Seeds of South Australia
Gahnia clarkei (Cyperaceae)
Tall Saw-sedge
List of species for Gahnia
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Seed collecting:
December to April
Herbarium region:
South Eastern
NRM region:
South East
IBRA regions
Mount Gambier (SVP02)Southern Volcanic Plain
 Near Threatened
Bridgewater (NCP01)Naracoorte Coastal Plain
 Rare   (IUCN: RA d(ii))   (Probable Decline)
Glenelg Plain (NCP02) 
 Near Threatened
Lucindale (NCP03) 
 Rare   (IUCN: RA d(i,ii))   (Probable Decline)   [edge of range]
RSCA map:
Regional Species Conservation Assessments per IBRA subregion. Please click the thumbnail map.
AVH map:
Australian distribution map (external link)
SA Census:
Census of South Australian plants (external link)     [genus Gahnia]
Name derivation:
Gahnia named after Dr. Henricus Gahn, 19th century Swedish botanist and student of Linnaeus. Clarkei named after Charles Baron Clarke (1832-1906), a British botanist who wrote several books on Cyperaceae.
Distribution:
Found only in the lower South-east in South Australia, growing along water-courses and in swamps and can tolerate somewhat saline conditions. Also found in Queensland, New South Wales and Victoria.
Status:
Native. Uncommon in South Australia. Common in the other states.
Plant description:
Tall tussick-forming perennial sedge with woody rhizomes and  sprawling, elongated, cane-like culms to 2 m long. Leaf-blades flat, recurved, scabrous, mostly shorter than culms, sheaths pinkish to brown, dull or with some shining patches. Inflorescence erect and spreading with long lax branches to 125 cm long. Flowering in spring and summer.
Fruit type:
Large dark brown spike.
Seed type:
Orange-red ovoid seed to 3.5 mm long and 2 mm wide, with a shiny and smooth surface.
Embryo type:
Capitate.
Seed collecting:
Collect heads that are dying off, turning dark brown with obvious hard orange-red seeds. Break off whole spike or collect individual spikelets. Be careful as the leaf-blades can be sharp.
Seed cleaning:
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:
From three collections, the seed viability were low to high, ranging from 45% to 85%.
Seeds stored:
LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA 
MSB
33157 (122.68 g)
34151 (125 g)
40-5020-Jan-2005MKJ 67
South Eastern
28-Mar-200645%-18°C
BGA41200 (195.55 g)306-Mar-2007TST171
South Eastern
1-Aug-200785%+5°C, -18°C
BGA6200 (17.82 g)17-Jan-2008Kangaroo Flat NFR
South Eastern
20-Jul-200960%-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.