Prasophyllum retroflexum

Prasophyllum retroflexum, commonly known as the congested leek orchid or Kiandra leek orchid, is a species of orchid endemic to a small area near the border between New South Wales and Victoria, growing in subalpine herbfields. It has a single tubular leaf and up to forty densely-crowded, pale green flowers with pinkish markings.

Congested leek orchid
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Subtribe: Prasophyllinae
Genus: Prasophyllum
Species:
P. retroflexum
Binomial name
Prasophyllum retroflexum

Description

Prasophyllum retroflexum is a terrestrial, perennial, deciduous, herb with an underground tuber and a single tube-shaped leaf 200–400 mm (8–20 in) long and 3–6 mm (0.1–0.2 in) wide. Between ten and forty flowers are crowded along flowering stem 50–80 mm (2–3 in) long which reaches to a height of 250–400 mm (10–20 in). The flowers are lemon-scented, pale green with pinkish markings and open widely. As with others in the genus, they are inverted so that the labellum is above the column rather than below it. The dorsal sepal is lance-shaped to egg-shaped, 5–6 mm (0.20–0.24 in) long and about 3 mm (0.1 in) wide. The lateral sepals are a similar length but narrower, linear to lance-shaped and are free from each other. The petals are a similar size to the lateral sepals and spread widely with their tips curved backwards. The labellum is pink to purplish, broadly egg-shaped, about 4 mm (0.2 in) long, 3 mm (0.1 in) wide and curves upwards near its middle. There is a raised green, fleshy, channelled callus in the centre of the labellum and extending almost to its tip. Flowering occurs from November to December.[2][3]

Taxonomy and naming

Prasophyllum retroflexum was first formally described in 2000 by David Jones and the description was published in The Orchadian from a specimen collected near Adaminaby.[1] The specific epithet (retroflexum) is derived from the Latin words retro meaning "backwards"[4]:657 and flexum meaning "a bending or turning".[4]:139

This species was formerly known as Prasophyllum morganii, but that species is now regarded as a Victorian endemic.[5]

Distribution and habitat

The congested leek orchid grows in subalpine herbfield in the Tantangara - Kiandra - Yarrangobilly area in the Kosciuszko National Park of New South Wales and in a single population on the Nunniong Plain in Victoria.[2][5]

Conservation

Prasophyllum retroflexum is listed as "Vulnerable" under the New South Wales Biodiversity Conservation Act 2016.[6]

References
  1. "Prasophyllum retroflexum". APNI. Retrieved 22 December 2017.
  2. Jeanes, Jeff. "Prasophyllum retroflexum". Royal Botanic Gardens Victoria. Retrieved 22 November 2017.
  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. 213. ISBN 1877069124.
  4. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.
  5. McDougall, Keith L.; Walsh, Neville G. (2002). "The flora of Nungar Plain, a treeless sub-alpine frost hollow in Kosciuszko National Park". Cunninghamia. 7: 601–610. Retrieved 22 December 2017.
  6. "Kiandra Leek Orchid - profile". New South Wales Government Office of Environment and Heritage. Retrieved 22 December 2017.
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