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- Under Assessment
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Butyriboletus querciregius D. Arora & J.L. Frank
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- Scientific name
- Butyriboletus querciregius
- Author
- D. Arora & J.L. Frank
- Common names
- IUCN Specialist Group
Mushroom, Bracket and Puffball- Kingdom
- Fungi
- Phylum
- Basidiomycota
- Class
- Agaricomycetes
- Order
- Boletales
- Family
- Boletaceae
- Assessment status
- Published
- Assessment date
- 2024-12-09
- IUCN Red List Category
- LC
- Assessors
- Gregory Mueller (Chicago Botanic Garden / IUCN SSC Mushroom, Bracket and Puffball Specialist Group); Noah Siegel (25 Prospect Hill Road, Royalston, MA 01368, US / Global Fungus Assessment)
- Reviewers
- Anders Dahlberg (Swedish Species Information Centre, Uppsala / IUCN SSC Cup-fungus, Truffle and Ally Specialist Group)
Assessment Notes
The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/272184235/272184626
Justification
Butyriboletus querciregius is a pink-capped butter bolete, growing with coastal oaks in California, Oregon, Washington in the USA and possibly into southern British Columbia, Canada. This species occurs over a widespread range, and based on the number of observation in iNaturalist, it does not appear to be rare. Local threats may be negatively impacting its population size, but over its distribution it is could be relatively stable. The potential future impact on its population due to increasing drought and Sudden Oak Death should be followed. For now, though, it is assessed as Least Concern.Taxonomic notes
For many years, this species was one of three western North American ‘cryptic’ species being called Boletus regius (Thiers 1975, Arora 1986). Arora and Frank (2014) described the three species, and erected the genus Butyriboletus for the group of closely related ‘butter boletes’.Geographic range
This species is found growing with oaks (Quercus spp.) in coastal and coast range forests in California from San Diego County northward, and in the Sierra Nevada and Cascade Range foothills into the Pacific Northwest, where it occurs with Oregon White Oak (Quercus garryana) in the Willamette Valley of Oregon, and Columbia River Valley in Washington; and possibly into southern British Columbia, Canada.Population and Trends
The population occurs over a widespread area, with most over 160 iNaturlaist records, with a majority from California (iNaturalist 2024). Being a recently described species (Arora and Frank 2014), in the ‘Boletus regius’ complex, pre-2014 records need extra scrutiny.
Population Trend: Unknown
Habitat and Ecology
It is ectomycorrhizal with oaks (Quercus spp.), especially Coast Live Oak (Quercus agrifolia) in California, and Oregon White Oak (Quercus garryana) in the Pacific Northwest. Fruiting occurs in fall, especially in seasons with substantial early rainfall.Threats
This species occurs across a fairly widespread area with oaks (Quercus spp.). Overall, the habitat has threats from urban development and agriculture leading to loss of habitat and invasive plants, especially grasses growing in oak woodlands. Sudden Oak Death caused by Phytophthora ramorum is a threat to its host and may negatively impact its population.This species tends to fruit in seasons with early fall rains; research into trends due to climate change, and the fall rainy season occurring much later in the year should be investigated.
