Described by Thiers (1975), based on a Type collection made in Mendocino County, California, USA.
Boletus fibrillosus is a common bolete in northern California and the Pacific Northwest (in both coastal and montane forests), and occasional in the Sierra Nevada on California, and the northern Rocky Mountains.
This species is edible, and is often collected for food; no sign of decline has been noted due to picking.
Population is widespread, and no decline has been observed. We recommend it should be listed as Least Concern (LC).
From southern British Columbia, Canada, throughout the forested parts of the Pacific Northwest, east into the northern Rocky Mountains; south to San Francisco, California, USA in coastal forests, and into the southern Sierra Nevada in the mountains.
This species is common in conifer forests across much of its range; population is widespread, and shows no sign of decline.
Population Trend: Stable
Ectomycorrhizal with conifers, in a wide variety of forests types. Fruiting in fall.
No threats have been identified.
This species is edible, and if often collected for food; although to a lesser extent than other true Boletus species (the Porcini).
Desjardin, D.E., Wood, M.G. and Stevens, F.A. 2015. California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
iNaturalist. Accessed 31 Dec. 2020. https://www.inaturalist.org/observations?place_id=any&taxon_id=118150
Siegel, N. and 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.