Boletus luteum is Boletus, a typical species of the genus Boletus. It is a common fungus in Eurasia, from the British Isles to Korea, and has been widely introduced in other places, including North and South America, Southern Africa, Australia and New Zealand. In English-speaking countries, it is usually called "slip jack" or "fat bun". Its name refers to the brown cap, which is usually sticky in wet conditions. This fungus was first described as Boletus luteus by Carl Linnaeus in 1753 and is now divided into different families and genera. The luteal boletus is edible, although not as highly regarded as other boletus mushrooms, and is usually prepared and eaten in soups, stews or fried dishes. However, if the mucus coating is not removed before consumption, it may cause indigestion.
The fungus grows in coniferous forests in its native range, while pine trees are grown in naturalized countries. It wraps the underground roots of trees with a sheath of fungal tissue, thereby forming a symbiotic ectomycorrhizal connection with living trees. The fungus produces a large number of fruit bodies with spores on the ground in summer and autumn. Before flattening over time, the fruit cover usually has a unique conical shape, up to 13 cm (5 inches) in diameter. Like other boletus, its tube extends downward from under the cap instead of g. The spores escape through the opening or hole of the tube when they are mature. The surface of the pores is yellow, and when they are young, they are partially covered by a membranous veil. The pale stalk or stalk is 10 cm (4 inches) long and 3 cm (1.2 inches) high, with small spots near the top. Unlike most other boletus, it has a unique membranous ring with brown to purple underside.