Description from Flora of China
Plants annual, prostrate. Stems longitudinally 3-winged. Leaves alternate. Flowers 1-3 on extremely short branches, sessile or shortly pedicellate. Calyx epigynous, 5-lobed, lobes dentate. Corolla epigynous, tubular-campanulate, 5-lobed. Stamens 5, free from corolla and free from each other; filaments slightly dilated and sparsely ciliate at base. Ovary inferior, 3-locular; stigma 3-fid; lobes linear, recurved. Fruit dry, irregularly dehiscent or irregularly poricidal in lower part. Seeds ellipsoid, not angular, shallowly reticulate.
These species have been included in Heterocodon Nuttall, but their flowers are on short branches, not solitary and opposite to leaves on main stems; and their seeds are terete and reticulate, not angular and smooth.
Two species: Bhutan, China; two species (one endemic) in China.
(Authors: Hong Deyuan (洪德元); Thomas G. Lammers)