A quote from "Flora of the A.C.T." Nancy T. Burbidge & Max Gray: "the uppermost leaf sheath thickened, truncate and mucronate at orifice". Mucronate means "ending with a stiff point". The Sample Photos show this feature, which is diagnostic of the species. The drawing below is from that book.
Eleocharis acuta is listed in the following regions:
Canberra & Southern Tablelands | Albury, Wodonga | South Coast | Far West New South Wales | Loddon Mallee
Maps
Aranda Bushland Back Creek TSR Bibbenluke Common Black Mountain Bluetts Block (402, 403, 12, 11) Bruce Ridge Bruce Ridge to Gossan Hill Bullen Range Conder Community Wetlands Crace Grasslands Dryandra St Woodland Dunlop Grasslands Flea Bog Flat, Bruce Gibraltar Pines Gorman Road Bush Reserve, Goulburn Goulburn Mulwaree Council Hall Horse Paddocks Hughes Grassy Woodland Isaacs Ridge Isaacs Ridge and Nearby Isaacs Ridge Offset Area Jerrabomberra Grassland Kosciuszko National Park Lake Burley Griffin Central/East Lawson North Grasslands Lions Youth Haven - Westwood Farm A.C.T. Mcleods Creek Res (Gundaroo) Mount Ainslie Mount Majura Mount Mugga Mugga Mount Painter Mount Taylor National Arboretum Forests Pine Island to Point Hut Piney Ridge Point Hut to Tharwa Red Hill Nature Reserve Red Hill to Yarralumla Creek Rob Roy Range Sth Tablelands Ecosystem Park The Pinnacle Tuggeranong Hill Wanniassa HillPlaces
Bannister, NSW Binalong, NSW Bungonia, NSW Gundaroo, NSW Gunning, NSW Hackett, ACT Jembaicumbene, NSW Lade Vale, NSW Laggan, NSW Lerida, NSW