Plants of
South Australia
Cyperus gymnocaulos
Naked Spiny Sedge,
Spiny Flat-sedge,
Spiny Sedge
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Critically endangered
Data deficient
Coober Pedy
Mount Gambier
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Botanical art

Kath Alcock paintings: 8

Prior names

Cyperus vaginatus var. densiflora

Common names

Naked Spiny Sedge

Spiny Flat-sedge

Spiny Sedge


Cyperus from the Latin 'cyperos' and derived from the Greek 'kypeiros', an ancient Greek name used by Homer and Theophrastus for several plants of this genus. Gymnocaulos from the Greek 'gymnos' meaning bare, naked and Latin 'caulis' meaning stem.

Distribution and status

Found across most part of South Australia except the far west growing on banks of creeks, streams, lakes and artesian bores. Also found in all mainland States. Native. Common in South Australia. Common in the other States.
Herbarium regions: North Western, Lake Eyre, Gairdner-Torrens, Flinders Ranges, Eastern, Eyre Peninsula, Northern Lofty, Murray, Yorke Peninsula, Southern Lofty, South Eastern, Green Adelaide
NRM regions: Adelaide and Mount Lofty Ranges, Alinytjara Wilurara, Eyre Peninsula, Northern and Yorke, South Australian Arid Lands, South Australian Murray-Darling Basin, South East
AVH map: SA distribution map (external link)

Plant description

Densely tufted perennial sedge, with a short stout horizontal rhizome. Stems erect or spreading, to 70 cm high, cylindrical or somewhat trigonous particularly at the top; rather prominently and closely striate. Leaves reduced to thin membranous sheaths; bracts mostly 3-6, sometimes longer than the inflorescence; usually less than 5 cm long, very rigid and pungent, the margins incurved.Flower spike a dense head or with 1-4 shortly pedunculate globose heads often proliferating. Spikelets very numerous (very rarely few) in the heads; 8-20-flowered, usually rich-brown or pallid, linear to lanceolate-ovate, acute, 3-5.5 mm long, 2.5-3 mm wide; rhachilla not winged; glumes tightly packed, with slightly spreading tips, acute in profile (thinner and less rigid than in C. vaginatus which they otherwise resemble), 3-nerved on the back and sometimes with 1 or 2 faint nerves on each side, shining, 2.5-3 mm long. Flowers throughout the year. Fruits are brown globular fruit-head. Seeds are black ovoid triangular nut to 2 mm long and 1 mm wide. Seed embryo type is capitate.

Seed collection and propagation

Collect seeds between January and December. Collect fruits by picking off the mature heads, those turning brown and come-off easily. Place the heads in a tray and leave to dry for one to two weeks. Then rub the heads with a rubber bung to dislodge the seeds. Use a sieve to separate any unwanted material. Store the seeds with a desiccant such as dried silica beads or dry rice, in an air tight container in a cool and dry place. Seed viability is usually high.

Seeds stored:
LocationNo. of seeds
(weight grams)
of plants
Collection number
Collection location
% ViabilityStorage
BGA17,900 (5.18 g)50+3-May-2007RJB70971
Flinders Ranges
Location: BGA — the seeds are stored at the Adelaide Botanic Gardens, MSB — the seeds are stored at the Millennium Seed Bank, Kew, England.
Number of plants: This is the number of plants from which the seeds were collected.
Collection location: The Herbarium of South Australia's region name.
% Viability: Percentage of filled healthy seeds determined by a cut test or x-ray.