Small annuals with rigid, glandular-pubescent, dichotomously branched stems. Leaves opposite or spuriously clustered, setaceous, subulate or filiform, with stipules adnate to blade. Flowers axillary, solitary or clustered, sessile. Calyx 5-parted; sepals acuminate, carinate, rigid, scarious-margined with a lateral, subulate and ciliate appendage on either side:. Petals 3-5, minute, sometimes 0. Stamens 3-5. Ovary 1-celled, many-ovuled; style. short, with a capitate or 2-3-lobed stigma. Capsule 3-valved. Seeds obovoid; embryo somewhat curved.