The New Zealand Plant Conservation Network

Species

Pterostylis silvicultrix

Etymology

Pterostylis: winged column

Common Name(s)

tutukiwi, Chatham Island greenhood

Current Conservation Status

2012 - At Risk - Naturally Uncommon

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - At Risk - Naturally Uncommon
2004 - Range Restricted

Qualifiers

2012 - IE
2009 - IE

Authority

Pterostylis silvicultrix (F.Muell.) Molloy, D.L.Jones et M.A.Clem.

Family

Orchidaceae

Flora Category

Vascular - Native

NVS Species Code

PTESIL

Structural Class

Orchids

Synonyms

Pterostylis banksii var. silvicultrix F.Muell.

Distribution

Endemic to the Chatham Islands where it present on Chatham (Rekohu) Pitt, Mangere and South East Islands.

Habitat

A widespread species of forests, restiad bog and stream, lake, pond and other wetland margins. Often found as a low epiphyte on tree fern trunks.

Features

Terrestrial tuberous orchid growing in colonies, sometimes found as a low epiphyte perching on the bases of tree fern trunks. Plants dimorphic, sterile plants 20-150 mm tall; leaves 30-80 x 10-20 mm, light green, elliptical to elliptical-lanceolate, margins entire or rarely minutely sinuate; flowering plants with 3-6 cauline leaves obliquely erect to spreading; lamina 40-150 x 0.6-22 mm, elliptical to elliptical-ovate to lanceolate, sessile, sheathing at base; margfins entire; apex acute to acuminate. Pedicel 5-30 mm long, stout. Ovary 10-15 mm long, asymmetric, ribbed. Flower solitary, 18-25 mm long, erect, translucent white and green with red brown suffusions toward the tips of the galea and lateral sepals; galea erect and gibbous at base, then curving forwards to the apex; dorsal sepal slightly longer than the petals, 20-25 x 10-16 mm ovate-lanceolate, expanded in proximal third then narrowed and tapered to the acute apex.Lateral sepals erect, loosely embracing the galea leaving a narrow lateral gap to the petal margins, upper part of sinus curved when viewed from the side, sloping to a broad V when viewed from the front; conjoined part 10-15 mm long, 8-10 mm at the tope, narrowed to 3 mm wide at the base, the margins inrolled, tapered towards the free points; free points 8-10 mm long curved forwards, tips equal to or protruding slightly above the galea (often curled forward). Petals 25-30 x 4-6 mm, obliquely oblong-lanceolate, falcate, acute, green with a narrow white central area towards the base, the apex reddish-brown; flange vestigial. Labellum erect, curved forward distally,the apex prominent through the sinus in the set position; labellum hinge ligulate 3 x 1 mm; lamina 12-14 mm, green narrow-obovate, callus 0.5-0.7 mm reddish green, raised; appendange 2 mm, decruved, apex penicillate. Column 15 mm, green and white, column foot 4 mm, wings 7 mm; basal lobes 3 x 1 mm, apex obtuse,inner margins incruved, sparsely ciliate; mid-section 3 mm, green; apical lobe 1 mm. Stigma 5 x 1.5-2 mm, elliptic scutiform, medial on the column to edges, raised. Rostellum 0.5 mm diameter, brownish, below anther and high up above stigma and connected to it by a narrow groove. Capsule 25-30 x 6-8 mm, initially green to brown, narrowly obovoid, peduncle up to 50 mm long.

Similar Taxa

Distinguished from other indigenous Pterostylis R.Br. species by the relatively short, broad, suberect to erect, ovate to lanceolate leaves, the upper most overtopping the solitary green and white striped flower whose sepals and petals are characteristically orange-tipped. The lateral sepals are distinctive in that they curl forward while the dorsal sepals only just exceed the petals and are often curved upwards. On the Chathams P. silvicultrix has often been confused with P. banksii A.Cunn., which though highly variable is on the Chathams at least, a much smaller plant, whose uppermost leaves overtop the flower, and whose flower is more darkly green-striped, and without any orange colouration.

Flowering

November - December

Flower Colours

Green,White

Fruiting

Late summer

Propagation Technique

Difficult - should not be removed from the wild.

Threats

Although very common in suitable habitat it cannot be denied that forest clearance has decreased the available habitat for this species. Cattle, sheep, pigs and weka browse, trample and - weka especially - uproot the tubers.

Chromosome No.

2n = 44-46

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 31 Oct 2014