Assessment Notes

Justification

Xerocomellus diffractus is a common and widespread bolete in western North America. It occurs in a wide variety of habitat types, from young to mature forests, in association with both conifers and hardwoods. No decline has been observed. It is listed as Least Concern (LC).

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Taxonomic notes

This western North America 'Cracked-capped Bolete' has long been known by the misapplied European name Xerocomellus (or Boletus) chrysenteron. It was recently described as a distinct species (Frank et al. 2020).

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Geographic range

It occurs from southern California, USA, through the Pacific Northwest into British Columbia, Canada, east to the Rocky Mountains of Wyoming, and south into Arizona (Frank et al. 2020).

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Population and Trends

The population is widespread and stable across western North America. It occurs in many different habitat types; from young to mature forest, and is especially common in urban areas.

Population Trend: stable

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Habitat and Ecology

It is ectomycorrhizal with both conifers (especially Pinus and Pseudotsuga) and hardwoods (especially Quercus), in a wide variety of habitat types; from live oak woodlands in southern and central California, into northern Californian mixed evergreen forests and throughout the Pacific Northwest in coast to montane conifer forests. It is also quite common in urban and parkland settings. Fruiting is in fall and early winter, or occasionally in spring on the California and Oregon coast, and summer in the south-west and at higher elevations.

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Threats

This species is common and widespread in a wide variety of habitats, and no threats have been observed.

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Conservation Actions

No specific conservation action is currently needed in regards to this species, but more population data are needed from the Rocky Mountains. It is currently known from Arizona and Wyoming, but no collections were noted in between by Frank et al. (2020).

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Use and Trade

This species is edible, and occasionally collected for food.

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Source and Citation

Siegel, N. 2021. Xerocomellus diffractus. The IUCN Red List of Threatened Species 2021: e.T198481149A198490119. https://dx.doi.org/10.2305/IUCN.UK.2021-2.RLTS.T198481149A198490119.en .Downloaded on 26 September 2021

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• Country occurrence