Lactarius is a genus of mushroom-producing, ectomycorrhizal fungi, containing several edible species. The species of the genus, commonly known as milk-caps, are characterized by the milky fluid ("latex") they exude when cut or damaged. Like the closely related genus Russula, their flesh has a distinctive brittle consistency. It is a large genus with roughly 450 known species, mainly distributed in the Northern hemisphere. Recently, the genus Lactifluus has been separated from Lactarius based on molecular phylogenetic evidence.