Thelymitra grandiflora

Giant sun orchid
In the Scott Creek Conservation Park
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Embryophytes
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Genus: Thelymitra
Species:
T. grandiflora
Binomial name
Thelymitra grandiflora
Synonyms[1]

Thelymitra aristata (Adelaide Hills)

Thelymitra grandiflora, commonly called giant sun orchid,[2] is a species of orchid that is endemic to South Australia. It has a single large, erect, linear to lance-shaped leaf and up to forty large, dark metallic to greenish blue flowers with darker veins.

Description

Thelymitra grandiflora is a tuberous, perennial herb with a single erect, fleshy, channelled, dark green, linear to lance-shaped leaf 250–400 mm (10–20 in) long and 25–35 mm (0.98–1.4 in) wide. Up to forty dark metallic to greenish blue flowers with darker veins, 30–40 mm (1–2 in) wide are arranged on a flowering stem 300–1,000 mm (10–40 in) tall. The sepals and petals are 15–20 mm (0.6–0.8 in) long and 6–7 mm (0.2–0.3 in) wide. The column is white to cream-coloured, 6–7 mm (0.24–0.28 in) long and about 5 mm (0.2 in) wide. The lobe on the top of the anther is pale brown with a yellow tip, strongly curved with a shallow notch and irregular teeth. The side lobes have mop-like tufts of white hairs on their ends. The flowers are insect pollinated and open in warm weather. Flowering occurs from September to December.[2][3]

Taxonomy and naming

Thelymitra grandiflora was first formally described in 1882 by Robert Fitzgerald and the description was published in The Gardeners' Chronicle.[4][5] The specific epithet (grandiflora) means 'large-flowered'.[6]

In 2014, Robert Bates described two subspecies and the names have been accepted by the World Checklist of Selected Plant Families:

  • Thelymitra grandiflora subsp. grandiflora;[7][8]
  • Thelymitra grandiflora subsp. exposa.[9][10]

Distribution and habitat

The giant sun orchid grows in forest and scrubland, often in rocky places. It is widespread and locally common in the Mount Lofty Ranges and Southern Flinders Ranges. It has also been recorded on the Yorke Peninsula and Kangaroo Island but is possibly now extinct there.[2][3]

References

  1. 1 2 "Thelymitra grandiflora". Australian Plant Census. Retrieved 24 October 2025.
  2. 1 2 3 Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. p. 239. ISBN 1877069124.
  3. 1 2 Jeanes, Jeffrey A. (2004). "Resolution of the Thelymitra aristata (Orchidaceae) complex of south-eastern Australia" (PDF). Muelleria. 19: 120–121. Retrieved 23 May 2018.
  4. ↑ "Thelymitra grandiflora". APNI. Retrieved 23 May 2018.
  5. ↑ Fitzgerald, Robert D. (1882). "New Australian orchids". The Gardener's Chronicle. 17: 495. Retrieved 23 May 2018.
  6. ↑ George, Alex S.; Sharr, Francis A. (2023). Western Australian Plant Names and Their Meanings - A Glossary (fifth ed.). Kardinya: Four Gables Press. p. 214. ISBN 9780645629538.
  7. ↑ "Thelymitra grandiflora". APNI. Retrieved 23 May 2018.
  8. ↑ "Thelymitra grandiflora". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew. Archived from the original on October 16, 2022.
  9. ↑ "Thelymitra grandiflora subsp. exposa". APNI. Retrieved 23 May 2018.
  10. ↑ "Thelymitra grandiflora". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew. Archived from the original on October 21, 2022.
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