Stems erect, ca. 1 m, few branched, finely pubescent. Petiole 0.5-2 cm; leaf blade ovate to lanceolate-ovate, 2-5 × 0.8-3 cm, ± membranous, adaxially puberulent or subglabrous, abaxially pubescent, base obtuse to cordate, margin irregularly serrate, apex acute. Verticillasters 2-16-flowered, numerous, widely spaced; bracts leaflike; bracteoles sublinear, shorter than pedicels, ciliate. Pedicel ca. 3 mm. Calyx campanulate, dilated after anthesis, 8-12 mm, villous, lateral teeth of upper lip close to middle tooth, teeth of lower lip lanceolate. Corolla yellow-white, to 1.5 cm, pubescent; middle lobe of lower lip rounded, slightly overlapping circular lateral lobes. Stamens included. Nutlets oblong-ovoid. Fl. Jul-Aug, fr. Sep.