Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east to Montana.
Habitat: Open to fairly dense woodlands, thickets, and balds, sea level to middle elevations in the mountains; common in logged areas.
Conservation Status: Not of concern
Dioecious perennial with slender, trailing stems up to 6 m. long, abundantly armed with slender, hooked prickles.
Leaves trifoliate, the lateral leaflets ovate-lanceolate, 3-7 cm. long, doubly serrate; terminal leaflet larger, deeply 3-lobed.
Floral branches several, 1-3 dm. long, erect, bearing several leaves and 1-several flat-topped flower clusters, the inflorescence with stalked glands; calyx hairy and glandular, the 5 lobes lanceolate, 5-11 mm. long; staminate petals 5, white, elliptic-spatulate, 7-11 mm. long, with 75-100 stamens; pistillate petals broader and shorter, with numerous pistils.
Drupelets purplish-black, coherent, attached to the elongate receptacle; fruit up to 2.5 cm. long.