RESUMEN
William Alphonso Murrill was an American mycologist of the early 20th century. He described 1453 new species of Agaricales, Boletales, and Polyporales. Within these were 44 taxa that he described as Hebeloma or that he recombined into Hebeloma. Additionally, there are five species, of which we are aware, that Murrill described within other genera that should be referred to the genus Hebeloma. A further three species described from northern America by J. P. F. C. Montagne, and transferred to Hebeloma by Saccardo, were commented on by Murrill and not accepted within the genus. These 52 taxa are analyzed here, both morphologically and molecularly, as far as possible. For 18 of his types, internal transcribed spacer (ITS) sequences were generated. For two species (H. harperi and H. subfastibile), which were mixed collections, lectotypes are designated. Twenty-three of the taxa analyzed are Hebeloma, as the genus is recognized today, and six of these (H. australe, H. harperi, H. paludicola, H. subaustrale, H. subfastibile, and H. viscidissimum) are regarded as current, i.e., they are names that should be accepted and used. Hebeloma paludicola is an earlier name for H. hygrophilum, described from Europe. Gymnopilus viscidissimus is synonymous with H. amarellum but has priority and is here recombined into Hebeloma. The remaining 17 Hebeloma taxa are synonymized with other species that have priority. The remaining 29 species belong to a range of genera; molecularly supported were Agrocybe, Cortinarius, Inocybe, Inosperma, Phlegmacium, Pholiota, Pseudosperma, and Pyrrhulomyces. Recombinations and synonymizations are made as appropriate and necessary. The names H. alachuanum and H. vatricosum, respectively Inocybe vatricosa, are considered doubtful and should be avoided.