420 LABRADOR 
Hooker,! which in all essential points agrees with the the- 
ories advanced in the latest edition (10th) of the Encyclo- 
pedia Britannica :— 
“Tt 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. 
