III. THE COMPONENTS 

 OF THE BRYOPHYTE FLORA. ' "- 



ii9 



IN consequence of the geographical situation and climate of the 

 island, the vegetation of Iceland has a composition which cor- 

 responds most nearly to that of Scandinavia and South Greenland. 

 With the exception of the species found only in Iceland, there is 

 only one species (Bryoxiphiiim norvegiciim) which has not been 

 found in the other parts of Europe, but whicli has its home in 

 North America, and one species (Tortilla obtiisifoliaj which I do not 

 think has been found in Scandinavia. The other species are all 

 common to Iceland and Scandinavia. At present it is not possible 

 to compare the Bryophyte flora of Iceland and Greenland, partly 

 because there is no collective account of the distribution of the 

 species found in Greenland, and partly because the older Greenland 

 collections and lists of species greatly need revision. 



The Bryophyta found in Iceland can be arranged in four geo- 

 graphical groups (Arnell and Jensen, 1910, p. 238): — 



1. Ubiquitous species, which are almost equally distributed 

 over the whole of North Europe as far as north of the Arctic 

 Circle. 



2. Meridional species, which are most frequent in Southern 

 Scandinavia and far rarer in Northern Scandinavia. 



3. Bo real species, which are more frequent in Northern than 

 in Southern Scandinavia, and have their main distribution 

 below the tree-limit. 



4. Alpine species, which have their main distribution above 

 the tree-limit. 



In Table II and in the folio wing Tables the plant-geographical 

 character of the species is denoted by the initial letters u, m, b and 

 a, which are prefixed to the name of the species. Icel. indicates 

 that the plant is known only from Iceland. As already mentioned, 

 the species found only on warm soil — almost all of which belong 



