Taxonomy and systematics of Lentinula, Gymnopus, and Rhodocollybia (agaricales, fungi), with emphasis on Oak forests of southern Costa Rica

This dissertation comprises a taxonomic and systematic study of Lentinula, Gymnopus and Rhodocollybia as found in the Talamanca Mountains of southern Costa Rica, based primarily on morphological descriptions and supported by mating studies and ITSI-5.8S-ITS2 nuclear ribosomal DNA sequence analyses. Each morphological description includes analysis of extant or authentic material, examination of the type specimen when possible, and a nomenclatural revision. The genus Lentinula in the Americas comprises three distinct morphological, biological and phylogenetic species. Lentinula boryana and L. raphanica form two intersterility groups distinguished by micromorphology and ITS nrDNA. Assignment of correct names to each species was based on examination of all type specimens of synonymous names for the L. boryana species complex. Both L. boryana and L. raphanica have a widespread tropical-subtropical distribution but only L. raphanica seems to fruit in the Gulf Coast region of the United States. Lentinula aciculospora is the third species known to fruit in the Talamanca Mountains of Costa Rica. Based on ITS nrDNA sequence analysis, all Lentinula species in the Americas form a phylogenetic clade separated from those species in the L. edodes biological species group from Asia and Australia.