The fungus collections of the Smithsonian Institution were transferred to the U.S. Department of Agriculture in 1869 as the foundation of the Pathological Collections. Later they became the Mycological Collections and finally the U.S. National Fungus Collections, as changes in the title reflected a broadened role and status of the technical resources. In 1885, when the herbarium had fewer than 3,000 collections, F. Lamson Scribner assumed charge as the first Federal pathologist. He was followed by Franklin S. Earle in 1891, and Flora W. Patterson in 1896. Patterson organized programs and assembled a staff that notably influenced subsequent development of the U.S. National Fungus Collections. Emphasis was on the taxonomy of plant pathogens, but significant pathogens and closely related potential pathogens were also listed for nearly every fungus family.
The presence in America of the bubble disease of mushrooms, which threatened the entire industry, was first recognized in 1909 by scientists working with the U.S. National Fungus Collections. This group of scientists also was responsible for the earliest American investigations of "Plaster molds" and other important pathogens of mushrooms. Before the Plant Quarantine Act was passed in 1912, Vera K. Charles and Patterson conducted pathological inspection of imported plants. Among their interceptions was the dangerous potato wart disease caused by Synchytrium endobioticum, which they identified for the first time in the United States on imported potatoes.
In 1917 the Plant Disease Survey was organized as a distinct project coordinated with the Pathological Collections. Cooperation between these units stimulated progress on taxonomic and host-distribution inventory of American pathogens, as documented by specimens in the U.S. National Fungus Collections. At first, nearly all research and service activities of the Pathological Collections were the personal responsibility of Patterson and Charles. In addition to Charles' studies of mushrooms, she did research on the fungal pathogens of insects. In 1941 this work culminated in the publication of a comprehensive checklist of entomogenous fungi of North America. The scientific staff working on the U.S. National Fungus Collections was enlarged by the appointments of Anna E. Jenkins in 1912, Edith K. Cash in 1913, and William W. Diehl in 1917. Jenkins was the foremost authority on spot-anthracnose fungi, which cause leaf and blossom disease and scab of many economically important plants. The representation of these fungi in the U.S. National Fungus Collections is the most comprehensive and taxonomically authoritative anywhere. Cash was widely recognized for her investigation of cup fungi (discomycetes), which also include major plant pathogens. Diehl's work culminated in the publication of the only modern monograph on Balansia, a genus of pathogens significant in causing sterility in grasses.
Patterson retired in 1923, and James R. Weir was in charge of the U.S. National Fungus Collections until 1927. While in charge of the collections, he prepared a comprehensive report on the fungi that cause diseases of the Hevea rubber tree. In 1927 Cornelius L. Shear collaborated with B.O. Dodge in the publication of a pioneering report on the life histories and heterothallism of red bread-mold fungi. This was the study that later brought Neurospora into prominence as an experimental genetic organism and opened a broad new field of genetic research.
After 1927, when John A. Stevenson succeeded Weir in charge of the collections, buildup of the herbarium and associated reference material was intensified. Stevenson had worked in Puerto Rico as a plant pathologist. He retained his interest in tropical pathology while in charge of the Mycological Collections. As a result, he collaborated extensively with tropical plant pathologists, such as F.D. Wellman, in development of the herbarium, specimen identification, preparation of Geographical and host compendia, and research publications. Working relationships also were developed with outstanding national authorities, such as J.L. Lowe and G.B. Cummins, specialists in the taxonomy of wood-decay polypores and rust fungi, respectively. Ross W. Davidson was employed in 1928 to work with the U.S. National Fungus Collections. After a few years, his transfer to the Office of Forest Pathology stimulated further cooperation with that organization in the acquisition of wood-decay fungi as herbarium specimens.
In 1947 Paul L. Lentz joined the research staff of the collections. His interests in the classification and biology of wood-decay fungi resulted in a monograph on Stereum in 1955 and led then to the recognition and description of the fungus that causes pecky cypress. In 1958 Marie L. Farr came to the U.S. National Fungus Collections as a taxonomic specialist in the myxomycetes. She also worked extensively with black mildews and other fungi prevalent in the tropics as leaf parasites, epiphyses, and hyperparasites. Chester R. Benjamin was placed in charge of the U.S. National Fungus Collections as Stevenson's successor in 1960. Within a few years, he increased the staff by adding mycologists. John L. Cunningham, a specialist in rust taxonomy, arrived in 1965, as did Francis A. Uecker, whose specialization was in the cytology and developmental morphology of pyrenomycetes. Kent H. McKnight reestablished a program of mushroom taxonomy and ecology in 1966. The following year, Lekh R. Batra was employed to continue his diverse research projects in the classification of discomycetes, hemiascomycetes, and fungus-insect relationships. After Benjamin's departure in 1971, Lentz assumed charge of the U. S National Fungus Collections and its associated research. Joseph F. Ammirati was employed in 1973 as an agaricologist, and he was succeeded by David F. Farr, who joined the mycology staff in 1974 to work primarily with noncultivated mushrooms and later to become the expert in computer technology.
With Paul Lentz's retirement in 1983, Amy Y. Rossman became director of the U.S. National Fungus Collections and continued the program of specimen data computerization. Her knowledge of plant pathogenic fungi in general and the Hypocreales continued the tradition of research on fungi important to U.S. agriculture. Under the guidance of Farr, two research associates -- Gerald F. Bills and George P. Chamuris -- provided the expertise for the relational database that resulted in the monumental account of 13,000 species of fungi reported on plants and plant products in the United States. A companion volume on the vascular plant hosts was completed by Lois A. Brako, who was assisted by Rossman and Farr.
In 1989 Gary J. Samuels was hired to develop a program on the systematics of fungi useful in the biological control of plant diseases following the retirement of M.L. Farr and K. McKnight. This work concentrated on Hypocrea-Trichoderma, with molecular expertise provided by Robert Meyer followed by Stephen Rehner. Tackling this extremely difficult but important group of fungi has required a team effort using morphological and molecular approaches. Samuel's strains of Trichoderma isolated from tropical specimens of Hypocrea are combined with asexual isolates to determine systematic relationships that are the basis for predicting their effectiveness. In 1994 Samuels worked with Rehner to discover a technique for producing sexuality in asexual strains of Hypocrea. Francis A. "Bud" Uecker retired in January 1995. He was working on the systematics of plant pathogenic fungus, Phomopsis, using both morphological and molecular approaches.
Lisa A. Castlebury was hired as a research associate in 1997 to distinguish Karnal bunt of wheat from a similar-looking fungus on ryegrass. The false positive response to the ryegrass bunt fungus threatened the U.S. export of wheat for several months until this distinction could be determined. The ryegrass bunt was described as the new species, Tilletia walkeri. Castlebury joined the SBML in 1999 to serve as the expert in the systematics of smut and bunt fungi and to provide expertise in molecular systematics. Castlebury, Rossman and Farr are continuing research on the canker-causing genus Phomopsis and its teleomorph Diaporthe as well as working on all members of the Diaporthales.
In 2002 permanent funds were received to initiate a program in the molecular systematics of rust fungi (Uredinales). Cathie Aime was hired to serve as the scientist in that position. She worked with José Hernández, Visiting Scientist from Argentina, who provided morphological expertise. Hernández developed an interactive database for the identification of species of Ravenelia and other rusts of importance.
The U. S. National Fungus Collections are under the care of Collections Manager Erin B. McCray, who also serves as the main contact for the fungal databases and computer network assisting David Farr. Recent progress has been made in the computerization of specimens of the agarics and the "lower" fungi including the Oomycetes and Chytridiomycetes.