420 LABRADOR 



Hooker, 1 which in all essential points agrees with the the- 

 ories advanced in the latest edition (10th) of the Encyclo- 

 pedia Britannica: 



"It appears to me difficult to account for these facts, 

 unless we admit Mr. Darwin's hypotheses, first, that the 

 existing Scandinavian flora is of great antiquity, and that 

 previous to the glacial epoch it was more uniformly dis- 

 tributed over the polar zone than it is now ; secondly, that 

 during the advent of the glacial period this Scandinavian 

 vegetation was driven southward in every longitude, and 

 even across the tropics into the south temperate zone; 

 and that on the succeeding warmth of the present epoch, 

 those species that survived both ascended the mountains 

 of the warmer zones, and also returned northward, accom- 

 panied by aborigines of the countries they had invaded 

 during their southern migration. ... If it be granted 

 that the polar area was once occupied by the Scandinavian 

 flora, and that the cold of the glacial epoch did drive this 

 vegetation southwards, it is evident that the Greenland 

 individuals, from being confined to a peninsula, would 

 be exposed to very different conditions to those of the 

 great continents. In Greenland many species would, as 

 it were, be driven into the sea, that is, exterminated; 

 and the survivors would be confined to the southern por- 

 tion of the peninsula, and not being there brought into 

 competition with other types, there could be no struggle 

 for life amongst their progeny, and consequently no selec- 

 tion of better-adapted varieties. On the return of heat, 

 these survivors would simply travel northwards, unaccom- 

 panied by the plants of any other country. In Arctic Amer- 

 ica and Asia, on the other hand, where there was a free 

 southern extension and dilatation of land for the same 

 Scandinavian plants to occupy, these would multiply 

 enormously in individuals, branching off into varieties and 



1 Distribution of Arctic Plants, pp. 253 f . 



