Relic Gondwanan Mushroom Discovered in a Perth Urban Bushland
Participants at a PUBF workshop in 2004 discovered a possible relic from Gondwana: an unusual mushroom growing under a thick layer of shrubs overarched by taller gum trees and paperbarks.
The geographical distributions and abundances of most Australian fungi are poorly known. The Fungimap program is helping to address the question as to where our fungi occur. It is however known already that the geographical distributions of mycorrhizal fungi are closely tied to those of their host partner plants. At least some mycorrhizal fungi had established their plant partners before the breakup of the southern super continent Gondwana. These ancient fungi are presently found scattered in portions of former Gondwana including Australia, New Zealand, New Caledonia, New Guinea, and South America. Some of the fungi have a present-day distribution similar to that of the southern beech – Nothofagus, which was probably a major mycorrhizal plant partner for fungi in Gondwanan times, as it continues to be today.
Forrestdale Lake is a groundwater-fed lake on the southern outskirts of the Perth Metropolitan Area. Areas of paperbarks and open woodland surround the lake. The unusual fungus discovered at Forrestdale by PUBF workshop participants in July 2004 was growing under a thick layer of Astartea shrubs overarched by eucalypts and paperbarks (Melaleuca). The fungus is a member of the large, well-known genus Cortinarius. This brown-spored genus is usually characterised by its cobweb-like partial veil (cortina) and by not having a ring or cup on its stem. However the Forrestdale Cortinarius fungus has a distinctive white cup (volva) at the base of its stem and large white patches on its bright brown cap. The fungus is Cortinarius phalarus – “the Volvate Cortinar”. This fungus was first named and published in 1989 by N.L. Bougher and R.N. Hilton from near the town of Denmark on the south coast of Western Australia, and has been rarely recorded since. The Volvate Cortinar may occur across southern Australia, as indicated by collections in Tasmania, but it is possibly scattered or quite rare. Cortinarius phalarus is considered a probable gondwanan fungus because it and several similar species in south-eastern Australia are members of an unusual small group of volvate cortinarii also found in South America.
Why does this Fungus occur in a Perth Urban Bushland?
The question may be asked as to why a putative relic gondwanan fungus such as the volvate cortinar occurs in an urban bushland in Perth. Nothofagus has been extinct for many thousands of years in the region. However, it is likely that at least some former fungal partners of gondwanan plants such as Nothofagus survive today in areas where those plants are now locally extinct. The fungi may have survived local extinction of Nothofagus and other plants of Gondwana in regions such as south-west Australia by forming partnerships with other plants, such as those of the family Myrtaceae. Today many of the so-called gondwanan fungi such as the Volvate Cortinarii are distributed both within and outside the current geographic range of Nothofagus. In W.A. these fungi are most likely now confined to the higher rainfall zones in the south west where a high number of relic plants also occur. Most, if not all species of Cortinarius are considered to be mycorrhizal. The partner plants of the Volvate Cortinar at Forrestdale are likely to include the myrtaceous plants occurring there such as Melaleuca preissiana, Eucalyptus rudis, and Astartea sp.
Conservation of Forrestdale Lake area
Forrestdale Lake is being rapidly encroached by agricultural, urban or semi-urban land. The wetlands area at Forrestdale Lake is managed by the Department of Environment and Conservation. The finding of a putatively ancient gondwanan fungus such as the Volvate Cortinar, together with numerous other fungi found in the area around the lake by participants of the 2004 PUBF workshop, helps to support the conservation status of Forrestdale Lake. The area is listed as a wetland of international importance in the Ramsar Convention on Wetlands for a number of criteria such as: ‘A wetland should be considered internationally important if it supports populations of plant and/or animal species important for maintaining the biological diversity of a particular biogeographic region.’
How to recognise the Volvate Cortinar and contribute to knowledge
See page J-12 of the Perth Fungi Field Book.
Further records of the volvate cortinar fungus would add to our knowledge of its distribution and ecology. Any data, such as the species of plants nearby and photographs or specimens (if you have a licence) that may aid verification of identity of the fungus would be helpful. Please contact PUBF if you come across this fungus at the earliest possible time. You will probably need to mark the location so that it is able to be found again.
Habit: in litter on ground near myrtaceous plants, e.g. Eucalyptus, Agonis, Leptospermum, Melaleuca.
Cup: white cup (volva) at the base of the stem.
Cap: white patches adhering on a bright brown cap 25-70 mm broad.
Stem: cream, longitudinally shiny, silky, 40-70 mm tall x 6-15 mm wide.
Gills: fawn brown, closely-spaced.
Spore print: brown.
For more details to help recognise the Volvate Cortinar fungus see:
Bougher, N.L., & Hilton, R.N. (1989). Three species of Cortinarius from Western Australia. Mycological Research 93: 424-428.
Bougher, N.L., & Syme, K. (1998). Fungi of Southern Australia. University of Western Australia Press. Page 254-255.