SURVIVAL OF PLANTS ON NUNATAKS IN NORWAY 



269 



This strange concentration of rare species cannot be explained as casual. 

 The geologist O. T. Gronlie (1927) has published numerous observations 

 from northern Norway showing that there must have been quite extensive 

 ice-free areas. He is of the opinion, among others, that ice-free areas have 

 existed as far east as the boundary between Norway and Sweden, exactly in 

 this area where the concentration of important species is found. 



Fig. 9. The total distribution of Carex sciipoidea (after Hulten, 1958). 



Let US return to southern Norway. As already mentioned, Blytt (1876) 

 pointed out that his Arctic element was encountered exclusively within 

 continental mountains consisting of calcareous rocks and schist. Our know- 

 ledge of the distribution of the plants has increased gradually so that we now 

 have a very detailed picture of it. A sensational observation might still be 

 made, of course, but most likely the present picture of distribution will be 

 but slightly altered. 



If we look at the distribution of the bicentric and the southern unicentric 

 species, we see that they are restricted to the interior mountains, thus con- 

 firming the theory of Blytt (1876). He maintained, indeed, that they were 

 continental, and undoubtedly he had in mind the mountains of Dovre and 

 Jotunheimen. Since then it has been proved that the mountains south of 

 Sunndalen and the TroUheimen Mts. should be included in the "species-rich 

 area". Particularly the mountains of TroUheimen are strongly influenced by 

 oceanic weather conditions (high precipitation). 



Let us again look at Artemisia norvegica and its Norwegian distribution 



