Species Profile and Threats Database

For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Vulnerable as Diuris praecox
Listing and Conservation Advices Commonwealth Conservation Advice on Diuris praecox (Newcastle Doubletail) (Threatened Species Scientific Committee, 2008bk) [Conservation Advice].
Recovery Plan Decision Recovery Plan not required, included on the Not Commenced List (1/11/2009).
Adopted/Made Recovery Plans
Policy Statements and Guidelines Draft survey guidelines for Australia's threatened orchids (Department of the Environment, 2013b) [Admin Guideline].
Federal Register of
    Legislative Instruments
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument] as Diuris praecox.
State Government
    Documents and Websites
NSW:Rough Double Tail - profile (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2005cr) [Internet].
State Listing Status
NSW: Listed as Vulnerable (Threatened Species Conservation Act 1995 (New South Wales): December 2013 list) as Diuris praecox
Scientific name Diuris praecox [55086]
Family Orchidaceae:Orchidales:Liliopsida:Magnoliophyta:Plantae
Species author D.L.Jones
Infraspecies author  
Reference Austral. Orchid Res. 2 (1991) 60
Other names Diuris praecox Jones ms. [67284]
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images
Line drawing in Jones (1991) Aust. Orchid Res 2; and plate 26 in Bishop (1996) Field Guide to Orchids

Scientific Name: Diuris praecox

Common Name: Newcastle Doubletail

Other Names: Rough Doubletail

Conventionally accepted as Diuris praecox (CHAH 2010).

The Newcastle Doubletail is a terrestrial orchid with two or three linear leaves. These leaves are 15–35 cm in length, 3–5 mm in width and folded flat together lengthwise. The flowering stem is 20–40 cm in height, with 6–10 flowers. Flowers are 'nodding', yellow in colour with a few dark brown markings at the base of the dorsal sepal (the rear leaf-like part of the flower) and labellum (median petal), and are approximately 2.5 cm in width. The dorsal sepal is narrow to obovate (egg-shaped), 9–11 mm in length, 4.5–6 mm in width and is obliquely erect (erect but at a slight angle). Side sepals are straight to lance-shaped, 12–15 mm in length, 1.5–2 mm in width, and bent sharply downward and parallel. The petals are obliquely erect, widely divergent and curved backwards. The broadest section (lamina) of the petal is narrow-elliptic to ovate in shape, 8–12 mm in length and 5–6 mm in width. The labellum is 9–12 mm in length, with side lobes linear to more or less obovate and 3–4 mm in length and 0.8–1.4 mm in width. The Newcastle Doubletail has a blackish 'claw'; a 4–6 mm long narrow stalk-like structure at the base of the flower (Bishop 1996; Jones 1991b; NSW DECCW 2005cr). The species has been found both as a solitary plant and in clumps (Jones 1991b).

The Newcastle Doubletail occurs between Ourimbah and Nelson Bay on the New South Wales (NSW) north coast (NSW DECCW 2005cr). This species has also been identified on the Wallarah Peninsula, near Lake Macquarie in NSW (Conacher Travers 2006).

The Newcastle Doubletail grows on hills and slopes of near-coastal districts, in open heathy forests which have a grassy to fairly dense understorey (Jones 1991b; NSW DECCW 2005cr).

The species exists as an underground tuber for much of the year, with leaves and flowering stems appearing in winter (Jones 1991b; NSW DECCW 2005cr). Flowers have been recorded from late July to early September (Jones 1991b).

The Newcastle Doubletail is closely related to the Lemon Doubletail (D. abbreviata). However the former differs in that it flowers earlier, occupies a different habitat (coastal and near-coastal heath as opposed to ranges and tablelands for the Lemon Doubletail) and is morphologically distinct; especially the labellum which has a much narrower mid-lobe (elliptical to ovate in shape) and longer lateral lobes (Jones 1991b).

The Newcastle Doubletail is threatened by loss and fragmentation of habitat; especially through clearing for urban development, weed invasion, uncontrolled track expansion and impacts from recreational use within its habitat (NSW DECCW 2005cr).

Commonwealth Conservation Advice

Refer to the Commonwealth Conservation Advice (TSSC 2008bk) for information on research and monitoring priorities and recovery priority actions to mitigate threats including habitat loss, disturbance and modification, weeds and fire. Increasing the level of legislative protection for private and public sites is also encouraged in the Advice.

Management documents for the Newcastle Doubletail can be found at the start of this profile.

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Climate Change and Severe Weather:Sea level rise:Inundation associated with climate change Inundation study (Environmental Resources Information Network, 2007) [Database].
Human Intrusions and Disturbance:Recreational Activities:Disturbance, especially from human recreational activities and development Commonwealth Conservation Advice on Diuris praecox (Newcastle Doubletail) (Threatened Species Scientific Committee, 2008bk) [Conservation Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds Commonwealth Conservation Advice on Diuris praecox (Newcastle Doubletail) (Threatened Species Scientific Committee, 2008bk) [Conservation Advice].
Residential and Commercial Development:Housing and Urban Areas:Habitat loss, modification and fragmentation due to urban development Diuris praecox in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006hn) [Internet].
Transportation and Service Corridors:Roads and Railroads:Development and/or maintenance of roads Commonwealth Conservation Advice on Diuris praecox (Newcastle Doubletail) (Threatened Species Scientific Committee, 2008bk) [Conservation Advice].

Bishop, A. (1996). Field Guide to Orchids of New South Wales and Victoria. Sydney, NSW: University of New South Wales Press.

Conacher Travers Environmental Consultants (Conacher Travers) (2006). Ecological Site Report Coastal and Northern Sectors, Wallarah Peninsula.

Council of Heads of Australasian Herbaria (CHAH) (2010). Australian Plant Census. [Online]. Australian National Herbarium, Australian National Botanic Gardens and Australian Biological Resources Study . Available from:

Jones, D.L. (1991b). New Taxa of Australian Orchidaceae. Australian Orchid Research. 2. Essendon: Australian Orchid Foundation.

NSW Department of Environment, Climate Change and Water (NSW DECCW) (2005cr). Rough Double Tail - profile. [Online]. Available from:

Threatened Species Scientific Committee (2008bk). Commonwealth Conservation Advice on Diuris praecox (Newcastle Doubletail). [Online]. Department of the Environment, Water, Heritage and the Arts. Available from:

EPBC Act email updates can be received via the Communities for Communities newsletter and the EPBC Act newsletter.

This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Diuris praecox in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: Accessed Tue, 2 Sep 2014 11:09:48 +1000.