HOOKER ON ARCTIC PLANTS. 100 



district is oven less marked, for the lapse of European and West 

 American species is trifling, and the appearance of East- American 

 one is equally so ; the transition in vegetation from this district 

 again to that of Greenland is, as I have stated above, compara- 

 tively very abrupt. 



The general uniformity of the Arctic flora, and the special dif- 

 ference between its subdivisions may bo thus estimated : the 

 Arctic Phsenogamic flora consists of 762 species; of these, 6 16 

 ai-e Arctic-European, many of which prevail throughout the polar 

 area, being distributed in the following proportions through its 

 different long-itudes : — 



Scandinavian 



Asiatic and 







forms. 



An^erican. 







Arctic Europe - 616 



- 586 



- 30=1 



: 19-57 



„ Asia - 233 



- 189 



- 44 = 1 



:4-2 



„ W. America 364 



- 254 



- 110=1 



: 2-3 



„ E. America 379 



- 269 



- 110=1 



: 2*4 



„ Greenland - 207 



- 195 



- 12 = 1 



: 16-2 



This table places in a most striking point of view the anoma- 

 lous condition of Greenland, which, though so favourably situated 

 for harbouring an Arctic- American vegetation, and so unfavourably 

 for an Arctic-European one, presents little trace of the botanical 

 features of the great continent to which it geographically belongs, 

 and an almost absolute identity with those of Europe. 



Moreover, the peculiarities of the Greenland flora are not con- 

 fined to these ; for a detailed examination shoAvs that it differs 

 from all other parts of the Arctic regions in wanting many ex- 

 tremely common Scandinavian plants, which advance far north in 

 all the other polar districts, and that the general poverty of its 

 flora in species is more due to an abstraction of Arctic types than 

 to a deficiency of temperature. This is proved by an examination 

 of the Temperate portion of the Greenland peninsula, which adds 

 very few plants to the entire flora as compared with a similar 

 area south of any other iVrctic region, and these few are chiefly 

 Arctic plants and almost without exception Arctic-Scandinavian 

 species. 



There is nothing in the physical features of the Arctic regions, 

 their oceanic or aerial currents, their geographical relations, nor 

 their temperature, which, in my opinion, at all accounts for the 

 exceptional character of the Greenland flora ; nor do I see how it 

 can be explained except by assuming that extensive changes of 

 climate, and of land and sea, have exerted great influence, first in 

 directing migration of the Scandinavian species over the whole 

 polar zone, and afterwards in introducing the Asiatic and American 

 species with which the Scandinavian are so largely associated in all 

 the Arctic Districts except those of Europe and Greenland. It 

 is inconceivable to me that so many Scandinavian plants should, 

 under existing conditions of sea. land, and temperature, have not 

 only found their way westward to Greenland, by migration across 

 the Atlantic, but should have stopped short on the east shore of 

 Baffin's Bay, and not crossed to America ; or that so many 



