Pterostylis dubia

Pterostylis dubia, commonly known as the blue-tongued greenhood, is a plant in the orchid family Orchidaceae and is endemic to Tasmania. It has a rosette of fleshy leaves at its base and a dark green and white flower with narrow petals and a dark blue-green labellum.

Blue-tongued greenhood
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Cranichideae
Genus: Pterostylis
Species:
P. dubia
Binomial name
Pterostylis dubia

Description

Pterostylis dubia, is a terrestrial, perennial, deciduous, herb with an underground tuber. It has a rosette of leaves which are 15–60 mm (0.6–2 in) long, 8–20 mm (0.3–0.8 in) wide and have a stalk. Flowering plant have a single dark green and white flower 20–26 mm (0.8–1 in) long and 9–12 mm (0.4–0.5 in) wide is borne on a flowering stem 80–200 mm (3–8 in) tall with stalkless stem leaves. The dorsal sepal and petals are joined, forming a hood called the "galea" over the column. The petals are not flared and are similar in length to the dorsal sepal which ends in a point. There is a wide gap at each side of the flower between the galea and the lateral sepals. The lateral sepals are erect and have a tapering tip, 14–22 mm (0.6–0.9 in) long, only slightly taller than the galea and there is a notch in the bulging sinus between them. The labellum is 13–17 mm (0.5–0.7 in) long, about 3 mm (0.1 in) wide, dark bluish-green, curved and protrudes prominently above the sinus. Flowering occurs from November to January.[2][3]

Taxonomy and naming

Pterostylis dubia was first formally described in 1810 by Robert Brown and the description was published in Prodromus Florae Novae Hollandiae et Insulae Van Diemen.[1][4] The specific epithet (dubia) is a Latin word meaning "wavering", "uncertain" or "doubtful".[5]

Distribution and habitat

The blue-tongued greenhood grows in wet forest at altitudes above 500 m (1,600 ft) in central and southern Tasmania.[2][3]

References
  1. "Pterostylis dubia". APNI. Retrieved 26 June 2017.
  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. 307. ISBN 978-1877069123.
  3. Jones, David L. (1998). "Contributions to Tasmanian Orchidology (7)". Australian Orchid Research. 3: 142.
  4. Brown, Robert (1810). Prodromus florae Novae Hollandiae. London. p. 327. Retrieved 26 June 2017.
  5. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 277.
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