Erect annual herb, 15–75 (100) cm. in height, simple or branched from below and sometimes for some way up the stem, quite glabrous, stem and branches more or less sulcate and angled, smooth or minutely papillose when young, upper branches elongate and lax to short and very densely floriferous. Leaves glabrous, c.12–60 × 1–10 mm. including the slender petiole, which may be as long as the lamina; lamina linear to narrowly oblanceolate, narrowly elliptic or elliptic-oblong, long-attenuate below into the petiole, at the apex acute to obtuse with a very distinct, pale mucro up to 1.5 (2) mm. long formed by the excurrent nerve. Flowers green, in dense axillary clusters c. 3–6 mm. in diam., normally extending well down towards the base of the plant, the clusters approximate above, the superior leaves scarcely reducing, or sometimes so rapidly so that a few upper clusters are leafless; male and female flowers intermixed, the males more numerous in the upper clusters. Bracts and bracteoles pale-membranous with the lamina lanceolate, terminating in an arista (which may be up to as long as the lamina) formed by the percurrent nerve; bracteoles 2–3 mm., slightly more rigid and slightly longer than the bracts. Male flowers with 4 elliptic-ovate tepals 1.5–2 mm. long, pale with a brownish midrib, distinctly mucronate, the mucro very variable in length. Female flowers with 4–5 tepals, tepals narrowly oblong to narrowly oblong-lanceolate or more rarely oblanceolate, (1.5) 2–3 mm. long, tapering (rarely more abruptly narrowed) into the erect or spreading, pale or brownish, long mucro which is commonly c. half the length of the lamina. Styles 3, broad at the base and gradually narrowed above, c. 0.5–0.75 mm. long. Capsule ovoid to obpyriform, somewhat shorter than the perianth, circumcissile, convolute-rugose, commonly blackish when dry. Seeds shining, compressed, lenticular, c. 1 mm. in diam., only very faintly patterned centrally, more distinctly reticulate over a wide margin.
