Plants 0.6–2 m, stout. Rootstock cylindrical. Stem single, erect, striate, hollowed and branching, base densely covered in fibrous remnant sheaths. Lower leaf petioles 20–40 cm; blade triangular-ovate, 30–35 × 20–25 cm, ternate-3-pinnate; ultimate segments ovate or oblong-ovate, 2–4 × 1–1.5 cm, puberulent on the veins, abaxially olivaceous, purplish. Upper leaves much reduced. Umbels 5–10 cm across, terminal and lateral; peduncle 20–40 cm, base of umbels densely pubescent; bracts 5–8, linear, 5–20 mm; rays 30–50, extremely unequal, 3–12 cm; bracteoles numerous, linear, 4–6 mm, shorter than umbellules. Calyx teeth obsolete. Petals white, ovate. Fruit oblong-ovoid, ca. 4 × 2.5 mm; dorsal and intermediate ribs filiform, lateral ribs narrowly winged; vittae 3–4 in each furrow, 8–10 on commissure. Seed face plane. Fl. and fr. Jul–Sep.
