Spiculaea

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Elbow orchid
Spiculaea ciliata - Flickr. 003 cropped.jpg
S. ciliata growing on Boyagin Rock
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Subtribe: Drakaeinae
Genus: Spiculaea
Lindl.
Species: S. ciliata
Binomial name
Spiculaea ciliata
Lindl.
Synonyms[1]

Drakaea ciliata (Lindl.) Rchb.f.

Spiculaea ciliata, commonly known as elbow orchid, is the only species in the flowering plant genus Spiculaea in the orchid family, Orchidaceae and is endemic to the south-west of Western Australia. It is unusual in a number of respects, including that it grows in shallow soil on granite rock outcrops, grows and flowers in the hottest months of the year and has a unique method of using thynnid wasps as pollinators.

Description[edit]

Spiculaea ciliata is a terrestrial, perennial, deciduous, sympodial herb with a few inconspicuous, fine roots and an oval-shaped tuber lacking a protective sheath. The tuber produces a replacement tuber and daughter tubers on the end of short, root-like stolons. There is a single stalked leaf about 2 cm (0.8 in) long, 1 cm (0.4 in) wide at the base of the plant and purplish on the lower surface. The leaf is fully developed before the first flowers appear but withers before the first flowers open in late October.[2][3][4]

There are up to ten resupinate flowers on the end of a wiry stem 10–18 cm (4–7 in) high which is thickest near the top and which gradually withers from the base as the flowers mature. Each flower is straw-coloured, 20 mm (0.8 in) long and 10 mm (0.4 in) wide on a short stalk. The dorsal sepal curves over the top of the flower, with its side edges curved downwards. The two lateral sepals are shorter than the dorsal sepal and the two petals are narrower than both. The petals are sepals are separate from each other. As is usual in orchids, one petal is highly modified as the central labellum. The labellum is shaped like a wingless insect, and is attached to the base of the column by a flexible, hinge-like "claw". The labellum is much smaller than in other orchids and is rod-like, fleshy and has many club-shaped hairs. The sexual parts of the flower are fused to the column, which has wing-like structures on its sides. Flowering occurs from October to January and is followed by a fruit which is a non-fleshy, glabrous, dehiscent capsule containing a large number of seeds.[2][3][4]

Labelled image

Taxonomy and naming[edit]

This orchid was first formally described in 1840 by John Lindley and the description was published in A Sketch of the Vegetation of the Swan River Colony.[5][6] In 1871, Heinrich Reichenbach changed the name to Drakaea ciliata[7] but in 1989, David Jones and Mark Clements reverted to Lindley's name.[8]

The origin of the genus name, "Spiculaea", is unclear but spicula is a Latin word meaning "an ear of grain"[9]:737 and the specific epithet "ciliata" is a Latin word meaning "eyelash" or "eyelid".[9]:390

Distribution and habitat[edit]

Spiculaea ciliata grows in shallow, sandy soil over granite between the Darling Scarp, Paynes Find and Mount Ney in the Avon Wheatbelt, Coolgardie, Esperance Plains, Geraldton Sandplains, Jarrah Forest and Mallee biogeographic regions.[2]

Ecology[edit]

The flowers of elbow orchid have been described as "bizarre" and the production of flowers during the hottest months is unusual.[4] One author described: "When most other plants dead or dying, this tiny orchid at its fascinating best. When everything else was brittle underfoot these are still succulent. A specimen continued to flower in my collection in the fridge after I got home, weeks later."[10]

Spiculaea ciliata is thought to be pollinated by a male thynnid wasp of the genus Thynnoturneria which is initially attracted to the labellum of the orchid by a pheromone, flying from downwind towards the flower. At rest, the labellum resembles a wingless female wasp, resting on a blade of grass. The insect picks up the dummy females and tries to fly off with it, rising into the column where the column wings hold the insect, and its abdomen comes into contact with the sexual parts of the flower.[4][11]

Conservation[edit]

Elbow orchid is classified as "Not Threatened" by the Western Australian Government Department of Parks and Wildlife.[3]

References[edit]

  1. ^ "Spiculaea". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew. Retrieved 25 June 2016. 
  2. ^ a b c Hoffman, Noel; Brown, Andrew (2011). Orchids of South-West Australia (3rd ed.). Gooseberry Hill: Noel Hoffman. pp. 216–218. ISBN 9780646562322. 
  3. ^ a b c "Spiculaea". FloraBase. Western Australian Government Department of Parks and Wildlife. 
  4. ^ a b c d Pridgeon (ed.), Alec M.; Cribb (ed.), Phillip J.; Chase (ed.), Mark W.; Rasmussen (ed.), Finn (2001). Genera Orchidacearum, Volume 2, Orchidoideae (part 1). Oxford, England: Oxford University Press. pp. 152–155. ISBN 0198507100. 
  5. ^ "Spiculaea ciliata". APNI. Retrieved 1 July 2016. 
  6. ^ Lindley, John (1840). A Sketch of the Vegetation of the Swan River Colony (Appendix). Piccadilly, London: James Ridgway. p. 53. Retrieved 1 July 2016. 
  7. ^ "Drakaea ciliata". APNI. Retrieved 1 July 2016. 
  8. ^ Jones (ed.), David L.; Clements, Mark A. (1989). "Catalogue of Australian Orchidaceae". Australian Orchid Research. 1: 135. 
  9. ^ a b Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. 
  10. ^ Nikulinsky, Philippa; Hopper, Stephen D. (2008). Life on the rocks : the art of survival. Fremantle (Australia): Fremantle Press. p. 92. ISBN 9781921361289. 
  11. ^ Cingel, Nelis A. van der (2000). An atlas of orchid pollination : America, Africa, Asia and Australia. Rotterdam: Balkema. p. 208. ISBN 9054104864. 
  • Media related to Spiculaea at Wikimedia Commons
  • Data related to Spiculaea at Wikispecies