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

Leccinum californicum Thiers

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Scientific name
Leccinum californicum
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Proposed by
Noah Siegel
Comments etc.
Noah Siegel

Assessment Notes

Taxonomic notes

Described based on a collection made in El Dorado County, California (Thiers 1975).

Leccinum in general are taxonomically confounded by lack of informative morphological criteria, as well as poorly-known and competing species concepts. By virtue of combination of morphology and ecology, this species seems somewhat distinctive, but a pigment abnormality can’t be ruled out given the small number of known collections and lack of genetic data. Leccinum californicum should be compared genetically with L. montanum; which has a brown to gray brown or cinnamon-brown cap, but otherwise is very similar. It co-occurs with this species at both known locations in California (Siegel et al. 2019)

Why suggested for a Global Red List Assessment?

Leccinum californicum is a white to pale buff-capped bolete growing with aspen in the Sierra Nevada mountains of California. This appears to be a rare species; known from four high elevation aspen groves.

Leccinum are in need of modern taxonomic work, especially species reported from California. Until such time, it’s probably best to list this species as Data Deficient (DD).

Geographic range

Currently known from scattered disjunct populations in high elevation aspen groves in the Sierra Nevada mountains in California, USA.

Population and Trends

This species is currently known from four Quaking Aspen groves in the high Sierra Nevada of California. In total, aspen comprises only a small fraction (<1%) of the Sierra Nevada landscape (Shepperd et al. 2006), and many of these stands are not habitat ideal for mushroom growth (ie. exceptionally dry or rocky habitat). However, this habitat has been poorly surveyed for fungi.

Leccinum californicum was first collected in 1969, with a subsequent collection in 1971, and has not been collected again until 2018. There was an unsubstantiated report from the Type location in 2012. There were a few iNaturalist observations posted in 2020 which appear to be this species; spanning several months of fruiting in the same aspen grove (D. Morton pers. comm.).

Population Trend:

Habitat and Ecology

Ectomycorrhizal. Fruiting solitary or scattered in soil and duff under Quaking Aspen (Populus tremuloides) at higher elevations. Fruiting in summer and early fall.


Decline of aspen groves in the Sierra Nevada, due in part to conifer encroachment and fire suppression, and cattle grazing.

Conservation Actions

This species was included in A Field Guide to the Rare Fungi of California’s National Forests (Siegel et al. 2019), and was recommended for the Forest Service sensitive species list.

Although aspen restoration projects are ongoing, effort should be made to cause minimal damage to the duff and under story.

Research needed

Targeted surveys of aspen groves in the Sierra Nevada and southern Cascade Range in California. Modern taxonomic work on California Leccinum.

Use and Trade

This species is edible (based on the 2012 reported find of this species); however, based on current knowledge on rarity, it should not be collected for food.

Food - human


iNaturalist. 2021. Available at: http://www.inaturalist.org

MyCoPortal. 2021. 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.

Thiers, H.D. 1975. California Mushrooms A Field Guide to the Boletes. Hafner Press.

Country occurrence

Regional Population and Trends

Country Trend Redlisted