Description from Flora of China
Herbs perennial, rhizomatous. Stems slender, leafless basally. Leaves mostly aggregated at apex. Racemes terminal, solitary or sometimes 3 together; verticillasters 2-flowered; bracteoles opposite, persistent. Flowers pedicellate. Calyx broadly campanulate, conspicuously 2-lipped; upper lip 3-toothed; lower lip longer, 2-toothed, teeth narrower. Corolla tubular, straight, narrow, base not saccate, sometimes slightly constricted at middle, slightly dilated at throat; limb very short, 2-lipped; upper lip 4-lobed, lobes subequal or middle 2 smaller; lower lip larger, margin entire, ± concave. Stamens 4, included, anterior 2 longer; filaments glabrous; anther cells 2, divaricate, apex confluent. Ovary glabrous. Style apex equally 2-cleft. Nutlets oblong to ovoid, dotted, with a small basal white scar.
Two species: China, India, Myanmar, Vietnam; both species in China.