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

Chaetothiersia vernalis B.A. Perry & Pfister

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Scientific name
Chaetothiersia vernalis
B.A. Perry & Pfister
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 in 2008 from Yuba Pass in Sierra County, California, USA. (Perry, B.A. & D.H. Pfister. 2008.)

Why suggested for a Global Red List Assessment?

A rare cup fungus known from montane forest in the southern Cascades and Sierra Nevada in California and Oregon, USA. Currently known from ~10 locations.

Geographic range

Currently known from 8 voucher confirmed locations, and a few additional photograph records in high elevation forest from the central Sierra Nevada in California, north into the Cascade Range in southern Oregon. It has also been reported from coast range forest in Santa Cruz County, CA.

Population and Trends

Known from the southern Sierra Nevada into southern Oregon, and a purported location from the California Coast Range. Being recently described (2008), little is known of status and trend of this species.

Population Trend: Uncertain

Habitat and Ecology

Scattered or clustered on decaying logs, stumps, bark and woody debris in soil; typically in Red Fir (Abies magnifica) forests. Fruiting in spring, soon after snowmelt.

Temperate Forest


(All threats are conjectural, as little is known about this species).

Prolonged droughts and decades of fire suppression have drastically altered the high Sierra Nevada forests, leading to thicker, denser Abies dominated forest. As a result, hotter, stand replacing fires (rather than patchwork and understory burns) are commonplace, altering appropriate habitat drastically, and in particular, consuming much large woody debris, likely resulting in habitat ill-suited for this species.

Although this species hasn’t been shown to require thick winter snowpacks, it appears to benefit from them,  as it fruits in the spring and summer, as the snow melts and recedes. As the climate changes; warmer and drier winters have increased the average elevation of snowpack, and lessened the average depth of the snowpack. Likewise, hotter temperatures can melt the snowpack more rapidly in spring and summer, shortening the fruiting window.

Increase in fire frequency/intensityOther impacts

Conservation Actions

Little is known of the life history of this species or of its habitat requirements; until they are identified, conservation actions are unknown.

Research needed

A poorly known species; habitats requirements need to be identified, and a better understanding of ecology is needed. Research into if this species requires a dense winter snowpack, and is declining snow fall is detrimental. Targeted surveys should be made in suitable habitat, for presence or absence of this species.

Use and Trade

None known.


Desjardin, D.E., Wood, M.G. & Stevens, F.A. (2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
Perry, B.A. & Pfister, D.H. (2008). Chaetothiersia vernalis, a new genus and species of Pyronemataceae (Ascomycota, Pezizales) from California. Fungal Diversity 28: 65-72.
Siegel, N., Vellinga, E.C., Schwarz, C., Castellano, M.A. & Ikeda, D. (2019). A Field Guide to the Rare Fungi of California’s National Forests. Bookmobile: Minneapolis, MN. 313 p.

Known distribution - countries

Regional Population and Trends

Country Trend Redlisted