Pterostylis paludosa
Common name
swamp greenhood
Synonyms
Pterostylis furcata var. linearis Hatch
Family
Orchidaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Orchids
Chromosome number
2n = 44
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | At Risk – Declining | Qualifiers: RR
Previous conservation statuses
2009 | At Risk – Declining
2004 | Serious Decline
Distribution
Endemic: North, South and Stewart Islands. In the North Island present from Great Barrier Island to Waiouru. In the South Island confined to the west from north-west Nelson to about Westport.
Habitat
Peat bogs and heathlands, usually in well-lit sites amongst mosses and sedges.
Features
Terrestrial tuberous herb growing in dense colonies. Sterile plants 40-80 mm tall, 2-4-leaved; leaves linear-lanceolate, 25-60 x 7-11 mm, pale green to yellow-green (rarely dark green), margins entire or finely denticulate, apex subacute. Flowering plants 80-900 mm tall.Leaves 3-4, cauline, obliquely erect, pale green to yellowish green; lamina linear-lanceolate, 50-80 x 7-11 mm wide, sessile, sheathing at the base; margins entire or rarely finely denticulate; apex subacute. Pedicel 20-30 mm long, slender. Ovary 9-17 mm long, asymmetric, ribbed. Flower solitary, 18-20 x 5-6 mm, erect, translucent white and pale green to yellow green; galea gibbous at the base then erect before curving forwards in a shallow curve to the apex, the dorsal sepal slightly longer than the petals. Dorsal sepal ovate-lanceolate in outline when flattened, 24-26 x 13-16 mm, prominently expanded in the proximal third then suddenly narrowed and gradually tapered to the acute apex. Lateral sepals erect, tightly embracing the galea, with no lateral gap; upper part of the sinus very shallowly curved when viewed from the side, sloping to a narrow v when viewed from the front, scabrous; conjoined part 9-11 x 6-9 mm wide at the top, narrowed to 4 mm wide at the base, tapered into the free points; free points 9-11 mm long, tapered, erect, the tips extending just above galea. Petals obliquely oblong-lanceolate, 14-20 x 305 mm, falcate, acute, green with a white central area; flange vestigial. Labellum erect, curved suddenly forwards near the apex, raised; basal appendage 2.5-3.0 mm long, decurved, apex penicillate. Column 11.0-13.5 mm long, erect, green and white; column foot 1.5 mm long. Column wings 5.5-7.0 mm long; basal lobe 3.0 x 0.8 mm, at an angle of about 40 degrees, apex obtuse, inner margins incurved, sparsely ciliate; mid-section 2.5 mm long; green; apical lobe linear 1.2 mm long, obtuse. Stigma cordate, 3.0-3.3 x 2.0-2.2 mm, situated just below the column wings, raised. Anther 1.4 mm long, obtuse. Pollinia linear, 2 mm long, yellow, mealy. Capsules narrowly ellipsoid 15-17 x 3.0-3.5 mm, initially yellow green, maturing grey.
Similar taxa
Pterostylis micromega Hook.f. and an unnamed swamp dwelling orchid allied to P. graminea Hook.f., grow with and may be confused with P. paludosa. When flowering P. paludosa and P. micromega are clearly different, but sterile specimens are harder to separate. Basal leaves of P. micromega are distinctly broader, spreading and have undulating margins. The basal leaves of the unnamed orchid allied to P. graminea are much smaller, finer, and grass-like. Flowering specimens are distinctive because the flowers are much smaller, and very conspicuously striped white and dark green.
Flowering
September to January
Flower colours
Green, White
Fruiting
November to March
Propagation technique
Easily grown in a pot partially submerged in water. However, as with all indigenous orchids, this species should not be removed from the wild.
Threats
Habitat loss through wetland drainage, and natural succession to taller vegetation. This species requires frequent disturbance to maintain itself. It is especially abundant following peat fires. The species is also at risk from plant collectors.
Etymology
pterostylis: Winged column
paludosa: Of the swamps
Where To Buy
Not commercially available.
Attribution
Fact Sheet prepared for NZPCN by P.J. de Lange 14 April 2007: Description based on Jones et al. (1997).
References and further reading
Jones, D.L.; Molloy, B.P.J.; Clements, M.A. 1997: Six new species of Pterostylis R.Br. (Orchidaceae) from New Zealand. The Orchadian 12: 266-281.
Citation
Please cite as: de Lange, P.J. (Year at time of access): Pterostylis paludosa Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/pterostylis-paludosa/ (Date website was queried)