Wyong Sun Orchid - 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: Thelymitra adorata

Conservation status in NSW: Critically Endangered

Commonwealth status: Critically Endangered

Gazetted date: 10 Jun 2016

Profile last updated: 27 Jul 2023

Description

A ground orchid up to 60 cm tall with a single leaf. The leaf is 10-40 cm long, 5-20 mm wide, erect or drooping, fleshy, ribbed on the back, green with a purplish base, and sheathes the flowering stem at the base. The flowering stem, which usually emerges in September, is dark bluish-purple and 20-60 cm tall by 2-5 mm diam. Flowers are fragrant, 2-13 in number, and borne on slender stalks 1-14 mm long. Individual flowers are 15-27 mm across, pale to dark blue and only open in warm, sunny weather. The dark, thick, rigidly erect stems aid field recognition, as compared to other Thelymitra species in the area, even when the flowers are closed. The species is currently listed by the Commonwealth as Thelymitra adorata.

Distribution

Currently known from several local government areas (LGA) within the Central Coast Council region of New South Wales. These include but are not limited to the LGAs of Wyong, Warnervale and Wyongah. Also recorded in the southern portion of Lake Macquarie City Council area.

Habitat and ecology

Occurs from 10-40 m a.s.l. in grassy woodland or occasionally derived grassland in well-drained clay loam or shale derived soils. The vegetation type in which the majority of populations occur (including the largest colony) is a Spotted Gum - Ironbark Forest with a diverse grassy understorey and occasional scattered shrubs.
A number of sites where the species occurs are subject to past and ongoing disturbance, including sites on the edges of roads that contain a mixture of native and introduced species in the understorey, though competition with invasive introduced species is a threat. There are some locations where the species occurs as the only native amongst an array of exotic species and where weedy grasses dominate.
Known locations/populations of plants exhibit dormancy, whereby individuals emerge some years when conditions are favourable and not in other years (likely to persist underground for greater than four years). Therefore, absence in a given year may be a 'false absence' and the plants can re-emerge once conditions are favourable (e.g. rainfall in winter and appropriate disturbance).
Some reports suggest that the species may also occur within the margin of two other vegetation types where these adjoin or constitute portions of the remnant vegetation areas in which the orchid has been recorded. Alluvial Redgum Footslopes Forest (Bell 2002) adjoins Dooralong Spotted Gum - Ironbark Forest at one population, and may constitute habitat for the species. Alluvial Floodplain Shrub Swamp Forest (Bell 2002) also adjoins Dooralong Spotted Gum - Ironbark Forest at one extant population with a report of a small orchid colony on the margin (B. Branwhite pers. comm.), and one apparently extinct population occurred in vegetation probably assignable to this type near Warnervale.

Regional distribution and habitat

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

Sydney Basin

Threats

Erosion of soils from nearby road verges impacting soil chemistry and substrate condition
Loss and fragmentation of individual plants/habitat as a result of activities such as infrastructure maintenance and clearing for development.
A restricted distribution and small total population size places the species at risk from demographic and environmental uncertainties, and natural catastrophes.
Illegal collecting of tubers by orchid-growers.
Invasive grasses overcrowding the species and reducing available habitat.
Inappropriate slashing regimes during leaf emergence, flowering and fruiting periods impacting the species reproduction
Soil compaction and habitat destruction by vehicles.
Competition and overshading from native and introduced plants
Risk of extinction from stochastic events due to small population size and restricted distribution.
Physical damage to plants and/or habitat as a result of recreational activities. Recreational activities may include but are not limited to 4WDs, trail bikes, horse riders, bushwalkers and rubbish dumping.
Insufficient understanding of the species ecology, including genetics, pollination, seed germination, mycorrhizae, reproductive ecology and response to fire.
Fungal attack from various strains of fungus - most likely naturally occurring strains. The fungus affects plant growth and seed production.
Browsing by feral herbivores such as rabbits on stems and damage/remove individuals above ground.
Potential for thick undisturbed habitat that may prevent plants emerging and flowering
Potential for disturbance due to infrastructure development in close proximity to where the species occurs.
Inappropriate fire regimes, including too frequent or infrequent fire impacting the species survival and reproduction
Browsing by native herbivores on leaf/stem can cause damage/remove the plants above ground parts.

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

Control invasive weeds species which threaten to outcompete the Wyong Sun Orchid.
Conduct targeted surveys for the species in September and October in areas where further development is planned so as to ensure that no further habitat is lost to development.
Eliminate grazing by cattle and horses in known populations.
Avoid above ground growth phase (May to late November), when undertaking maintenance activities
Protect populations from vehicular traffic
Develop and implement appropriate fire regimes