Annual herb, ascending or erect, attaining c. 1.25 m or more in cultivation. Stem stout, usually much-branched, it and the branches angular, glabrous or furnished in the upper parts with sparse (or denser in the inflorescence), ± crisped hairs. Leaves glabrous, or thinly pilose on the lower surface of the primary venation, green or purplish-suffused, very variable in size, long-(up to c. 8 cm) petiolate, the lamina broadly ovate, rhomboid-ovate or broadly elliptic to lanceolate-oblong, emarginate to obtuse or acute at the apex, at the base shortly cuneate to attenuate, decurrent along the petiole. Flowers green to crimson in ± globose clusters c. 4-25 mm in diameter, all or only the lower axillary and distant, the upper sometimes without subtending leaves and increasingly approximate to form a thick terminal spike of variable length, male and female flowers intermixed. Bracts and bracteoles broadly or deltoid-ovate, bracteoles subequalling or shorter than the perianth, pale-membranous, broadest near the base and narrowed upwards to the green midrib, which is excurrent to form a long, pale-tipped awn usually at least half as long as the basal portion and not rarely equalling it. Perianth segments 3, 3-5 mm long, elliptic or oblong-elliptic, narrowed above, pale-membranous, the green midrib excurrent into a long, pale-tipped awn; female flowers with the perianth segments slightly accrescent in fruit. Stigmas 3, erect or recurved, c. 2 mm. Capsule ovoid-urceolate with a short neck below the style-base, 2.25-2.75 mm, circumscissile, membranous, obscurely wrinkled. Seed 1-1.5 mm, black or brown, shining, very faintly reticulate, lenticular.