Page authors: David Giblin, Don Knoke
Frangula purshiana
buckthorn, false buckthorn, cascara

Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana.

Habitat: Forest understory and margins from low to moderate elevations in the mountains.

Flowers: April-June

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern


Deciduous shrub or small tree up to 10 m. tall, yellow- or brownish-puberulent.


: Leaves alternate, with stout petioles 5-20 mm. long, the blades oblong-ovate to oblong-obovate, 6-13 cm. long, very finely serrulate, with 10-12 prominent, lateral veins on each side.


Flowers in umbels on axillary peduncles, perfect or imperfect (if imperfect, the plant monoecious); calyx bell-shaped, 5-lobed, 3-4 mm. long, greenish, lined with a thin disk to which the petals and stamens are attached; petals 5, small, hooded; stamens 5, nearly sessile; ovary superior, free of the disk.


Berries purplish-black, 6-9 mm. long.

Accepted Name:
Frangula purshiana (DC.) A. Gray ex J.G. Cooper
Publication: Pacif. Railr. Rep. 12(2): 57. 1860.

Synonyms & Misapplications:
Rhamnus purshiana DC. [HC]
Additional Resources:

PNW Herbaria: Specimen records of Frangula purshiana in the Consortium of Pacific Northwest Herbaria database

WA Flora Checklist: Frangula purshiana checklist entry

OregonFlora: Frangula purshiana information

E-Flora BC: Frangula purshiana atlas page

CalPhotos: Frangula purshiana photos

61 photographs:
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