, commonly known as the woolly milkcap
or the bearded milkcap
, is a large agaric fungus. A common and widely distributed species, it is found in North Africa, northern Asia, Europe, and North America. It was first described scientifically by Jacob Christian Schäffer in 1774 as an Agaricus
, and later transferred to the genus Lactarius
in 1821 by Samuel Frederick Gray. A variety, L. torminosus
, is known from the United States, Canada, and Switzerland. L. torminosus
officially became the type species of Lactarius
in 2011 after molecular studies prompted the taxonomic reshuffling of species between several Russulaceae genera.
A mycorrhizal species, L. torminosus
associates with various trees, most commonly birch, and its fruit bodies (mushrooms) grow on the ground singly or in groups in mixed forests. The caps of L. torminosus
mushrooms are convex with a central depression, and attain a diameter of up to 10 cm (3.9 in). A blend of pink and ochre hues, the cap sometimes has concentric zones of alternating lighter and darker shades. The edge of the cap is rolled inward, and shaggy when young. On the underside of the cap are narrow flesh-colored gills that are crowded closely together. The cylindrical stem is a pale flesh color with a delicately downy surface and brittle flesh; it is up to 8 cm (3.1 in) long and 0.6–2 cm (0.2–0.8 in) thick. When cut or injured, the fruit bodies ooze a bitter white latex that does not change color upon exposure to air. The variety nordmanensis
, in contrast, has latex that changes from white to yellow. Lactarius torminosus
can be distinguished from similar species like L. pubescens
or L. villosus
by differences in morphology and coloration, or by microscopic characteristics like spore shape and size. (Full article...