Plant: Annual herb, prostrate, 3-7 dm, monoecious Leaves: cauline petiole 4-30 mm, blade 5-40 mm, elliptic to widely (ob)ovate, early-deciduous; axillary leaves smaller, persisten Inflorescence: clusters axillary, throughout plant; bracts 1-3.5 mm, < or = sepals, midrib thick, spine-tipped, green, margins scarious especially near base Flowers: Staminate flower: sepals 4-5, 1.5-2.5 mm; stamens (3)4-5; Pistillate flower: sepals 4-5, 1-3.5 mm, oblong to ovate, outer 2 > others, more reflexed, tips more tapered and spiny Fruit: ± 2.5 mm, circumscissile; lid often rough below; Seed 1.3-1.7 mm wide, black; margin acute Misc: Waste places; < 2200 m.; Jul-Nov