Assessment Notes

Justification

Protogautieria substriata is a rare species; reported from seven collections from four localities. It occurs in high elevation forests, under fir (Abies magnifica and A. concolor) and Lodgepole Pine (Pinus contorta) in the Sierra Nevada Mountains of California, USA. There are no new records of this species since 1987 (GBIF 2024, MyCoPortal 2024). More recent data are needed to accurately assess its population status or trends, but it is likely a very rare species and a precautionary estimate is that its population size is fewer than 250 mature individuals. It is assessed as Endangered.

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Taxonomic notes

This species was described by Thiers (1979), from a collection made at Huntington Lake, in Sierra National Forest. Placement in Gomphaceae is assumed. Although it superficially resembles Gautieria (which reside in Gomphaceae), no DNA sequences exist for Protogautieria substriata confirming family.

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Geographic range

Protogautieria substriata is currently only known from seven collections recorded from four sites in the Sierra Nevada in California, USA (Siegel et al. 2019). There are no records post 1987 on GBIF (2024) or MyCoPortal (2024) and zero records on iNaturalist (2024). Suitable habitat continues into the southern Cascade mountains of California.

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Population and Trends

This species is known from seven collections, from four sites and hasn’t been collected in nearly 40 years (GBIF 2024, MyCoPortal 2024). The lack of recent reports, even from areas that are relatively frequently sampled suggest that this is a rare species. Even so, it is probable that the species persists. Taking a precautionary approach we estimate that it occurs in 10 times the number of recorded locations, each with up to 6 mature individuals (40 site x 6 mature individuals) resulting in an estimated population size of 240 mature individuals.

Population Trend: Unknown

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Habitat and Ecology

With so few records, and no reports of the species over the past c. 40 years the following discussion is based on the historical collections. It is hypogeous, solitary or scattered, buried in duff or soil. It is known from subalpine forest, in association (likely ectomycorrhizal) with Pinaceae, especially under fir (Abies magnifica and A. concolor), and Lodgepole Pine (Pinus contorta). Collections were recorded during spring and fall so it is likely to fruit through summer if conditions are favourable. This species is dependent on mycophagy (primarily eaten by small mammals) for spore dispersal.

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Threats

Prolonged droughts and decades of fire suppression have drastically altered the high Sierra Nevada 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.

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Conservation Actions

This species should be added to United States Forest Service sensitive species list. Potential habitat for the species should be identified and managed it for fungi. Targeted surveys for presence or absence of this species in potential habitat is needed. Taxonomic revision is also needed to confirm its generic placement.

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Use and Trade

No use/trade is known.

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Source and Citation

Mueller, G.M. & Siegel, N. 2025. Protogautieria substriata. The IUCN Red List of Threatened Species 2025: e.T273227599A273247051. Accessed on 23 November 2025.

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