Perennial herb; stems upright or climbing, glabrous to stiff-hairy, 30-80 cm tall.
Alternate, pinnately compound; leaflets 8 to 16, linear-oblong to oblanceolate or egg-shaped, 1.5-3.5 cm long, squared-off to notched and with a slender point at the tip; tendrils well developed, branched, grasping; stipules 3-8 mm long, often deeply toothed, sometimes arrowhead-shaped, often with a dark blotch.
Inflorescence an axillary, barely-stalked raceme of 1-3 (usually a pair of) pea-like flowers; corollas purple to whitish, 15-25 mm long, the wings sometimes reddish; calyx-teeth nearly equal in size, awl-shaped, the lower teeth equalling or exceeding the bell-shaped tube.
Pods, narrowly oblong, 3-7 cm long, initially hairy becoming glabrous; seeds 4 to 12.
Two varieties occur in BC:
1. Flowers usually at least 18 mm long, the wings often red; leaflets oblanceolate or broader................... var. sativa
1. Flowers usually less than 18 mm long, the wings usually not red; leaflets variable but often linear.................... var. angustifolia (L.) Wahlenb.
Source: The Illustrated Flora of British Columbia