Abstract Chromatographic studies, using several solvent systems with thin‐layer polyamide and silica gel G plates, indicated that Paxillus panuoides (Fr.) Fr. and P. atrotomentosus (Batsch) Fr. contain several common pigments in both carpophores and surface cultures. Atromentin was isolated and identified from the carpophores of P. panuoides , and atromentic and xerocomic acids were recovered and identified from the cultures of this species. These pigments were reported previously from the corresponding growth forms of P. atrotomentosus . Identification of the pigments was based on comparisons of chromatographic properties and spectral data (IR, UV, and high‐resolution mass spectra) with authentic materials. Preliminary interpretation of the complex mass spectrum of atromentin suggested the involvement of at least three basic fragmentation pathways. The pKa values and fluorescent spectra (before and after exposure to radiant energy) of atromentic, pulvinic, and xerocomic acids were determined, and the response of xerocomic acid to thermal energy during sublimation was clarified.