Hypodiscus aristatus culms emerge from the ground in a dense tussock, erect and slightly curving. The plants thrive in sandy soils on mountain slopes that drain well. This male plant has few culms tipped with single spikelets or small groups of them.
The female plants bear spikelets of flowers with membranous petals as long as the sepals. The smooth, shiny fruits to follow are black or dark brown, hard and woody, about 8 mm long (Euston-Brown and Kruger, 2023; Dorrat-Haaksma and Linder, 2012; Bean and Johns, 2005; iNaturalist).