1903-4. | How PtantT LIFE Is DISTRIBUTED IN CANADA AND WHY. 31 
are greatly diminished in force. Whilst the smaller representatives 
of plant life find within the line of forests or bluffs such congenial con- 
ditions, they afford, as they die, some return to the trees by joining 
with the trunks and leaves of these trees in enriching the soil by their 
decay. 
Whilst there are natural changes in climate and consequently in 
vegetation arising from increasing nearness to the Arctic Circle, other 
important factors which influence the range of trees and the smaller 
plants in Northern Canada, east of the Rocky Mountains are the relative 
masses of the land and the water, the direction of the great mountain 
chains, which here somewhat parallel the Pacific coast, and the much 
lower altitude above the sea of the Peace River country east of these 
mountains. The effect of the great breadth and length of that cold 
inland sea, which we call Hudson Bay, is very marked. On the east 
side, the trees are sparingly met with on the coast until they disappear 
entirely immediately beyond Richmond Bay. On the Atlantic side 
of Labrador, the growth of trees on the coast line is directly affected by 
the wide Boreal current which comes south through Davis Straits, and 
the last trees on the coast are met with at about Hamilton Inlet. Far 
inland, however, between Hamilton Inlet and Richmond Bay, away 
from the influence of the sea, three or four species range farther north- 
ward for 200 miles. Again, on the west coast of Hudson Bay, the last 
trees seen are immediately beyond Fort Churchill, but inland, beyond 
the influence of the bay, the northern limits of the forest country run 
north-westward from about this point towards the mouth of the Mac- 
kenzie River. The great mass of the land in this direction results in a 
more moderate climate, which improves as the numerous lakes and mus- 
kegs are left behind and the Slave and Peace Rivers are reached. 
The enormous coast line of Canada fronting on the Pacific and 
again on the Atlantic Ocean, with the Arctic Sea between, has led to the 
occurrence of sea shore plants exclusively confined, some to the Pacific 
and some to the Atlantic coast, whilst others are common to both. 
Quite a number of these sea shore plants are also now found along the 
shores of the Great Lakes and on saline ground farther westward. They 
are evidently the remains of a larger maritime flora which margined 
the interior coast in Pleistocene times when the ocean made great in- 
roads over the Province of Quebec and up the Ottawa River. The fact 
of their flourishing now on the lake coasts and inland shows how they 
have, but in greatly diminished numbers, adapted themselves to new 
conditions in which, in the one case, the saline element, and in the other, 
the moist atmosphere of the seashore, were wanting. That the larger 
number of these inland seashore plants are found around Lake Ontario 
