Pterostylis aspera
| Rough shell orchid | |
|---|---|
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Orchidaceae |
| Subfamily: | Orchidoideae |
| Tribe: | Cranichideae |
| Genus: | Pterostylis |
| Species: | P. aspera
|
| Binomial name | |
| Pterostylis aspera | |
| Synonyms[2] | |
|
Diplodium asperum (D.L.Jones & M.A.Clem.) D.L.Jones & M.A.Clem. | |
Pterostylis aspera, commonly known as the rough shell orchid, is a species of orchid endemic to the south-west of Western Australia. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves flat on the ground but the flowering plants have a single flower with leaves on the flowering spike. In this common species, the flower is white with green and reddish-brown stripes and a short, straight labellum.
Description[edit]
Pterostylis aspera is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of bluish-green leaves lying flat on the ground. Each leaf is 6–20 mm (0.2–0.8 in) long and 4–17 mm (0.2–0.7 in) wide. Flowering plants usually only have a single flower 22–30 mm (0.9–1 in) long and 10–12 mm (0.4–0.5 in) wide which leans forwards on a flowering stem 60–200 mm (2–8 in) high. There are between three and five stem leaves 20–30 mm (0.8–1 in) long and 3–5 mm (0.1–0.2 in) wide . The flowers are white with green and reddish-brown stripes. The dorsal sepal and petals are fused, forming a hood or "galea" over the column and the dorsal sepal has a sharp point. The lateral sepals are held closely against the galea and have narrow tips 30–35 mm (1.2–1.4 in) long and a broad sinus with a small notch between their bases. The labellum is 13–15 mm (0.5–0.6 in) long, about 4 mm (0.2 in) wide, relatively straight, and only just visible above the sinus. Flowering occurs from May to July.[3][4][5]
Taxonomy and naming[edit]
Pterostylis aspera was first formally described in 1989 by David Jones and Mark Clements from a specimen collected near Eaton and the description was published in Australian Orchid Research.[1] The specific epithet (aspera) is a Latin word meaning "rough", "harsh" or "uneven",[6] referring to hairs on the labellum.[4]
Distribution and habitat[edit]
The rough shell orchid grows in shrubland and woodland between Dongara and Jerramungup in the Avon Wheatbelt, Esperance Plains, Jarrah Forest, Mallee and Swan Coastal Plain biogeographic regions.[3][4][5][7]
Conservation[edit]
Pterostylis aspera is listed as "not threatened" by the Government of Western Australia Department of Parks and Wildlife.[7]
References[edit]
- ^ a b "Pterostylis aspera". APNI. Retrieved 16 June 2017.
- ^ "Pterostylis aspera". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
- ^ a b Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. pp. 290–291. ISBN 978-1877069123.
- ^ a b c Brown, Andrew; Dixon, Kingsley; French, Christopher; Brockman, Garry (2013). Field guide to the orchids of Western Australia : the definitive guide to the native orchids of Western Australia. Simon Nevill Publications. p. 346. ISBN 9780980348149.
- ^ a b Hoffman, Noel; Brown, Andrew (2011). Orchids of South-West Australia (3rd ed.). Gooseberry Hill: Noel Hoffman. p. 398. ISBN 9780646562322.
- ^ Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 669.
- ^ a b "Pterostylis aspera". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.