''Pterostylis silvicultrix'', commonly known as the Chatham Island greenhood or tutukiwi, is a species of orchid which is endemic to Chatham Island and nearby islands. Non-flowering plants have a rosette of leaves but flowering plants have leaves on the flowering stem, some of which reach above the single translucent white flower with dark green stripes. It is similar to ''

Pterostylis banksii ''Pterostylis banksii'', commonly known as greenhood or tutukiwi, is a species of orchid endemic to New Zealand. Non-flowering plants have a rosette of leaves. Flowering plants have leaves on the flowering stem, some of which reach above th ...

'' which occurs on both of the main islands of New Zealand but that species lacks the orange or reddish-brown tips on the flowers of this species.

Description

''Pterostylis silvicultrix'' 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 often grows in colonies. Non-flowering plants have light green, elliptic to lance-shaped leaves which are long and wide on a stem tall. Flowering plants have between three and six leaves long, wide with their bases wrapped around the flowering stem. A single erect, translucent white flower with dark green stripes and a reddish-brown tip is borne on a flowering stem tall. The flower is long. 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 long, wide, slightly longer than the petals and tapered towards the tip. The lateral sepals are erect, there is a wide gap between them and the galea and they are joined at the base to close off part of the front of the flower. The lateral sepals taper suddenly to narrow tips and there is a broad, sloping, V-shaped sinus between them. The labellum is erect and green and protrudes through the sinus. Flowering occurs in November and December.

Taxonomy and naming

This greenhood was first formally described in 1864 by

Ferdinand von Mueller Baron Sir Ferdinand Jacob Heinrich von Mueller, (german: Müller; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist. He was appointed government botanist for the then colony of Vict ...

who gave it the name ''Pterostylis banksii'' var. ''silvicultrix'' and published the description in ''The Vegetation of the Chatham-Islands''. In 2002, Brian Molloy, David Jones and Mark Clements raised the variety to species status.

Distribution and habitat

''Pterostylis silvicultrix'' is widespread in forests, near streams, bogs and wetland margins, often growing on the trunks of tree ferns. It is found on Chatham,

Pitt Pitt most commonly refers to: *The University of Pittsburgh, commonly known as Pitt, a university located in Pittsburgh, Pennsylvania, United States **Pitt Panthers, the athletic teams of the University of Pittsburgh * Pitt (surname), a surname o ...

, Mangere and

South East Island Hokorereoro, Rangatira, or South East Island is the third largest island in the Chatham Islands archipelago, and covers an area of . It lies east of New Zealand, New Zealand's South Island off the south-east coast of Pitt Island, south-east of ...

References

{{Taxonbar, from=Q15493449 silvicultrix Orchids of New Zealand Flora of the Chatham Islands Plants described in 1864