190 



JAMES POWLEE ON THE AECTIC 



principle. It serves to explain, better than any other existing hypothesis, the projection 

 of Arctic species into the temperate and tropical regions ; their existence on mountain 

 summits ; the passage of a few species across the equator into southern latitudes, and the 

 existence of the numerous varieties recognised by botanists among Arctic plants. 



The whole surface of the province of New Brunswick has been striated by glacial 

 action, and much of it is covered by the drift. During the continuance of the cold, all 

 vegetation must have been extinct. Our loftiest forests flourish on the debris which covers 

 the glaciated rocks. As the milder temperature advanced towards the north, the vegeta- 

 tion would follow it, leaving, in every region passed over, such species as were adapted to 

 the climate and other conditions. The large number of species that have found a congenial 

 home in New Brunswick, suggests enquiry as to the causes or conditions which have 

 made it a suitable dwelling-place for them. 



By consulting the list appended to this paper, we find that the number of Arctic 

 phsenogamous plants found growing wild in New Brunswick, amounts to 305 ; and that 

 of these, 104 are found in Greenland ; 241 in Arctic Europe ; 55 in Arctic Asia; 81 in 

 Arctic America, west of the Mackenzie, and 16*7 east of the Mackenzie. The list contains 

 48 species which have been introduced into the province ; by deducting these from the 

 whole number (305) we have 25*7 remaining as representatives of the aboriginal flora. 



According to J. D. Hooker, the total number of Arctic plants known to occur within 

 the Arctic circle, amounts to *762 species. A comparison of the distribution of these with 

 the number found in New Brunswick, will give some interesting results : — 



The remarkable fact here presents itself, that of 25*7 Arctic species embraced in the 

 flora of this province, 241 occur within the Arctic circle in Europe, a much larger number 

 than has been observed in all Arctic America, or in any other Arctic region in the world. 

 How can this remarkable phenomenon be accounted for ? Why should a larger number of 

 the plants found in Arctic Europe, occur in the limited area of New Brunswick, than in 

 the immense regions of Arctic Asia or Arctic America ? The flora of northern Scandinavia 

 or Lapland is the richest Arctic flora in the world, but why should so many species be 

 common to it and the distant province on the shore of the St. Lawrence Gulf Y 



A satisfactory explanation of all the phenomena may not be possible at present, but 

 several agencies or causes can be detected which are now in operation and have exercised 

 a very important influence in the past. The chemical composition of the rocks or soil 



