Thelymitra orientalis

Thelymitra orientalis
Conservation status
Critically Endangered  (IUCN 3.1) [1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Order:	Asparagales
Family:	Orchidaceae
Subfamily:	Orchidoideae
Tribe:	Diurideae
Genus:	Thelymitra
Species:	T. orientalis
Binomial name
Thelymitra orientalis R.J.Bates [2]

Thelymitra orientalis is a rare species of orchid in the family Orchidaceae and is endemic to southern continental Australia. It has a single thread-like, cylindrical leaf and a single deep blue, streaked flower. It is similar to T. mucida but is distinguished from that species by its filiform leaf and smaller flower.

Description

Thelymitra orientalis is a tuberous, perennial herb with a single thread-like, cylindrical leaf about 50 mm (2 in) long and 2 mm (0.08 in) wide with a red base. A single deep blue flower with 6 to 8 darker streaks, up to 10 mm (0.4 in) wide is borne on a flowering stem up to 100 mm (4 in) tall. The sepals and petals are 5–7 mm (0.2–0.3 in) long and 4–5 mm (0.16–0.20 in) wide. The column is a rich purple colour, 3–4 mm (0.12–0.16 in) long and about 2 mm (0.08 in) wide. The lobe on the top of the anther is black with a yellow tip divided into two parts with wavy edges. The side lobes have a few yellow hairs. Flowering occurs between late October and early-November and the flowers only open on hot days. ^{[3] [4]}

Taxonomy and naming

Thelymitra orientalis was first formally described in 2010 by Robert Bates from a specimen he collected in The Marshes Native Forest Reserve near Millicent in 2003. The description was published in the Journal of the Adelaide Botanic Garden . ^[5] The specific epithet (orientalis) is a Latin word meaning "of the east", ^[6] referring to fact that this orchid is related to T. mucida which is mainly a Western Australian species. ^[3]

Distribution and habitat

This thelymitra grows in damp heath in high rainfall areas. It is found in western Victoria and the far south-east of South Australia. ^{[3] [4]}

References

1. Australian Government, Threatened Species Scientific Committee (2025). "Thelymitra orientalis". IUCN Red List of Threatened Species . 2025: e.T254086113A254086352. Retrieved 2 June 2025.
2. "Thelymitra orientalis". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
3. Bates, Robert J. (2010). "The Thelymitra pauciflora R.Br. complex (Orchidaceae) in South Australia with the description of seven new taxa" (PDF). Journal of the Adelaide Botanic Garden. 24: 28–308. Retrieved 22 June 2018.
4. Jeanes, Jeff; Stajsic, Val. "Thelymitra orientalis". Royal Botanic Gardens Victoria. Retrieved 22 June 2018.
5. "Thelymitra orientalis". APNI. Retrieved 22 June 2018.
6. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 291.