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Dichomitus newhookii P.K. Buchanan & Ryvarden

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Scientific name
Dichomitus newhookii
P.K. Buchanan & Ryvarden
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Assessment date
IUCN Red List Category
Buchanan, P. & Cooper, J.A.
Mueller, G.M.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/154923184/154923191


Due to its low level of detectability and lack of unique ecology and habitat (it occurs growing on broadly distributed tree species), the true distribution, population size, and trends can not be estimated. It is therefore assessed as Data Deficient.

Taxonomic notes

Dichomitus newhookii PK Buchanan & Ryvarden was established for two collections (1955, 1956) previously by G. Cunningham as Poria leucoplaca (Berk.) Cooke (=Dichomitus leucoplacus (Berk.) Ryvarden), a species with smaller pores ((3-)4-5 per mm) and spores (10-14 x 4-5.5 µm). D. newhookii is microscopically distinctive in occasionally septate basidiospores possibly related to spore maturity.

In macroscopic appearance it strongly resembles the New Zealand species Perenniporia podocarpi.

Geographic range

This polypore wood decay fungus is endemic to New Zealand. It is known only from single collections from two offshore islands - Great King Island and Little Barrier Island. Little Barrier Island has occasionally been surveyed for fungi; Great King Island rarely so. It has not been recorded on the mainland.

This species has not been collected since 1956. It is not conspicuous and requires microscopy for correct identification, hence, it is possible that it has a broader distribution.

Population and Trends

It is only known from two collections; both were initially misidentified and deposited in Fungarium PDD under D. leucoplacus. Intense polypore collecting occurred from 1940-1950 (Dingley, Cunningham) and further in the 1990s (Buchanan). This species has not been collected since 1956. Its population and trend are unknown.

The species is not conspicuous and requires microscopy for correct identification, hence, it is possible that it has a broader distribution.

Population Trend: unknown

Habitat and Ecology

On the basis of the two known specimens, D. newhookii is a saprobic species on dead wood, possibly of Knightia excelsa and Kunzea sp. Both tree species have broad distributions. It is possible that the species also occurs on additional tree species. The reported data are insufficient to explain the limited distribution of D. newhookii.


Both island locations have high conservation status, with removal of herbivorous vertebrates, so hosts should be safe on these islands, and both hosts are common and widespread on the mainland.

Conservation Actions

No conservation actions are currently in place for this species.

Further collecting is needed on both islands (permits and access are challenging) to confirm survival there, and targeted collecting especially on the two named hosts on mainland New Zealand. Phylogenetic study is needed, requiring fresh specimens.

Use and Trade

The species is not utilized.

Source and Citation

Buchanan, P. & Cooper, J.A. 2019. Dichomitus newhookii. The IUCN Red List of Threatened Species 2019: e.T154923184A154923191. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T154923184A154923191.en .Accessed on 3 February 2024

Country occurrence