The U.S. National Fungus Collections (BPI) are the “Smithsonian for fungi” and are the repository for over one million fungal specimens worldwide - the largest such collections in the world. The collection includes preserved organisms, their parts and products, and their associated data. Information associated with these specimens constitute an enormous data resource, especially about plant-associated fungi. The collections document fungi through time and space for the past 200 years. Data from the labels of more than 750,000 of the specimens have been entered into a database. These labels have information on the host on which the fungus was found and the locality in which the specimen was collected. Sixty percent of these specimens are from the United States and thus represent a large body of information about the fungi in this country. Data entry has been completed for the Uredinales (rusts), the Ustilaginales (smuts), the Polyporales (polypores), the Deuteromycetes (imperfect fungi), the Ascomycetes, and the C.G. Lloyd collections. Recent progress has been made in the computerization of specimens of the agarics and the "lower" fungi including the Oomycetes and Chytridiomycetes.

The USDA Nematode Collection is one of the largest and most valuable nematode collections in existence. It contains over 49,000 permanent slides and vials, with a total repository of nematode specimens reaching several million, including Cobb-Steiner, Thorne, and other valuable collections. Nematodes contained in this collection originate from world-wide sources. The USDA Nematode Collection Database contains over 38,000 species entries. A broad range of data is stored for each specimen, including species, host, origin, collector, date collected and date received. All records are searchable and available to the public through the online database. The physical collection is housed at the USDA Nematology Laboratory in Beltsville, MD. Specimens are available for loan to scientists who cannot personally visit the collection. Please see the Policy for Loaning USDANC Specimens for more information on this process. Scientists and other workers are always welcomed and encouraged to deposit material into the collection.