Australian Orchid Foundation


Project: 259/2007

Title: Conservation of the nationally endangered Arachnorchis atroclavia (Black-clubbed spider orchid)
Applicant: Dr. John Dearnaley (Chief Investigator)¹, Dr. Andrew Le Brocque¹, Dr. Michael Mathieson²

¹ Australian Centre for Sustainable Catchments, The University of Southern Queensland.
² Queensland Department of Environment and Resource Management.

Institute: The University of Southern Queensland

The nationally endangered “Black-clubbed spider orchid” or Arachnorchis (syn. Caladeniaatroclavia (Fig 1) has a total remaining wild population of less than 120 plants. Although secure in a national park, the species is threatened by grazing, inappropriate fire regimes and potentially, climate change.

We have isolated fungi from stems of the orchid and used DNA sequencing to determine the identity of these mycobionts. In common with other Caladenia spp. the main fungal partner was a member of the Sebacina vermifera complex. The fungus successfully germinates seeds under laboratory condition (Fig 2) suggesting that it is capable of forming mycorrhizas with the orchids.

It is intended to produce a number of seedlings of the orchid under horticultural conditions which can then be reintroduced into the natural state to bolster the dwindling natural populations.

Dearnaley J.D.W., Murray A.J. and Mathieson M.T. (2009). Molecular identification of a mycorrhizal Sebacinaceae from the endangered Caladenia atroclavia (Black-clubbed spider orchid). Australasian Mycologist 28: 45-50.