Carex riparia

Rhizomes long; shoots tufted. Culms erect, trigonous, smooth or minutely scabrous-angled distally, 100–195 cm long, c. 2.5–4 mm diam. Leaves equaling or longer than culms, to 220 cm long, 8–17 mm wide, conduplicate or W-shaped to varying degrees in cross-section, septate-nodulose (more obvious when dry), margins strongly scabrid in the upper third; abaxial surface smooth or papillate (x 40 magnification); sheath pale to mid red, sometimes streaked, distinctly septate-nodulose, the ventral face of sheath ladder fibrillose (i.e. deteriorating into a network of fibres arranged in a feather-like pattern); ligule 15–22 mm long, obtuse. Spikes 5–10, lower spikes remote and upper spikes approximate, solitary at nodes; lowest involucral bract longer than inflorescence; upper 3–6 spikes male, oblong-cylindric or cylindric, 2-6 cm, subsessile; lower spikes entirely female, 2–5 cm long; fruiting spikes 6–9 mm diam.; male glumes 6–9 mm long, lanceolate, pale to mid chestnut brown (in Victorian plants) with midrib and margins paler, apex acute to acuminate, mucro 0.2–0.7 mm long; female glumes 6–7 mm long, oblong-lanceolate, dark, red-brown with pale midrib, apex acuminate; utricles 4.1–4.8 mm long, 1.4–1.8 mm diam., narrowly ovoid to narrowly ellipsoid, membranous 14–18-nerved, glabrous, green when immature, light brown at maturity; beak c. 0.5–0.8 mm long, truncate; style 3-fid. Nut c. 1.7 mm long, c. 0.8 mm diam., trigonous, brown. (Description based on the Victorian plants).