NSW National Parks and Wildlife Service, September 2002
ISBN 0 731 36905 X
3 Conservation Status
The Illawarra Greenhood orchid is currently known from only five locations consisting of approximately 4,500 individuals. Population numbers have probably decreased since the arrival of Europeans due to clearing of habitat for grazing, urban development and other activities. Extensive surveys conducted as part of the implementation of the initial recovery plan have failed to locate any populations on the Cumberland Plain in western Sydney, where it was originally discovered in 1803. It is considered that the species is probably now extinct on the Cumberland Plain.
The species is listed as 2E (Endangered and inadequately conserved) on the Rare or Threatened Australian Plants (RoTAP) listing (Briggs and Leigh 1996).
The ROTAP ranking has not been amended to include reference to those populations in the Hunter Valley and Shoalhaven regions.
P. gibbosa is present in one conservation reserve, Worrigee Nature Reserve.