Pterostylis angulata, commonly known as the Helena River snail orchid or limestone snail orchid, is a species of greenhood orchid endemic to south-western Australia.[2][3][4]
| Pterostylis angulata | |
|---|---|
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Orchidaceae |
| Subfamily: | Orchidoideae |
| Tribe: | Cranichideae |
| Genus: | Pterostylis |
| Species: | P. angulata
|
| Binomial name | |
| Pterostylis angulata | |
| Synonyms[1] | |
| |
Description
editPterostylis angulata is a herbaceous terrestrial orchid with a basal rosette of 4-7 ovate leaves, dark blue-green in colour, each measuring 5–20 mm (0.20–0.79 in) long and 3–12 mm (0.12–0.47 in) wide. This rosette is present on both flowering and non-flowering plants. When flowering, this species produces a single flower on a stalk measuring 70–180 mm (2.8–7.1 in) tall with 3-5 stem leaves. The flowers are a translucent white with green stripes and markings, 17–22 mm (0.67–0.87 in) long. Flowering occurs from August to September.[2][3][4]
Taxonomy and naming
editDiplodium angulatum was first formally described in 2017 by David L. Jones and Christopher J. French in the Australian Orchid Review, based on a type specimen collected in 1994.[5] The specific epithet was derived from the Latin word angulatus, meaning 'angular', in reference to the angular nature of the flowers.[4] In 2018, Jones and French transferred the species to the genus Pterostylis as P. angulata in a later edition of Australian Orchid Review.[6] Prior to its formal description in 2017, informal names used to refer to this species in various publications included Pterostylis aff. nana,[7][3] Pterostylis sp. 'Helena River',[8][2] and Pterostylis sp. 'limestone'.[9]
Distribution and habitat
editPterostylis angulata is restricted to south-western Western Australia, with a somewhat coastal distribution ranging between Perth in the north and Bunbury in the south, reaching as far east as York and Collie. It is common within this range, which includes a number of reserves and national parks, though populations in some locations have declined due to fires and soil disturbance. It can be found in a variety of habitats including woodlands, swamps, and coastal forests and heaths. It tolerates a range of soil conditions, from sandy soils to heavy clay loams.[4][3]
Conservation status
editThis snail orchid is listed as "not threatened" by the Government of Western Australia Department of Biodiversity, Conservation and Attractions.[10]
References
edit- ^ a b "Cryptandra angulata". Australian Plant Census. Retrieved 13 February 2023.
- ^ a b c Brown, Andrew; Dixon, Kingsley; French, Christopher; Brockman, Garry (2013). Field Guide to the Orchids of Western Australia. Simon Nevill Publications. p. 361. ISBN 978-0-9803481-4-9. OCLC 850906217.
- ^ a b c d Hoffman, Noel; Brown, Andrew (2011). Orchids of South-West Australia (3rd ed.). Noel Hoffman. p. 409. ISBN 978-0-646-56232-2. OCLC 747426309.
- ^ a b c d Jones, David L.; French, Christopher J. (2017). "New species in the Diplodium nanum (R.Br.) D.L.Jones & M.A.Clem. complex (Orchidaceae) from Western Australia – 5". Australian Orchid Review. 82 (4): 42–44. ISSN 0045-0782 – via Biodiversity Heritage Library.
- ^ "Diplodium angulatum". APNI. Retrieved 14 February 2023.
- ^ Jones, David L.; French, Christopher J. (2018). "New Combinations in the Pterostylidinae". Australian Orchid Review. 83 (4): 55. ISSN 0045-0782 – via Biodiversity Heritage Library.
- ^ "Pterostylis aff. nana". APNI. Retrieved 14 February 2023.
- ^ "Pterostylis sp. 'Helena River'". APNI. Retrieved 14 February 2023.
- ^ "Pterostylis sp. 'limestone'". APNI. Retrieved 14 February 2023.
- ^ "Pterostylis angulata". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.