Edmonds, RobertHonan, Amy2021-10-292021-10-292021Honan_washington_0250E_23539.pdfhttp://hdl.handle.net/1773/48037Thesis (Ph.D.)--University of Washington, 2021Tulostoma is speciose group of stalked puffballs with a high diversity in grasslands and arid environments. This cosmopolitan genus exhibits a high degree of spore morphological variation. Recent molecular analysis suggests the center of diversity of this genus occurs in European steppe habitats. In North America, taxonomic literature indicates that the center of diversity for the genus occurs in the southwestern United States. In this research, I reconstructed the phylogeny of Tulostoma using newly sequenced collections combined with available sequence data. This phylogeny, inferred from ITS, LSU, and Tef1α sequence data confirms the monophyly of the genus. The taxonomy of the Tulostoma recovered from the southwestern United States is outlined and a dichotomous key for these species is provided. The phylogeny is then used to investigate phylogeographic patterns in the genus. The phylogeographic analysis indicates a Palearctic origin for the genus. The phylogeography also suggests both vicariance and long-distance dispersal events contributing to the diversification of the species over the evolutionary history of the genus. The evolution of spore morphology is then investigated using a phylogenetic approach. The ancestral character state for spores is medium to strong ornamentation with ornamentation being lost at least 4 times over evolutionary history. It was hypothesized that spore ornamentation and spore size are correlated with moisture availability, however comparisons between spore ornamentation and size and annual precipitation were not able to discern this pattern. Finally C:N isotopic ratios were evaluated to confirm the saprotrophic habit of Tulostoma species. These analyses split Tulostoma into 2 clusters, one associated with largely biotrophic species and the other consisting predominately of saprotrophic species. The saprotrophic status of Tulostoma is as expected, however the biotrophic status of Tulostoma as suggested by isotopic analysis warrants further investigation.application/pdfen-USCC BY-NC-NDEcologyMycologyPhylogenyPhylogeographyTulostomaEcologyBiologyForestryThesis