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.
Fls perfect; cal of one herbaceous abaxial sep; stamen 1, between the sep and the ovary; ovary compressed; styles 2, very short; pericarp free from the seed, but apparently adherent when dried, cellular-reticulate; seed flat, vertical, acute-margined; embryo annular; branched annuals with small, entire or few-toothed lvs and dense clusters of small sessile fls in the upper axils, forming a leafy terminal spike. 3, w. N. Amer.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.