Annual up to 60 cm high, glabrous, simple or slightly branched below very diffusely farinaceous; root slender, radical and lower cauline leaves with very long petioles, runcinate, with a larger triangular-hastate terminal lobe and oblong or linear lateral lobes, usually mucronulate at apex; upper merely triangular-hastate with shorter petioles, uppermost sometimes lanceolate. Inflorescence of male plants a panicle of almost leafless spike; female inflorescence leafy. Staminate flowers 4-merous; stamens strongly exserted. Pistillate flowers in the axils of nearly all leaves except the radical, with horn-like outgrowths, united in fruit into a spiny-corniculate aggregate of mostly 4-6, measuring 10-15 mm in diameter; horns commonly lanceolate, 3-angled, channelled above, mostly (3-) 5-8 mm long, very rarely broader triangular-ovate and to 3-4 mm long (in var. brevispinis Iljin).