Eleocharis R.Br.

Leaves reduced to scales sheathing the base of the culms Eleocharis
Culms transversely septate only or not septate. Glumes with a few nerves only or nerveless either side of midrib
Culms not transversely septate. Spikelet c. 5 mm wide or less. Glumes membranous, with a distinct midvein, usually distinctly keeled. Spikelets much wider than the culms unless the latter is flat
Nut obscurely 3-angular or terete, vertically ribbed
Nut pyriform with c. 8 ribs on each face. Spikelets cylindrical, 5–18 mm long. Glumes to 3.5 mm long. Plant to 75 cm high. Wet areas on clay. Uncommon. Fl. spring–summer Eleocharis macbarronii
Nut obovoid, with 3–5 ribs on each face