Tallong Midge Orchid - profile

Scientific name: Genoplesium plumosum 
 Conservation status in NSW: Critically Endangered
National conservation status: Endangered

Description

The Tallong Midge Orchid has flower spikes up to 20 cm tall, with one to eight flowers on each spike. Individual flowers are approximately 8 mm across and are green, with pinkish-purple stripes. Flowers appear in late summer to autumn after heavy rainfall. The labellum (petal ‘lip’ in the centre of the flower) has long hairs. When not in flower, only a single, thin, green leaf is present above the ground; this is indistinguishable from the leaves of other midge orchids. Its habitat is a useful identifier. Genoplesium is a genus of relatively inconspicuous ground orchids with clustered spikes of dark-coloured flowers that are non-resupinate (i.e. they are ‘upside down’ relative to most other orchids) and have a single flat, not tubular, leaf. This leaf distinguishes them from the very similar genus Prasophyllum, the leek orchids, their closest relatives.

Location and habitat

Distribution
 The Tallong Midge Orchid was originally collected at Kurnell in 1947; presumably it also occurred south of there, but it is now only known from two areas - the village of Tallong and its immediate environs, and a site in Morton National Park 8.5 km south-east of the town of Wingello. At Tallong, it occurs in an area of less than three kilometres north and east of the town centre. The Morton National Park site was discovered in 2001 and is less than 0.2 hectares in area.

• Occurs exclusively in heathland, generally dominated by Violet Kunzea (Kunzea parvifolia), Common Fringe-myrtle (Calytrix tetragonal) and parrot-peas (Dillwynia spp.).
• Grows on very shallow soils or within mosses on sandstone conglomerate shelves.
• Plants exists only as a dormant tuber for much of the year, dying back after flowering and fruiting in late summer or early autumn.
• Reproduces by seed and has no mechanism for vegetative reproduction.
• While the pollination biology of this species is not known, most midge orchids are pollinated by vinegar flies, although some are self-pollinating.

Regional information
This species is found in the following catchment management authority regions. Click on a region name to see more details about the distribution, vegetation types and habitat preference of the species in that region.

• Southern Rivers

Threats

• The Tallong Midge Orchid can be difficult to survey as flowering is highly dependant on seasonal conditions.
• Loss, degradation and fragmentation of habitat and/or populations for residential developments.
• Loss and degradation of habitat and/or populations from road works (particularly widening or re-routing).
• Any species with such a small range and population size is vulnerable to disturbance (e.g. fire, drought, disturbances), and the loss of even a few plants can be of major significance.

Recovery strategies

Priority actions are the specific, practical things that must be done to recover a threatened species, population or ecological community. The Department of Environment and Conservation has identified 9 priority actions to help recover the Tallong Midge Orchid in New South Wales.

What needs to be done to recover this species?

• Protect known populations from changes to land use.
• Develop management agreements with landowners to ensure the species is managed sustainably on private land.
• Monitor known populations to ensure that management is retaining populations.
• Search for new populations in potential habitat; surveys should be conducted in good flowering seasons in suitable habitat.
• Mark sites and potential habitat onto maps used for planning (road works and residential developments, rehabilitation and recovery).

References

• Bishop T. (2000). Field Guide to the Orchids of New South Wales and Victoria. New South Wales University Press, Sydney.
• Harden G.J. (ed.) (1993). Flora of New South Wales Vol. 4. UNSW Press, Kensington, NSW.
• NSW National Parks and Wildlife Service (2002) Genoplesium plumosum (a terrestrial orchid) Recovery Plan. NSW NPWS, Hurstville NSW.
• NSW Scientific Committee (1997) Genoplesium plumosum (a terrestrial orchid) - Endangered species determination - final. DEC (NSW), Sydney.