THE 



CANADIAN NATURALIST. 



SECOND SERIES. 



THE DISTRIBUTION OF PLANTS IN CANADA 



IN SOME OF ITS RELATIONS 



'to physical axd past geological conditions. 



By A. T. Drummond, B.A., LL.B. 



More than two years ago, in this journal, the writer endeavoured 

 to indicate and illustrate some of the more obvious features in the 

 distribution of Canadian plants. It was shown that in taking a 

 general view of this distribution several distinct floras could be 

 recognized, viz. : — a general Canadian flora composing species 

 which range over the whole or greater part of the Province ; a 

 second flora whose species are confined to the districts around the 

 northern shores of Lakes Superior and Huron ;' a third to the com- 

 paratively narrow district bordering Lakes Erie and St. Clair and 

 the south-western parts of Lake Ontario ; a fourth to the Gulf 

 and Lower St. Lawrence shores; and a fifth which had an un- 

 doubted boreal aspect. Besides these, were a small inland mari- 

 time flora, and two other floras whose limits and characteristics 

 could not then be accurately defined, but which appeared to be 

 limited — the one to Upper Canada and the other chiefly to Lower 

 Canada. A number of plants were also indicated which were 

 apparently confined to the tract of country around the northern 

 shores of Lakes Huron and Superior and to the more eastern 

 parts of Lower Canada, whilst several species were named whose 

 occurrence was quite local. These prefatory references will render 

 subsecment remarks more intelligible. 



In investigating the causes which have influenced the diffusion 

 of species in Canada, we find that whilst some have in past time 

 been and are still exerting their influences, others are perhaps 

 correctly referred to far distant periods. And whilst the operation 

 of some is confined to narrow limits, others extend their effects 



Vol. III. L No. 3. 



