Diuris tricolor

Diuris tricolor, commonly known as the long-tailed donkey orchid[2] or pine donkey orchid,[3] is a species of orchid that is endemic to New South Wales, although a single plant has been found in Victoria. It has up to three grass-like leaves and up to six orange-coloured to yellow flowers with white and purplish tints. The lateral sepals are unusually long.

Long-tailed donkey orchid
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Genus: Diuris
Species:
D. tricolor
Binomial name
Diuris tricolor
Synonyms[1]

Description

Diuris tricolor is a tuberous, perennial herb with up to three linear leaves 200–300 mm (8–10 in) long, 3–4 mm (0.1–0.2 in) wide and folded lengthwise. Between two and six orange-coloured to yellow flowers with white and purplish tints, 25–30 mm (0.98–1.2 in) wide are borne on a flowering stem 200–400 mm (8–20 in) tall. The dorsal sepal curves upwards, 10–15 mm (0.4–0.6 in) long, 6–9 mm (0.2–0.4 in) wide and broadly egg-shaped. The lateral sepals are narrow linear, 20–65 mm (0.8–3 in) long, much less than 1 mm (0.04 in) wide and turned downwards. The petals are more or less erect or turned backwards, egg-shaped to elliptic, the blade 10–16 mm (0.4–0.6 in) long and 6–10 mm (0.2–0.4 in) wide on a reddish purple stalk 3–7 mm (0.1–0.3 in) long. The labellum is 8–12 mm (0.3–0.5 in) long and has three lobes. The centre lobe is egg-shaped, 6–9 mm (0.2–0.4 in) long and wide with a central ridge. The side lobes are 3–4.5 mm (0.1–0.2 in) long and about 2 mm (0.08 in) wide. There are two callus ridges about 4 mm (0.2 in) long near the mid-line of the labellum. Flowering occurs from September to November.[2][4][5]

Taxonomy and naming

Diuris tricolor was first formally described in 1885 by Robert FitzGerald and the description was published in the Journal of Botany, British and Foreign.[6][7] The specific epithet (tricolor) is derived from the Latin prefix tri- meaning "three",[8]:798 and color meaning "hue", "tint" or "complexion".[8]:219

In 1940, Herman Rupp described D. colemaniae[9] in honour of Edith Coleman and which he noted had shorter lateral sepals and a "quite different" labellum.[10] Diuris colemaniae is now regarded as a synonym of D. tricolor.[1]

Distribution

The long-tailed donkey orchid grows in grassland and forest in New South Wales, sporadically distributed south from Deepwater and in the Australian Capital Territory. A single specimen has been recorded in Victoria, just south of the border.[2][3][4]

Conservation

Diuris tricolor is classed as "vulnerable" in New South Wales under the Biodiversity Conservation Act 2016. The main threats to the species are habitat alteration and grazing by rabbits and goats.[3]

References
  1. "Diuris tricolor". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  2. Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. pp. 133–134. ISBN 1877069124.
  3. "Pine Donkey Orchid - profile". New South Wales Government Office of Environment and Heritage. Retrieved 9 April 2018.
  4. Jones, David L. "Diuris secundiflora". Royal Botanic Garden Sydney. Retrieved 9 April 2018.
  5. Jeanes, Jeff; Stajsic, Val. "Diuris tricolor". Royal Botanic Gardens Victoria. Retrieved 9 April 2018.
  6. "Duiris tricolor". APNI. Retrieved 9 April 2018.
  7. Fitzgerald, Robert D. (1885). "New Australian Orchids". Journal of Botany, British and Foreign. 23: 137–138. Retrieved 9 April 2018.
  8. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.
  9. "Duiris colemaniae". APNI. Retrieved 9 April 2018.
  10. Rupp, Herman M.R. (1943). The Orchids of New South Wales. Glebe, N.S.W.: Australasian Medical Publishing Company. p. 13.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.