红柴胡 hong chai hu

Bupleurum falcatum Linnaeus subsp. scorzonerifolium (Willdenow) Koso-Poljansky; B. falcatum var. scorzonerifolium (Willdenow) Ledebour; B. sinensium Gandoger.

Plants 30–60 cm, perennial. Taproot stout, dark reddish-brown, branched. Stems 1–3, flexuose, greatly dichotomously branched, base clothed with fibrous remnant sheaths. Basal leaves linear, 6–16 × 0.2–0.7 cm, thick-papery, rigid, nerves 3–5, prominent abaxially, margin white cartilaginous, base slightly narrowed and clasping. Upper leaves small. Umbels numerous, 1.2–4 cm across; bracts 1–3, subulate, 0.5–4 × 0.2–0.6 mm, unequal, deciduous; rays (3–)4–6(–8), 1–2 cm, very slender, spreading; bracteoles 5, lanceolate, 2.5–4 × 0.5–1 mm, equaling or slightly exceeding umbellules; umbellules 2–5 mm across, (6–)9–11(–15)-flowered; pedicels 0.2–1 mm. Petals yellow. Stylopodium low-conic, dark yellow. Fruit ellipsoid, dark brown, 2.5–3 × 1.5–2 mm; ribs pale, prominent; vittae 5–6 in each furrow, 4–6 on commissure. Fl. and fr. Jul–Sep. n = 6*.

Shrub forest margins, sunny mountain slopes, dry grasslands; 100–2300 m. Anhui, Gansu, Guangxi, Hebei, Heilongjiang, Jiangsu, Jilin, Liaoning, Nei Mongol, Shaanxi, Shandong, Shanxi [Japan, Korea, Mongolia, Russia].

This Bupleurum is one of two primary species the roots of which are used for the major traditional Chinese medicine “chai hu” (see also B. chinense).

Two forms are endemic in China: f. longiradiatum R. H. Shan & Yin Li (Acta Phytotax. Sin. 12: 282. 1974), distinguished by having rays longer, 11–35 mm, and bracts larger, 4–7 mm (Hebei, Liaoning, Qinghai); and f. pauciflorum R. H. Shan & Yin Li (loc. cit.), distinguished by having rays usually fewer, 2–3(–5), and shorter, 3–12 mm, and umbellules only 4–6(–8)-flowered (Jiangsu, n = 6*).