Plants of
South Australia
Thelymitra grandiflora
Orchidaceae
Scented Sun-orchid,
Great Sun-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
Yunta
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Prior names

Thelymitra aristata (Adelaide Hills)

Common names

Scented Sun-orchid

Great Sun-orchid

Etymology

Thelymitra from Greek 'thelys' meaning a bishop and 'mitra' meaning a headwear, hat, hence a bishop's mitre, referring to the sometimes plumed or decorated wings of the column, which is usually produced behind and over the anther in a hood-like projection. Grandiflora referring to the species large-flower, the largest of any sun-orchid flowers in South Australia.

Distribution and status

Endemic to South Australia and found in the Flinders Ranges, Mount Lofty Ranges and Kangaroo Island, growing on ridges in dry rocky heathland and in well drained soils in woodland. Native. Rare in South Australia.
Herbarium regions: Flinders Ranges, Eyre Peninsula, Northern Lofty, Southern Lofty, Kangaroo Island, Green Adelaide
NRM regions: Adelaide and Mount Lofty Ranges, Eyre Peninsula, Kangaroo Island, Northern and Yorke, South Australian Arid Lands
AVH map: SA distribution map (external link)

Plant description

Terrestrial orchid growing to 100 cm tall in flower, with large, broad-lanceolate leaf to 30 cm long. Inflorescence a large glaucous spike with  pale to deep blue, lilac or pinkish-mauve flowers to 40 mm across. Flowering between September and November. Fruits are brown papery ellipsoid capsule. Seeds are very small brown ellipsoid seed with an ovoid translucent brown mesh-like covering.

Seed collection and propagation

Collect seeds between November and December. 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. 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 germination in Thelymitra species is difficult in the absence of symbiotic mycorrhizal fungi.

Fire response

Obligate re-spouter and re-seeder.

Longevity: ?? years

Time to flowering: ?? years

Recovery work

In 2020-2021 this species was assessed post-fire in 1 year old fire scars. A total of 296,200 seeds have been collected & banked for a population outside the 2020 fire scar. Further populations will be assessed and seeds collected on Kangaroo Island in 2021–2022. Germination screening testing the response to fire cues will be undertaken in 2021. This project was supported by the World Wildlife Fund program.

Seeds stored:
  Hide
LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA100,000 (0.078 g)117-Nov-2011K. Brewer
Southern Lofty
1-Nov-201685%-80°C
BGA 
MSB
500,000
500,000
53-Dec-2007RJB76042
Southern Lofty
1-Nov-2016N/C-80°C
BGA269,000 (0.21 g)29-Nov-2016Alligator Gorge
Flinders Ranges
1-Nov-2017N/C-18°C, -80°C
BGA84,000 (0.066 g)314-Nov-2019TST1436
Southern Lofty
24-Jun-2020N/C-18°C
BGA423,000 (0.33 g)414-Nov-2019Goondooloo, Deep Creek CP
Southern Lofty
24-Jun-2020N/C-18°C, -80°C
BGA296,200 (0.230 g)1024-Nov-2020DJD3945
Southern Lofty
28-Jun-2021N/C-18°C, -80°C
BGA3,711,600 (2.894 g)129-Dec-2021TST1483
Southern Lofty
10-Aug-2022N/C-18°C, -80°C
BGA444,785 (0.347 g)630-Nov-2021BKB20
Kangaroo Island
10-Aug-2022N/C-18°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.