PLANT MIGRATIONS ACROSS THE NORTH ATLANTIC OCEAN 



179 



Table 2 gives a similar break-down of the flora of Iceland. In the Amphi- 

 Atlantic group are included species belonging either to the western Amphi- 

 Atlantic element in Europe or the eastern Amphi- Atlantic element in America. 

 Some European species reach their westernmost and some American species 

 their easternmost Umit in Iceland. 



Table 2 



Comparison of the Different Elements in the Flora of Iceland (based on Love, 1945; 

 Love and Love, 1956) as to Adaptations to Long-distance Dispersal. 



Taraxacum and Hieraciiim excluded from the enumerations. 



[Upper figure = observed, lower figure (in brackets) = statistically expected number of 



species per element.] 



The European character of the Icelandic flora is clearly evident ; there are 

 about 12 times as many European as American species. The same facts 

 apply to the Icelandic fauna (Lindroth, 1957). There is some over-representa- 

 tion of hmnic species in the other flora elements, and a tendency to over- 

 representation of types adapted to long-distance dispersal among the American 

 species, but the numbers are too low to yield any statistical significance. 

 However, considering also taxa of lower rank than species, 16 American taxa 

 are found in Iceland of which only 4 are not adapted to long-distance dis- 

 persal. This is certainly significant. Similarly, Lindroth (1957) found that the 

 American animals in Iceland are adapted to long-distance dispersal. In the 

 Amphi-Atlantic and European elements in the Icelandic flora there is an 

 under-representation of types adapted to long-distance dispersal. Thus, there 

 is no evidence that the Amphi-Atlantic and European species reached 



