The Department maintains major research collections of vascular plants, lichens and fossils. The Vascular Plant Herbarium has over 200,000 specimens with an emphasis on the American Southwest, although substantial collections from throughout the Americas are included. The collections are particularly rich in the Cactaceae, Compositae and Myrtaceae. The Lichen Herbarium has well over 85,000 specimens. Although the emphasis is on the western U.S. and Mexico, representation is world-wide in scope.
Collections are particularly rich in the Lecanoraceae and Parmeliaceae.
The Plant Fossil Collections include over 5,000 megafossil specimens of worldwide representation, as well as fossil and extant palynomorph samples and extant wood and other anatomical specimens. Special emphasis in the collections is on the American West, including permineralized and petrified Tertiary materials. Within the Department as a whole there are a large number of desktop PC's, Macintosh's, Hewlett-Packard, Sun and Silicon Graphics' Unix work stations, as well as digitizers, color scanners, printers and plotters. Although many computer systems are located in individual laboratories, part of these facilities are centered in a separate computer room primarily utilized by graduate students. In addition, the Department manages a 24 station computer teaching laboratory.