54 ERIC HULTEN 



Atlantic point of view they might as well have been included in other Circum- 

 polar groups. 



In Figs. 8, 9, and 10 are treated plants which have a more or less Circum- 

 polar area with gaps frequently occurring in different places, but, contrary to 

 the plants of the preceding groups, they appear as different races or as 

 corresponding, slightly differing species on both sides of the Atlantic. There 

 are altogether 107 of these taxa. 



Figure 8 includes 76 species not occurring on Iceland or in Greenland, 

 while Fig. 9 includes cases where the European type reaches Iceland or 

 Greenland: in all 21 species. Figure 10 represents American species reaching 

 Greenland and Iceland: 10 species. It is remarkable that all plants with such 

 different races on both sides of the Atlantic are comparatively southern 

 plants, mostly of the Boreal type. Their Atlantic connections are very feeble. 



Figures 11 to 14 deal with the so-called Amphi- Atlantic plants. As they 

 are of special interest in this connection, they have been subdivided into 

 smaller groups. Thus, species not occurring in central Europe have been 

 divided into the two groups: namely one having a northern distribution in 

 Greenland, and another with a southern area there. Species found in central 

 Europe have also been divided into two groups : one that reaches Iceland and 

 Greenland, and one that does not. 



The sketches illustrating the corresponding total areas indicate that species 

 occurring on Iceland and in Greenland are Arctic or Arctic-montane types, 

 whereas those lacking there are of a Boreal, lowland type. All form a chain of 

 species with the largest part of their ranges in the Atlantic sector, but with 

 gaps in the Pacific sector. In my opinion they are remnants of earlier con- 

 tinuously Circumpolar plants which have lost part of their area due to pressure 

 of changing conditions, but are not remnants of plants which once inhabited a 

 land-bridge in the Atlantic. They comprise 71 species of which 25 occur on 

 Spitsbergen, 7 on Bear Island, 6 on Jan Mayen, 41 on Iceland, and 26 on the 

 Faeroe Islands. Their Atlantic connections are thus not very strong. This is, 

 however, perhaps of less importance, as it must be assumed that their areas 

 became much reduced when the continental climate that must once have 

 existed in what is now the North Atlantic changed to a coastal one when the 

 land-bridge disappeared. Their total areas do not indicate that they are 

 truly continental plants; on the contrary, their ranges even now are reduced in 

 the interior of the continents. 



Figure 15 shows the distribution of American or American-eastern Asiatic 

 plants which do not reach Greenland or the Atlantic islands, and Fig. 16 

 indicates the corresponding European plants which do not extend out into the 

 Atlantic. Both contain a great number of species. Their approximate numbers 

 in different places have been indicated on the map in order to stress the great 

 difference in the flora of the Atlantic shores in Europe and in America. 



Figures 17 and 18 show the areas of American plants (with variable ranges 



