Caleana gracilicordata

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Slender-leafed duck orchid

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

Caleana gracilicordata, commonly known as the slender-leafed duck orchid[3] is a species of orchid endemic to the south-west of Western Australia. It is a small, late flowering duck orchid with a single small, smooth, heart-shaped leaf and a single greenish yellow and red flower. It usually grows in mossy places on granite outcrops.

Description[edit]

Caleana gracilicordata has a single smooth, narrow heart-shaped, dull green to dull red leaf, 15–20 mm (0.6–0.8 in) long and 3–4 mm (0.1–0.2 in) wide. The leaf is usually withered by flowering time. Usually only one greenish-yellow and red flower, about 20 mm (0.8 in) long and 15–20 mm (0.6–0.8 in) wide is borne on a flowering stem 55–70 mm (2–3 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-half to one-third of the outer part of the labellum is covered with glossy black glands or calli and the labellum has a flattened top. Flowering occurs from late October to November.[3][4]

Taxonomy and naming[edit]

The slender-leafed duck orchid was first formally described in 2006 by Stephen Hopper and Andrew Brown who gave it the name Paracaleana gracilicordata. The description was published in Australian Systematic Botany from a specimen collected near Jarrahdale.[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 gracilicordata.[1][6] The specific epithet (gracilicordata) is derived from the Latin words gracilis meaning "slender" or "gracile"[7]: 791  and cordata meaning "heart-shaped",[7]: 231  referring to the shape of the leaf of this orchid.[3][4]

Distribution and habitat[edit]

Caleana gracilicordata grows with mosses and lichens on granite outcrops between Waroona and the Brookton Highway in the Jarrah Forest biogeographic region.[3][4][8]

Conservation[edit]

Caleana gracilicordata (as Paracaleana gracilicordata) is classified as "Priority One" by the Government of Western Australia Department of Parks and Wildlife,[8] meaning that it is known from only one or a few locations which are potentially at risk.[9]

References[edit]

  1. ^ a b "Caleana gracilicordata". APNI. Retrieved 15 April 2018.
  2. ^ "Caleana gracilicordata". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  3. ^ a b c d Hoffman, Noel; Brown, Andrew (2011). Orchids of South-West Australia (3rd ed.). Gooseberry Hill: Noel Hoffman. p. 255. ISBN 9780646562322.
  4. ^ a b c Brown, Andrew; Dundas, Pat; Dixon, Kingsley; Hopper, Stephen (2008). Orchids of Western Australia. Crawley, Western Australia: University of Western Australia Press. p. 302. ISBN 9780980296457.
  5. ^ "Paracaleana gracilicordata". APNI. Retrieved 15 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 15 April 2018.
  7. ^ a b Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.
  8. ^ a b "Paracaleana gracilicordata". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.
  9. ^ "Conservation codes for Western Australian Flora and Fauna" (PDF). Government of Western Australia Department of Parks and Wildlife. Retrieved 28 October 2019.