Caustis pentandra R.Br.

Thick Twig-rush

Prodr. 240 (1810) APNI

Taxonomic status:Accepted

Occurrence status:Present

Establishment means:Native

Perennial with short, stout rhizome. Culms smooth, 45–60 cm high or more, 3–8 mm diam. Leaf sheaths very dark red-brown to blackish. Inflorescence with 5–12 distant clusters of branches, 20–120 cm long, ultimate branches straight or somewhat spreading. Spikelets 1–2-flowered, 10–15 mm long; glumes 4–6, acute, long-mucronate (lower glumes) to short-mucronate (upper glumes), red-brown to dark grey-brown, puberulous, margins hyaline and ± ciliate, 9–13 mm long; stamens 5; anthers 5.0–6.0 mm long, excluding apical appendage 0.5–1.1 mm long; style 4–5-fid; persistent style-base 2.5–3.5 mm long, straw-coloured. Nut narrow-ellipsoid to narrow-ovoid, minutely dotted, whitish to pale yellow-brown, 4.5–8 mm long, 2.0–2.3 mm diam. Flowers spring–summer.

CVU, DunT, EGL, EGU, GipP, Glep, GGr, LoM, OtP, Strz, VVP, WPro, Wim. All states except NT. In heaths and open woodlands, usually on sandy soils and generally occurring in damper situations than C. flexuosa, rarely co-extensive (as in the Grampians).

Characteristically, the leaf-sheaths are wrinkled.

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 Caustis
Higher taxa


Source: AVH (2014). Australia's Virtual Herbarium, Council of Heads of Australasian Herbaria, <>. Find Caustis pentandra in AVH ; Victorian Biodiversity Atlas, © The State of Victoria, Department of Environment and Primary Industries (published Dec. 2014) Find Caustis pentandra in Victorian Biodiversity Atlas
  Bioregion Occurrence status Establishment means
Lowan Mallee present native
Wimmera present native
Glenelg Plain present native
Victorian Volcanic Plain present native
Gippsland Plain present native
Otway Plain present native
Central Victorian Uplands present native
Greater Grampians present native
Dundas Tablelands present native
East Gippsland Lowlands present native
East Gippsland Uplands present native
Wilsons Promontory present native
Strzelecki Ranges present native

State distribution

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