Variable, decumbent to erect annual to c. 80 cm high (commonly detaching near ground level at maturity and dispersing as a tumbleweed). Stems whitish (often turning red at maturity), glabrous or glabrescent. Leaves shortly petiolate to subsessile, ovate to obovate, lamina 5–20(–50) mm long, 2–10(–20) mm wide; margin often undulate; apex usually shortly mucronate. Flowers in axillary cymose clusters c. 5 mm long, unisexual; bracts c. 3 mm long; bracteoles c. 2 mm long, spinescent; tepals 3, oblong to spathulate, 1–2 mm long, acute; stamens 3. Utricle circumsciss (rarely indehiscent), slightly exceeding perianth, abruptly tapered toward apex, finely wrinkled or blistered; seed biconvex, brown, shiny, c. 1 mm diam. Flowers mainly Jan.–Apr.