Annual herb to c. 50 cm (rarely to 1 m) high, rooting from lower nodes; dioecious (rarely monoecious). Leaves ovate, lamina 20–60 mm long, 10–25 mm wide, thin-textured, margin crenate-serrate, glabrous or with a few short marginal hairs; petiole 3–15 mm long; stipules triangular, 1–2 mm long. Male inflorescences with fine peduncles to c. 5 cm long, bare in the lower half; flowers sessile or subsessile, in tight clusters of up to c. 10, the clusters crowded toward the apex; sepals broadly ovate, c. 2 mm long at anthesis; stamens c. 15 per flower, the very fine filaments equal to or shortly exceeding the sepals. Female flowers solitary, rarely paired, in axils, subsessile at anthesis, pedicels to 5 mm long in fruit; sepals broadly ovate, c. 1.5 mm long; ovary bristly, styles feathery. Capsule 2–3 mm long; seed ovoid, c. 2 mm long, rugulose.
VVP, GipP, HSF. Also naturalised WA. Native to northern Africa, Europe, and parts of temperate Asia. Known from a 2001 collection along a creek in outer eastern Melbourne, and a few early 1900s collections from Coode Island (Melbourne dock area).
