Assessment Notes

Justification

Flammulina stratosa is a rare wood-inhabiting mushroom recorded from a living stem of a beech tree and known from a single site in New Zealand. It has not been re-found since 1994 despite several dedicated searches at the type locality and extensive surveying of mushrooms across New Zealand over 50 years. Over the last five years, 2,500 observers have recorded 54,000 observations of fungi in New Zealand using the iNaturalist platform. 20,000 observations have been verified by multiple experts. This mushroom has not been seen. Despite this increased level of recording, there is a strong possibility of multiple undetected sites. Therefore, it is assessed as Data Deficient (DD).

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Taxonomic notes

Flammulina stratosa is a diminutive Flammulina with a long stipe reminiscent of Phaeocollybia and growing on wood of southern beech (Nothofagaceae). The species is sequence barcoded and occupies an isolated and basal position in the genus. Its nearest relative is Flammulina similis from Argentina indicating a Gondwana distribution for the two species.

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Geographic range

This species is endemic to New Zealand. It has only been recorded from one site in 1994 at St Arnaud, South Island.

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Population and Trends

Flammulina stratosa is known from a single location in 1994 and has not been found since, despite several dedicated searches at the type locality and extensive surveying of mushrooms across New Zealand over 50 years. This is a relatively small mushroom (15 mm) but clustered with bright colours and likely to be present at eye-level. Over the last five years, 2,500 observers have recorded 54,000 observations of fungi in New Zealand using the iNaturalist platform. 20,000 observations have been verified by multiple experts. This mushroom has not been seen and must be considered rare. Despite this increased level of recording, there is a strong possibility of multiple undetected sites.

Population Trend: unknown

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Habitat and Ecology

Flammulina stratosa is known only from a single location and collection on the Peninsula Track at alpine Lake Rotoiti in the South Island of New Zealand. It was collected on a living standing beech tree (Nothofagaceae). It is likely that the species is a saprophyte rather than parasite. It is also likely that the spores are wind-dispersed, but dispersal may be supported by ingestion by native animals. Its micro-habitat of trunks of living beech trees is shared with the beech scale-insect which produces copious amounts of honeydew which is then colonised by extensive areas of sooty moulds. These in turn provide food for invertebrates, birds, reptiles. In recent years the introduced German Wasp populations have increased significantly, feeding on the honeydew, and reducing associated native animal populations which may support dispersal of the fungi associated with beech/sooty-mould colonies.

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Threats

The type locality, whilst in a protected area, is on a popular walking track in an area with increasing tourism and with beech-associated species potentially impacted by invasive species.

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Conservation Actions

The species needs to be re-found and its ecological requirements assessed.

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Use and Trade

The species is not utilized.

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Source and Citation

Cooper, J.A. 2019. Flammulina stratosa. The IUCN Red List of Threatened Species 2019: e.T154239816A154239907. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T154239816A154239907.en .Accessed on 3 February 2024

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• Country occurrence