''Pterostylis venosa'', commonly known as a greenhood, is a species of orchid endemic to New Zealand and which usually grows in colonies. Both flowering and non-flowering plants have a rosette of erect to spreading leaves, and flowering plants have a single yellowish-green to dark green flower with white stripes. It is similar to '' P. humilis''.

Description

''Pterostylis venosa'' 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 which usually grows in colonies of three or more plants. It has a loose rosette of between two and four erect to spreading leaves at the base and which in flowering plants are about the same height as the flowering stem. The leaves are a broad oval shape, long and wide. Flowering plants have a single yellowish-green to dark green flower with white stripes on a flowering stem tall. 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 is more or less erect near its base then curves forward to the horizontal, the petals about the same length as the dorsal sepal. There is a wide gap between the lateral sepals and the galea and the lateral sepals which are erect, spread slightly apart from each other and no higher than the galea. There is a broad V-shaped sinus between the lateral sepals. The labellum has a furry upper surface and is curved, protruding above the sinus. Flowering occurs between October and February.

Taxonomy and naming

''Pterostylis venosa'' was first formally described in 1895 by

William Colenso William Colenso (17 November 1811 – 10 February 1899) FRS was a Cornish Christian missionary to New Zealand, and also a printer, botanist, explorer and politician. He attended the signing of the Treaty of Waitangi and later wrote an accou ...

from a specimen collected on the east side of the

Ruahine Range The Ruahine Range is the largest of several mountain ranges in the North Island of New Zealand that form a ridge running parallel with the east coast of the island between East Cape and Wellington. The ridge is at its most pronounced from the cen ...

. The description was published in '' Transactions and Proceedings of the New Zealand Institute''. 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 ...

(''venosa'') is a Latin word meaning "veiny".

Distribution and habitat

This greenhood mostly grows in montane ecosystems, usually in '' Nothofagus'' forest, often in deep leaf litter or moss beds. It is found on the North,

South South is one of the cardinal directions or Points of the compass, compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Pro ...

and

Stewart Island Stewart Island ( mi, Rakiura, ' glowing skies', officially Stewart Island / Rakiura) is New Zealand's third-largest island, located south of the South Island, across the Foveaux Strait. It is a roughly triangular island with a total land ar ...

References

{{Taxonbar, from=Q15492127 venosa Orchids of New Zealand Plants described in 1895