BRITISH ALPINES. 67 



For how long a period this struggle has been going 

 on it were difficult to say ; but the commencement 

 must have been at the termination of the last glacial 

 epoch. The destruction of plants during that period 

 must have been enormous. As the cold increased in 

 the north, and glaciers covered the greater part of 

 Britain, the plants that had survived would find them- 

 selves pushed further and further south. By similar 

 causes the plants of Switzerland would be pushed 

 northwards ; and hence there would be to some extent 

 an intermingling of the old Arctic and Alpine floras. 

 " At the epoch when glaciers attained their maximum 

 dimensions/' writes Kerner, " the places now covered 

 by the forests of pines and firs which are so character- 

 istic of the Baltic flora, and by vast scrubs of heath and 

 broom, were occupied by low Alpine plants, which may 

 for the sake of brevity be spoken of collectively as an 

 Alpine flora.'* " Formerly," he adds, " botanists 

 were of the opinion that this wonderful flora spread 

 southwards Hke a flowing stream from the Arctic 

 regions at the epoch in question. This view is not, 

 however, in harmony with more recent discoveries. 

 It was based on the erroneous assumption that the 

 flora of the Arctic regions was the same as that of the 

 Alpine regions of Central and Southern Europe.'* He 

 proceeds to prove that the assumption was erroneous, 

 amongst other points dwelling on the fact that the 

 Alpine flora is so much larger than that of the Arctic 

 regions, that its chief components are alien to the latter ; 

 and he ends by saying " there is much more reason 

 for concluding that the scanty flora of the Arctic regions 



