Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana, also in central and eastern North America where native.
Habitat: Riparian corridors, moist bottomlands, and other areas near water, often disturbed.
Origin: Introduced from central and eastern North America
Growth Duration: Perennial
Conservation Status: Not of concern
Large tree to 35 m. tall from a short trunk up to 1 m. in diameter, dividing into several large, ascending limbs; bark thin and gray on young trees, flaking when old.
Leaves opposite, palmately 5-lobed, up to 15 cm. long and nearly as broad, deeply indented, with a truncated base, the lobes sharply toothed; leaves are pale green and shiny above, smooth and silvery below.
Plant monoecious or dioecious; flowers yellowish-green, in short-stalked, thick clusters.