36 TRANSACTIONS OF THE CANADIAN INSTITUTE. {Vot. VIII. 
have, however, a remarkable effect on the climate and productions of 
British Columbia. Only within the past year or two has our know- 
ledge of the flora of this, the most westerly province of Canada, reached 
a point where it is possible to indicate, with a reasonable definiteness, 
the geographical distribution of its flowering plants. Perhaps in no 
other country are there so many varied physical conditions affecting 
this distribution. Four great mountain ranges, the Rockies, the Sel- 
kirks (including the Purcell and Gold ranges), the Cascades, and the 
Vancouver and Queen Charlotte Island ranges, traverse more or less 
the length of the province in serrated ridges somewhat parallel to the 
Pacific coast, and between the ranges on the mainland are extensive, 
highly elevated, rolling plateaus, and long river valleys. By standing 
directly in the path of the low pressure areas crossing British Columbia 
from the Pacific coast, these ranges result in very greatly increased 
precipitation on their western slopes, whilst to the immediate eastward 
of them, the very limited moisture leads more or less to irrigation being 
necessary and to the presence of plants from the arid plains to the south. 
Apart from the marked effects of the excess or deficiency of the pre- 
cipitation on the character of the vegetation—effects often seen within 
a few miles of each other—the great heights to which the peaks of the 
Rocky Mountains in unbroken succession rise, form barriers to eastward 
and westward distribution, whilst, on the other hand, the long river 
valleys, as those of the Kootenay, the Columbia, and the Fraser, lying 
between the mountain ranges, facilitate the northward course into Bri- 
tish Columbia of plants from Washington, Oregon and even from Nevada 
and California. On the coast, the Japanese current which off Vancouver 
Island has registered as high as 54°, plays a strong part in modifying the 
climate, and during long ages past has no doubt been one of the means 
by which Asiatic plants have been introduced into America. 
The groups into which British Columbia plants may be divided have 
some points of special interest. The seashore plants comprise over forty 
species, but of these, eighteen are common in Canada, to both the Atlan- 
tic and Pacific coasts, and at the same time are, with two exceptions, 
also found in Europe, and in a few cases, in Japanand Manchuria. This 
wide, disconnected range would suggest that they form an older flora 
than those confined to the shores of the Pacific Ocean. 
The large and well marked assemblage, referred to here as the 
Cascade Group, is confined in its range, more or less, to the westerly 
side of Vancouver Island or to the vicinity of the Cascade range of moun- 
tains on the mainland. The vegetation there is largely influenced by 
the great precipitation which prevails, and the milder climate arising . 
from the Japanese current. The rain and snow fall at Cape Scott in 1902 
