The New Zealand Plant Conservation Network

Species

Pterostylis alobula

Etymology

Pterostylis: winged column

Common Name(s)

greenhood

Current Conservation Status

2012 - Not Threatened

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 - Not Threatened
2004 - Not Threatened

Authority

Pterostylis alobula (Hatch) L.B.Moore

Family

Orchidaceae

Flora Category

Vascular - Native

NVS Species Code

DIPALO

Structural Class

Orchids

Synonyms

Pterostylis trullifolia var. alobula Hatch; Pterostylis crypta Nicholls Diplodium alobulum (Hatch) D.L.Jones, Molloy et M.A.Clem.

Distribution

Endemic. New Zealand: Three Kings, Poor Knights, North, South and Chatham Islands. In the South Island found in the east as far south as South Canterbury and the lower Waitaki Valley, and in the west as far south as Cape Foulwind.

Habitat

Coastal to montane (up to 1100 m a.s.l.). Usually on the forest floor in sparse leaf litter, open clay pans under scrub or amongst mosses in semi-shaded successional forest. Occasional invades rough pasture and lawns bordering forest remnants. Often growing with Pterostylis trullifolia

Features

Terrestrial, colony forming, perennial herb. Plants at flowering up to 150 mm tall. Stem green or reddish-green, slender, terete, smooth; internodes rarely > leaves. Petiolate leaves in separate loose rosette or more or less loosely spaced up the lower part of flowering stem; petiole up to 10 mm long, initially distinct soon merging into leaf lamina on lower cauline leaves; leaf lamina 5-15 x 4-15 mm, dark green or green, broad-ovate, orbicular-cordate to trowel-shaped, apex acute to subacute, upper leaf surface smooth. Cauline leaves 2-6, mostly all sessile, 5-25 x 3-6 mm, dark green to green, linear to narrow-lanceolate or narrow-elliptic, uppermost slightly overtopping ovary. Flower 1(-2) erect, pale green and white striped. Dorsal sepal 20-25 mm tall, apex acuminate, usually horizontal; lateral sepals diverging at a wide angle to form a V shape when viewed from the front, sinus smoothly rounded and not jugate in side view, tips long-caudate and much overtopping galea. Petals almost as long as dorsal sepal, with the exposed marginal strip of medium width, and often nearly horizontal. Labellum arched and protruding, basal portion lanceolate, gradually tapering to mid-length, then abruptly contracted; margins recurved such that distal third is linear in outline and deeply channelled beneath, apex bluntly truncate. Column shorter than labellum; stigma elliptic, slightly prominent.

Similar Taxa

Most often confused with Pterostylis trullifolia, with which it often grows. From that species it is easily distinguished by the presence of loose rosettes, or their complete absence, and that the rosette leaves have smooth rather than embossed surfaces. The flowers of P. alobula are bigger and usually paler green coloured than P. trullifolia. The lateral sepals when in side view are smooth and rounded, lacking the jugate shape typical of P. alveata, P. brumalis. and P. trullifolia.

Flowering

March to November

Flower Colours

Green,White

Fruiting

May - January

Propagation Technique

Difficult - should not be removed from the wild

Threats

Not Threatened

Chromosome No.

2n = c.50

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

Minute seeds are wind dispersed (Thorsen et al., 2009).

This page last updated on 8 May 2017