Rhamnus purshiana
cascara buckthorn
Habitat:
grows on moist well drained soils. Ranges from western and southern British Columbia south on the west side of the Cascade Mountains to lower Calfornia, east through Idaho to western Montana (Randall et al 1988).
A tree up to 50' tall and 10" to 20" in diamter. Leaves alternate, deciduous, 2" to 6" long, oblong to oblong-elliptical; dark glossy green
above paler below, leaf margins wavy or serrate. Flowers small and green white. Bark thin and grayish brown, smooth to somewhat scaly with white patches (Randall et al 1988).
Map Courtesy of USGS