Lactarius uvidus
Lactarius uvidus is a European and North American "milk-cap" mushroom, of which the milk turns violet when the flesh is damaged. The fungi generally identified as "L. uvidus" are part of a complex of closely related species and varieties which are difficult to delimit definitively. It gives its name to the section "Uvidi" within the genus "Lactarius". It is generally thought to be poisonous. Taxonomy. "Lactarius uvidus" was first described by Swedish mycologist Elias Magnus Fries as "Agaricus uvidus" in 1818, before being given its current binomial name by the same author in 1838. Distribution. This cluster  of species is found in deciduous and coniferous woods, with a preference towards acid soils. It has a wide distribution in Europe, North Africa, and North America, being fairly common in some regions but rare in others. It appears classified as vulnerable or endangered in the Danish and Dutch Red Lists of Fungi. Related species. "Lactarius uvidus" belongs to section "Uvidi" of the genus, the members of which are characterized by milk which discolours violet, and by the greasy cap surface. These mushrooms are divided into two sub-sections: the "Aspidieni", which have a whitish, ochre or greyish cap, and  the "Uvidini" (including "L. uvidus"), which have a lilac, violaceous, or brownish cap. A more complete list of these species can be found in the List of Lactarius species. Some less well-known but closely related European species are "L. pseudouvidus" Kühner (1985) (found in alpine zone, up to 4 cm in diameter, with ochraceous yellow gills), "L. robertianus" Bon (1985) (also alpine, darker coloured, with smell of cedar wood), and "L. luridus" (Pers.) Gray (1821) (whose milk goes a deep violet). Since "L. uvidus" seems to be a cluster of species, it is particularly difficult to pin down the  correspondence between descriptions and collections originating from Europe (on one hand) and from North America (on the other). Some examples of varieties inside the main species are "L. uvidus var. pallidus" Bres. (which is whitish), and "L. uvidus var. candidulus" Neuh. (which is small and pale and comes in muddy places).