''Pterostylis paludosa'', commonly known as swamp greenhood, is a species of greenhood orchid endemic to New Zealand. As with similar orchids, plants in flower differ from those that are not. Those not in flower have a rosette of leaves on a short stalk but plants in flower lack a rosette and have a single flower with leaves on the flowering spike. This greenhood has a translucent white flower with pale to yellowish-green stripes.

Description

''Pterostylis paludosa'' 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. When not in flower, plants have a stalked rosette of two to four, linear to lance-shaped, pale to yellowish-green leaves that are long and wide. Plants in flower lack a rosette but have a single flower long and wide on a flowering stem tall. There are three or four linear to lance-shaped, grass-like leaves that are long and wide on the flowering stem. The flower is translucent white with pale to yellowish-green stripes. 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 galea is inflated near its base then suddenly narrows to a pointed tip with the dorsal sepal slightly longer than the petals. The lateral sepals are erect, in close contact with the galea and taper to narrow tips long, only slightly higher than the galea. The sinus between the lateral sepals bulges slightly and has a small V-shaped notch in the centre. The labellum is dark green, erect near its base then suddenly curves and protrudes above the sinus. Flowering occurs from September to January.

Taxonomy and naming

''Pterostylis paludosa'' was first formally described in 1997 by David Jones, Brian Molloy and Mark Clements from a specimen collected between the Greymouth suburbs of Taylorville and Cobden. The description was published in ''The Orchadian''. 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 ...

(''paludosa'') is a Latin word meaning "boggy" or "marshy".

Distribution and habitat

This swamp greenhood grows in sunny places in peat bogs and heath. It is found on the

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

between the Great Barrier Island and Waiouru. On the

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

it is mainly found on the west coast between Nelson and Westport. It also grows on Chatham Island.

Conservation

''Pterostylis paludosa'' is classed as "at risk – declining". The main threats are wetland drainage and changed fire regimes.

References

{{Taxonbar, from=Q15500588 paludosa Orchids of New Zealand Plants described in 1997