Bupleurum microcephalum Diels

This species is used as a regional substitute for the Chinese Medicine “chai hu.” It is similar to Bupleurum malconense but differs in the unbranched rootstock and the narrow, longer leaf blades.

Plants 50–100 cm, biennial. Taproot yellowish-brown, elongate-terete, unbranched. Stem solitary, several-branched above, slender, base purplish-tinged, without fibrous remnant sheaths. Basal leaves numerous, narrowly linear, 16–30 × 0.25–1 cm, thin-papery, abaxially slightly glaucous, 5-nerved, base tapering into petiole, margin white scarious. Cauline leaves shorter, sessile, somewhat clasping. Umbels numerous, 1.2–3 cm across; peduncles and rays very slender; bracts 3–5, very small, 0.2–2 × 0.1–0.4 mm, lanceolate or squamose; rays (3–) 4–6(–9), 7–50 mm, unequal; bracteoles 5, elliptic or spatulate, 1.5–2.5 × 0.5–1 mm, mostly shorter than umbellules in fruit; umbellules 2.5–5 mm across, 6–12-flowered; pedicels 1–1.5 mm. Petals yellow, midvein dark. Stylopodium low-conic, yellow. Fruit ovoid, brown, 2.6–3 × 2–2.2 mm, glaucous, base rounded; ribs inconspicuous; mericarps pentagonal in cross section; vittae 3 in each furrow, 4 on commissure. Fl. Jul–Aug, fr. Aug–Oct.

S Gansu, W Sichuan, SE Xizang.

Among shrubs, open slopes, roadsides; 1400–3200 m.

Bupleurum microcephalum là một loài thực vật có hoa trong họ Hoa tán. Loài này được Diels mô tả khoa học đầu tiên năm 1900.

马尾柴胡（学名：Bupleurum microcephalum）为伞形科柴胡属的植物，为中国的特有植物。分布于中国大陆的四川、甘肃等地，生长于海拔1,400米至3,200米的地区，一般生于路旁、开旷山坡及灌丛下，目前已由人工引种栽培。