RESUMO
The evolutionary history of the genus Omphalotus was inferred from DNA sequences of the ITS1-5.8S-ITS2 rDNA region. We analyzed 32 collections from different geographical areas: O. olearius (Europe), O. illudens (Europe, North America), O. subilludens (North America), O. olivascens var. olivascens (North America) and var. indigo (Mexico), O. mexicanus (Middle America), O. nidiformis (Australia), and O. japonicus (Japan). Phylogenetic analysis was performed declaring Nothopanus eugrammus as outgroup. Our analyses show that the genus Omphalotus is split into two major clades, the first consisting of O. illudens and O. mexicanus and the second comprising O. olearius, O. olivascens, O. japonicus, O. nidiformis and O. subilludens. Moreover, the often discussed synonymy of O. illudens and O. olearius is rejected. Omphalotus japonicus, a species formerly placed in the genus Lampteromyces Sing. for morphological reasons, clustered as the sister group of O. olearius.