Description from Flora of China
Herbs perennial, lanate. Roots thick, terete. Leaf blade rhombic to subcircular, lower stem leaves sometimes reduced, scalelike. Verticillasters 6-flowered, compact or basally widely spaced; bracteoles spinelike. Flowers sessile. Calyx broadly campanulate, ± transparent, 10-veined; teeth 5, subequal, triangular, apex acuminate. Corolla purplish to reddish, 2-lipped; tube included, without hairy annulus inside; upper lip broad, galeate, incurved, covering lower lip; lower lip subpatent, 3-lobed; middle lobe slightly larger than lateral lobes, emarginate to rounded; lateral lobes circular. Stamens 4, anterior 2 longer, apex dentate, ascending beneath upper lip. Posterior filaments basally thickened; anthers close together in pairs, cells 2, apex divaricate, confluent, villous. Style apex subequally 2-cleft, lobes subulate. Ovary glabrous. Nutlets broadly triquetrous, oblong, large, apex rounded, smooth.
Monotypic: China, India, Nepal.