Seeds of South Australia
Gahnia radula (Cyperaceae)
Thatch Saw-sedge
List of species for Gahnia
Display more images
Click on an image to enlarge it
Seed collecting:
November to March
Herbarium regions:
Southern Lofty, South Eastern
NRM regions:
Adelaide and Mount Lofty Ranges, South East
IBRA regions
Mount Gambier (SVP02)Southern Volcanic Plain
 Rare   (IUCN: RA d(ii))
Glenelg Plain (NCP02)Naracoorte Coastal Plain
 Rare   (IUCN: RA d(ii))
Lucindale (NCP03) 
 Rare   (IUCN: RA d(i,ii))   (Probable Decline)   [edge of range]
Fleurieu (KAN02)Kanmantoo
 Critically Endangered   (IUCN: CR B2ab(i,ii,iii,iv,v))   (Probable Decline)   [climate sensitive; only known from Macclesfield area]
Mount Lofty Ranges (FLB01)Flinders Lofty Block
 Critically Endangered   (IUCN: CR B2ab(i,ii,iii,iv,v))   (Probable Decline)   [used to be a Mt Bold; limited habitat; weed invasion prevents regeneration; climate sensitive]
Murray Lakes and Coorong (MDD03)Murray Darling Depression
 Regionally Extinct   [very old record, possibly extinct]
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. Radula from the Latin 'radere' meaning to scrape; referring to the scabrous leaves with sharp edges. 
Distribution:
Found in the southern Mount Lofty Ranges and the lower South-east in South Australia, growing in seasonally wet or poorly drained silty soils in woodland or forest-clearings. Also found in New South Wales, Victoria and Tasmania.
Status:
Native. Rare in South Australia. Common in the other states.
Plant description:
Narrowly tufted, rhizomatous perennial sedge with culms to 100 cm high and 5 mm diameter. Leaf-blades flat, erect, scabrous, with sharp edges, longer than inflorescence. Inflorescence narrow, erect to ascending, to 70 cm long, dark brown to black. Flowers in spring and summer.
Fruit type:
Dark brown to black narrow spike.
Embryo type:
Capitate.
Seed collecting:
Collect heads that are dying off, turning dark brown and containing hard dark seeds. However, it is very difficult to collect viable seeds in South Australia.
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:
Most seeds are non-viable.