The wood degrading ability of basidiomycetes, 41 wood decomposers, 22 litter decomposers, and 5 mycorrhizal symbionts, was measured in aseptic culture on an agar medium. The wood decomposers had greater variation in this ability than the litter decomposers. Ratios of percent lignin loss to percent weight loss of the wood specimens (the lignin loss ratio) were somewhat higher in the white-rot fungi than in the brown-rot fungi. The species collected from the L and F layers of litter deposits, such as Collybia confluens, Collybia dryophila, and Hygrocybe sp., and Marasmius maximus, decomposed wood more than the species from the H layer. These species also produced lignin loss ratios two to three times that of the white-rot species of wood decomposers. Ten litter decomposers bleached wood specimens to yellowish white, as typical white-rot species do. None of the mycorrhizal species degraded wood during 80 days of culture. The wood and litter decomposers showed highly significant variation among species within a genus for wood degrading ability.