Pterostylis vittata explained

Pterostylis vittata, commonly known as the banded greenhood or green-banded greenhood, is a plant in the orchid family Orchidaceae and is endemic to the south-west of Western Australia. The plants either have a rosette of leaves on a short stalk in the years when not flowering or stem leaves on a flowering spike. When flowering, it has up to about twenty five flowers which are translucent green with darker green stripes. It was formerly thought to occur in South Australia and Victoria but those collections are now thought to be of Pterostylis sanguinea.

Description

Pterostylis vittata, is a terrestrial, perennial, deciduous, herb with an underground tuber. Non-flowering plants have a rosette of between three and seven leaves, each leaf NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide, the rosette on a stalk NaNsigfig=1NaNsigfig=1 long. When flowering, there are up to twenty five transparent green flowers with darker green bands borne on a flowering spike NaNsigfig=1NaNsigfig=1 high. The flowering spike has between three and fourteen stem leaves which are NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. The flowers are NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide. The dorsal sepal and petals form a hood or "galea" over the column. The lateral sepals turn downwards, are NaNsigfig=2NaNsigfig=2 long, NaNsigfig=1NaNsigfig=1 wide and joined at their bases. The labellum is green, hairy and insect-like, about 4sigfig=1NaNsigfig=1 long and 3sigfig=1NaNsigfig=1 wide and flicks upwards when touched. Flowering occurs from May to September.[1] [2] [3] [4]

Taxonomy and naming

Pterostylis vittata was first formally described in 1840 by John Lindley and the description was published in A Sketch of the Vegetation of the Swan River Colony.[5] The specific epithet (vittata) is a Latin word meaning "striped" or "banded",[6] referring to the striped galea.

Distribution and habitat

The banded greenhood occurs to the south of Perth and as far east as Balladonia, growing in forest, woodland and heath, although more often on granite outcrops in the east of its range. It was previously thought to occur in South Australia, Victoria and Tasmania, but those collections are now thought to be of P. sanguinea.[7] [8]

Conservation

Pterostylis vittata is classified as "not threatened" by the Government of Western Australia Department of Parks and Wildlife.

Notes and References

  1. Book: Brown. Andrew. Dundas. Pat. Dixon. Kingsley. Hopper. Stephen. Orchids of Western Australia. 2008. University of Western Australia Press. Crawley, Western Australia. 9780980296457. 387.
  2. Book: Jones. David L.. A complete guide to native orchids of Australia including the island territories. 2006. New Holland. Frenchs Forest, N.S.W.. 978-1877069123. 339.
  3. Book: Hoffman. Noel. Brown. Andrew. Orchids of South-West Australia. 2011. Noel Hoffman. Gooseberry Hill. 9780646562322. 426. 3rd.
  4. Web site: Archer. William. Banded greenhood - Pterostylis vittata. Esperance Wildflowers. 31 May 2017. 2008-07-24.
  5. Web site: Pterostylis vittata. APNI. 31 May 2017.
  6. Book: Brown. Roland Wilbur. The Composition of Scientific Words. 1956. Smithsonian Institution Press. Washington, D.C.page =660.
  7. Jones. David L.. Contributions to Tasmanian Orchidology. Australian Orchid Research. 1998. 3. 151.
  8. Web site: Pterostylis vittata. Royal Botanic Garden Melbourne; vicflora. 31 May 2017.