Diuris venosa

Veined doubletail
D. venosa growing in Barrington Tops National Park
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Asparagales
Family: Orchidaceae
Genus: Diuris
Species: D. venosa
Binomial name
Diuris venosa
Rupp

Diuris venosa, commonly known as the veined doubletail is a species of orchid which is endemic to New South Wales. It has a few thin, erect leaves and up to four white to lilac-coloured flowers with deep red to purple blotches and lines.

Description

Diuris venosa is a tuberous, perennial, terrestrial herb, with three to five erect, thread-like leaves 5–12 cm (2–5 in) long and 1–3 mm (0.04–0.1 in) wide.

There are up to four flowers arranged on a raceme 10–40 cm (4–20 in) high, each flower about 25 mm (1 in) wide. The flowers are white to lilac-coloured with many purple lines and blotches. The dorsal sepal is broadly egg-shaped, 9–12 mm (0.4–0.5 in) long, 4–9 mm (0.2–0.4 in) wide and forms a hood over the column. The lateral sepals are linear to lance-shaped, 11–18 mm (0.4–0.7 in) long, 2–3.5 mm (0.08–0.1 in) wide and hang vertically below the flower. The petals are narrow egg-shaped, 3–10 mm (0.1–0.4 in) long, 3–6 mm (0.1–0.2 in) wide spreading more or less horizontally and resemble the shape of cow's ears. The labellum is 10–13 mm (0.4–0.5 in) long and is divided into three lobes. The lateral lobes are linear to wedge-shaped, 3–4 mm (0.1–0.2 in) long, 1–3 mm (0.04–0.1 in) wide with a wavy edge. The medial lobe is a broad egg-shape to almost circular when flattened, 6–11 mm (0.2–0.4 in) wide with a callus 5–6.5 mm (0.2–0.3 in) long.[1][2]

Labelled image

Taxonomy and naming

Diuris venosa was first formally described in 1926 by Herman Rupp and the description was published in the journal, Victorian Naturalist.[3][4] The specific epithet (venosa) is derived from a Latin word meaning "veiny".[5]

Distribution and habitat

This orchid is only found in New South Wales, in the Barrington Tops and New England National Parks, where it grows in swampy, grassy areas.[1]

Conservation

Diuris venosa is listed as "Vulnerable" (VU) under the Australian Government Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The threats to its survival include invasion by introduced weeds, particularly English broom (Cytisus scoparius), illegal removal of plants, and predation by feral pigs (Sus scrofa).[6]

References

  1. 1 2 Jones, David L. "Diuris venosa". Royal Botanic Gardens Sydney:plantNET. Retrieved 14 September 2016.
  2. "Veined Doubletail - profile". New South Wales Government Office of Environment and Heritage. Retrieved 14 September 2016.
  3. "Duiris venosa". APNI. Retrieved 14 September 2016.
  4. Rupp, Hermann (1926). "A new species of Diuris". The Victorian Naturalist. 43 (5): 153. Retrieved 14 September 2016.
  5. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 832.
  6. "Approved Conservation Advice for Diuris venosa (Veined Doubletail)" (PDF). Australian Government Department of Environment and Energy. Retrieved 14 September 2016.
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