Postmeiotic nuclear behavior inLentinns, Partus, andNeolentinus

We investigated nuclear behavior during basidiosporogenesis in Lentinw, Panus, and Neolenti- nus in an attempt to discover characters for taxonomic segregation of lentinoid-pleurotoid fungi. In Lentinus tigrinus and Panus lecomtei somatic hyphae are binu- cleate. Karyogamy and meiosis occur in the basidia, meiotic products migrate into spores and postmeiotic mitosis occurs; this is followed by back-migration of one nucleus from each spore into the basidium. Ma- ture spores are consequently uninucleate and dis- charged basidia are quadrinucleate. In Neolentinus le- pideus many somatic cells are multinucleate. Karyogamy, meiosis, and postmeiotic mitosis occur as in L. tigrinus and P. lecomtei, but there is no back- migration, mature spores are binucleate, and dis- charged basidia are anucleate. The patterns of nuclear behavior in L. tigrinus and P. lecomtei correspond to type C nuclear behavior as defined by Duncan and Galbraith, whereas that of Neolentinus corresponds to type D nuclear behavior. Lentinus and Panus cannot be distinguished on the basis of postmeiotic nuclear behavior, but both can be distinguished from Pleurotus