Glabrous annuals or shrubs with milky white stems, shining or not. Leaves opposite, pseudofasciculate or alternate, fleshy, terete obtuse or ± clavate. Flowers perfect, 1-3 in the axil of leaves, often surrounded by hairs, with 2 ovate, naviculiform bracteoles. Perianth segments 5, free nearly to the base, membranous, elliptic, obtuse, retuse or emarginate at apex, winged in fruit; usually the outermost wing turbinate, the innermost sometimes bent back, covering the fruit, the rest spreading, Stamens 5; anthers not appendaged, oval–oblong. Ovary with 2 broad, flat, linear, subsessile stigmas. Fruit horizontal, with glabrous, smooth pericarp; seeds horizontal with spiral embryo, exalbuminous.