Name in North American Boletes: Boletus pulverulentus
- Genus 2: Boletus
- Genus 3: Xercomus
Species: cyaneitinctus (add “f. reticulatus” for the rare specimen with netting)
- Species 2: pulverulentus
Tells: Quick-bluing stem flesh is yellow high & brown at the base. Yellow pores and stem (gets redder going down) bruise blue but resolve to brown.
Other Information: Variable-color cap instantly stains blackish blue & usually has a dust or powder on its surface. Yellow cap flesh stains straight blue. White mycelium darkens to brown when handled. Stem often has raised ridges but true reticulation is quite rare.
Science Notes: DNA testing moved this mushroom from Boletus to a newly erected genus called “cyanodoboletus” (“cyano” referring to the characteristically brilliant blue stains). A later paper then confirmed what people had long suspected: that America’s Cyanoboletus is a distinct species from Europe’s lookalike, C. pulverulentus.
Edibility: Good. But it should be noted that at least one paper has said the European lookalike, C. pulverulentus, is a hyperaccumulator of arsenic. That would reduce the rating there to no better than “iffy” if a similar study shows the same for cyaneitinctus.
- NH4OH (Ammonia): Cap surface flashes green. Blued flesh loses its staining.
- KOH: According to Mushroom Expert, the cap skin turns black and stained flesh turns orangish.
- FeSO4 (Iron Salts): According to Mushroom Expert, the cap skin has no reaction but the blued flesh loses its staining.