Cyperus gymnocaulos, commonly known as spiny flatsedge, is a sedge of the family Cyperaceae that is native to Australia.
The rhizomatous perennial grass-like sedge typically grows to a height of 0.35to and has a tufted habit. It blooms between July and March producing brown flowers. It normally has a short thick rhizome with smooth, trigonous and terete culms. The leaves are reduced to sheaths, except for juvenile plants.[1]
C. gymnocaulos is usually smaller and less robust than C. vaginatus.[1]
The species was first formally described by the botanist Ernst Gottlieb von Steudel in 1854 as part of the work Synopsis Plantarum Glumacearum. Known synonyms include; Cyperus cruciformis and Cyperus vaginatus var. densiflorus. The name is commonly misapplied to Cyperus textilis.[2]
It is found in swamps and along creeks and rivers and other damp areas in all the states of mainland Australia as well as the Northern Territory.[1] In Western Australia it is found in the Mid West, Wheatbelt, South West and Goldfields-Esperance regions where it grows in sandy-clay soils.
Used sometimes in net making.[3]