Only four collections have ever been made of this fungus at four different sites and three widely fragmented locations. The rarity of the fungus makes it vulnerable to stochastic events. Using Dahlberg and Mueller’s approach, we estimate the population to be 8 mature individuals. Its supposed host is widely spread through New Zealand and given the small size of the fungus we would think it fair to expect that there are probably up to 10 times mores sites yet to be discovered. That would yield estimates of a population of 80 spread over 30 severely fragmented locations.  We conclude that this species should be considered endangered.

Mycena mamaku is a distinctive species with a pleated parabolic cap 2-3mm in diameter and found growing on Cyathea. Often confused with a similar and undescribed species M. sp. ‘Erua Forest’ in similar habitats and equally uncommon. Australian records of this species refer to a similar but different species.

Proposed by Pat Leonard. Distinctive species known with certainty from 3 records and 2 locations. Often confused with a similar and undescribed species M. sp. ‘Erua Forest’ in similar habitats and equally uncommon. Australian records of this species referr to a similar but different species. Extent of Occurrence 0.557 km2 Area of Occupancy 8.000 km2

Only four collections have ever been made. It is probably overlooked because of its very small size, yet its parabolic shape is very distinctive. Several mycologists have taken an interest in the genus Mycena in New Zealand but this species has not featured in their collections. Its host is relatively widespread. Two collections were made north of Auckland in the mid 1980s, two more in South Island are much more recent.

This Mycena grows on the decaying trunks of the tree fern genus Cyathea.

Climate changes may threaten its host. We suspect that the species may be vulnerable to both intense drought conditions and to higher temperatures that its host might survive. The main threat is from stochastic events due to the seeming rarity of this fungus.

Recognition of the importance of large old growth logs as hosts for this and other fungal species in Park and Forest management plans would improve the future security of Mycena mamaku.

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

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

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

Segedin, B.P. 1991: Studies in the Agaricales of New Zealand: some Mycena species in sections Longisetae, Polyadelpha, Rubromarginatae, Galactopoda, Lactipedes, and Calodontes. New Zealand Journal of Botany 29(1): 43-62.