• Proposed
  • 2Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Xerocomellus mendocinensis (Theirs) N. Siegel, C.F. Schwarz & J.L. Frank

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Scientific name
Xerocomellus mendocinensis
(Theirs) N. Siegel, C.F. Schwarz & J.L. Frank
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Proposed by
Noah Siegel
Comments etc.
Noah Siegel

Assessment Notes

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).

Why suggested for a Global Red List Assessment?

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, associating with both conifers and hardwoods. No decline has been observed. We recommend it should be listed as Least Concern (LC).

Geographic range

Currently known from southern California north into Washington, USA. Likely also occurring in northwestern Mexico, and expected into southern British Columbia, Canada (Frank et al. 2020, Siegel & Schwarz 2016).

Population and Trends

Population is widespread and stable across the Pacific States in western USA.  Occurring in many different habitat types; from young to mature forest.

Population Trend: Stable

Habitat and Ecology

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


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

Conservation Actions

None needed.

Research needed

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

Use and Trade

This species is edible, and occasionally collected for food.

Food - human


Frank, J., Siegel, N., Schwarz, C., Araki, B. and Vellinga, E. 2020. Xerocomellus (Boletaceae) in western North America. Fungal Systematics and Evolution 6: 265-288.

Siegel, N. & Schwarz, C. 2016. Mushrooms of the Redwood Coast. Ten Speed Press: Berkeley, CA. 601 p.

Thiers, H.D. 1975. California Mushrooms—A Field Guide to the Boletes. Hafner Press: New York, NY. 261 p.

Wood, M. and Stevens, F. 2020. Mykoweb; The Fungi of California. https://www.mykoweb.com/CAF/species/Xerocomellus_mendocinensis.html

Country occurrence

Regional Population and Trends

Country Trend Redlisted