The oxygenase enzyme converts the variegatic acid to its quinone methide, which is blue. Interestingly, in many other boletes, in the absence of oxygen, variegatic acid is converted to variegatorubin, which is responsible to the red color found in many members of this group.

What causes blue staining in bolete?

Many boletes become infected by the parasitic Hypomyces chrysospermus (see Fungus Factsheet 57/2011), of which the blue staining boletes are common hosts. The scientific name refers to the stature and colour of the fruit body.

What boletes are toxic?

The dangerous boletus

A genre , Rubroboletus, includes large Boletes with red, orange, yellow pores. All are toxic, starting with the known Bolet de satan, Rubroboletus satanas. After ingestion nausea, diarrhea and vomiting are triggered.