Rubroboletus satanas

Morphological Features:

Pileus of spectacular size, perhaps the most robustly built bolete there is, it can reach 30 cm in diameter and is fleshy and sturdy. Hemispherical when young, later becoming convex, never flattening out. Dirty white in color, sometimes blotched with earthy tones, but it never exhibits red or pinkish hues on its surface, which is smooth and dry. Margin slightly overhanging and incurved in young specimens.

Tubes long, yellowish to olivaceous, staining very slowly pale blue when cut.

Pores red in color, sometimes zonally orange, round and small, with scarce and slow blue staining.

Stipe generally shorter than the pileus diameter, blunt and stout, lacking a reticulum. Yellow above and red below, but over time the red coloration spreads to cover practically the entire stipe.

Flesh thick and compact, predominantly white, slightly tinged yellow in areas, staining slowly and weakly blue when cut. Its odor is not very pleasant, whereas its taste is sweet and agreeable.

Habitat:

It has consistently been found under broadleaf trees, particularly oaks, during summer and early autumn. It is a thermophilous species that disappears with the onset of cold weather. It is rather scarce and warrants protection.

Observations:

A markedly toxic mushroom, somewhat unusual for the genus, causing significant gastrointestinal disturbances. Based on pileus coloration, it closely resembles Suillellus rhodoxanthus; however, the latter possesses a conspicuous red reticulum on the stipe and exhibits differential blue staining between the pileus and stipe when cut. Other congeners lack a white pileus, although there is some confusion regarding this group.