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

Choiromyces alveolatus (Harkn.) Trappe

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Scientific name
Choiromyces alveolatus
(Harkn.) Trappe
Common names
IUCN Specialist Group
Cup-fungi, Truffles and Allies
Assessment status
Proposed by
Noah Siegel
Comments etc.
Noah Siegel

Assessment Notes

Taxonomic notes

Described by Harkness (1899) as Piersonia alveolata, based on a collection made in Placer County, California, USA, later transferred to the genus Choiromyces (Trappe 1975).
Choiromyces cookei Gilkey, Hydnobolites excavata Harkn., Piersonia bispora Gilkey and Piersonia scabrosa Harkn. are synonyms.

Why suggested for a Global Red List Assessment?

Choiromyces alveolatus is a widespread, but uncommon hypogeous fungus in western North America; occurring from near sea-level to subalpine forests. Fruiting from early spring into fall; most common in spring; typically buried quite deep in mineral soil. Currently known from about 30 disjunct populations; mostly in California, but nine locations from Oregon, and single sites in Washington, Idaho, Wyoming and Utah.

Geographic range

Widespread in western North America; but rarely collected. Known from the central coast, the Sierra Nevada and Cascade Range in California, USA, north into Oregon and from solitary sites in Washington, Utah, Wyoming and Idaho (Siegel et al. 2019, MyCoPortal.org)

Population and Trends

Currently known from about 30 disjunct populations; mostly in California, but nine locations from Oregon, and single sites in Washington, Idaho, Wyoming and Utah. (Siegel et al. 2019) This species is probably more common than current records indicate, but due to the cryptic nature (hypogeous fruiting, and often deep in soil), under reported. Six collections were made in California during the 2011-2013 USFS Mt Shasta California Survey and Manage mushroom surveys, and an additional collection was found during the 2019 USFS Rare Fungal Species workshop at Yuba Pass in California (N. Siegel, unpublished)

Population Trend: Stable

Habitat and Ecology

Hypogeous, solitary or scattered in ‘nests’, usually buried quite deep in the mineral soil. Ectomycorrhizal, growing with Pinaceae, especially Red Fir (Abies magnifica). Occurring from near sea-level to subalpine forests; fruiting from soon after snow melt in early spring, through summer, or into fall.

Temperate Forest


Most recent collections have been made in high elevation, old growth Red Fir (Abies magnifica) forests; a number of historic collections come from the Sierra Nevada foothills, in areas that have been largely developed. Continued loss of habitat, decline in old growth forests, and hotter, stand replacing fires are likely detrimental to this species. 

Housing & urban areasUnintentional effects: subsistence/small scale (species being assessed is not the target) [harvest]Increase in fire frequency/intensityHabitat shifting & alteration

Conservation Actions

No specific conservation actions have been identified with regards to this species at this time.

Research needed

Continued surveys for this species in western North America.

Population size, distribution & trends

Use and Trade

This species is edible, but due to its scarcity, rarely collected.

Food - human


Castellano, M., Smith, J.E., O’Dell, T., Cázares, E. and Nugent, S. 1999. Handbook to Strategy 1 Fungal Species in the Northwest Forest Plan. General Technical Report PNW-GTR-476. United States Department of Agriculture.

Gilkey, H.M. 1954. Tuberales. North American Flora 2(1): 1–36.

Harkness, H.W. 1899. Californian hypogaeous fungi. Proceedings of the California Academy of Sciences. 1(8):241–291

MyCoPortal. 2020. Mycology Collections Portal. Available at: http://mycoportal.org

Siegel, N., Vellinga, E.C., Schwarz, C., Castellano, M.A. and Ikeda, D. 2019. A Field Guide to the Rare Fungi of California’s National Forests. Bookmobile: Minneapolis, MN. 313 p.

Trappe, J.M. 1975. Generic synonyms in the Tuberales. Mycotaxon 2:109-12

Country occurrence

Regional Population and Trends

Country Trend Redlisted