April 30, 1806, along the Walla Walla River, Washington.

Shrub or small tree with rounded crown of spreading and drooping branches; usually forming clumps and often in thickets. Flowers tiny, in early spring. Leaves 2.5-5cm long, 2-2.5cm wide. Height: 7.5m Diameter: 15-30cm.

Moist soils along streams in mountain canyons; usually in coniferous forests and with cottonwoods and willows.

Northeastern British Columbia east to southern Manitoba and south to northern New Mexico and California; at elevations of 1,969-8,202 ft (600-2,500m).