Description from Flora of China
Stems 20-60 cm, glabrous, glandular near apex. Leaves opposite or in whorls of 3; petiole 2-3 mm; leaf blade elliptic to ovate, 0.7-2 X 0.5-1 cm, leathery, glabrous, adaxially drying wrinkled, abaxially not punctate, base broadly cuneate to rounded, margin entire, apex acute to rounded; lateral veins invisible. Cymes axillary, 1-flowered; peduncle absent; bracts persistent, green, linear, 3-4.5 X 0.6-1 mm. Pedicel 4-10 mm, glabrous. Calyx green, 5-sect from base; segments linear to lanceolate-linear, 3.5-6 X 0.8-1.1 mm, outside glabrous. Corolla purple-red, 1.8-3.1 cm, outside glabrous, inside sparsely glandular puberulent, without tufts of hairs, mouth oblique; limb distinctly 2-lipped; adaxial lip ca. 4.5 mm; abaxial lip ca. 8 mm, 3-parted from near base. Stamens exserted; filaments 2-2.9 cm; anthers coherent in pairs at apex, 1.6-2 mm; staminode ca. 1 mm. Pistil ca. 2.8 cm; ovary glabrous. Style ca. 5 mm, glabrous. Capsule 6.2-9.5 cm. Seeds with 1 flat, narrowly triangular appendage at each end, appendages 0.5-1 mm. Fl. Jun-Nov, fr. Nov.
On trees and rocks in forests; 1300-2200 m. Guangxi, SW Guizhou, Yunnan [Vietnam].