128 B Canadian Arctic Expedition, 1913-18 



has developed in the mountains as far apart as Caucasus and Altai; the American 

 species undoubtedly originated in Altai, and its occurrence on the arctic shore 

 may simply indicate the road it followed from these mountains across the Bering 

 strait. It is a peculiar fact that the species, in spite of this enormous range 

 eastward and southward, has developed no varieties on this continent as is the 

 case with the plant in Altai, Baikal, and Davuria. 



