1903-4.] How PLanT LIFE 1S DISTRIBUTED IN CANADA AND WhHy, 23 
HOW PLANT LIFE IS DISTRIBUTED IN CANADA AND WHY. 
By A. T. Drummonp, LL.D. 
(Read 12th March, 1904.) 
It helps us to understand the vastness of the territory included 
within the limits of Canada when we know that in proceeding northward 
from the United States boundary line we pass through, on the average, 
about 1,000 miles of forest or open country before we reach the point, 
within the Arctic Circle, where the trees, so familiar in our landscapes, 
entirely disappear; whilst, on the other hand, from Nova Scotia to Van- 
couver, differences in climate and physical conditions are so marked as 
to admit of three great distinctive floras, each keeping its own character- 
istic territory, each absolutely different from the other, and all within 
the Northern Temperate Zone. We are accustomed to look for wonder- 
ful changes in vegetation when travelling southward to tropical countries, 
but nearly as striking to the resident along the Great Lakes is the entire 
absence on the Western prairies of nearly all of the trees he has been so 
familiar with in Ontario, and their replacement further west, in British 
Columbia, by a large number of new forest giants some of which tower , 
to heights not met with on this side of the continent. Trees most attract 
the ordinary observer, and this is natural because they are most striking 
in appearance and size, and commercially, form an important asset of 
the Dominion. On the other hand, on the Western prairies he cannot 
fail to be struck with the large splashes of colour due to the prairie flowers, 
which in the summer months everywhere brighten the dull green of the 
sward. These flowers, so characteristic of Manitoba and westward, find 
the forests, east of the Red River, a wall preventing their eastward dis- 
tribution, whilst the Rocky Mountains, and sometimes even the dry wes- 
tern plains of the South Saskatchewan, form equally a barrier on the west. 
Thus, it does not require any scientific knowledge to see that, looking at 
Canada as a whole, and without regard to the United States, there are, 
apart from the wide spread but dwarfed plants which make up the Arctic 
flora, three great groups:—That included in the east and having its 
highest development in Ontario, that on the prairies of Manitoba and 
westward, and that in British Columbia, west of the Rocky Mountains. 
And the distinctions between these groups are as marked among the 
smaller flowers and shrubs as among their more giant congeners, the trees. 
