Assessment Notes

Justification

Otidea smithii is an uncommon but widespread cup fungus in western North America. It is currently known from coastal populations from the San Francisco Bay Area in California, USA, north into British Columbia, Canada; across the Cascade Range in the Pacific Northwest, and the Rocky Mountains from Colorado, USA north into Yukon, Canada.

Despite the widespread population, it is currently known from only ~40 sites (MyCoPortal 2021), but likely remains under reported. It does not seem to be tied to any threatened habitat, and no decline has been recorded. It is assessed as Least Concern.

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Taxonomic notes

This species was described from California, USA, based on a collection made in the coastal dune forests of Del Norte County (Kanouse 1939).

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Geographic range

This species is widespread in western North America, from San Francisco Bay Area on the northern California coast, north into British Columbia; through much of the Cascade Range in Oregon and Washington, east into the Rocky Mountains from Colorado north to Yukon. Records reported from India (MyCoPortal 2021) probably pertain to a distinct species, and are not included in this assessment.

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Population and Trends

The population is very widespread, although only occasionally reported. It is currently known from around 40 localities, from a wide variety of habitats; coastal forested dunes, coastal temperate rainforest, and drier mixed conifer cascade forests in the Pacific Northwest, and mixed conifer to boreal forests in the Rocky Mountains. It is also known from urban habitat with an introduced Cedrus sp. in California. Data to fully assess trends are lacking, but recent collections suggest the population is stable.

Population Trend: Stable

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Habitat and Ecology

It it scattered, often clustered, in humus or moss, occasionally in grassy areas. It is found in a wide variety of habitats; typically found under conifers and Bigleaf Maple Acer macrophyllum in the northern part of its range; pine, fir and spruce in coastal dunes, and under live oak to the south. It also occurs with introduced Cedrus.

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Threats

No specific threats have been identified with regard to this species.

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Conservation Actions

This species is included on the United States Forest Service Northwest Forest Plan Survey and Manage list of rare/old-growth forest-dependent fungi, and has been actively surveyed for since the late 1990's (Castellano et al. 1999). A better understanding of habitat requirements is required.

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Use and Trade

No use/trade is known.

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Source and Citation

Siegel, N. & Mueller, G.M. 2025. Otidea smithii. The IUCN Red List of Threatened Species 2025: e.T198480554A198487201. Accessed on 23 November 2025.

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• Country occurrence