Plants perennial 1–2.5 m, stout. Root cylindric, brown, 3–5 cm thick, strongly aromatic. Stem purplish green, 2–5(–7–8) cm thick, ribbed, pubescent above. Basal and lower leaves long-petiolate, sheaths oblong-inflated, glabrous; blade triangular-ovate, 30–50 × 25–40 cm, 2–3-ternate-pinnate; leaflets sessile, oblong-elliptic to oblong-lanceolate, 4–10 × 1–4 cm, base slightly decurrent, margin white-cartilaginous and coarse-cuspidate-serrate, apex acute, pubescent along nerves adaxially. Upper leaves reduced, sheaths saccate-inflated, bladeless. Umbels 10–30 cm across; peduncles 5–20 cm, scabrous; bracts absent or 1–2, like uppermost leaves; rays 18–40(–70), short-hairy; bracteoles many, linear-lanceolate, scarious; pedicels many, scabrous. Calyx teeth obsolete. Petals white, obovate and notched. Ovary glabrous or pubescent. Fruit suborbicular, 4–7 × 4–6 mm; dorsal ribs prominent, obtusely thick-rounded, much wider than furrows, lateral ribs broad-winged; vittae 1 in each furrow, 2 on commissure. Fl. Jul–Aug, fr. Aug–Sep.