Pterostylis gibbosa (R.Br.) Illawarra Greenhood Orchid Recovery Plan

NSW National Parks and Wildlife Service, September 2002
ISBN 0 731 36905 X

4 Description

4.1 Description

Harden (1993) provides the following description of Pterostylis gibbosa in "Flora of New South Wales":

"Terrestrial herb. Rosette leaves 4-7, elliptic to ovate, 1.5-3.5 cm long, 8-15 mm wide, margins entire. Scape to 45 cm high, with 3-6 closely sheathing stem leaves. Flowers 2-7, c.1.5 cm long, bright green with transparent patches in the petals and galea, tips of lateral sepals brownish, shiny, semi-erect. Dorsal sepal with an upcurved filiform point 2-3 mm long. Lateral sepals broad-ovate in outline when flattened; joined part flat, margins strongly reflexed, glabrous, free points filamentous, 3-4 mm wide, brownish black, deeply grooved; marginal trichomes 2-4 pairs, c. 2 mm long, white; basal lobe large, with numerous trichomes c. 0.3 mm long. Flowers Aug - Nov. Grows among grass in sclerophyll forest; rare, chiefly in the southern parts of the CC, with a disjunct population in the Hunter Valley. NC CC. [P. ceriflora Blackmore & Clemesha]" (see Figure 1).

4.2 Taxonomic Significance

Pterostylis is a genus of around 120 species confined to Australia, New Zealand, New Guinea and New Caledonia. The majority of the species are found in Australia, with the main centre of diversity being the south-east of the continent (Jones 1993). The group is easily recognisable, due to the structure of the flower, which gives rise to the common name "greenhoods".

P. gibbosa is closely related to Pterostylis saxicola, being distinguished principally by features of the flower and by habitat.

The species taxonomy is as follows:

Division: Magnoliophyta
Class: Magnoliopsida
Subclass: Liliidae
Order: Orchidales
Family: Orchidaeceae
Genus: Pterostylis
Species: gibbosa
Flowering P. gibbosa plants
Plate 1: Flowering P. gibbosa plants (Photo R. Tunstall)
P. gibbosa flower
Plate 2: P. gibbosa flower (Photo R. Tunstall)
P. gibbosa leaf rosettes
Plate 3: P. gibbosa leaf rosettes (Photo L. Johnston)
Pterostylis gibbosa drawing by A. W. Dockrill
Figure 1: Pterostylis gibbosa drawing by A. W. Dockrill (reproduced from The Orchardian Volume 12, Number 3, March 1997 with the permission of the Editor).