Butyriboletus querciregius (“Red-Capped Butter Bolete”)

Oft-pitted/wrinkled cap is usually bright rose- pink to -red. Yellow, oft-bulbous, finely netted stem stains blue. Grows w/oak in autumn.

Description

Name in North American Boletes: Boletus regius

Genus: Butyriboletus

  • Genus 2: Boletus

Species: querciregius

  • Species 2: regius

Common Name: Red-Capped Butter Bolete

Tells: Oft-pitted/wrinkled cap is usually bright rose- pink to -red. Yellow, oft-bulbous, finely netted stem stains blue. Grows w/oak in autumn.

Other Information: Yellow pores age darker & bruise blue. Yellow cap flesh stains slowly & erratically. The cap sometimes has yellow or brown tones, especially near the margin. The stem sometimes has reddish tints, especially by the base.

Science Notes: Genetic tests have moved the mushroom f/k/a “Boletus regius” to a newly erected genus called “Butyriboletus” (“butyri” being latin for “butter” and this being one of the Butter Boletes); reserved the name “regius” for the European species; and divided the North American version into three separate species. This one (grows w/oak in autumn), Butyriboletus primiregius (grows w/mountain conifers in spring), & Bu. autumniregius (grows w/mid-elevation mixed woods or conifers, NOT oak, in autumn).

Edibility: Good

CHEMICAL TESTS:

  • NH4OH (Ammonia): No data.
  • KOH: No data.
  • FeSO4 (Iron Salts): Cap surface turns pale purplish. Cap flesh turns grayish.

Links:

National Audubon Society Field guide to Mushrooms, Gary Lincoff 0 Mushrooms of West Virginia and the Central Appalachians 0 North American Boletes 147

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