198 MISC. PUBLICATION 303, U. 8S. DEPT. OF AGRICULTURE 
yI importance commercially ; root sprouts formed; seed vitality transient, much 
abortive; generally a transient Species invading and quickly occupying burned 
and logged areas and soon giving way to other species; the shade of these trees 
is never dense in spite of the closeness of stands; frequently supports an under- 
story of weeds. 
Stomach records: Three species of birds, including ruffed grouse and sharp- 
tailed grouse; black-tailed deer, northern white-tailed deer, mountain sheep, 
plains white-tailed deer; composed 3.2 percent of winter food of northern sharp- 
tailed grouse in Quebec and Ontario. Observations: Highly palatable to captive 
deer; pika; mountain beaver; white-tailed deer; important food of snowshoe 
hare; important browse of moose; important food of Pacific coast and Shasta 
beaver; of outstanding importance as browse for mule deer; red squirrel; the 
principal food of beaver throughout its range; black bear, cottontail rabbit, 
porcupine. Frequently supports understories of weeds and browse highly 
esteemed by livestock. Very palatable to sheep and goats. 
Populus trichocarpa Torr. and Gray. Black cottonwood. 
AM Tea D er An Ge akees. lezeed: 
Site: Moist, sun. 
Fruit: Capsule. 
A large tree; commonly occurs in sandy humus or gravel; root system shallow ; 
very rapid growing, longest-lived of the poplars although comparatively short- 
lived; storm-damaged, not wind-firm; wood of importance commercially, espe- 
cially for pulp; seed with a high percentage germination, vitality transient. 
Stomach records: Ruffed grouse. 
Populus tweedyi Britt. 
Range: 9. 
Site: Well-drained, moist, sun. 
Fruit: Capsule. 
A small to large tree. 
Tweedy cottonwood. 
Populus vancouveriana, see Populus tremuloides. 
Populus virginiana, see Populus deltoides. 
Populus wislizenii (Wats.) Sarg. Valley cottonwood. 
P. fremontii wislizenii Wats. 
Range: 11, 17. 
Site: Well-drained, moist, sun. 
Fruit: Capsule. 
A large tree; commonly occurs in sandy Soil; rapid growing in moist situa- 
tions, slow in intermittently moist situations; short-lived, muck cultivated 
throughcut New Mexico; wood used locally, especially for fence posts. Eaten 
by cattle. 
Porlieria angustifolia (Hngelm.) Gray. Soap-bush. 
Guiacum angustifolium HWngelm. 
Range: 11, 17, 20. 
Site: Dry, well-drained, sun. 
Fruit: Capsule. 
A large shrub to small tree; evergreen; branches rigid, spreading or strag- 
gling; wood very durable, used locally for fence posts. An important honey 
plant. 
Potentilla fruticosa L. Shrubby cinquefoil. 
Dasiphera fruticosa (i.) Rydb. 
Ranges) 4) 1213514) 1518 2 2223 24 226 eee. 
Site: Dry, well-drained, moist, sun, shade. 
Fruit : Achene. 
A small evergreen shrub; flowers June-September; often sprawling; much 
branched; an aggressive species commonly invading pastures in New England, 
but plowing and close pasturing have successfully checked its spread; some 
14 varieties are in cultivation. 
Observations: Rarely browsed by moose; casually browsed by northern white- 
tailed deer. Considered inferior forage for cattle, but of importance for sheep 
and goats in the Southwest. 
Prinos coriacea, see Ilex coriaced. 
