71 
SILVER LEAVED WILLOW. 
SALIX argophylla , foliis lineari-sublanceolatis acutis 
sessilibus integerrimis utrinque argenteo-sericeis , stipulis 
obsoletis , amentis serotinis diandris , capsulis villosis lan- 
ceolatis. 
In our devious progress to the West, we at length 
approached one of the branches of the Oregon, the river 
Boisee, towards its junction with the Shoshonee; its 
banks were not fringed with a belt of forest, but so 
stripped of every character of an alluvial nature, that 
when we suddenly approached it, there appeared no 
break in the plain, and the clear and rapid flood shot 
through a deep perpendicular chasm of columnar basal- 
tic rocks. We descended towards its brink and pur- 
sued our path along its obstructed banks, climbing over 
fearful rocks and along the margins of impending preci- 
pices, night approached without any cessation of our 
incessant toil. At length we hailed with satisfaction 
a small portion of the river bottom, almost covered by 
tall bushes of a remarkable silvery appearance, which 
proved to be the subject of our present examination, a 
very curious species of Willow, which, with a kind 
of Mock Orange, ( Philadelphia , ) composed nearly all 
the conspicuous vegetation of this sterile chasm. At 
length our new Alnus, (A. Oregona ,) the Narrow-leaved 
Balsam Poplar, and the Long-leaved tree W illow, gave 
evidence of an ample alluvial plain and the proximity of 
the great Shoshonee. 
This species becomes a small tree from 12 to 15 feet 
in height, as silvery and white as the Leucodendron 
