| Midget greenhood | |
|---|---|
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| Pterostylis mutica growing near Lake King, Western Australia | |
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Orchidaceae |
| Subfamily: | Orchidoideae |
| Tribe: | Cranichideae |
| Genus: | Pterostylis |
| Species: | P. mutica |
| Binomial name | |
| Pterostylis mutica R.Br. | |
| Synonyms | |
Pterostylis mutica, commonly known as the midget greenhood, is a plant in the orchid family Orchidaceae and is endemic to Australia, occurring in all states but not the Northern Territory. There is a rosette of leaves at the base of the flowering stem and up to fifteen pale green flowers which have a sensitive labellum.
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Description
Pterostylis mutica, is a terrestrial, perennial, deciduous, herb with an underground tuber. There is a rosette of between six and twelve, egg-shaped leaves, each leaf 10–30 mm (0.4–1 in) long and 5–15 mm (0.2–0.6 in) wide at the base of the plant. Between two and twenty well-spaced flowers are borne on a flowering spike 150–350 mm (6–10 in) high with five to ten stem leaves wrapped around it. The flowers are pale green, 8–10 mm (0.3–0.4 in) long and about 5 mm (0.2 in) wide. The dorsal sepal and petals are joined to form a hood called the "galea" over the column. The galea is curved with a pointed tip turning downwards. The lateral sepals turn downwards and are about 7 mm (0.3 in) long, 8 mm (0.3 in) wide, cupped and joined for most of their length. The labellum is about 4 mm (0.2 in) long, about 2 mm (0.08 in) wide and whitish-green with a dark green appendage. Flowering occurs from July to December.
Taxonomy and naming
Pterostylis mutica was first formally described in 1810 by Robert Brown from a specimen collected near Port Jackson and the description was published in Prodromus Florae Novae Hollandiae et Insulae Van Diemen. The specific epithet (mutica) is a Latin word meaning "shortened" or "docked" referring to the blunt petals and sepals.
Distribution and habitat
Pterostylis mutica is widespread and often common, growing in a wide range of habitats from near the coast to mountains, but usually in well-drained soil. It tolerates dry conditions, poor soil and exposed positions. It is widespread in New South Wales and Victoria and also occurs in south-east Queensland, south-eastern South Australia and the south-west of Western Australia. There is doubt about its presence in Tasmania
Ecology
The labellum of P. mutica is attractive to a species of gnat which lands on the labellum and grasps the dark green appendage. When it does so, the labellum springs upward, trapping the insect inside the now-closed flower. The gnat can now only escape by pushing between "wings" on the sides of the column. As it does so, it either removes a pollinium or deposits one from a previously visited flower of the same species, and pollination occurs.
References
- ^ "Pterostylis mutica". APNI. Retrieved 21 May 2017.
- ^ Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. p. 321. ISBN 978-1877069123.
- ^ Jeanes, Jeff. "Pterostylis mutica". Royal Botanic Gardens Victoria: vicflora. Retrieved 13 May 2017.
- ^ Jones, David L. "Pterostylis mutica". Royal Botanic Gardens Sydney: plantnet. Retrieved 21 May 2017.
- "Pterostylis mutica". State Herbarium of South Australia: eflora SA. Retrieved 21 May 2017.
- ^ Brown, Andrew; Dundas, Pat; Dixon, Kingsley; Hopper, Stephen (2008). Orchids of Western Australia. Crawley, Western Australia: University of Western Australia Press. p. 374. ISBN 9780980296457.
- ^ Hoffman, Noel; Brown, Andrew (2011). Orchids of South-West Australia (3rd ed.). Gooseberry Hill: Noel Hoffman. p. 418. ISBN 9780646562322.
- Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 428.
- "Pterostylis mutica". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.
- Jones, David L. (1998). "A taxonomic review of Pterostylis in Tasmania". Australian Orchid Research. 3: 146–147.
- Cingel, Nelis A. van der (2000). An atlas of orchid pollination : America, Africa, Asia and Australia. Rotterdam: Balkema. p. 210. ISBN 978-9054104865.