Assessment Notes

Justification

Rubroboletus eastwoodiae is a common bolete in California, USA. Most subpopulations occur within the range of its preferred ectomycorrhizal partner, Coast Live Oak. It is also occasionally found with other oak species around the Central Valley in California, and there are scattered subpopulations elsewhere in western USA. The species is widespread, and despite there being identified threats, there have been no reported declines. It is, therefore, assessed as Least Concern (LC) at this time.

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Taxonomic notes

This species was described as Suillellus eastwoodiae from a collection made by Alice Eastwood from the San Francisco Bay Area (Murrill 1910); it was soon after transferred to the genus Boletus (Saccardo and Trotter 1912). For many years, the California species was called Boletus satanas (an European species now in the genus Rubroboletus) and "Boletus" eastwoodiae was misapplied to what is now known as Rubroboletus pulcherrimus (Thiers and Halling 1976, Siegel et al. 2019, Wood and Stevens 2020).The Californian Boletus eastwoodiae was shown to be distinct from the European B. satanus, and was transferred into the genus Rubroboletus. The initial transfer (Frank 2015) was invalid because of an incorrect basionym, but was corrected in Tibpromma et al. (2017).

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Geographic range

This species is common in the range of Coast Live Oak (Quercus agrifolia); occurring from southern California, USA, into Mendocino County in coastal/Coast range forests. There are also scattered subpopulations inland around the Central Valley of California, and more rarely with Quercus garryana in the Willamette Valley of Oregon, and the Columbia River valley into Washington.

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Population and Trends

The population is widespread, and shows no sign of decline.

Population Trend: stable

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Habitat and Ecology

It is ectomycorrhizal with oaks (Quercus spp.), especially Coast Live Oak (Quercus agrifolia). Typically it is found in stands of oak with thick duff, or duff buildup, without a grassy or weedy under story. Fruiting occurs in fall.

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Threats

Sudden oak death caused by the soil mould Phytophthora ramorum has been spreading through California's oak woodlands, causing considerable mortality in some regions. Additionally, urban development is leading to loss of habitat, and invasive plants, especially grasses growing in oak woodlands could also have an impact. Droughts in southern California are a further potential threat.

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Conservation Actions

Control of invasive plants in oak woodlands is required.

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Use and Trade

This species is toxic.

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Source and Citation

Siegel, N. 2021. Rubroboletus eastwoodiae. The IUCN Red List of Threatened Species 2021: e.T195922746A195926982. https://dx.doi.org/10.2305/IUCN.UK.2021-2.RLTS.T195922746A195926982.en .Accessed on 2 October 2024

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• Country occurrence