Aerial shoots 8-30(-35) cm. Basal leaves: lateral leaflets 1×-lobed; ultimate lobes 0.4-2 mm wide. Inflorescences: involucral bracts with terminal leaflet 2-8 × 1-3(-3.5) cm, base cuneate, margins crenate to deeply serrate, apex acuminate to acute; lateral leaflets unlobed or 1×-lobed; ultimate lobes 0.5-2 mm wide. Flowers: sepals blue to purple, reddish, or purple to pink, rarely nearly white; stamens 30-60, occasionally more. Achenes: body puberulous to pilose, rarely glabrous. 2 n =16. Flowering spring (Mar-Jun). Shaded, moist woods, open hillsides; 100-1800 m; Calif., Oreg., Wash.