Seeds of South Australia
Diuris sulphurea (Orchidaceae)
Hornet Orchid
List of species for Diuris
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Seed collecting:
December to March
Herbarium region:
South Eastern
NRM region:
South East
IBRA region
Bridgewater (NCP01)Naracoorte Coastal Plain
 Endangered   (IUCN: EN B2ab(i,ii,iii))   (Probable Decline)
Glenelg Plain (NCP02) 
 Rare   (IUCN: RA d(ii))   (Probable Decline)
Lucindale (NCP03) 
 Rare   (IUCN: RA d(ii))   (Probable Decline)   [limited habitat; weeds a threat]
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 Diuris]
Name derivation:
Diuris from the Greek 'dis' meaning two and 'oura' meaning a tail; referring to the pendulous lateral sepals resembling tails on some species. Sulphurea from Greek meaning sulphur-coloured; referring to the colour of the flowers.
Distribution:
Found in the lower South-east in South Australia, growing in damp sandy soils in open Eucalyptus baxteri forest and around swamp margins. Also found in Queensland, New South Wales, Victoria and Tasmania.
Status:
Native. Rare in South Australia. Common in the other states.
Plant description:
Terrestrial orchid to 50 cm tall in flower. Leaves 1-3, linear, to 50 cm long, channelled, lax. Inflorescence on a slender stem with 1–7 bright yellow flowers with prominent dark brown markings. Dorsal sepal obliquely erect, ovate, to 20 mm long, with a pair of large dark brown blotches near base. Lateral sepals deflexed, usually parallel, linear, to 25 mm long, green or green and brown. Petals erect or spreading, to 26 mm long, claw short, brown, lamina ovate to elliptic, yellow. Labellum obliquely deflexed, yellow with transverse dark brown blotches near apex and other brown markings, to 15 mm long, 3-lobed with lateral lobes about half as long as mid-lobe, mid-lobe spade-shaped. Flowering between September and January.
Fruit type:
Brown papery ellipsoid capsule.
Seed type:
Very small brown ellipsoid seed with an oval translucent brown mesh-like covering.
Seed collecting:
Collect fat capsules as they start to dry and turn brown. Pods will split and release the seeds quickly and will require monitoring. To increase the chances of collecting mature pods, it is recommended that a small breathable bag (ie. Organza bags) be used to enclose the developing capsules.
Seed cleaning:
Place the capsules in a container that will hold fine seeds and leave to dry for a few weeks or until the capsule split. Then carefully hold the capsule and tap it gently to release the seeds. 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, refrigerator or in liquid nitrogen.
Seed viability:
For the NVC South East Orchid Project a total of two populations consisting of more than X individuals in total were recorded from Binnim and Nangwarry Native Forest Reserve. Approximately 89,000 seeds (0.04g) were banked for these two observed populations. The seed viability was low for Nangwarry at 17%,  the Binnum collection was higher however at 78%.