Herbs annual or biennial. Stems to 30 cm, much branched at base, ascending, subglabrous. Upper leaves sessile; petiole of basal leaves at least as long as blade; leaf blade circular to reniform, 1-2 × 0.7-1.5 cm, sparsely strigose, base truncate to broadly truncate-cuneate, semi-clasping, margin deeply crenate to almost palmately lobed, apex rounded. Verticillasters 6-10-flowered; bracts ca. 4 × 0.3 mm, ciliate. Calyx tubular-campanulate, 4-5 × 1.7-2 mm, densely villous, glabrous except for white villous apically inside; teeth lanceolate-subulate, 1.5-2 mm, margin ciliate. Corolla purple-red or reddish, ca. 1.7 cm, puberulent; tube ca. 1.3 cm, throat ca. 3 mm wide, annulus absent; upper lip densely purple-red pubescent on outside, straight, oblong, ca. 4 mm, apex slightly curved; lower lip slightly longer; middle lobe obcordate, 2-lobulate. Filaments glabrous; anthers hirsute. Nutlets grayish yellow, obovoid, triquetrous, constricted at base, ca. 2 × 1 mm, white tuberculate. Fl. Mar-May, fr. Jul-Aug.