Bolboschoenus fluviatilis

Rhizomatous perennial. Culms 100–200 cm high, 5–10 mm diam. Leaves recurved above, 7–11 mm wide. Inflorescence with 6–9 branches 2–10 cm long, bearing clusters of 1–6 spikelets; involucral bracts 15–25 cm long, 3–6 mm wide. Spikelets 1–2.5 cm long; glumes yellow-brown, 6–7 mm long, plus awn 1.5–3 mm long; hypogynous bristles about as long as nut, usually persistent; style 3-fid. Nut equally trigonous, with dorsal angle acute, pale yellow or grey and dull to blackish and shining, minutely (but often obviously) reticulate, 3–4 mm long, 1.5–2 mm diam. Flowers spring–summer.