 Lactarius deterrimus , also known as false saffron milkcap or orange milkcap , is a species of fungus in the family Russulaceae . The fungus produces medium @-@ sized fruit bodies ( mushrooms ) with orangish caps up to 12 cm ( 4 @.@ 7 in ) wide that develop green spots in old age or if injured . Its orange @-@ coloured latex stains maroon within 30 minutes . Lactarius deterrimus is a mycorrhizal fungus that associates with Norway spruce and bearberry . The species is distributed in Europe , but has also found in parts of Asia . A visually similar species in the United States and Mexico is not closely related to the European species . Fruit bodies appear between late June and November , usually in spruce forests . Although the fungus is edible — like all Lactarius mushrooms from the section Deliciosi — its taste is often bitter , and it is not highly valued . The fruit bodies are used as source of food for the larvae of several insect species . Lactarius deterrimus can be distinguished from similar Lactarius species by difference in the mycorrhizal host or latex colour . 
