Giant Sedge, Tall Flat -sedge
Perennial sedge to 2m tall. Leaves with a purplish-brown sheath at the base, about as long as the flowering stems or longer, 3-15mm wide, flat, with rough edges. Spikelets 4-18mm long, 1-2mm wide, yellow to brown, with 0 petals, in open umbels subtended by 3-6 leaflike bracts at the tops of the flowering stems. Each ray of the umbel composed of spikelets arranged in spikes. Grows in water and mud.
Description and photo in G.M. Cunningham, WE Mulham, PL Milthorpe and J H Leigh (1981 and later printings) Plants of Western New South Wales pages 159-160