Annual herbs or small stiffish shrubs, glabrous or with papillae or with villous hairs in leaf axils. Stems not jointed, rigid; branches thorny or not. Leaves sessile, alternate, slightly fleshy or not, linear-filiform, subamplexicaul. Flowers hermaphrodite, solitary and sessile in upper leaf axils., subtended by 2 leaf-like bracts.. Perianth deeply 5-lobed; lobes membranous in flower and dorsally winged in fruit; wings equal or unequal, coloured or not. Stamens 5; connective with a short non-vesicular terminal appendage. Seeds vertical compressed; embryo spiral; endosperm absent.