Cascara, Cascara Buckthorn, False Buckthorn: Rhamnus purshiana (Synonym: Frangula purshiana)

The photo above shows the ripening berries and leaves of cascara as seen along the Grande Ronde River near Grouse Creek several miles downstream from Troy, OR.........July 7, 2008.

Cascara is a small deciduous tree ranging to 10 meters in height with stems to 250 cm in diameter in older trees. On the east side of the Cascades, its form may be more shrub-like. The limbs are relatively few and ascending. The bark is smooth and slightly gray mottled. Older bark may be somewhat scaly near the base of the trunk.

The leaves are typically alternate on the branches, but may occasionally be opposite. The leaves are elliptic to obovate in shape with acute or obtuse apexes. The upper leaf surface is smooth and glabrous while the lower surface is pubescent on each of the 10-15 pairs of prominent, parallel lateral veins. The leaves range from 6-13 cm long with very finely-toothed margins.

The 8-50 small green flowers are umbellate in the leaf axils. The 5 petals are barely longer than the nearly sessile anthers. The short style does not project past the hypanthium. The purplish black fruit are widest (8 mm in diameter) at their apex. 2-3 seeds are found in each fruit. The seedy fruits are edible but are mainly useful as survival food.

The drug Cascara Sagrada is made from the bark. This drug has laxative properties.

Cascara may be found from British Columbia southward along the west side of the Cascade Mts. to northern coastal and Sierran California. It may be found eastward to Idaho and western Montana.

The cup-shaped hypan and white petals that are present (the short white petals are visible at the notches between the calyx lobes) indicate that this buckthorn is probably Rhamnus purshiana rather than R. alnifolia. Photographed at about 5070' of Crofton Butte on the southern slopes of Mt. Adams.........June 19, 2005. The hypan of the flowers of R. alnifolia tend to be wider or saucer-shaped and the petals are very minute or generally lacking.

The photo above shows a close-up of the inflorescence of cascara as seen at about 5070' of Crofton Butte on the southern slopes of Mt. Adams..........June 19, 2005. Cascara (Rhamnus purshiana typically has 8-40 flowers in a pedunculate umbel in the upper leaf axils. Its cousin, alder buckthorn (R. alnifolia), typically has 2-5 flowers found in sessile umbels from the upper leaf axils.

The photo above shows a close-up of the ripening berries and leaves of cascara as seen along the Grande Ronde River near Grouse Creek several miles downstream from Troy, OR...........July 7, 2008.

The photo above shows the leaves and axillary inflorescence of what appears to be cascara as seen on the east-facing slopes at about 5070' of Crofton Butte on the southern slopes of Mt. Adams...........June 19, 2005.