IMPORTANT WESTERN BROWSE PLANTS 15 
or manufactured into emergency feed, is confined to the flowers and 
youngest leaves in dry seasons when other range feed is scarce. 
Lacking the pulpy stem of Y. elata, it is distinctly inferior to that 
species as feed. 
RELATED GENERA 
Plants of the related genera, sotol (Dasylirion) and sacahuista or 
beargrass (Nolina), are also sometimes machine-cut or shredded, like 
soapweed, as emergency feed or silage, especially for cattle. Because 
of their small size, lack of trunk, and failure to sprout after cutting 
they are distinctly inferior to soapweed as emergency feed, though 
of approximately equal feeding value pound for pound. The leaves 
of Nolina, however, are often grazed closely during drought. 
Texas sotol (Dasylirion texanum), as found in western and south- 
ern Texas, is a species that can, according to Smith (124, p. 25) sup- 
port sheep for four or five months in winter without access to water. 
A chemical analysis of the plant shows about 12 per cent of sugar 
and gum, 65 per cent of water, and 3 per cent of crude protein. 
WILLOW FAMILY (SALICACEAE) 
WILLOWS (SALIX SPP.) 
At least 80 (perhaps considerably more) species of willow occur 
natively in the far Western States. The great majority of these 
have value as browse for livestock. Willows as browse are usually 
of most importance on cattle range, being common in moist meadows 
and along streams where this class of stock is wont to congregate. 
Willows form the most important summer browse of reindeer in 
Alaska (51, p. 25-26). Vigorous vegetative reproduction by root 
shoots and suckers enables most willows to contend successfully 
against severe grazing. Dwarf willows are common at alpine ele- 
vations in the high mountains. 
Scouler willow (Salia scouleriana, syn. S. nuttalliz) (pl. 1, C), 
known also as fire, Nuttall, mountain, and black willow, is one of 
the most common, abundant, and widely distributed willows in west 
North America, its range extending from British Columbia to 
, ee New Mexico, and Saskatchewan; a variety occurs in 
laska. 
Scouler willow is usually an erect shrub, sometimes a tree, but 
rarely as much as 50 feet high. Its best development is attained in 
such moist or moderately moist sites as the borders of mountain 
streams, meadows, and many north and west slopes. It is, how- 
ever, broad in its moisture and soil tolerances and not infrequently 
occurs in coarse, dry soils and on warm southerly slopes, where the 
growth is more stunted and bushy and the leaves are generally 
smaller, more hairy, and darker green above. The altitudinal range 
is from about 2,000 feet in the north to nearly or quite 11,000 feet 
at the southerly limits. The species is never found at alpine and 
rarely at subalpine altitudes. On areas denuded by fire it forms a 
thicket of a transition type until the climax conifer cover is reestab- 
lished. 
Because of its abundance, wide distribution, and accessibility, as 
well as its quick growth, recuperative powers, moderate size, and 
