Plants of
South Australia
Orthoceras strictum
Orchidaceae
Horned Orchid
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Rare
Vulnerable
Endangered
Critically endangered
Extinct
Data deficient
Adelaide
Arkaroola
Ceduna
Coober Pedy
Hawker
Innamincka
Marla
Marree
Mount Gambier
Oodnadatta
Renmark
Wudinna
Keith
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Botanical art

Kath Alcock paintings: 8.

Etymology

Orthoceras, from the Greek 'orthos', meaning upright and 'ceras', horn, referring to the erect lateral sepals. Strictum, from the Latin 'strictus', from 'stringere', meaning to draw tight, often used botanically to mean very straight, upright or narrow.

Distribution and status

Very widely distributed through much of South Australia, with small to extensive populations found in a variety of habitats that receive greater than 300 ml rainfall annually,; grows in open forest, grassland and mallee. Also found in Queensland, New South Wales, Victoria, Tasmania, New Zealand and New Caledonia. Native. Common in South Australia. Uncommon in Tasmania and Queensland. Common in the other States.
Herbarium regions: Flinders Ranges, 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

Terrestrial orchid to 80 cm tall with up to 9 flowers on a brittle dark or yellow stem. Leaves are basal, 2-5; grass-like, linear to filiform, to 30 cm long. Flowers are yellowish green to dark brown, fleshy with a hooded dorsal sepal; lateral sepals filiform to 25 mm long; small hidden petals, and a labellum with a central yellow patch. Flowering between November and January. Fruits are brown papery ellipsoid capsule. Seeds are very small brown ellipsoid seed with a long cylindrical translucent brown mesh-like covering.

Seed collection and propagation

Collect seeds between January and February. Collect stout capsules as they start to dry and turn brown. Pods will split and quickly release the seeds, so will require monitoring. To increase the chances of collecting mature pods, it is recommended that a small breathable bag (eg. Organza bags) be used to enclose the developing capsules. Place the capsules in a container that will hold fine seeds and leave to dry for a few weeks or until the capsules 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. For the NVC South East Orchid Project, two populations of more than 30 individuals in total were recorded from Comaum Native Forest Reserve and Geegeela area. Approximately 40,000 seeds (0.28 g) were banked from this population. Seed viability ranged from 50% to 82%. Seed germination in orchid species is difficult in the absence of symbiotic mycorrhizal fungi. More research is needed to understand the seed germination requirements in Orthoceras species.

Seeds stored:
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LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA20,000 (0.016 g)1K. Brewer
South Eastern
1-Nov-201650%-80°C
BGA320,000 (0.265 g)712-Dec-2013JRG88
South Eastern
1-Nov-201695%-80°C
BGA27,000 (0.022 g)K. Brewer
South Eastern
1-Nov-2017N/C-80°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.