''Pterostylis alpina'', commonly known as the mountain greenhood, is a species of orchid endemic to south-eastern

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. It has a rosette of fleshy leaves at the base and usually only one white flower with green markings and back-swept lateral sepals.

Description

''Pterostylis alpina'' is a terrestrial, perennial, deciduous,

herb In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...

with an underground tuber and a rosette of three to five leaves surrounding the base of the flowering stem. Each leaf is egg-shaped to elliptic, 30–60 mm long and 15–30 mm wide. A single white flower with dark green marks and 25–30 mm long and 9–12 mm wide is borne on a spike 120–300 mm high. The dorsal sepal and

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s are fused, forming a hood or "galea" over the

column A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. ...

. The dorsal sepal curves forward with a pointed tip. There is a wide gap between the galea and the lateral sepals. The lateral sepals are swept back, have thread-like tips 13–18 mm long and a bulging sinus between them. The labellum is 12–14 mm long, about 3 mm wide, dark green to brown, blunt, and curved and protrudes above the sinus. Flowering occurs from August to October.

Taxonomy and naming

''Pterostylis alpina'' was first formally described in 1915 by

Richard Rogers Richard George Rogers, Baron Rogers of Riverside (23 July 1933 – 18 December 2021) was a British architect noted for his modernist and Functionalism (architecture), functionalist designs in high-tech architecture. He was a senior partner a ...

and the description was published in '' Proceedings of the Royal Society of Victoria''. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

(''alpina'') is a Latin word meaning "of high mountains".

Distribution and habitat

The mountain greenhood is widespread in northern and eastern Victoria but is restricted to the Batlow region in New South Wales. It grows in high rainfall forests on the ranges, often on south-facing slopes.

Conservation

''Pterostylis alpina'' is classed as "Vulnerable" in New South Wales under the ''

Threatened Species Conservation Act 1995 The ''Threatened Species Conservation Act 1995 (TSC Act)'' was enacted by the Parliament of New South Wales in 1995 to protect threatened species, populations and ecological communities in NSW. In 2016 it was replaced by the '' Biodiversity Co ...

''.

References

{{Taxonbar, from=Q7256917 alpina Endemic orchids of Australia Orchids of New South Wales Orchids of Victoria (Australia) Plants described in 1915