Gyroporus cyanescens

Gyroporus cyanescens, commonly known as the bluing bolete or the cornflower bolete, is a species of bolete fungus in the family Gyroporaceae. First described from France in 1788, the species is found in Eurasia, Australia, and eastern North America, where it grows on the ground in coniferous and mixed forests. The yellowish to buff cap surface is fibrous and roughened, and reaches up to 12 cm (4.7 in) in diameter. The thick stem, roughly the same color as the cap or lighter, is hollowed out into chambers. All parts of the mushroom turn an intense blue color within a few moments of bruising or cutting. The mushroom is edible, despite its hard stem. A less common variety occurs where the color change is to deep violet rather than blue. The bluing reaction results from the enzymatic oxidation of a chemical called gyrocyanin....read more on Wikipedia.