Suillus luteus is a basidiomycete fungus, and the type species of the genus Suillus. It is a common fungus indigenous to coniferous forests of Eurasia and North America, and introduced to southern Australia and New Zealand. Commonly referred to as slippery jack or sticky bun in English-speaking countries, its names refer to the brown cap, which is characteristically viscid in wet conditions. The fungus fruits abundantly in autumn, and is harvested for food. The slime coating, however, may cause indigestion if not removed.