Suffruticose perennial, 1-2 m. Stems all 4-angled or main ones 6-angled, the angles sometimes developed as wings 0.1-0.5 mm broad, with thickened ridges on angles or wing margins; flat sides striate, glabrous or occasionally pubescent. Leaves ovate or broadly ovate, 15-80 x 10-50 mm, opposite or in whorls of 3, persistent and rather rigid, apex acute or obtuse, base rounded, truncate or subcordate, serrate to crenate with 5-9 teeth per side, glarbous and ± shining or pubescent above, glabrous beneath or with hairs along main veins, both surfaces with few to many yellowish or brownish resin-dots. Inflorescences cymose, 1-3 per axil, 3- to many-flowered. Peduncles 4-18 mm, pedicels 5-8 mm, often with resin-dots towards apex. Bracteoles ciliate, linear or lanceolate. Calyx lobes ovate, 4 mm, long-acuminate, with resin-dots and sometimes with hairs along mid-vein. Corolla red, 10-15 mm, tubular, upper lip emarginate, lower-3-lobed, with hairs on inside of median lower lobe and near insertion of stamens. Stamens 6 and 8 mm. Staminode 1-3 mm, with knob at apex. Style 9-11 mm. Capsule globose, 3-4 mm, filled with hairs; seeds numerous, small, verrucose.