Microscopic fungi (microfungi) represent a diverse assemblage that is distributed worldwide and includes bread molds, plant pathogens, powdery mildews, rusts, slime molds, and water molds. A large percentage of these organisms are harmless or even beneficial, but some cause disease and death in animals, plants, and other fungi resulting in major economic loss and serious negative implications for human and ecosystem health. Despite their importance, little is known about their distribution, diversity, ecology, or host associations. This project is a collaborative effort involving 38 institutions in 31 states and aims to consolidate data from specimens housed in biodiversity collections for 2.3 million microfungi specimens and make these data available through online resources. The consolidation and increased accessibility of these data is critical to inform and promote new and innovative research, education and community engagement around this little-known but important group of organisms.<br/><br/>Specimen data generated by this project will be used to assess natural and human-induced environmental changes on microfungi distributions, and evaluate the impact of these changes on the function and health of ecosystems. This project fills a critical gap in the national digitization effort by contributing images, digitizing specimen label data, and linking associated ancillary data for over 1.2 million North American specimens of microfungi. Additionally, nomenclature and taxonomic information will be updated to reflect the newest practices as dictated by the International Codes for Nomenclature. These data will provide a foundation for making informed decisions by agribusinesses, educators, forest managers, government agencies, horticulturalists, policy makers, researchers, and the general public. The broader education goals of this project will be facilitated through the development and implementation of a teaching module for high school biology on the economic importance of microfungi. This award is made as part of the National Resource for Digitization of Biological Collections through the Advancing Digitization of Biological Collections program and all data resulting from this award will be available through the national resource (iDigBio.org).