Shrubs or trees, glabrous, or cottony in leaf axils. Stem erect, much branched; older branches terete, annual ones green or blue-green, pointed. Leaves opposite, reduced to scales or nearly absent, bases united, apex obtuse or with a short awn. Flowers solitary in leaf axils, bisexual, with 2 bractlets. Perianth segments 5, free, papery or dry membranous, abaxially with a distal, transverse wing in fruit, adaxially concave, base usually arachnoid; wing horizontal, membranous, longitudinally veined. Disk cupular. Stamens 5, inserted on disk; anthers elliptic, without an appendage. Ovary base sunken into disk; style very short; stigmas 2-5. Utricle hemispheric, apically slightly concave; pericarp fleshy, adnate to seed. Seed horizontal; embryo green, spiral; perisperm absent.

About 11 species: from the Mediterranean region to C Asia; two species in China.