Description from Flora of China
Hymenidium pilosum (C. B. Clarke ex H. Wolff) Pimenov & Kljuykov.
Plants 20–40 cm, white-setose throughout. Root stout and branched. Stem ribbed, lower parts purple-red. Stem leaves petiolate, petioles ca. 10 cm; sheaths broadly ovate, 2.5–4 cm, purple-red adaxially, densely white-setose abaxially; blades triangular-oblong, 10–15 × 5–7 cm, 3-pinnate; pinnae 5–7 pairs, only basal pinnae short-petiolulate; ultimate segments obovate or oblanceolate, 3–5 × 2–3 mm, setose along nerves abaxially, entire or 2–3 toothed, cuspidate at apex. Umbels 3–15(–20) cm across (in fruit); bracts 1–3, 1–3 cm, white-setose abaxially, apex acute or pinnate; rays 6–17, 8–10 cm; bracteoles 8–10, broadly cuneate-obovate, 6–15 mm, mottled purple-green, pubescent along nerves, abruptly acuminate to a short point; umbellules many-flowered. Calyx teeth obsolete. Petals obcordate, white, often purplish on reverse, ca. 2 × 1.2 mm. Fruit oblong, 3–6 × 1.5–2 mm; ribs narrowly winged; vittae 1 in each furrow, 2 on commissure. Fl. Jul–Oct, fr. Sep–Nov.
This species has reputed medicinal use.
Damp meadows, streamsides; ca. 4100 m. S Xizang (Yadong) [Bhutan, Sikkim].