Cyperus rigidellus

Cyperus rigidellus is a sedge of the family Cyperaceae that is native to Australia.
The short-lived perennial or annual herb or grass-like sedge typically grows to a height of . The terete culms are three sided with sharp edges and concave sides and are often rough higher up. The culms are typically in length and have a diameter of . The leaves are usually longer than the culms and often curly at the apex and have a width of around . It blooms between April to November producing brown-red flowers. The head-like or simple inflorescence has one to four branches that in length. Each inflorescence is loosely or densely clustered with a globose shape and around in diameter. The flattened spikelets occur in clusters of 5 to 15 each containing 6 to 25 flowers. Each spikelet is in length and wide. After flowering trigonous pale brown nuts form with a narrow-obovoid to narrow-ellipsoid shape.
The species was initially confused with "Cyperus gilesii" and "Cyperus enervis". It was first formally described by the botanist John McConnell Black in 1929 as part of the work "Additions and Corrections" as published in "Flora of South Australia". There are several synonyms including; "Mariscus rigidellus", "Cyperus subpinnatus" var. "subrigidellus", "Cyperus subpinnatus", "Cyperus subpinnatus" var. "subpinnatus", "Cyperus gracilis" var. "rigidellus" and "Cyperus gracilis" var. "rigidella".
It is found in all mainland states and territories in Australia. In Western Australia it is found along stream and creek, around clay pans, on flood plains and other damp areas in the Mid West, Pilbara, Gascoyne and Goldfields-Esperance regions where it grows in loamy-sand or clay-sand soils. In New South Wales it is found in inland areas usually in ephemerally wet places including floodways and roadside drains.