Trailing shrub, 2-5 m or more long; stems barely woody, 2-10 mm in diameter, arching, sprawling and trailing along the ground, some rooting at the tip, with slender, straight to slightly recurved prickles, somewhat hairy when young becoming smooth and glaucous; flowering branches ascending, to 50 cm tall.
Alternate, deciduous, pinnately compound, 5-15 cm long; leaflets 3 (rarely 5), narrowly to broadly egg-shaped, 3-10 cm long, coarsely double-saw-toothed, green and smooth or nearly so on both surfaces, the terminal leaflet largest and often deeply 3-lobed to divided, the leaf-stalks and midveins beneath fine-prickly; stipules linear, 8-11 mm long.
Inflorescence of few stalked flowers in small, open, flat-topped terminal clusters, the stalks often purplish stalked-glandular; male and female flowers on separate plants; corollas white, the petals 5, spreading, elliptic and 8-11 mm long in female flowers, lanceolate and 12-17 mm long in male flowers; calyces woolly and usually stalked-glandular, sometimes fine-prickly, 5-lobed, the lobes lanceolate, spreading to bent back, 7-11 mm long; ovaries superior; stamens 75 to 100.
Drupelets, generally smooth, coherent in a black oblong to nearly globe-shaped cluster that falls with the fleshy receptacle (a blackberry), the berries 1-1.5 cm long.
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
Synonyms and Alternate Names:
Rubus macropetalus Douglas ex Hook.
Rubus ursinus var. macropetalus (Douglas ex Hook.) S.W. Br.