Name in North American Boletes: Boletus regius
- Genus 2: Boletus
- 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).
- NH4OH (Ammonia): No data.
- KOH: No data.
- FeSO4 (Iron Salts): Cap surface turns pale purplish. Cap flesh turns grayish.