66 ERIC HULTEN 



on that continent) which reach respectively northern and southern Greenland, 

 and comprise altogether 74 species. Only 6 of them have extended as far as 

 Iceland, and 4, Spiranthes Romanzojfiano. Potaniogeton epi/iydrus, Eriocaulon 

 septentrionale, and Sisyrinchium sp., to the British Isles. A strong connection 

 between America and Greenland is thus demonstrated. 



Figures 19 and 20 represent the corresponding European or Eurasiatic 

 elements penetrating out into the Atlantic. The plants in Fig. 19 reach Iceland 

 or Greenland but not America, and those in Fig. 20 extend also to America. 



It is especially in these groups that the question about native or introduced 

 species is particularly important. In my opinion, many plants occurring in 

 Iceland have been introduced to that island, because the composition of the 

 group seems to indicate that it consists to a large extent of plants favored by 

 human activity. On the other hand, a few certainly do not belong to an 

 introduced flora, for instance, Saxifraga hypnoides, Vaccinium Myrtillus, 

 Salix lanota. Orchis macu/ata, Paris quadrifolia, Saxifraga Cotyledon, Hydro- 

 cotyle vulgaris, Gentiana aiirea, Gentiana detonsa, Veronica fruticans. Geranium 

 silvaticum, and a few others. 



Figure 20 includes those European species which occur in eastern America 

 and are considered by Fernald in his Manual to be native there. It seems to me 

 that most, if not all, of them probably have been introduced into America; 

 those which have the best chance to be of native origin are Pedicularis 

 silvatica, Juncus capilatus, J. bulbosus, J. subnoduJosus, and Ranunculus 

 hederaceus. 



In Figs. 21 and 22, respectively, are considered Atlantic Circumpolar and 

 coastbound plants. It seems preferable to treat coastbound species separately 

 because their distribution does not always conform to that of other plants. 

 Several of these species have large inland areas on salt soi! in the center of the 

 continents. A few have a fairly unbroken connection from the Atlantic to the 

 Pacific along the shores of the Arctic Ocean, whereas others show large gaps 

 there. This indicates that during a warmer period the latter may have had such 

 an unbroken connection which was later broken up by the deterioration of the 

 climate. 



Figures 23 and 24 represent endemics in Greenland or on Iceland-Faeroes. 

 They are all very weak neo-endemics, mostly of critical genera, and cannot 

 support a land-bridge theory. 



A few plants have unique areas and could not be placed in any of the 

 above-mentioned groups; thus, PotentUla stipularis and Draba sihirica have 

 their main ranges in northern Asia with only single outpost localities in 

 Greenland, whereas Cakile edentula occurs on the American coast with different 

 types in different places. It has reached Iceland, and furthermore it has also 

 extended to the Azores, apparently by means of sea currents. 



Summarizing the above, the following can be stated concerning the 

 phytogeographical connections of the North Atlantic: Very many species 



