Stems 20-150 cm, sparsely purple spotted, glabrous, branched or simple, with 4-15 nodes. Petiole 0.5-6.5 cm; leaf blade elliptic to ovate or broadly lanceolate, sometimes falcate, 5-20 X 2-8 cm, adaxially glabrous to sparsely pubescent, abaxially glabrous, base usually oblique, cuneate to narrowly cuneate, margin serrate to entire, rarely undulate or crenate, apex acuminate to acute, vermiform sclereids surrounding vascular bundles; lateral veins 4-14 on each side of midrib. Cymes (1-)3-12-flowered; peduncle 0.5-6.5(-10) cm, glabrous; involucre 1-2.5 cm in diam., outside glabrous. Calyx 5-sect from base; segments equal, ovate to elliptic-lanceolate or linear-lanceolate, 5-7 X 0.2-0.4 mm, outside and margin glabrous. Corolla outside pale yellow to white, inside purple spotted, 3-4.8 cm, outside sparsely glandular puberulent, inside with a ring of hairs; tube 2.3-3.3 cm; adaxial lip 6-10 mm; abaxial lip 7-15 mm. Anthers (2.5-)3-3.2 mm; staminodes 2 or 3, 2-7 mm. Pistil 1.7-2.5 cm, glabrous. Capsule 1.5-2.5 cm. Fl. Aug-Oct, fr. Oct-Dec.

Shaded areas in montane valleys, forests on calcareous mountains; 300-1600 m. Fujian, Guangdong, Guangxi, Guizhou, S Hunan, S Jiangxi, S Sichuan, SE Yunnan [N Vietnam].