Culms dark to light green, 1–4 m × 4–12 mm, firm to soft, larger air cavities in distal 1/4, 1–2.5 mm wide. Leaves: sheath fronts mostly delicately pinnate-fibrillose. Inflorescences to 3 times branched, branches sometimes flexible and drooping. Spikelets 4–190, 6–24 × 4 mm. Flowers: perianth bristles (4–)6(–8), equaling to less than 1/2 achene body, rarely rudimentary; styles from 2-fid with few 3-fid at spikelet apex to mostly (or all) 3-fid. Achenes plano-convex or compressed obtusely trigonous.