THE ELEMENTS AND AFFINITIES OF THE ICELANDIC FLORA 299 



excluding most species of Taraxacum and Hieracium) into two main groups, 

 A and E. Group A comprises Arctic and Subarctic species, having their main 

 distribution near or north of the forest limit; they are common in Greenland, 

 Spitsbergen, and on the Scandinavian mountains, but absent or occurring 

 sporadically in more southerly countries. To this group belong 151 species or 

 ca. 40 per cent of the Icelandic vascular plants. Group E comprises species of 

 common occurrence in central Europe, which have their main distribution 

 south of the forest limit. This group consists of 224 species, or ca. 60 per cent 

 of the vascular plants of Iceland, about half of which are also found in Green- 

 land. According to Molholm-Hansen, there is also some difference in the 

 distribution of the groups in various parts of Iceland. In north Iceland 

 60.3 per cent of the species belonging to Group A are common but only 

 38.8 per cent of the species belonging to Group E, In southwest Iceland, on 

 the contrary, 53.6 per cent of the A species and 41.5 per cent of the E species 

 are common. 



Ostenfeld and Grontved (1934) mention about 390 species of vascular 

 plants from Iceland, Taraxacum and Hieracium excluded. In 1942, Grontved 

 published a treatise on the Icelandic flora, in which every species of vascular 

 plants ever recorded from Iceland is mentioned, i.e. about 660 species. The 

 author considered critically which of these really belong to the Icelandic 

 flora. His conclusions are that about 400 species, Taraxacum and Hieracium 

 excluded, should be considered as Icelandic. During the last 20 years, however, 

 some of the species from the old plant lists, which were excluded by Grontved, 

 have been rediscovered in Iceland. 



Askell Love (1945) records 425 species of vascular plants from Iceland, 

 Taraxacum and Hieracium excluded, and finally in the third edition of Stefans- 

 son's manual, Steindor Steindorsson (1948) mentions 429 Icelandic vascular 

 plants, indigenous and naturalized, introduced species, with Taraxacum and 

 Hieracium excluded. Besides, both Stefansson (1901, 1924), Ostenfeld and 

 Grontved (1934), Grontved (1942), Love (1945), Steindorsson (1948) and 

 other authors record a considerable number of accidentally introduced, but 

 not naturalized species from Iceland. 



In a paper on the age and immigration of the Icelandic flora, Steindorsson 

 (1954) is of the opinion that between 430 and 440 species of vascular plants, 

 Taraxacum and Hieracium excluded, are native in Iceland. No sexually 

 reproducing species can be considered as endemic, but some endemic varieties 

 and subspecies of wider distributed species are found in Iceland. According to 

 Steindorsson (1954), about 21 per cent {ca. 90 species) of the 430-440 species 

 have been introduced to Iceland by man during the last 1100 years and are 

 now more or less naturaHzed in the country. Steindorsson points out, as do 

 all the previous authors, that the main part of the Icelandic vascular plants 

 is European, mostly Scandinavian species. Only six of the species, i.e. 1.4 

 per cent of the flora, are western and not found in Europe, whereas 106 



