Botanical art
Prior names
Cladium deustum
Common names
Heathy Saw-sedge
Limestone Saw-sedge
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%.
Location | No. of seeds (weight grams) | Number of plants | Date collected | Collection number Collection location | Date stored | % Viability | Storage temperature |
---|---|---|---|---|---|---|---|
BGA MSB | 10,500 (10.1 g) 10,500 (10.1 g) | 50+ | 19-Feb-2016 | DJD3330 South Eastern | 2-May-2017 | 76% | -18°C |