The original herbarium of Washington State University was founded in the early 1890's by Charles V. Piper, and the mycological collections were moved into a separate facility in the Plant Pathology Department around 1917 by Frederick D. Heald.  Renamed the Charles Gardner Shaw Mycological Herbarium in 2011, it currently includes nearly 75,000 accessioned specimens.

Important collections include: smuts (G.W. Fischer, R. Duran, L.M. Carris, K. Vanky); downy mildews (C.G. Shaw); powdery mildews (D.A. Glawe); Xylariaceae, Diatrypaceae, and other pyrenomycetes (J. D. Rogers & others); and fungi on grasses (R. Sprague), with a focus on the Northwest United States. Fungal exsiccati of historical Northwest collectors including Suksdorf, Piper, & others are available, as well as original complete sets of Fungi Columbiani (E. & E., Bartholomew) and North American Fungi (Ellis & Everhart). Collections from the USA including Alaska & Hawai'i, Canada, the UK, Austria, Germany, Finland, Romania & E. Europe, Mexico, Brazil, Taiwan & SE Asia, Russia, and New Zealand are also well represented.