206 HOOKER ON ARCTIC PLANTS. 



facilities for migration presented by the different continents. 

 Thus 



Of 616 Arctic-European species — 

 496 inhabit the Alps, and 

 450 cross them ; 

 126 cross the Mediterranean ; 

 26 inhabit Africa. 

 Of 379 Arctic-East- American — 



203 inhabit the United States (of which 21 are confined to 

 the mountains) ; 

 ^ 34 inhabit Tropical American mountains ; 



50 inhabit Tc iiperate South America. 

 Of 233 Arctic-Asiatic species — 



210 reach the Altai, Soongaria, &c. ; 

 106 reach the Himalaya ; 

 are found on the Tropical mountains of Asia ; 

 5 inhabit Australia and New Zealand. 

 Of 346 Arctic- West- American species — 

 274 are North-temperate ; 

 24 on Tropical mountains ; 

 37 in South-temperate zone. 



These tables present in a very striking point of view the fact of 

 the Scandinavian Flora being the most widely distributed over the 

 globe. The Mediterranean, South- African, Malayan, Australian, 

 and all the floras of the New World have narrow ranges com- 

 pared with the Scandinavian, and none of them form a prominent 

 featm'e in any other continent than their own ; but the Scandi- 

 navian not only girdles the globe in the Arctic Circle, and 

 dominates over all the others in the North -temperate zone of the 

 Old World, but intrudes conspicuously into every other Temperate 

 flora, whether in the northern or southern hemisphere, or on the 

 Alps of Tropical countries. 



The severest test to which this observation could be put is that 



supplied by the Arctic- Scandinavian forms, for these belong to the 



remotest corner of the Scandinavian area, and should of all plants 



be the most impatient of temperate, warm, and tropical climates. 



The following will, approximately, express the result : — 



Total Arctic-Scandinavian forms - - - 586 



In North-United- States and Canada, &c. - 360 



In Tropical America ----- 40 



In Temperate South America - - - 70 



In Alps of Middle Europe, Pyrenees,^&c. - 490 



Cross Alps, &c. - - - - ' - - 480 



Reach South Africa 20 



Himalaya, &c. 300 



Tropical Asia 20 



Australia, &c, ------ 60 



In one respect this migration is most direct in the American 

 meridian, where more Arctic species reach the highest southern 

 latitudes. This I have accounted for ('' Flora Antarctica," p. 230) 



