Perennial; stems erect or ascending, clustered, 3-9 dm long, glabrate or strigose to inflorescence; petioles 1-3 cm long; leaves trifoliolate; leaflets oblong-lanceolate, the terminal longest, to 3-6 cm, generally about 1 cm wide, 4-5 times longer than wide, glabrous to slightly strigose above, somewhat pale below and either glabrous or strigose on nerves; inflorescences axillary and terminal, elongating to 5-30 cm in fruit; pedicels spreading; calyx about 2 mm long; corolla about 5 mm long, purple; stamens with filaments united into a tube; fruits stipitate for 1-2 mm, segmented (fruits are loments), crenate above, moderately notched below, sometimes twisted, segments 2-5, each 5-6 mm long, surface with fine, stiff, hooked hairs. Flowers August to October.