Annual to perennial herbs. Hairs eglandular or glandular or 0. Cauline lvs usually opposite, exstipulate, linear to subulate, connate at base. Fls solitary, terminal or axillary; bracts leaflike; epicalyx 0. Sepals 4-5, free with narrow scarious margin. Petals 4-5, white, entire, 1-2× length of sepals or vestigial or 0; coronal scales 0. Stamens in 1-2 whorls of 4-5, outer whorl opposite sepals. Styles 4-5. Fr. an ovoid many-seeded capsule, 4-5-valved, dehiscing to base. Seeds triangular-ovoid or reniform to subglobose, smooth, papillate or tuberculate, not winged.