Description from Flora of China
Bupleurum falcatum Linnaeus var. angustissimum Franchet, Pl. David. 1: 138. 1883; B. falcatum f. angustissimum (Franchet) C. Pei & R. H. Shan; B. falcatum subf. angustissimum (Franchet) H. Wolff; B. scorzonerifolium Willdenow subsp. angustissimum (Franchet) Kitagawa; B. scorzonerifolium var. angustissimum (Franchet) Y. Huei Huang.
Plants 15–80 cm, perennial. Taproot long, slender, woody, reddish-brown. Stem slender, dichotomous-branched throughout, base clothed with fibrous remnant sheaths. Lower leaves sessile, linear, 6–18 × 0.8–1 cm, thick, rigid, 3–5-nerved, margins narrowly reflexed, apex and base tapering. Apical leaves short. Umbels numerous, 1.5–2 cm across, bracts 1 or absent, subulate, 0.5–2 × 0.2–0.5 mm, unequal; rays 5–7, 1.5–3 cm, unequal; bracteoles 5, linear-lanceolate, 1.2–2.5 × 0.5–0.7 mm, longer than pedicels in fruit; umbellules ca. 5 mm across, 12–16-flowered; pedicels ca. 0.8 mm. Petals yellow, midvein dark. Stylopodium low-conic, dark yellow. Fruit ellipsoid, ca. 2 × 1 mm; ribs prominent; vittae not recorded. Fl. Jun–Jul, fr. Aug–Sep.
This species is widely used as a substitute for the Chinese medicine “chai hu.”
Dry grasslands; 1600–2000 m. Gansu, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi [Mongolia].