Index Seminum (Göttingen) 1830: 4. 1830.
Herbs, annual, polygamous, ± farinose or glabrous. Stems arising from base, prostrate to ascending, not jointed, not armed, not fleshy; ultimate branches not filiform. Leaves alternate, succulent; blade triangular-lanceolate to oblanceolate or spatulate, base narrowly attenuate to cuneate, unlobed to hastate, margins sometimes with few teeth distally or completely entire, apex obtuse to rounded. Inflorescences 1–many-flowered glomerules in leaf axils. Flowers bisexual or pistillate; perianth segment usually 1 (2–3 in central flowers) or absent, bractlike, greenish; stamens 1(–2) or absent (in pistillate flowers); ovary superior; stigmas 2, connate proximally. Fruiting structures somewhat flattened utricles; pericarp loose when dry. Seeds vertical, lenticular; seed coat brown to black, smooth; embryo annular; perisperm copious. x = 9.
Temperate regions of w North America, c and ne Asia, s South America.
Species 5 (2 in the flora).