细柄柴胡 xi bing chai hu

Plants 50–90 cm, perennial. Root long, thickened, branched. Stem usually solitary, erect, branched at base, base without fibrous remnant sheaths. Basal leaves oblanceolate, 8–18 × 1–1.4 cm including petioles, base narrow, clasping, apex acute. Cauline leaves subsessile, oblanceolate or narrowly long-elliptic, 5–9 × 0.7–1 cm, abaxially grayish-green, 5–7-nerved, apex obtuse, apiculate. Upper leaves sessile, small, lanceolate. Umbels 1.5–4 cm across; bracts 3–5, elliptic or ovate, 3–7 × 1–3 mm, unequal; rays 2–3(–5), thin and rigid, 1–3 cm, unequal; bracteoles 4–5, green, 3–4 × 2–2.5 mm, margin membranous, exceeding umbellules in flower, but shorter in fruit; umbellules ca. 5 mm across, 5–10-flowered; pedicels ca. 1 mm. Petals pale yellow, midvein dark. Stylopodium low-conic, yellow. Fruit oblong-ellipsoid, brown, ca. 4 × 1.5 mm, glaucous; ribs prominent; vittae 3 in each furrow, 2–4 on commissure. Fl. and fr. Jun–Aug.

Forests, shady valleys; 1400–1700 m. Chongqing (Nanchuan).

This poorly known taxon is recorded only from a few collections.