Caleana disjuncta

Caleana disjuncta, commonly known as the little duck orchid,[3] is a species of orchid that is found in Western Australia but with a few disjunct populations in Victoria and South Australia. It has a single smooth leaf and a single greenish yellow and red flower with a flattened labellum, the calli only near its tip.

Little duck orchid
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Genus: Caleana
Species:
C. disjuncta
Binomial name
Caleana disjuncta
Synonyms[2]
  • Paracaleana disjuncta D.L.Jones
  • Sullivania disjuncta (D.L.Jones) & M.A.Clem.

Description

Caleana disjuncta has a single smooth, dull green or dull red leaf, 10–20 mm (0.4–0.8 in) long and 3–10 mm (0.1–0.4 in) wide. Usually only one greenish yellow and red flower, 12–18 mm (0.5–0.7 in) long and 8–12 mm (0.3–0.5 in) wide is borne on a thin, wiry stalk 50–130 mm (2–5 in) high. The dorsal sepal, lateral sepals and petals are 7–10 mm (0.3–0.4 in) long, 1–2 mm (0.04–0.08 in) wide and hang downwards. The dorsal sepal is pressed against the column which has broad wings, forming a bucket-like shape. The labellum is about 10 mm (0.4 in) long on the end of a strap-like stalk about 5 mm (0.2 in) long. The labellum is flattened and only about one-third of the outer part of the labellum is covered with glossy black glands or calli. Flowering occurs from October to December.[3][4][5][6]

Taxonomy and naming

The little duck orchid was first formally described in 2003 by David Jones from a specimen collected in the Cox Scrub Conservation Park. Jones gave it the name Paracaleana disjuncta and published the description in The Orchadian.[7] A 2014 paper reported that molecular studies had suggested that Caleana and Paracaleana are congeneric, so the present species was renamed Caleana disjuncta.[1][8] The Western Australian Herbarium and several recent field guides to the orchids of Western Australia retain the name Paracaleana disjuncta.[3][4][9] The specific epithet (disjuncta) is a Latin word meaning "separate", "distinct", "different" or "remote",[10] referring to the widely separated populations of this orchid.[4]

Distribution and habitat

Caleana disjuncta mainly grows in shrubland between Margaret River and Israelite Bay in Western Australia[3][4] but there are small populations at three locations in the south-east of South Australia and two in Victoria in and near the Grampians National Park.[5][6]

References
  1. "Caleana disjuncta". APNI. Retrieved 15 April 2018.
  2. "Caleana disjuncta". 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. 249. 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. 301. ISBN 9780980296457.
  5. Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. p. 147. ISBN 1877069124.
  6. Jeanes, Jeff. "Caleana disjuncta". Royal Botanic Gardens Victoria. Retrieved 15 April 2018.
  7. "Paracaleana disjuncta". APNI. Retrieved 15 April 2018.
  8. 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 15 April 2018.
  9. "Paracaleana disjuncta". FloraBase. Western Australian Government Department of Parks and Wildlife.
  10. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 264.
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