Caloboletus calopus

Caloboletus calopus, commonly known as the bitter bolete, bitter beech bolete or scarlet-stemmed bolete, is a species of fungus in the bolete family. Christiaan Persoon first described Boletus calopus in 1801. Modern molecular phylogenetics showed that it was only distantly related to the type species of Boletus and required placement in a new genus; Caloboletus was erected in 2014, with C. calopus designated as the type species. The stout fruit bodies are attractively coloured, with a beige to olive cap up to 15 cm (6 in) across, yellow pores, and a reddish stipe up to 15 cm (6 in) long and 5 cm (2 in) wide. The pale yellow flesh stains blue when broken or bruised. Its red stipe distinguishes it from Boletus edulis. Appearing in coniferous and deciduous woodland in summer and autumn, the species is found in Eurasia and North America. Although not typically considered edible due to an intensely bitter taste that does not disappear with cooking, there are reports of it being consumed in eastern Europe.