Upright summer annual to about 1 m, branching occasionally. It has a tendency to sprawl and lean on adjacent plants for support. The hairless stems are green or red. Common in damp places. Possibly introduced. Alternate leaves up to 100 mm long, lanceolate, smooth along the margins, and usually hairless. Upper surface is often olive-green. Each leaf has a short petiole; the base of this petiole has a membranous sheath (an ocrea) that wraps around the stem. This sheath has a few bristly hairs along its upper rim. Spike-like racemes of flowers that are about 10 cm long, quite slender with sparsely distributed flowers. Racemes often often nod at their tips or droop sideways. The flowers are shy to open and usually bud-like in shape. The seed is three-angled, dull-looking, black or dark brown.

Flowers close-up. Photo: Robert Whyte