Extracts of sixteen species of agarics were chromatographed using two different solvent systems, and the patterns of Ehrlich–positive constituents in the extracts were determined. The data suggest that the lack of accumulation of urea is characteristic of the genus Tricholoma, that Armillaria zellerii is closely related to T. aurantium and both species appear to belong in Tricholoma subgenus I, that T. sclerotaideum belongs in the genus Clitocybe, and that T. inamoenum and T. sulphureum may be only varieties of the same basic form rather than distinct species.