British North American Plants. 17 
sea. With lofty mountains to the immediate northward 
in glacial times, these plants were probably, then, not 
uncommon. As the waters receded and formed the present 
lakes, and the climate became as it now is, these northern 
plants were driven to localities like the headlands of Lake . 
Superior, where conditions were favourable to their con- 
tinuance. In all other localities they would disappear. 
Even on Lake Superior, the struggle with changed condi- 
tions must have resulted in the extinction there of maay of 
the more northern forms. 
The following are some representatives of this group 
and of the boreal group presently occurring around Lake 
Superior :— 
Draba incana, L. Solidago virga-aurea, L. 
Viola palustris, L. v. alpina, Big. 
Parnassia parviflora, D. C. Arnica mollis, Hook. 
Hedysarum boreale, Nutt. Vaccinium uliginosum, L. 
Dryas Drummondii Hook. Y. cespitosum, Mx. 
Rubus arcticus, L. Castilleia pallida, Hun. 
R. Chamzemorus, L. Euphrasia officinalis, L. 
Erigeron acre, L. Empetrum nigrum, L. 
Solidago thyrsoidea, Mayer. Tofieldia palustris, Huds. 
Arotic GROUP. 
The species of this group include many that are common 
to Scandinavia, Lapland and the higher Alps, and to our 
arctic coasts. Whilst numerous arctic plants find their way 
southward on the higher summits of the Rocky Mountains, 
on the Pacific side of the continent, and along the Labra- 
dor coasts, even up to Anticosti and the Mingan Islands on 
the Atlantic side, the home of this large group is in the 
great stretch of country, continental and insular, from the 
high northern coasts of Labrador, and Greenland to Alaska, 
It is unnecessary to illustrate the group. 
RELATIONS oF THE LARAMIE FLORA. 
Since the last number of this journal was published, [ 
have had an opportunity of seeing, in the publications of 
2 
