Description from Flora of China
Stems 60-100 cm, sparsely puberulent, glabrescent, usually simple. Leaves opposite, spread along stem, unequal to subequal in a pair; petiole 0.5-4 cm, sparsely pubescent; leaf blade ovate to broadly elliptic, 8-19 X 3.2-8 cm, adaxially sparsely appressed puberulent, abaxially glabrous to sparsely appressed puberulent, base oblique, cuneate to slightly rounded, margin repand to serrulate, apex acuminate. Cymes branched 2-5 , 5-18-flowered; peduncle 5-18 cm, sparsely puberulent, glabrescent; bracts ovate to broadly ovate, 5-10 X 1.6-8 mm, margin denticulate to repand. Pedicel 1-2 cm. Calyx 5-sect from near base; segments equal, ovate to broadly triangular, 6-8 X 3-5 mm, margin denticulate to entire. Corolla white to lavender, purple spotted inside, 4.2-4.8 cm, outside sparsely pubescent, inside glabrous; tube 3-3.5 X 1.5-2 cm; adaxial lip ca. 6 mm, lobes semiorbicular, 4-5 X 4-5 mm; abaxial lip 1-1.2 cm, lobes semiorbicular, 4-5 X 6-7 mm. Adaxial stamens ca. 1.7 cm, abaxial ones ca. 2.5 cm, glabrous; staminode ca. 2 mm. Pistil 2.2-2.5 cm, glabrous. Style 1.1-1.3 cm. Capsule 5-6 cm. Seed appendages 1.1-1.2 mm. Fl. Sep-Nov.
* Rock crevices, on limestone, or epiphytic in forests; 900-1600 m. Guangxi (Bose Xian), SE Yunnan.