Plants of
South Australia
Gahnia deusta
Cyperaceae
Heathy Saw-sedge
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Rare
Vulnerable
Endangered
Critically endangered
Extinct
Data deficient
Adelaide
Arkaroola
Ceduna
Coober Pedy
Hawker
Innamincka
Marla
Marree
Mount Gambier
Oodnadatta
Renmark
Wudinna
Keith
Yunta
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Botanical art

Kath Alcock paintings: 2.

Etymology

Gahnia named after Dr. Henricus Gahn, 19th century Swedish botanist and student of Linnaeus. Deusta from Latin 'deustus' meaning burned, possibly alluding to it being more abundant post fire or black in colour.

Distribution and status

Found in southern South Australia, except in the lower South-east, growing on calcareous loam. Also found in Western Australia and Victoria. Native. Common in South Australia. Very rare in Victoria. Rare in Western Australia.
Herbarium regions: Eyre Peninsula, Northern Lofty, Murray, Yorke Peninsula, Southern Lofty, Kangaroo Island, South Eastern, Green Adelaide
NRM regions: Adelaide and Mount Lofty Ranges, Eyre Peninsula, Kangaroo Island, Northern and Yorke, South Australian Murray-Darling Basin, South East
AVH map: SA distribution map (external link)

Plant description

Tufted perennial sedge to 50 cm high, viscid on younger parts. Leaves and bracts with woolly orifices to the sheaths; blades rigid with involute margins, scabrous downwards and almost pungent-pointed in the upper part. Inflorescence a narrow panicle to 30 cm long, with erect distant branches; spikelets numerous in spike-like clusters with prominent secondary bracts; sheaths black. Flowering between September to November. Fruits are brown spike. Seed embryo type is capitate.

Seed collection and propagation

Collect seeds between November and February. Collect heads that are dying off, turning dark brown and containing hard dark seeds. 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. From one collection, the seed viability was average, at 76%.

Seeds stored:
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LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA 
MSB
10,500 (10.1 g)
10,500 (10.1 g)
50+19-Feb-2016DJD3330
South Eastern
2-May-201776%-18°C
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.
Germination table:
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