Indicative distribution
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: Zieria obcordata
Profile last updated:
01 Nov 2022
Description
Dense, rounded, perennial shrub to 0.5 m high. Dark green leaves composed of 3 wedge-shaped leaflets, covered with small warts on the upper surface. The tip of the central leaflet is characteristically recurved to give it a notched appearance. Each leaflet 3-8.5 mm long and 1.3-3.7 mm wide, the margins somewhat toothed. Flowers with 4 petals, each 2-2.5 mm long, pale pink rapidly fading to white. Fruit a capsule about 5 mm across, deeply divided into 4 chambers.
Distribution
Occurs at two sites with a geographic range of 105 km. These are in the Wuuluman area near Wellington, comprising of a single subpopulation over 3 sites comprising up to 200 plants and Crackerjack Rock/Rock Forests area NW of Bathurst, with a subpopulation comprising of 14 sites, totaling to approximately 700 adults plants after good seasons.
Habitat and ecology
- Grows in eucalypt woodland or shrubland dominated by species of Acacia on rocky hillsides. Also occurs in Eucalyptus and Callitris dominated woodland with an open, low shrub understorey, on moderately steep, mainly west to north-facing slopes in sandy loam amongst granite boulders. The altitude range of sites is 500 to 830 metres.
- Associated vegetation includes Eucalyptus blakelyi, Brachychiton populneus and Acacia implexa woodland with pockets of low shrub understorey. Also in E. goniocalyx, E. blakelyi, E. macrorhyncha, A. doratoxylon, A. vestita and Callitris glaucophylla woodland with a shrubby understorey.
- Understorey species include Pandorea pandorana, Isotoma axillaris, Westringia eremicola, Leucopogon attenuatus, Dillwynia sericea, Olearia ramulosa, Stypandra glauca, Stellaria pungens, Acacia vestita, Melichrus urceolatus, Cryptandra amara, Lepidosperma, Styphelia, Kunzea, Haloragis and Cheilanthes species.
- Main flowering period is in spring (September-October), but plants tend to have flowers present throughout the year.
- In wild populations, plants tend to grow in crevices between granite boulders, often in lines running downslope. The species has proved to be very difficult to cultivate. Best growth has been achieved with plants in a very sandy well-drained soil. Wild plants have strongly aromatic leaves.
- Zieria obcordata is extremely sensitive to grazing and browsing disturbances by domestic stock and native herbivores. Heavily browsed plants and vigorous regrowth (following severe browsing by wallabies) have been recorded at sites.
- Plants are tolerant of prolonged moderate drought conditions but highly susceptible to extreme summer heatwaves that occur over more than five consecutive days.
- Mass regeneration events can occur after above-average rainfall seasons, otherwise very low levels of recruitment occur each year.
- Plants known to first flower at 10cm high and 12 months of age.
Regional distribution and habitat
Click on a region below to view detailed distribution, habitat and vegetation information.
Threats
- Preferential grazing by domestic stock.
- Wallaby grazing.
- Weed invasion.
- Habitat degradation, and destruction of native understorey and microhabitats.
- Sites vulnerable to changes in stocking practices (such as the introduction of goats).
- Limited observation of seedlings and juveniles. Browsing may be destroying the flowers.
- Stock introduction poses significant risk of disturbance to the species.
- Burrowing near and under stems and eating seedlings.
- Unknown total population size, extent of occurrence, or area of occupancy.
- Loss of mature plants due to drought and extreme temperatures.
- Low genetic diversity, and high genetic disparity between Wellington and Bathurst populations.
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
- Monitoring of extant populations to increase knowledge about biobogy and ecology of the species.
- Fence all sites to exclude grazing by domestic stock and goats.
- Control vigorous weeds such as Tree of Heaven (Ailanthus altissima) and Bridle Creeper (Asparagus asparagoides).
- Raise awareness of this species in areas of where potential habitat is present to increase the chance of recognition and reporting by landholders
- Report all new sightings of the species to the Department of Planning, Industry and Environment.
Information sources
- Armstrong, J.A. (1991) Zieria. In Harden, G.J. (ed.) Flora of New South Wales. Volume 2. New South Wales University Press, Sydney.
- Briggs, J.D. and Leigh, J.H. (1990) Delineation of Important Habitats of Threatened Plant Species in South-eastern New South Wales. Research Report to the Australian Heritage Commission. (CSIRO, Canberra)
- Briggs, J.D. and Leigh, J.H. (1996) Rare or Threatened Australian Plants. Revised Edition. (CSIRO Publishing, Melbourne)
- CANB Herbarium Records. () Databased specimen records from the Canberra Botanic Gardens and Australian National Botanic Gardens (CSIRO and Australian National Botanic Gardens: Canberra).
- Department of Environment and Conservation (NSW) (2005) Draft NSW and National Recovery Plan Zieria obcordata - Draft Recovery Plan. NSW NPWS, Sydney.
- Field, B. (1825) Zieria obcordata sp. nov. Geographical Memoirs on New South Wales 330.
- Jacobs, S.W.L. and Pickard, J. (1981) Plants of New South Wales. A census of the cycads, conifers and angiosperms (Royal Botanic Gardens: Sydney).
- NSW Herbarium Records. () Databased specimen records from the National Herbarium of New South Wales (Royal Botanic Gardens: Sydney).
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