Potamophila parviflora R.Br.

Aquatic reed-like perennial. Culms erect, 0.3–1.5 (–2) m high. Leaves: ligule 4–15 mm long, acute, lacerated; blade 20–55 cm long, 4–14 mm wide, flat or involute, smooth to lightly scabrous. Panicles 15–45 cm long, loosely contracted, subtended by a conspicuous flag leaf; rachis angular to subterete and slightly grooved on one side, woolly-or cobwebbed-hairy at nodes. Unisexual spikelets female with vestigial staminodes or male. Bisexual spikelets 3–5.5 mm long; pedicel 1.5–6 mm long; bisexual floret: lemma 3–5.5 mm long; palea equalling or slightly exceeding lemma; anthers 2.5–3 mm long.

Grows on the banksand beds of rivers, often on stony or rocky areas that may be exposed part ofthe year.