Seeds of South Australia
Microtis atrata (Orchidaceae)
Yellow Onion-orchid
List of species for Microtis
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Seed collecting:
January to February
Herbarium regions:
Eyre Peninsula, Southern Lofty, Kangaroo Island, South Eastern
NRM regions:
Adelaide and Mount Lofty Ranges, Eyre Peninsula, Kangaroo Island, South East
IBRA regions
Glenelg Plain (NCP02)Naracoorte Coastal Plain
 Endangered   (IUCN: EN B2ab(i,ii,iii))   (Probable Decline)
Lucindale (NCP03) 
 Endangered   (IUCN: EN B2ab(i,ii,iii))   (Probable Decline)
Kangaroo Island (KAN01)Kanmantoo
 Rare   (IUCN: RA d(ii))   [salinity a threat; possibly VU; needs more survey work]
Fleurieu (KAN02) 
 Endangered   (IUCN: EN B2ab(i,ii,iii,iv); D)   (Definite Decline)   [seen after fires, floods]
Mount Lofty Ranges (FLB01)Flinders Lofty Block
 Critically Endangered   (IUCN: CR B2ab(i,ii,iii,iv,v); D)   (Definite Decline)   [gone from a number of areas; has been searched for; recently seen in Kaiser Stuhl by R Bates]
Eyre Hills (EYB03)Eyre Yorke Block
 Endangered   (IUCN: EN D)   (Probable Decline)   [Wanilla forest]
Lowan Mallee (MDD04)Murray Darling Depression
 Endangered   (IUCN: EN B2ab(i,ii,iii,iv))   (Definite Decline)
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 Microtis]
Name derivation:
Microtis from the Greek 'mikros' meaning small and 'otos' meaning ear; in reference to the small ear-like column wings. Atrata meaning blackened or dark; referring to the color of dried or senescent plants.
Found at the bottom of Eyre Peninsula, Kangaroo Island, southern Mount Lofty Ranges and the lower South-east in South Australia. It grows in moist, swampy areas in areas of high rainfall. It is semi-aquatic and is often found adjacent to areas of Leptospermum continentale on the margins of shallow creek lines, soaks and in damp heath. Also found in Western Australia, Victoria and Tasmania.
Native. Rare in South Australia. Common in the other states.
Plant description:
Grows to 12 cm tall (rarely to 20 cm) with up to 40 flowers. It has a single yellow-green terete leaf often with a dried blackened tip, 3-9 cm long, 3 mm wide. Flowers emerge from just below the leaf apex, they are small, yellow-green, with an eliptical labellum, dorsal sepal to 1 mm. Flowering between September and December.
Fruit type:
Brown papery ellipsoid capsule.
Seed type:
Very small brown ellipsoid seed with a long cylindrical 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 three populations consisting of more than X individuals in total were recorded from Border Swamp, Bangham Conservation Park and Topperwien Native Forest Reserve. Approximately 60,000 seeds (0.07g) were banked for these three observed populations. Seed viability ranged from 72% to 83%.