Amphibromus fluitans

Rhizomatous and stoloniferous aquatic or semi-aquatic perennial; culms decumbent (at least when growing in water), sometimes only the inflorescence emergent, to 80 cm high overall. Leaves glabrous, scabrous; blade flat, to 25 cm long and 2–5 mm wide; ligule acute, (3.5–)6.5–12 mm long. Inflorescence to 35 cm long. Spikelets (6.5–)9–15 mm long, 5–12-flowered, lower glume (2–)2.7–3.7 mm long, upper glume (2.5–)3.4–4.5 mm long; lemma 3.7–5 mm long, scabrous to hispid, apical teeth 2, 0.3–0.6 mm long; awn 9–17 mm long, inserted 30–60% of the lemma length from the apex, column and bristle not distinguished; palea from one-quarter to three-quarters as long as lemma. Flowers Nov.–Mar.