Cyperus decompositus is a species of sedge that is endemic to north eastern Australia.

[1] The species was first formally described by the botanist Robert Brown in 1810 as Mariscus decompositus,[2] then reclassified by Ferdinand von Mueller in 1874[1] as a part of the work Fragmenta Phytographiae Australiae.

[3] The range of the plant extends from the Northern Territory in the west to Queensland in the east from sea level to an altitude of 200 m (660 ft) usually as a part of rain forest, open forest or forest communities.

[3]