British North American Plants. 7 
Nova Scotia of the white oak and butternut. A more imme- 
diate cause for the absence of Ontario and Eastern Quebec 
plants is, however, the lower temperature arising from the 
Labrador current, which, by a branch through the Strait& 
of Belle Isle, extends its influence up the St. Lawrence om 
both sides towards Quebec, whilst its main stream, after 
washing the eastern coasts of Newfoundland, spreads along’ 
the Nova Scotia and New Brunswick coasts in its course 
south westward. Of the effect of this culd current on plant 
life on the immediate coast, there is no question. 
ERIE GROUP. 
The area in Canada in which this group of plants is dis- 
tributed, is practically limited to that part of Ontario lying 
between Lake Erie and a line drawn from the eastern end 
of Lake Ontario to the mouth of the St. Clair River. This 
area is in the latitude of Southern Michigan and of Central 
and Southern New York State, and forms the most southern 
portion of Canada. It has, further, its climate modified by 
the proximity of the three lakes, Huron, Erie and Ontario. 
These facts sufficiently account for the middle temperate 
nature of the flora which, in its relations to Canada, has 
here been termed the Erie group. 
The south-western peninsula of Ontario is also marked by 
the great variety in species of its trees, and by, in the past, 
their remarkable growth. It is possible to find on a single 
farm of two hundred acres, more than half of the species of 
trees which occur in Ontario. The peninsula is now well 
denuded of its large trees, but fifty or more years ago its 
splendid forests were the admiration of travellers. Near 
where the present city of London stands, were white pines 
six feet in diameter and one hundred and sixty feet in 
height, and magnificent button-woods averaging about 
eighteen feet in girth and sending upwards straight stems 
to a height of even thirty feet before branching. Farther 
north, these button-woods were sometimes found of nearly 
twelve feet in diameter. Oaks in the district watered by 
the River Thames, varied from ten to fifteen feet in circum- 
ference, and had often forty-five to fifty feet of clear, straight 
