goz RYDBERG: PHYTOGEOGRAPHICAL NOTES 
Most of these extend to the western slopes of the Rockies in 
British Columbia or northern Montana, but Tsuga Mertensiana, 
Osmorrhiza Leibergii and Synthyris reniformis are restricted to the 
western slopes of the Bitter Root Mountains in Idaho. 
4. WESTERN IMMIGRANTS FROM THE SIERRA NEVADA AND THE | 
CASCADES, WHICH HAVE INVADED THE NORTHERN 
ROCKIES 
There are a number of species which are common to the Pacific 
mountains and the Rockies, but have a wider distribution in the 
former than in the latter. Their home may therefore be regarded 
as being on the west coast, and they may be regarded as immigrants 
into the Rocky Mountains. Those of the following list are com- 
mon to the Sierra Nevada and the Cascades, and their range 
extends into the Northern Rockies. Some of these are found in 
the Bitter Root or the Selkirk Mountains only, and are without 
doubt immigrants. Others extend into the main Rockies of 
Alberta and Montana and even as far south as northern Wyoming. 
Whether these are immigrants or endemics to the Rockies is more 
doubtful. A very few reach the Wasatch Mountains in northern 
Utah. There are no immigrants from the Sierras to the southern 
Rockies. It is true that there are a few subalpine endemics com- 
mon to the Sierra Nevada and the Southern Rockies, but these 
are plants characteristic of the mountains of the Great Basin, and 
limited to the eastern slope of the Sierra Nevada and the western 
. slope of the Rockies. 
Trees 
Pinus albicaulis Salix sitchenstis 
Shrubs 
TSalix cascadensis Cassiope Mertensiana 
Ribes laxiflorum Vaccinium occidentale 
Ribes glandulosum Linnaea longiflora 
Herbs 
Stipa oregonensis Carex spectabilis 
Poa Cusicku Xerophyllum tenax 
