Distribution: Occurring on both sides of the Cascades crest in Washington; southern British Columbia to Northern California, east to northern Idaho and western Montana.
Habitat: Sagebrush slopes and open woods.
Growth Duration: Perennial
Conservation Status: Not of concern
Erect, stiff-branched, evergreen woody shrub 1.5-20 dm. tall, occasionally stoloniferous.
Leaves alternate, pinnate, leathery; leaflets 5-9, oblong to ovate or ovate-lanceolate, 3-8 cm. long and 2-5 cm. broad, pinnately nerved from the mid-vein, glossy above, with 12-29 spiny teeth.
Inflorescence of several bracteate racemes 3-8 cm. long; perianth of 5 alternating whorls of 3 members each; outer 3 greenish-yellow, 2-3 mm. long (bracts); next 6 bright yellow, 6-8 mm. long (sepals); inner 6 bright yellow, slightly shorter, bi-lobed, oblong (petals); stamens 6, opposite the petals; filaments with 2 divergent teeth at the tip; style none, stigma sessile.
Berry deep blue, glaucous, globose-ellipsoid, 7-14 mm. long.
PNW Herbaria: Specimen records of Mahonia aquifolium in the Consortium of Pacific Northwest Herbaria database.
WA Flora Checklist: Mahonia aquifolium checklist entry.
OregonFlora: Mahonia aquifolium information.
E-Flora BC: Mahonia aquifolium atlas page.
CalPhotos: Mahonia aquifolium photos.
USDA Plants: Mahonia aquifolium information.