Plants subacaulescent from a slender taproot and usually simple crown. Herbage: puberulent. Leaf blades obovate in outline, 4–20 cm long, triternate or tripinnate; ultimate segments well-separated, linear (rarely oblong), 1–12 cm long. Umbels: peduncles ascending, 2–40 cm; rays unequal, 1–7 cm long; involucel bracts few, linear, 2–4 mm long. Flowers yellow Mericarps lanceolate to narrowly elliptic, 7–15 mm long, glabrous; marginal wings 1–1.5 mm wide; oil tubes solitary in the intervals (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
Montana plants are varieties triternatum
(M.E. Jones ex. J.M. Coult. & Rose) Mathias, and platycarpum
(Torr.) B. Boivin.
Grasslands, sagebrush steppe, meadows, open forest, pine woodlands; valleys, montane (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)