ICE AGE REFUGIA IN ICELAND AS INDICATED 

 BY THE PRESENT DISTRIBUTION OF PLANT 



SPECIES 



Steindor Steindorsson 



Akureyri College, Akureyri, Iceland 



One of the most striking features of the flora of Iceland is its paucity of 

 species. According to Flora Islands (Flora of Iceland; Stefansson, 1948), only 

 about 430 species of Pteridophyta and Phanerogams can be considered as 

 native to the whole country. Without doubt some species have been added 

 since that time, but the entire number does not noticeably exceed 440. To 

 this number we can add the genera Hieracium and Taraxacum, but about 

 190 species of Hieracium have been recorded from Iceland and a rather 

 uncertain number of Taraxacum, since some specialists put the number at 20, 

 others at somewhat more than 100. From the distribution of these genera, one 

 could undoubtedly find certain features concerning the problem which is 

 dealt with in the present paper, but I have omitted these genera here especially 

 because we know so little about their real distribution (cf. Steindorsson, 1962). 



The total number of species, 440, however does not tell the whole story. 

 After a closer investigation we find that a considerable number of these have 

 been introduced by man since the first settlement of the country nearly eleven 

 hundred years ago. In another paper I have produced some arguments to 

 show that about 100 species have been brought into the country by human 

 agency. Although this number after a closer study may prove too high, it is 

 certain that up to 20 per cent of the flora of Iceland {Hieracium and Taraxa- 

 cum excepted) is anthropochorous. 



Ahhough our knowledge of the origin of the flora of Iceland and its 

 relationship to the floras of our neighboring countries is far from complete, it 

 is obvious that it is more closely related to the flora of Scandinavia than to 

 any other country. A considerable component of the flora is Circumpolar, or 

 at least is found on both sides of the North Atlantic Ocean, and the American 

 element is probably greater than hitherto generally considered. The cyto- 

 logical investigations of Askell Love point in that direction. It is certain that 

 the flora of Iceland does not differ remarkably from that of other countries 

 around the North Atlantic Ocean in other respects than its poverty of species. 



Then there is the question whether a considerable element of it is com- 

 prised of survivors which have overwintered at least the Last Glaciation or 



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