This is a distinctive species with a conical brown cap, purple tinged gills and a long thin rhizoid. It has a small population which is widely scattered. There are 11 collections at 5 widely separated location. Assuming that the fungus is mycorrhizal and following Dahlberg ^ Mueller’s guidance we have estimated that for each of the 11 functional individuals there will be 10 mature individuals. We have also allowed for twice the number of sites to allow for as yet undiscovered locations. That results in a population of 220 at 10 locations. GeoCat analysis suggests designation as Endangered based on the Area of Occupancy, but in view of the uncertainities about the ecology and life mode we propose that it be designated as vulnerable.

Phaeocollybia ratticauda Horak (1973)
Fungi with this name have been recorded in Australia and New Caledonia but are not thought to be identical to those in New Zealand. This assessment is made on the New Zealand taxon as described by Horak.

Proposed by Pat Leonard. Distinctive species in an uncommon genus known from 11 records distributed across Australia and 13 records in New Zealand. The species has two varieties with one named from Australia. The phylogenetic relationship between these taxa is currently unclear. Here we treat the NZ taxon as distinct. Extent of Occurrence 195,245.164 km2 Area of Occupancy 44.000 km2

North Island and South Island

A total of 11 collections have been made since the species was first described in 1968. Two in the 1980s, none in the 1990s, 8 in the 2000s, none in the 2010s.  There has been one repeat collection at the type locality but no repeats elsewhere.The best that can be said is that this seems to be a fluctuating population.

Horak speculates on the ecology of Phaeocollybia, it is known to associate with conifers in the northern hemisphere. In New Zealand it is found in Nothofagus forests but these almost always also contain some conifers. It is thought that Phaeocollybias are ectomycorrhizal but there is also some speculation that they may be weak parasites on tree roots.

All the known locations for this species are in Nothofagus forest and about half fall in to protected areas. The putative host trees are not thought to be under threat. Explaining the fluctuations in collections is difficult. It could be that weather conditions resulted in no collections in the 1990s and none since 2010. Feral animals are not known to be a particular threat to these fungi. Until there is a better understanding of the hosts and the fungus’s relationship with them, the precise nature and degree of threat will remain uncertain. The small and scattered population makes them vulnerable to stochastic events.

Defining the nature of the relationship between Phaeocollybia ratticauda and its host or hosts is essential to preparing effective conservation action.Clarification is needed of the relationship between the New Zealand, Australian and New Caledonian collections with this name.

Dahlberg A. and Mueller G.M. (2011) Applying IUCN red-listing criteria for assessing and reporting on the conservation status of fungal species. Fungal Ecology 4: 147-162.

Geospatial Conservation Assessment Tool: geocat.kew.org

Global Biodiversity Information Facility: gbif.org

Horak, E. (1973). Fungi agaricini Novaezelandiae I-V. Beihefte zur Nova Hedwigia. 43:1-200

Manaaki Whenau - Landcare Research databases: https://nzfungi2.landcareresearch.co.nz/

Mycobank: http://www.mycobank.org/