PHYLOGENETIC-RELATIONSHIPS OF LENTINUS (BASIDIOMYCOTINA) INFERRED FROM MOLECULAR AND MORPHOLOGICAL CHARACTERS

Phylogenetic relationships of the basidiomycete Lentinus were investig ated using 20 morphological and 133 nucleic acid sequence characters f rom three regions in the 5' half of the nuclear-encoded large subunit rRNA. Molecular data were obtained from 34 individuals that represent 11 species in Lentinus, nine in the Polyporaceae, eight in the Trichol omataceae, and one in the Corticiaceae. Thanetephorus cucumeris (Tulas nellales) was used as an outgroup for rooting purposes. Most of the se quence variation was in regions that correspond to eukaryote-specific divergent domains D1 and D2. Molecular data alone yielded a well-resol ved cladogram but morphological data alone were insufficient to resolv e phylogenetic relationships. The most resolved cladograms were obtain ed with a combined analysis of molecular and morphological characters. Bootstrap and decay index measures of branch robustness had a signifi cant positive correlation, but some branches with high bootstrap value s were contradicted by near-minimal trees. Monophyly of Lentinus sensu Pegler was not supported. Rather, three monophyletic groups of Lentin us species were resolved. These largely correspond to Neolentinus, Pan us, and Lentinus s. str. The latter appears to be derived from the Pol yporaceae, suggesting that lamellae are products of convergent evoluti on.