Description from Flora of China
Herbs, erect, to 1 m tall, branched, blackish when dry. Stems subquadrangular, pith white. Petiole ca. 5 cm, decurrent on stem and becoming winglike ribs, glandular hairy; leaf blade cordate-ovate, to 10 cm, short hairy on veins when young, margin coarsely double serrate. Thyrses often terminal, narrowly spicate, to 20 cm; cymes opposite, widely spaced, usually 4-flowered; peduncle short, glandular hairy. Flowers crowded. Pedicel short, glandular hairy. Calyx 3-4 mm; lobes ovate-lanceolate, glandular hairy, apex acute. Corolla 5-6 mm, glabrous; lower lip middle lobe smaller than lateral lobes; upper lip slightly longer than lower lip. Stamens slightly shorter than lower lip; staminode small or absent. Ovary ovoid, ca. 1.5 mm. Style as long as ovary. Capsule ovoid, 6-8 mm.
Along streams, sandy and wet places; 2000-3500 m. Xizang (Yadong Xian) [Bhutan, India (Darjeeling), Nepal, Sikkim].