Charles Bessey, the founder of the Ada Hayden Herbarium, added approximately 1500 fungal specimens to the herbarium's holdings. Bessey's first student was J. C. Arthur, who eventually became the leading authority on the rust fungi. His early work on fungi increased the holdings of the herbarium. L. H. Pammel and his students, including George W. Carver, continued to build the mycological collection. Pammel himself added approximately 7,500 specimens. In 1916, Irving E. Melhus was hired as Iowa State's first plant pathologist. Two years later, Joseph C. Gilman joined Melhus as a mycologist and plant pathologist.
Subsequent studies of plant diseases, continued through the work of
Lois H. Tiffany, who added numerous specimens from Iowa State parks
and preserves. Dr. Tiffany is also responsible for the placement here
of the prestigious University of Iowa Mycological Herbarium when it
was decided that the collection could no longer be housed at Iowa
City. This collection contains the specimens of George Martin, Thomas
H. Macbride, and A. P. Morgan, and is rich in type specimens.
Currently the mycological collection contains an estimated 25,000
packeted and boxed specimens and numerous bound exsiccatae.