A survey will be conducted for three years to collect, identify and isolate Ascomycetes (fungi) from freshwater habitats. Ascomycetes will be collected from submerged aquatic macrophytes and woody debris in both lentic and lotic habitats along two latitudinal gradients in North America. Identified specimens will be deposited in major herbaria; cultures will be screened for the production of asexual states and novel antibiotics, and deposited at the American Type Culture Collection. Descriptions of new or noteworthy species will be published in international journals and a monograph with descriptions, illustrations and a key will be prepared. Data from this study will contribute to our understanding of phylogenetic relationships among Ascomycetes, the influence of latitude on fungal diversity and composition, teleomorph-anamorph relationships, and the morphological adaption of Ascomycetes to freshwater habitats. Cultures obtained during this study represent a new source of secondary compounds and provide material to mycologists for further study in systematic, developmental, physiological, molecular, and ecological studies. This project will provide training to graduate student sin ascomycete systematics, preparing and depositing herbarium specimens, identifying and describing taxa, isolating fungi and depositing cultures, and manipulating a large taxonomic database.