Pterostylis elegans (a terrestrial orchid) - vulnerable species listing

NSW Scientific Committee - final determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the terrestrial orchidPterostylis elegansD.L. Jones, as a VULNERABLE SPECIES in Schedule 2 of the Act. Listing of vulnerable species is provided for by Part 2 of the Act.

The Scientific Committee has found that:

1. Pterostylis elegans (Orchidaceae) has been described by Jones (1997) (The Orchadian, Vol. 12, No. 6, pp. 247-248) as: sterile and fertile plants dimorphic. Rosette separate; leaves 2-4; lamina ovate, 10-20 mm long, 8-13 mm wide, bright green; margins entire; apex subacute; petioles 4-10 mm long. Scape 15-28 cm tall, slender, smooth; stem leaves 4 or 5, obliquely erect, narrowly ovate-lanceolate, 8-25 mm long, 3-4.5 mm wide; margins entire; apex acuminate. Ovary 9-12 mm long, green, smooth. Flower solitary, 14-18 mm long, 6-8 mm wide, erect, translucent white with dark green suffusions and stripes, reddish brown towards the apex of the galea and petals. Dorsal sepal 25-30 mm long, 8-10 mm wide, prominently inflated at the base then tapered; filiform point 4-8 mm long. Lateral sepals erect, tightly embracing the galea; sinus protruding in a shallow bulge when viewed from the side, from the front sloping inwards at a shallow angle, deeply notched medially, folded internally; conjoined part 8-11 mm long, 8-9 mm wide, narrowed to c. 2 mm across at the base; upper margins inrolled, gradually tapered into the free points; free points 14-18 mm long, filiform, erect or slightly recurved, held high above the galea. Petals obliquely oblong-lanceolate, 20-25 mm long, 4-5 mm wide, slightly dilated distally; margins entire or slightly irregular; apex acute; flange deltate, c. 1 mm wide, broadly obtuse. Labellum erect, sharply curved forwards in the distal third, mostly dark red-brown to blackish brown, greenish towards the base, distal half protruding prominently from the sinus in the set position; claw c. 1.5 mm long, c. 1.2 mm wide; lamina narrowly oblong to narrowly oblong-lanceolate, 8-11 mm long, 2-2.5 mm wide, slightly constricted in the distal half; apex obtuse; basal apendage linear, 2-3 mm long, curved at right angles near the middle; apex pencillate. Callus c. 0.6 mm across, raised, expanding to c. 0.8 mm across near the apex, dark reddish brown throughout. Column 10-14 mm long, curved away from the ovary at c. 70o at the base, then erect, reddish brown; wings 4.5-5 mm long; basal lobe c. 2.2 mm long, c. 1.2 mm wide, brown, at an angle of c. 30o; inner margins incurved, adorned with short white cilia; apex obtuse; mid-section c. 2.3 mm long, dark brown; apical lobe linear, c. 0.5 mm long, obtuse. Anther c. 1 mm long, obtuse. Pollinia linear, c. 1 mm long, yellow, mealy. Stigma elliptic, c. 2.6 mm long, c. 1.2 mm wide, situated centrally on the column. Capsules obovoid, 12-16 mm long, 3-4 mm wide, greenish.

2. The species is endemic to New South Wales, and is known to occur on red-brown loams at elevations between 950 m and 1200 m. It is found among grass and shrubs in tall open forest and flowers between January and April.

3. It is known from eight locations, with a restricted distribution from the Barrington Tops to the Walcha district. Four of these locations are within conservation reserves.

4. The species occurs in small numbers at each of the known locations.

5. The species is threatened by weed invasion, feral pigs and cattle grazing. There are further possible threats at some locations by disturbance from forestry and recreational activities.

In view of the above the Scientific Committee is of the opinion thatPterostylis elegans D.L. Jones is likely to become endangered in nature unless the circumstances and factors threatening its survival or evolutionary development cease to operate.

Proposed Gazettal date: 06/12/02

Exhibition period: 06/12/02 - 24/01/03

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Page last updated: 28 February 2011