ICE AGE REFUGIA IN ICELAND 



311 



Saxifraga Aizoon (Fig. 8) has its main center in the Austfirdir district; 

 il is found in the Eyjafjordur district and in mountains at Vatnsdalur in 

 Hunavalnssysla; a second center seems to be in the Hvalfjordur district or 

 more hkely in the nunatak area in the mountain range of Snaefellsnes. 



Arenaria nonegica and Carex hicolor do not have a distinct centricity. 

 But several points indicate a center of C. bicolor in the Eyjafjordur district, 

 and its distribution is connected to nunatak areas, especially in the highlands 

 north of the glacier Vatnajokull. 



* \ \ \ ! 



IJ 50 "00»i» 



Fig. 8. Saxifraga Aizoon. 



When we summarize what has been mentioned about the distribution of 

 these 18 species the result will be as follows: eleven species have a distinct 

 centric distribution, and 2 more show tendencies of the same kind. Only 

 6 species display no centricity at all. The distribution of the centric species 

 is mostly limited to four districts, and where the plants are found outside 

 these districts, distinct nunataks characterize the landscape. 



Seeing that the majority of the species in this group, which with certainty is 

 considered as overwintering in Scandinavia, is almost exclusively found in 

 limited areas in Iceland, one niay ask whether the peculiar distribution of these 

 species is a mere accident. If that were the case, it would certainly be a strange 

 accident. It would be more natural to seek the cause of this peculiar distribu- 

 tion in the conclusion that these species have actually survived the Ice Age in 

 refugia in the districts mentioned above, and that they have not been able to 

 disperse more widely through the country in Post-glacial times. 



Furthermore, the West Arctic plants are not the only ones in Iceland which 

 have such a peculiar distribution; about 80 other species have been found to 



