Assessment Notes

Justification

Xerocomellus mendocinensis 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 American species has long been known by the misapplied name Xerocomellus truncatus (Singer, Snell & E.A. Dick) Klofac (syn: Boletus truncatus (Singer, Snell, & Dick) Pouzar; Xerocomus truncatus Singer, Snell, & Dick). Genetic work by by Frank et al. (2020), has shown that the western North American species is distinct from the eastern North American X. truncatus, and that it is conspecific with a rarely used name, X. mendocinensis (Thiers 1975).

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Geographic range

Currently this species is known from southern California north into Washington, USA. It likely also occurs in north-western Mexico, and is expected to be found in southern British Columbia, Canada (Frank et al. 2020, Siegel and Schwarz 2016).

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Population and Trends

The population is widespread and stable across the Pacific States in western USA. It occurs in many different habitat types, both conifer and hardwood forests, in young to mature stands.

Population Trend: stable

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Habitat and Ecology

It is found in a wide variety of forest types. It is ectomycorrhizal, in California commonly with Coast Live Oak (Quercus agrifolia) and Tanoak (Notholithocarpus densiflorus), occasionally with other hardwoods or conifers, and it is typically associated with conifers in the Pacific Northwest. Fruiting occurs from mid-fall into mid-winter, and occasionally in spring.

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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

This species should be looked for in areas outside the known range; i.e. southern British Columbia, Canada, the Rocky Mountains in the USA and Baja California, Mexico.

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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 mendocinensis. The IUCN Red List of Threatened Species 2021: e.T198481056A198487644. https://dx.doi.org/10.2305/IUCN.UK.2021-2.RLTS.T198481056A198487644.en .Downloaded on 27 September 2021

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• Country occurrence