太白柴胡 tai bai chai hu

Plant 50–75 cm, perennial. Taproot long-terete, unbranched. Stem solitary, erect, slender, branched above, base tinged purple, without fibrous remnant sheaths. Basal leaves linear, 5–7 × 0.3–0.5 cm including petioles, 5–7-nerved, thinly papery, abaxially greenish-white. Cauline leaves similar to basal, shortly petiolate. Apical leaves small, sessile. Umbels 3–4 cm across; bracts 1–2, lanceolate, 1–4 × 0.5–1.5 mm, unequal; rays (4–)6–10, 1–3 cm, unequal, very slender, spreading; bracteoles 5–6, elliptic, 1–2 × 0.5–1 mm, membranous; umbellules 4–5 mm across, 10–14-flowered; pedicels very slender, 5–7 mm in flower, up to 10 mm in fruit, greatly exceeding the bracteoles. Petals yellow. Stylopodium low-conic, discoid, yellow. Fruit ellipsoid, brown, ca. 4 × 2 mm, slightly glaucous; ribs inconspicuous; mericarps near round in cross section; vittae 3 in each furrow, 4 on commissure. Fl. and fr. Aug–Sep.

Mountain slopes; ca. 2000 m. SW Shaanxi (Taibai Shan).

This species is used as a regional substitute for the Chinese medicine “chai hu.” It is a rather poorly known taxon, recorded only from a few collections.