Seseli siamicum Craib.

Plants 30–80 cm, monocarpic. Caudex simple. Stem solitary, branching above, solid, terete, finely grooved, glabrous. Basal leaves numerous, petiolate; blade triangular or rhombic, 3–10 × 3–10 cm, 2–4-ternately dissected, every divided point articulated; ultimate segments narrowly linear, 7–65 × 0.5–3 mm, entire. Cauline leaves few, 1–3-ternately dissected; uppermost leaf 3-parted or simple. Synflorescence dichotomously branched, corymbose; umbels 2–4 cm across; bracts absent or occasionally 1, subulate, 1.5–4 mm; rays 6–10, 0.3–2(–4) cm, unequal; bracteoles 8–10, lanceolate, ca. 2.5 × 0.5 mm, about equaling flowers, bases connate, margin scarious; umbellules 15–30-flowered; pedicels ca. 2 mm. Calyx teeth obsolete. Petals pale yellow, oblong or almost square, veins 3–5, brown-yellow, conspicuous, abaxially puberulent. Stylopodium low-conic; styles short, stout. Fruit ovoid or oblong-ovoid, compressed dorsally, ca. 3 × 1 mm, glabrous; ribs ca. equal, narrowly keeled or rounded; vittae 1–2 in each furrow, 2–4 on commissure. Fl. and fr. Aug–Oct.

The roots are used in Yunnan as a regional substitute, known as “song ye fang feng,” for the traditional Chinese medicine “fang feng” (Saposhnikovia divaricata).

Coniferous forests, among shrubs, valleys; 600–3100 m. S Sichuan (Dechang, Leibo), NW Yunnan (Binchuan, Dali, Heqing) [Thailand].