• Proposed
  • Under Assessment
  • CRPreliminary Assessed
  • 4Assessed
  • 5Published

Pluteus bressollensis Eyssart., Ducousso & Buyck

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Scientific name
Pluteus bressollensis
Eyssart., Ducousso & Buyck
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Preliminary Assessed
Preliminary Category
CR Critically Endangered B1, B2a, B2b and D1
Proposed by
Patrick Leonard
Patrick Leonard
Marc Ducousso, Patrick Leonard, Anne-Marie Maviet
Philippe Bourdeau

Assessment Notes


Pluteus bressollensis is a distinctive species, easy to identify in the field. Distribution is limited to wet montane forests. The habitat is largely unmanaged and undergoing change due to feral animals.
There have only ever been 4 functional individuals of this fungus found from two sites. Using the Dahlberg & Mueller (2011) methodology we estimate that, allowing for previously known and as yet undiscovered sites, there might be up to 10 sites and a population of up to 50 mature individuals.  This takes in to account the very steep and inaccessible terrain of a substantial part of the Mont Mou reserve.
This species is assessed as “ critically endangered” on the basis of criteria B1, B2a and B2b with only one known site and a potential of 10 sites in an endangered ecosystem and D1 on account of the a very small estimated population of less than 50 mature individuals.

Taxonomic notes

Cap: applanate or plano-convex; 20 - 45 mm diameter; surface cellular and distinctly wrinkled at the apex; sometimes appearing radially wrinkled to margin and rimose; ochre brown with distinctive white spots.
Gills: free; fine; white at first becoming a deep pink as the spores mature.
Stipe: cylindrical to somewhat clavate; 10 - 40 × 1.5 - 3 mm; white to dirty grey with small brown squamules that are scarce or absent at the apex, but more dense at the base.
Flesh: thin, white.
Spores: subglobose; 4.9 - 6.5 × 4.6 - 6 µm, average Q = 1.1
Habitat: on a well rotted log of a native tree in montane forest above 800 M.
Notes: This species made be recognized in the field due to the dark pink free gills that typify Pluteus and the ochre brown cap with white spots.

Why suggested for a Global Red List Assessment?

There are at least seven endemic Pluteus species in New Caledonia that are found in motane and humid forests. Only one has a published name and formal description and is readily recognized because of its dark ochre brown cap with white spots. It was described from the high mountain forest reserve of Mont Mou. In the decade that has passed since its description the SMNC have visited most of the remaining areas of montane forests and it has only been seen again once. We may reasonably assume that this fungus species is naturally rare.

Geographic range

Population and Trends

There has been no system of formally recording fungi in New Caledonia in the past. Le Rat made many fungal collections between 1900 and 1910 some of which were then described and published by Patouillard.  Roger Heim published some further species in the 1930s. Horak visited New Caledonia during the 1970s and published several papers during that decade. It was not until 2009 (?) that a more formal system was established to monitor fungi, following Marc Ducousso’s formation of the Societe Mycologique du Nouvelle Caledonie. Since then some 25,000 fungi have been photographed by members of the SMNC and these form the basis of current records. There was also a formal survey of dry sclerophyll forests in 2010 directed by Ducousso which sets a base line for that forest type. In 2001 a website was established by Endemia NC to provide a record of all New Caledonia’s wildlife. In its early years it concentrated on birds and NC’s rich plant flora. It has recently (2018) started to accumulate fungal records.
The paucity of data might suggest that all NC fungi should be considered as data deficient. However for well defined species and particularly for those which can be reliably identified from photographic evidence we can claim relatively good information on current distributions but not on population trends. Pluteus bressollensis remains known from collections at two sites.

Population Trend: Uncertain

Habitat and Ecology

Pluteus bressollensis is a distinctive species, easy to identify in the field. Distribution is limited to wet montane forests. The habitat is largely unmanaged and undergoing change due to feral animals.


Only a very small portion of the original forest cover of New Caledonia remains. Clearing in the past for timber and to create grazing and agricultural land have destroyed much of the forest cover. Wild fires and open cast mining have also accounted for extensive losses. What remains is now partially protected by Botanical Reserves of which Mont Mou is one. There is however virtually no active management to encourage regeneration or to discourage invasive species.
Pigs are very numerous throughout New Caledonia’s forests. Thought to be the the legacy of Captain Cook’s visit in 1774. The gift of 12 Rusa deer to the Governor of New Caledonia in 1862 has resulted a large current population; estimates range from 400,000 to 1,000,000. There are also established populations of feral cattle and horses in parts of New Caledonia. All these introduced species cause damage to native forests, in particular through selective grazing which impedes regeneration,  changes species composition and through nutrient enrichment and digging (pigs) and compaction (horses and cattle).
Pigs are the main pest species at Mont Mou and Katricoin and probably specifically target fungal species. There is no known published research on the effect of pigs on the genus Pluteus.

Conservation Actions

Recognition of the role of fungi in the ecology of forests by including references in management plans would be helpful. More effective control of feral animals would be beneficial.

Research needed

Research on the effects of feral animals on vegetation is ongoing but needs to be extended to cover fungal populations.

Use and Trade


Atlas de la Nouvelle Caledonie (1983). Auteur?  Imprimerie H. Dridé
Global Biodiversity Information Facility: gbif.org
Endemia NC. http://endemia.nc/
Eyssartier G, Ducousso M. et Buyck B. (2009) Agaricales nouveaux ou interessants de Nouvelle-Caledonie. Cryptogramie, Mycologie 2009, 30 (4): 329 - 339.
Heim, R. 1966.Revue Mycol., 31(2), 157.

Horak E. & Mouccha J. (1998). Annotated check-list of New Caledonian
Basidiotmycota. 1. Holobasidiomycctcs. Mycolaxon 68: 75-129
Patoulliard N. (1887). Champignons de la Nouvcllc-Calcdonie (I) Bull
Trimestriel Soc. Mycol France 3: 168-178

Known distribution - countries

Regional Population and Trends

Country Trend Redlisted