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 transversely septate
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