Glabrous, fibrous-rooted perennial. Stems ascending to erect, 40–100 cm. Leaves pinnate; leaflets lance-linear, serrate, 2–9 cm long; submersed leaves narrower or bi- to tripinnate. Umbels: peduncles 5–15 cm long; rays 1–5 cm long; involucral bracts lanceolate, reflexed, 4–12 mm long; involucel bracts linear, 1–6 mm long, scarious-margined. Flowers white; sepals minute; stylopodium low-conical. Mericarps ellipsoid, glabrous, little compressed, 2–4 mm long; ribs raised, corky, not winged; oil tubes 1 to 3 per interval (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Shallow, fresh water and banks of ponds, swamps, marshes, slow streams; plains, valleys, montane (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).