Description: Succulent, glabrous, perennial herbs; stems rooting at nodes.
Leaves opposite, fleshy, fused at base.
Flowers solitary, axillary, pedicellate; bracts absent. Perianth tubular, lobes 5, with scarious margins, a dorsal fleshy mucro behind apex. Stamens numerous; staminodes absent. Ovary superior; styles and loculi 3; ovules several per loculus; placentation axile.
Fruit a circumsciss capsule, the upper part (operculum) ovoid, smooth; seeds several.
Distribution and occurrence: World: 6 species, pantropical. Australia: 1 species (endemic).
Text by S. W. L. Jacobs & J. Highet