extensively blue when cut and narrower spores, measuring 9–15 × 4–6 μm. Rubroboletus pulchrotinctus has a variable cap colour often featuring a pinkish band at the margin; has a dull-coloured stipe without deep red tinges, pores that remain yellow or orange even in mature fruit bodies, and somewhat narrower spores, measuring 12–15 × 4.5–6 μm. Rubroboletus rubrosanguineus is associated with spruce (Picea) or fir (Abies), has pinkish tinges on the cap and smaller spores, measuring 10–14.5 × 4–6 μm. Caloboletus calopus is usually associated with coniferous trees, has pores that remain persistently yellow even in overripe fruit bodies, has a more slender, cylindrical or clavate stipe and narrower spores, measuring 11–16 × 4–5.5 μm. Distribution and habitat Rubroboletus satanas is widely distributed throughout the temperate zone, but is rare in most of its reported localities. In Europe, it mostly occurs in the southern regions and is rare or absent in northern countries. It fruits in the summer and early autumn in warm, broad-leaved and mixed forests, forming ectomycorrhizal associations with oak (Quercus) and sweet chestnut (Castanea), with a preference for calcareous (chalky) soils. Other frequently reported hosts are hornbeam (Carpinus), beech (Fagus) and lime (Tilia). In the United Kingdom, this striking bolete is found only in the south of England. It is rare in Scandinavia, occurring primarily on a few islands in the Baltic Sea where conditions are favourable, with highly calcareous soil. In the eastern Mediterranean region, it has been reported from the Bar'am Forest in the Upper Galilee region of northern Israel, as well as the island of Cyprus, where it is found in association with the narrow-endemic golden oak (Quercus alnifolia). It has further been documented in the Black Sea and eastern Anatolia regions of Turkey, as well as Crimea and Ukraine, with its distribution possibly extending as far south as Iran. In the past, R. satanas had been reported from the coastal areas of California and the southeastern US, however, these sightings are instead of the closely related species Rubroboletus eastwoodiae. Toxicity Satan's bolete is poisonous, especially if eaten raw. The symptoms, which are predominantly gastrointestinal in nature, include nausea, abdominal pain, violent vomiting and bloody diarrhoea that can last up to six hours. A 2012 study on mushroom poisonings in Switzerland by Katharina M. Schenk-Jaeger and colleagues, found Rubroboletus satanas to have caused severe gastrointestinal symptoms, including recurrent vomiting and bloody diarrhoea. The toxic enzyme