Eleocharis

C. Stace, New flora of the British Isles, ed. 3. 2010E. J. Jäger, Rothmaler, Exkursionsflora von Deutschland, Gefäßpflanzen: Grundband, ed. 20. 2011
but modified
1Spikelets usually with 20-40 flowers; glumes from middle of spikelet 3.5-4.5 mm long; nut (1.3-)1.5-2 mm long
1'Spikelets usually with 40-70 flowers; glumes from middle of spikelet 2.5-3.5 mm long; nut 1.2-1.4(-1.5) mm long