Herbs perennial. Rhizomes white. Stems erect or inclined, 30-120 cm. Petiole 1-3 cm; leaf blade ovate to elliptic-ovate, 3-12 × 1.5-6 cm, base broadly cuneate to shallowly cordate, margin crenate-serrate, apex acute to acuminate. Spikes 5-15 cm; verticillasters 6-flowered, widely spaced; floral leaves bractlike, reflexed (especially in cultivated form), adaxial ones sessile, lanceolate, margin subentire, shorter than calyx; bracteoles linear, ca. 1 mm. Pedicel ca. 1 mm. Calyx narrowly campanulate, ca. 9 mm, glandular pubescent, ± conspicuously 10-veined; teeth narrowly triangular, ca. 4 mm, apex spinescent, slightly reflexed. Corolla red to purple; lower lip purple spotted, ca. 1.3 cm, tube ca. 9 mm, somewhat saccate, puberulent; upper lip oblong, ca. 4 × 2 mm, straight or slightly reflexed; lower lip ca. 7 × 7 mm, middle lobe subcircular, ca. 3.5 mm in diam., lateral lobes ovate. Filaments slightly dilated apically, puberulent. Nutlets black-brown, ovoid, ca. 1.5 cm in diam., tuberculate. Fl. Jul-Aug, fr. Sep.