Caleana alcockii

Caleana alcockii, commonly known as Alcock's duck orchid[3] is a rare species of orchid endemic to the south-west of Western Australia. It has a single smooth leaf and is distinguished by its humped labellum and relatively late flowering period. It only occurs north of Geraldton.

Alcock's duck orchid

Priority Two — Poorly Known Taxa (DEC)
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Genus: Caleana
Species:
C. alcockii
Binomial name
Caleana alcockii
Synonyms[2]

Description

Caleana alcockii has a single smooth green or red leaf, 20–30 mm (0.8–1 in) long and 5–12 mm (0.2–0.5 in) wide. Usually only one greenish-yellow and red flower, about 20 mm (0.8 in) long and 10 mm (0.4 in) wide is borne on a thin, wiry stalk 80–160 mm (3–6 in) high. The dorsal sepal, lateral sepals and petals are narrow and hang downwards with the dorsal sepal pressed against the column which has broad wings, forming a bucket-like shape. About one-third of the outer part of the labellum is covered with glossy black glands or calli and the labellum has a prominent hump at its centre. Flowering occurs from September to October.[3][4]

Taxonomy and naming

Alcock's duck orchid was first formally described in 2006 by Stephen Hopper and Andrew Brown who gave it the name Paracaleana alcockii. The description was published in Australian Systematic Botany.[5] In 2014, based on molecular studies, Joseph Miller and Mark Clements transferred all the species previously in Paracaleana to Caleana so that the present species became Caleana alcockii.[1][6] The specific epithet (alcockii) honours John Alcock who recognised the species as distinct.[4]

Distribution and habitat

Caleana alcockii grows with grasses or sedges in sandy soil in a small area north of the Murchison River in the Geraldton Sandplains biogeographic region.[3][4][7]

Conservation

Caleana alcockii (as Paracaleana alcockii) is classified as "Priority Two" by the Western Australian Government Department of Parks and Wildlife[7] meaning that it is poorly known and from only one or a few locations.[8]

References
  1. "Caleana alcockii". APNI. Retrieved 13 April 2018.
  2. "Caleana alcockii". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  3. Hoffman, Noel; Brown, Andrew (2011). Orchids of South-West Australia (3rd ed.). Gooseberry Hill: Noel Hoffman. p. 254. ISBN 9780646562322.
  4. Brown, Andrew; Dundas, Pat; Dixon, Kingsley; Hopper, Stephen (2008). Orchids of Western Australia. Crawley, Western Australia: University of Western Australia Press. p. 300. ISBN 9780980296457.
  5. "Paracaleana alcockii". APNI. Retrieved 13 April 2018.
  6. Miller, Joseph T.; Clements, Mark A. (2014). "Molecular phylogenetic analyses of Drakaeinae: Diurideae (Orchidaceae) based on DNA sequences of the internal transcribed spacer region". Australian Systematic Botany. 27 (1): 3–22. doi:10.1071/SB13036. Retrieved 13 April 2018.
  7. "Paracaleana alcockii". FloraBase. Western Australian Government Department of Parks and Wildlife.
  8. "Conservation codes for Western Australian Flora and Fauna" (PDF). Government of Western Australia Department of Parks and Wildlife. Retrieved 28 October 2019.
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