Annual, glabrous or glabrescent, sometimes with white or yellowish glands. Leaves triangular or rhombic, entire to lobate or pinnate. Flowers arranged in dense or lax inflorescences, with 5-merous perianth, segments connate at base, slightly keeled or almost without it. Stamens 5. Fruits 1.4-2.5 mm. in diam., pericarp often with small papillae (when dry look like honeycomb). Seeds black, with keel or without, surface reticulate, alveolate with depressions to 35 µm. deep; stalactites in the testa cells vertical or oblique; embryo horizontal.