Pterostylis despectans - profile

Indicative distribution


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Key:
known
predicted
The areas shown in pink and/purple are the sub-regions where the species or community is known or predicted to occur. They may not occur thoughout the sub-region but may be restricted to certain areas. ( click here to see geographic restrictions). The information presented in this map is only indicative and may contain errors and omissions.
Scientific name: Pterostylis despectans
Conservation status in NSW: Critically Endangered
Commonwealth status: Endangered
Gazetted date: 28 Mar 2008
Profile last updated: 17 Aug 2018

Description

Pterostylis despectans is a terrestrial herb with flowering stems 30-80 mm tall, 6-10 basal leaves in a rosette, and 3 or 4 stem-sheathing bract-like leaves above, the rosette leaves are 10-20 mm long and 6-9 mm wide. There are 1-6 flowers, usually with up to 4 open at a time, on slender pedicels up to 15 mm long spreading widely from the stalk. Flowering occurs in October and November. Pterostylis despectans is not easily confused with other orchid species, being characterised by the flower colours, a short flower stem, long spreading pedicels, sepal points often resting on the soil, and a labellum with two prominent basal bristles.

Distribution

In New South Wales the species is known only from a single population discovered in 2005 near Moama in the Riverina district. The site is within the Murray Local Government Area. Several surveys of Riverina grassland and regional Travelling Stock Reserves did not record P. despectans and it seems likely that the species is extremely rare in New South Wales. The species also occurs as very small fragmented populations in central Victoria and in South Australia. The total estimated number of individuals in the Victorian and South Australian populations is less than 1500. The Moama population has been assessed as comprising between 20 and 60 individual plants. All plants known to date occur within an area of about one hectare, within an apparently suitable habitat patch-size of about 20 ha. Pterostylis despectans is not known to occur in any NSW conservation reserves.

Habitat and ecology

  • The plant remains dormant underground as a tuber in late summer into early winter. In winter it develops a rosette of six to ten leaves. The flower stem is produced between late October and December and the leaves shrivel up by the time the flowers mature. Like most Australian terrestrial orchids the species is believed to be partly or fully dependent on a mycorrhizal symbiont.
  • The New South Wales population occurs in natural forb-rich grassland on flat alluvial plains and not derived from Acacia pendula woodland. The only tree species recorded as present at the site is Allocasuarina luehmannii.
  • The soil is a reddish, probably calcareous, clay loam.
  • The community is described as occurring on plains of Quaternary alluvial sediments with an annual rainfall of 405-465 mm.

Regional distribution and habitat

Click on a region below to view detailed distribution, habitat and vegetation information.


Threats

Recovery strategies

Activities to assist this species

Information sources

IBRA Bioregion IBRA Subregion Known or predicted Geographic restrictions region
Other StateSA Known None
RiverinaMurray Fans Known None