Pterostylis ventricosa - 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 ventricosa

Conservation status in NSW: Critically Endangered

Commonwealth status: Not listed

Gazetted date: 08 Jul 2011

Profile last updated: 25 Oct 2022

Description

Pterostylis ventricosa is a perennial terrestrial orchid. The 8-30 cm tall flowering stem emerges from an underground tuber and produces 1 to 6 flowers at the top each year. The flowers are between 10-13 mm long and 4.5-5.5 mm wide. They are quite bulbous and greener at the base merging to bright red-brown at the flower tips. A leaf rosette of 4 to 9, 3-12 mm long, dark green leaves emerges around the same time as the flowering stem.

Distribution

Pterostylis ventricosa is known from populations at St Georges Basin, Sussex Inlet and west of Nowra in the Shoalhaven and also near Tallong and Mittagong in the Southern Highlands. Surveys carried out at various times between 2007 to 2010 estimate a total population of about 1,200 plants. The two largest populations, one at St Georges Basin and one at Sussex Inlet, are located on estates of private land. Two smaller populations, comprising a total of less than 10% of the known plants, are within Conjola National Park.

Habitat and ecology

Predominantly in more open areas of tall coastal eucalypt forest often dominated by one or more of the following tree species:- Terpentine, Spotted Gum, Grey Ironbark, Blackbutt, White Stringybark, Scribbly Gum and Sydney Peppermint.
Often favours more open areas such as along powerline easements and on road verges where the tree overstorey has been removed or thinned.
Grows in a range of groundcover types, including moderately dense low heath, open sedges and grasses, leaf litter, and mosses on outcropping rock. Small moss gardens are a commonly associated micro-habitat feature in most habitats.
Soil type ranges from moisture-retentive grey silty loams to grey sandy loams.
Sometimes found in skeletal soils on sandstone rock shelves.

Regional distribution and habitat

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

Sydney Basin

Threats

Urban development threatens several populations, including the two larger populations which are located on two separate private properties.
Powerline easement maintenance work is a potential threat to one of the small populations in Conjola National Park.
Road maintenance or road upgrading are potential threats to those populations which extend onto road verges.
The two largest populations occur on private properties and apart from the threat of proposed urban development, the survival of the species on these sites is also under threat from other possible future land uses that are unfavourable to the species.
Insufficient understanding of species’ phylogeny
At risk from catastrophic events because of small number of extant populations and low number of plants.

Recovery strategies

A targeted strategy for managing this species has been developed under the Saving Our Species program; click here for details. For more information on the Saving Our Species program click here

Activities to assist this species

Consent authorities should require any approved urban or other development to avoid any direct and indirect impacts on P. ventricosa populations.
Landholders with this species on their properties should be advised of its presence and encouraged to assist in the species' protection.
The electricity authority responsible for the maintenace of the powerline easment through Conjola National Park should be made aware of the presence of the species and any necessary works be undertaken to minimise adverse impacts on P. ventricosa.
All populations should be inspected at least every two years in order to detect any potential threats and then initiate action to control such threats.

IBRA Bioregion	IBRA Subregion	Known or predicted	Geographic restrictions region

Other State	Jervis Bay Territory	Known	None
Sydney Basin	Burragorang	Known	None
Sydney Basin	Ettrema	Known	None
Sydney Basin	Jervis	Known	None
Sydney Basin	Moss Vale	Known	None