Boletus is the botanical name of a large family of mushrooms, to which the famous penny bun belongs. No member of this family is considered poisonous (except Satan's bolete or Devil's bolete). The characteristic of these mushrooms, which grow in oak, chestnut, and beech woods, is the stumpy stem and the head that can reach up to 12 inches in diameter. Underneath, the cap is spongy, unlike many other mushrooms which are generally lamellar.