Cyperus eragrostis Lam.

Drain Flat-sedge

Tabl. Encycl. 1: 146 (1791) APNI

Taxonomic status:Accepted

Occurrence status:Present

Establishment means:Naturalised

Tufted perennial, with very short rhizome. Culms trigonous, smooth, 25–90 cm high, 2–4 mm diam. Leaves slightly septate-nodulose, as long as culms or shorter, 4–8 mm wide. Inflorescence simple to compound with up to 12 primary branches to 12 cm long; digitate clusters 1–5 cm diam.; involucral bracts leaf-like, 5–9 exceeding inflorescence. Spikelets flattened, numerous per cluster, to 30-flowered, 5–15 mm long, c. 3 mm wide; rachilla not winged, persistent; glumes with 3-nerved keel, surface conspicuously isodiametric-reticulate, greenish to white or straw-coloured, tinged yellowish or red-brown, 2–2.5 mm long; stamen 1. Nut triquetrous, obovoid, dark brown to greyish, c. one-half as long as glume, 1–1.4 mm long, c. 0.5 mm diam. Flowers spring–summer.

*CVU, *DunT, *EGL, *EGU, *GipP, *Glep, *Gold, *GGr, *HNF, *HSF, *LoM, *MuF, *MuM, *NIS, *OtP, *OtR, *RobP, *Strz, *VAlp, *VRiv, *VVP, *WaP, *Wim. Also naturalised in SA, Qld, NSW (including Lord Howe Is.), Tas. Native to North and South America. A common and often troublesome weed of ephemerally wet, open, disturbed situations (roadside gutters and drains, gardens etc.). It has extended its range and frequency considerably over the past 30 years. .

Source: Wilson, K.L. (1994). Cyperaceae. In: Walsh, N.G.; Entwisle, T.J. (eds), Flora of Victoria Vol. 2, Ferns and Allied Plants, Conifers and Monocotyledons. Inkata Press, Melbourne.
Hero image
Distribution map
life Life
kingdom Plantae
phylum Tracheophyta
superorder Lilianae
order Poales
family Cyperaceae
genus Cyperus
Higher taxa


Source: AVH (2014). Australia's Virtual Herbarium, Council of Heads of Australasian Herbaria, <>. Find Cyperus eragrostis in AVH ; Victorian Biodiversity Atlas, © The State of Victoria, Department of Environment and Primary Industries (published Dec. 2014) Find Cyperus eragrostis in Victorian Biodiversity Atlas
  Bioregion Occurrence status Establishment means
Lowan Mallee present naturalised
Murray Mallee present naturalised
Wimmera present naturalised
Glenelg Plain present naturalised
Victorian Volcanic Plain present naturalised
Victorian Riverina present naturalised
Robinvale Plains present naturalised
Murray Fans present naturalised
Gippsland Plain present naturalised
Otway Plain present naturalised
Warrnambool Plain present naturalised
Goldfields present naturalised
Central Victorian Uplands present naturalised
Greater Grampians present naturalised
Dundas Tablelands present naturalised
Northern Inland Slopes present naturalised
East Gippsland Lowlands present naturalised
East Gippsland Uplands present naturalised
Highlands-Southern Fall present naturalised
Highlands-Northern Fall present naturalised
Otway Ranges present naturalised
Strzelecki Ranges present naturalised
Victorian Alps present naturalised

State distribution

Distribution map
Western Australia
Northern Territory
South Australia
New South Wales
Australian Capital Territory