Genoplesium rufum

Genoplesium rufum, commonly known as the rufous midge-orchid, is a species of orchid endemic to New South Wales. It has a single thin, wiry leaf and up to twenty five drooping, pinkish or reddish flowers on a flowering stem which is fused to the lower part of the leaf. It was formerly thought to range from Queensland to South Australia and Tasmania but specimens in other states are now assigned to Genoplesium clivicola.

Rufous midge orchid
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Genus: Genoplesium
Species:
G. rufum
Binomial name
Genoplesium rufum
Synonyms[2]
  • Prasophyllum obovatum Rupp
  • Corunastylis rufa (R.Br.) D.L.Jones & M.A.Clem.
  • Prasophyllum rufum R.Br.
  • Prasophyllum mucronatum Rupp
  • Prasophyllum unicum Rupp

Description

Genoplesium rufum is a terrestrial, perennial, deciduous, sympodial herb with a single wiry leaf fused to the flowering stem. The leaf is 100–160 mm (4–6 in) long and the free part is 10–20 mm (0.4–0.8 in) long. Between five and twenty five pinkish to reddish flowers are crowded on a flowering stem 10–40 mm (0.4–2 in) tall. The flowers droop forwards, and are 3.5–4.5 mm (0.1–0.2 in) long, 3–5 mm (0.1–0.2 in) wide. As with others in the genus the flowers are inverted so that the labellum is above the column rather than below it. The dorsal sepal is egg-shaped, 2–3 mm (0.08–0.1 in) long, 1–2 mm (0.04–0.08 in) wide and sharply pointed. The lateral sepals are linear to lance-shaped, about 3 mm (0.1 in) long, 1 mm (0.04 in) wide, have an expanded base and diverge from each other. The petals are egg-shaped, about 2 mm (0.08 in) long, 1 mm (0.04 in) wide with a pointed tip. The labellum is egg-shaped, whitish or pinkish, 2–3 mm (0.08–0.1 in) long, 1.5–2 mm (0.06–0.08 in) wide, sometimes with small, irregular teeth on the edges. There is a blackish callus in the centre of the labellum and extending almost to its tip. Flowering occurs between January and May.[3][2]

Taxonomy and naming

The rufous midge orchid was first formally described in 1810 by Robert Brown who gave it the name Prasophyllum rufum and published the description in Prodromus Florae Novae Hollandiae et Insulae Van Diemen.[4][5] In 1989, David Jones and Mark Clements changed the name to Genoplesium rufum[6] and in 2002 changed the name again to Corunastylis rufa[7] but the change has not been accepted by the World Checklist of Selected Plant Families.[8] Jones and Brown have also listed Prasophyllum trifidum and P. unicum as synonyms of G. rufum[6] although later changed these names to Corunastylis trifida[9] and Corunastylis unica respectively.[10] The specific epithet (rufum) is a Latin word meaning "red".[11]

Distribution and habitat

The rufous midge-orchid is locally common in forest between Ku-ring-gai and Bargo.[2]

It was formerly understood to also occur in Queensland, Victoria, South Australia and Tasmania but specimens in those states are now assigned to Corunastylis clivicola, also known as Genoplesium clivicola.[12]

References
  1. "Genoplesium rufum". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  2. Jones, David L. "Genoplesium rufum". Royal Botanic Garden Sydney. Retrieved 7 January 2018.
  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. 187. ISBN 1877069124.
  4. "Prasophyllum rufum". APNI. Retrieved 7 January 2018.
  5. Brown, Robert (1810). Prodromus florae Novae Hollandiae et Insulae Van-Diemen. London. p. 319. Retrieved 7 January 2018.
  6. "Genoplesium rufum". APNI. Retrieved 7 January 2018.
  7. "Corunastylis nuda". APNI. Retrieved 1 January 2018.
  8. "Corunastylis rufa". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  9. "Corunastylis trifida". APNI. Retrieved 7 January 2018.
  10. "Corunastylis unica". APNI. Retrieved 7 January 2018.
  11. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 651.
  12. Jeanes, Jeff. "Corunastylis clivicola". Royal Botanic Gardens Victoria`. Retrieved 7 January 2018.
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