Pterostylis uliginosa

Marsh greenhood
Scientific classification
Kingdom: Plantae
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Genus: Pterostylis
Species: P. uliginosa
Binomial name
Pterostylis uliginosa
D.L.Jones[1]
Synonyms[2]

Speculantha uliginosa (D.L.Jones) D.L.Jones & M.A.Clem.

Pterostylis uliginosa, commonly known as the marsh greenhood, is a species of orchid endemic to south-eastern Australia. As with similar orchids, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves but the flowering plants lack a rosette at the base but have up to three rosettes on lateral growths and up to seven small green and white flowers. This species only grows in wet places, usually where there is free water. There are usually only two or three flowers per plant, and only one or two are open at a time.

Description

Pterostylis uliginosa is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of three to eight egg-shaped to elliptic, dark green leaves which lie flat on the ground. Each leaf is 5–16 mm (0.2–0.6 in) long and 4–9 mm (0.2–0.4 in) wide. Flowering plants have up to seven bright green and white-striped flowers 6–8 mm (0.2–0.3 in) long and 2–3 mm (0.08–0.1 in) wide, although the usual number is two or three and only one or two are open at a time. The flowers are borne on a fleshy flowering stem 60–150 mm (2–6 in) high. Up to three leaf rosettes are arranged on the side of the flowering spike. The dorsal sepal and petals are fused, forming a hood or "galea" over the column. The dorsal sepal curves forward and has a short point. The lateral sepals are erect and partly close off the front of the flower with thread-like tips about 2 mm (0.08 in) long that do not project above the galea. The sinus between the bases of the lateral sepals bulges forward and has a small notch in the centre. The labellum is 3–4 mm (0.1–0.2 in) long and 1–2 mm (0.04–0.08 in) and not visible outside the intact flower. Flowering occurs from November to March.[3] [4]

Taxonomy and naming

Pterostylis uliginosa was first formally described in 1998 by David Jones and the description was published in Australian Orchid Research.[1] The specific epithet (uliginosa) is a Latin word meaning "full of moisture", "wet" or "marshy",[5] referring to the habitat preference of this species.[4]

Distribution and habitat

The marsh greenhood grows in wet places such as swamps and marshes, with other small plants. It is widely, but disjunctly distributed in Queensland, New South Wales, Victoria, South Australia and Tasmania.[3][4][6]

References

  1. 1 2 "Pterostylis uliginosa". APNI. Retrieved 22 July 2017.
  2. ↑ "Pterostylis uliginosa". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  3. 1 2 Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. p. 311. ISBN 1877069124.
  4. 1 2 3 Jones, David L. (1998). "Contributions to Tasmanian Orchidology". Australian Orchd Research. 3: 155–156.
  5. ↑ Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 854.
  6. ↑ "Pterostylis uliginosa". Royal Botanic Garden Sydney; plantnet. Retrieved 22 July 2017.
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