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

Boletus rex-veris Arora & Simonini

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Scientific name
Boletus rex-veris
Arora & Simonini
Common names
Spring King
Spring King Bolete
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Proposed by
Noah Siegel
Comments etc.
Noah Siegel

Assessment Notes

Taxonomic notes

For many years this well known species was considered a form of Boletus eduis (Thiers 1975) or Boletus pinophilus (Bessette et al. 2000). Arora (1986) calls attention to the different ‘color forms’, and and states “sometimes called Boletus edulis var pinicola (=B. pinicola, B. pinophilus(?)”.

It was formally described as a distinct species, based on a California Type collection (Arora 2008).

Why suggested for a Global Red List Assessment?

Boletus rex-veris is a common bolete in the Sierra Nevada and Cascade Range in California, and across the Cascade Range, Blue Mountains and the northern Rocky Mountains in the Pacific Northwest.

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 major decline has been observed. We recommend it should be listed as Least Concern (LC).

Geographic range

Occurring in mid to high elevation forests of Sierra Nevada, Cascade Range and Siskiyou mountains of California, the Cascade Range in Oregon and Washington (mostly on the eastern slopes), into Southern British Columbia Canada, east through the Blue Mountain into the northern Rocky Mountains in Idaho and Montana. Also known from scatted Coast Range records.

Population and Trends

Population is widespread, and occurs in multiple conifer forests habitat types in the western North American mountains. This species is common, and appears stable.

Population Trend: Stable

Habitat and Ecology

Ectomycorrhizal with conifers, in montane conifer forests; especially with Ponderosa Pine (Pinus ponderosa), Lodgepole Pine (P. contorta subsp. murrayana), and true firs (Abies spp.) (Arora 2008). Fruiting in spring and summer.

Temperate Forest


Because of the widespread area, and different eco-zones this species occurs in, threats to this species are more localized, and likely have little affect on the population overall.

Droughts and climate change in the California mountains have led to mountain pine beetle outbreaks. Decades of fire suppression have drastically altered western montane forests, leading to thicker, denser, Abies dominated forests. As a result, hotter, stand replacing fires (rather than patchwork and understory burns) are commonplace, altering appropriate habitat drastically, and making it ill-suited for this species.

Increase in fire frequency/intensity

Conservation Actions

No specific conservation actions are needed with regards to this species.

Research needed

No specific research is needed with regards to this species.

Use and Trade

Boletus rex-veris is an edible species, and is widely harvested (even commercially) across much of its range.


Arora, D. 1986. Mushrooms Demystified. Ten Speed Press: Berkeley, CA. 959 p.

Arora, D. 2008. California Porcini: Three New Taxa, Observations on Their Harvest, and the Tragedy of No Commons. Economic Botany 62(3): 356-375.

Bessette, A.E., Roody, W.C. and Bessette, A.R. 2000. North American Boletes: A Color Guide to the Fleshy Pored Mushrooms. Syracuse University Press: Syracuse, NY. 400 p.

Desjardin, D.E., Wood, M.G. and Stevens, F.A. 2015. California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 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/Boletus_rex-veris.html

Country occurrence

Regional Population and Trends

Country Trend Redlisted