SUMMARYFive new species ofMelanoleuca(Tricholomataceae) from boreal, alpine and arctic habitats are described. In addition, five other species are treated including several previously unreported from North America. New ecological information and unreported distributions in tundra and boreal habitats are reported for all ten species. Microscopic and macroscopic features are described and discussed, accompanied by camera lucida drawings and black and white photographs. A key to the species is presented.