Perennial, glabrous, herbaceous vines, twining to the right, often with a rhizome or tuberous roots. Leaves spiral, sessile or petioled, entire, penninerved, often rather fleshy, exstipulate. Flowers bisexual (or unisexual), actinomorphous, in axillary (and/or terminal) spikes, racemes or panicles, each subtended by a small bract. Bracteoles 2 or 4, in the latter case in 2 decussate pairs, below the flower, sometimes accrescent and connate at the base, the upper pair often tepaloid. Perianth segments 5, often coloured, connate at the base in a shorter or longer tube, imbricate, persistent, often accrescent. Stamens 5, epitepalous; filaments inserted on the perianth; anthers 2-celled, dorsifixed, dehiscing lengthwise, rarely (in non-Mal. spp.) with an oblique apical slit. Ovary superior, 1-celled; styles simple or 3-armed, or 3 free styles; ovule 1, basal, campylotropous. Fruit indehiscent, surrounded by the persistent often fleshy-accrescent calyx (and eventually bracteoles). Seed globular; testa membranous; endosperm copious, surrounded by the spirally twisted or semi-circular to horseshoe-shaped embryo. Distr. Four genera with c. 15 spp., almost confined to the warmer parts of the New World, from Texas and the West Indies to Peru, Uruguay, and the Argentine, some spp. of Basella in E. Africa and Madagascar, in Malaysia cultivated and locally naturalizing.