are missing in South Sweden, than on the 

 fact that the South Swedish flora has some species of its own. 



With regard to these facts it may perhaps be questioned whether it is suitable 

 to class South Sweden (Skane with Oland and Gotland excepted) with the Sub- 

 arctic zone, as is done in the flora systems of Engler, Riibel, and other authors. 

 It would seem more natural to let the boundary between the Subarctic zone and 

 the Middle European one (» Central European* in Riibel) coincide w'ith the northern 

 limit of the oak or the boundary between the Central Swedish plain and the 

 Norrland coniferous forestland. — If we assume with Drude (i8go) a » Baltic 

 region* comprising the Middle European plain, the whole of South Sweden up 

 to the limit of the oak in the north should naturally (as is also the case in Drude) 

 be classed with this region. 



The intermediate position of the South Swedish flora in this Baltic flora district 

 appears from the above statements. However, the flora attaches itself most 

 closely to the special districts in the western part of the Sarmatian district 

 (Drude's »East Baltic*), West Prussia, Brandenburg and Livonia. 



I estimate the number of continental species in the South Swedish flora at 

 about 115, corresponding to about \2 % of the total number of species that are 

 real natives. Yet some of these continental species approach other types of 

 distribution. The statements given in Table i (p. 230) of the number of conti- 

 nental species in other Middle European special districts may be supplemented 

 by the statement that the Danish flora counts about 70 and the Norwegian flora 

 about 55 continental species, corresponding to 8 and 5 % respectively of the 

 total number of species in these districts. It must be noted, however, that 5 of 

 the Danish species occur only in Bornholm, and that a considerable part of the 

 Norwegian species is formed by Subarctic-Boreal species. 



In Table 2 (p. 234) are given some accounts about the mode of occurrence of 

 the continental species in South Sweden. It may be remarked that while the 

 South Swedish flora has about 42 steppe species, the Danish flora comprises 28 

 and the Norwegian flora only 14. On the other hand, Norway has got all the 

 continental coniferous forest species of South Sweden and all its continental 

 species of mesophytic thin broad-leaved forests except one. 



