Description from Flora of China
Herbs annual or small shrubs. Stem and branches stout, not jointed. Leaves sessile, alternate, subulate or acicular, base expanded, apex pellucid; leaf axils fascicular villous. Flowers solitary or clustered in leaf axils, minute, bisexual, with 2 bractlets. Perianth segments 5, free or fused, apex with a free, membranous lobe; fruiting perianth enlarged, hardened, and bearing an acicular appendage abaxially, forming a narrowly conic spine, apex of segment remaining unchanged, persistent at junction of perianth and spine. Disk present or absent. Stamens up to 5; anthers narrowly oblong, appendage obscure or absent. Ovary ovoid; stigmas 2, filiform. Utricle enclosed in enlarged perianth, ovoid, slightly compressed; pericarp membranous, adnate to seed. Seed vertical; testa membranous; embryo conic-spiral; perisperm absent.
About six species: NW Africa (Egypt), SW Asia (Syria, Iran, Caspian region), China; one species (endemic) in China.