Description from Flora of China
Ligusticum thomsonii var. evolutius C. B. Clarke; Pleurospermum longicaule H. Wolff.
Plants 20–90(–150) cm, subglabrous. Rootstock cylindrical, 5–15 × 1–2 cm. Stems multicipital, striate, base densely clothed with fibrous remnant sheaths. Basal leaves petiolate; petioles 2–10 cm; blade narrowly oblong, 2–12 × 1–3 cm, 1-pinnate (rarely 2-pinnate); pinnae 5–9 pairs, ovate or oblong, 5–20 × 5–10 mm, veins sparsely pubescent, margins irregularly serrate to deeply lobed. Cauline leaves 1–3, reduced upward becoming sessile. Terminal umbels 4–6 cm across, lateral umbels smaller, sometimes staminate; bracts 5–6(–8), linear, margins white membranous; rays 10–20, 1–2.5 cm; bracteoles 10–15, linear to linear-lanceolate, margins white membranous. Calyx teeth minute, triangular. Petals white ovate, base cuneate. Styles reflexed. Fruit oblong-ovoid, 3.5–5 × 2–3 mm; dorsal and intermediate ribs prominent, lateral ribs narrowly winged; vittae 2–4 in each furrow, 6–8(–10) on commissure. Seed face plane. Fl. Jul–Aug, fr. Sep–Oct. 2n = 22*.
This species has reputed medicinal value (in SW China).
Margins of coniferous forests, grassy valley slopes, alpine scrub and meadows; 2200–4200 m. Gansu, SE Qinghai, W Sichuan, Xizang, NW Yunnan [Afghanistan, NW India, Kashmir, Pakistan].