Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, disjunct to the east in northern Idaho.
Habitat: Moist areas at low elevations.
Growth Duration: Perennial
Conservation Status: Not of concern
Monoecious, deciduous trees to 25 m. tall, the bark thin, smooth and gray, the trunk up to 8 dm. thick; fresh wood tends to turn deep red.
Leaves alternate, simple, the blades broadly elliptic or elliptic-ovate, 5-15 cm. long, usually acute at each end, wavy and irregularly denticulate, the margins slightly revolute, the upper surface deep green and glabrous, the lower surface rusty-gray and gland-dotted.
Catkins developing before the leaves on growth of the previous season; staminate catkins clustered, pendulous, 5-12 cm. long; pistillate catkins cone-like, woody, ovoid-ellipsoid, 1.5-2 cm. long and 1 cm. thick, stout, thick peduncles under 1 cm. long.
Nutlet with thin, membranous wings 1/5-1/2 as broad as the nutlet