Long called by the European species, Boletus appendiculatus Schaeffer (Thiers 1975, Arora 1986), the western North American species was described as a distinct species, and the group of closely related “butter boletes” were giving a new genus, Butyriboletus (Arora & Frank 2014).
Butyriboletus persolidus is a locally common butter bolete, growing with oaks in western North America.
Not enough data is available to assess trends, therefore I recommend listing it as Data Deficient (DD).
Coastal and coast range forests in California from Monterey County to Mendocino County, and in the Sierra Nevada foothills from the central and northern part of the range. Rare in the Pacific Northwest, where it has been reported from with Quercus garryana in the Willamette Valley of Oregon, and southern British Columbia, Canada.
Population is fairly widespread; not enough data is available showing trends of this species.
Population Trend: Uncertain
Ectomycorrhizal with hardwoods, especially oaks (Quercus spp), fruiting in fall; especially in seasons with substantial early rainfall.
This species occurs across a fairly widespread area with oaks (Quercus spp.) and possibly other hardwoods. No threats have been directly linked to this species. This species tends to fruit in seasons with early fall rains; research into trends due to climate change, and the fall rainy season occurring much later in the year should be investigated.
No specific conservation actions have been identified with regards to this species.
If climate change, and the later arriving seasonal rains affect this species.
This species is edible, and is often collected for food.
Arora, D. & Frank, J.L. 2014. Clarifying the butter Boletes: a new genus, Butyriboletus, is established to accommodate Boletus sect. Appendiculati, and six new species are described. Mycologia 106(3): 464-480.
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
Wood, M.G. and Stevens, F.A. 2020. MykoWeb; California Fungi. https://www.mykoweb.com/CAF/species/Butyriboletus_persolidus.html