Ig15] SMILEY—LAKE TAHOE REGION 279 
Scouleri, Agastache urticifolia, and Solidago elongata, the two last 
being especially common about meadow borders within the ring of 
Salix macrocar pa argentea that commonly hedges the wet meadow. 
The dry meadow formation, as stated above, is less evident, but 
still exists and shows a considerable list of species: Sporobolus 
depauperatus, Zygadenus venenosus, Myosurus apetalus, Hosackia 
americana, H. crassifolia, Gomphocarpus cordifolius, Allocarya 
hispidula, Cryptanthe geminata, and Aster canescens being the 
more numerous. 
CANADIAN ZONE.—Of the several life zones discoverable in the 
Tahoe flora, the Canadian is at once the most extensive and most 
difficult to define. Its lower limit conforms generally to the 7000 
feet contour line, while the upper boundary may be placed at about 
8500 feet as a maximum; within this range of 1500 feet lies the 
greater part of the district. This zone includes most of the ridges 
connecting the peaks rising into the alpine region; it covers the 
lower flank of the Divide, and encircles Mt. Rose below gooo feet, 
for in the Carson Range the greater aridity and higher mean tem- 
perature of the growing season causes all the life zones to rise higher 
than they do in the mountains west of Lake Tahoe. This rise of 
the zonal limits reaches a maximum on Freel’s Peak, which has 
small groves of Pinus Murrayana, perhaps the one best “Leit- 
Pflanze”’ of the Canadian flora, even at the 10,000 feet level. These 
slopes are frequently composed of loose granite sand, and, as 
mentioned in the case of the slope east of Angora Peak, support a 
characteristic flora of shrubs rarely found outside the Canadian 
life zone. The edaphic factor must be constantly kept in mind 
in locating zonal limits, and in our district this is largely conditioned 
by the degree of glaciation and subsequent erosion. Where the 
country rock was swept bare, a typical Hudsonian assemblage of 
plants is apt to be found, even though well below the 8500 feet 
limit, as in Desolation Valley at 7800-8000 feet. Where depo- 
sition has given a sufficient soil cover, conditions are decidedly 
ameliorated, and the Canadian flora develops typically even above 
its general level, as in the high alpine valleys south of Lake Tahoe. 
The Canadian forest is, for the most part, a thin forest; as a 
tule the trees stand well apart, only exceptionally preventing 
