ig^ MISC. PUBLICATION 303, U. S. DEPT. OF AGRICULTURE 
of importance commercially ; root sprouts formed ; seed vitality transient, much 
abortive ; generally a transient species invading and quickly occupying iDurned 
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 8.2 percent of winter food of northern sharp- 
tailed grouse in Quebec and Ontario. Ohservations: 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. 
Populiis trichccarpa Torr. and Gray. Black Cottonwood. 
Range : 1, 2, 3, 4, 5, 6, 7, 8, 12, 13. 
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: RufCed grouse. 
Populus tweedyi Britt. Tweedy cottonwood. 
Range: 9. 
Site : Well-drained, moist, sun. 
Fruit: Capsule. 
A small to large tree. 
Populus vaneouveriana, 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, much cultivated 
throughout New Mexico; wood used locally, especially for fence posts. Eaten 
by cattle. 
Porlieria angustifolia (Engelm.) Gray. Soap-bush. 
G-iiiacum angustifolium Engelm. 
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. 
Dasiphora fruticosa (L.) Rydb. 
Range : 4, 12, 13, 14, 15, 18, 21, 22, 23, 24, 25, 26, 27, 28. 
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 coriacea. 
