Petals only slightly unequal, oblong-elliptic to obovate, white, ± 1.5–2 mm., glabrous, univittate.
Anthers small, yellowish to white.
Fruit glabrous, roundish to elliptic-oblong or obovate, ± 9–14 × 6–10 mm., the fertile centre 3–4 mm. wide, truncate or notched at the base, notched at the apex; vittae 2–5 in each vallecula, 4–6(–12) in the commissure, solitary vittae sometimes also present in or about the base of the wings; stylopodia shortly conical, subequalling the apical notch, often purplish when young, with a narrow undulate disk; styles deflexed to divergent, up to twice as long as the stylopodia.
Perennial herb with a stout, cylindrical, tuberous rootstock.
Basal leaves ± 8–35 × 3.5–26 cm., the lamina broadly deltoid-ovate to oblong-ovate in outline, 2(–3)-pinnate with 3–6(–7) pairs of pinnae, the lowest pinnae with 1–3(–4) pairs of pinnulae dissected into flat, broadly linear to narrowly linear-oblong or -obovate, entire to bluntly or sharply toothed 0.2–8 × 0.4–0.9 cm. segments, with narrowly revolute or thickened, smooth or ± scabrid margins and a rather bluntly mucronate tip; petiole 3.5–13 cm. including the 1.5–3 cm. shortly or more narrowly tapering, striate sheath; median stem leaves similar or more dissected, becoming sessile on the sheaths; upper leaves rapidly diminishing, becoming trisect and finally very small and bracteiform.
Stem erect, ± 11–90 cm. tall, broadly fistular, to 5 mm. wide at the base, terete, striate and ± smooth below, more sulcate and often minutely scabrid above especially at branch junctions; branches few to rather numerous, long and slender, ascending or divaricate.
Calyx-teeth distinct, subulate, ± 0.5–0.75 mm., often purplish.
Umbels with 6–14 rays 1.5–9 cm. long, smooth or more usually scabrid about base and apex; involucre of 0–6 linear 3–8 mm. bracts; partial umbels 7–17-flowered, the 3–12 mm. pedicels usually ± scabrid on the inner surface and at the apex; involucel of 4–9 linear bracteoles 2–8 mm. long; peduncles 3–14 cm., usually conspicuously scabrid beneath the umbel, rarely smooth.