The herbarium at the University of Arizona, with about 315,000 sheets at present, is the largest herbarium in the region. It holds the largest collection of plants from Arizona and from the state of Sonora, Mexico, and significant holdings form all other parts of the arid southwest and northwestern Mexico. A backlog of some 80,000 specimens has accumulated over the course of the herbarium s history. At the current rate of accession, more than a decade would be required to process this material for addition to the herbarium and for distribution of duplicates to other herbaria. Much of the materials is of historical significance and at least half of the backlog was collected form still poorly known areas of northwestern Mexico. Plants form this area are poorly represented in other herbaria, including those in Mexico. Access to all of this material will expedite a number of ongoing systematic, floristic, ethnobotanical and paleoclimatological research projects that are underway at the University of Arizona and other institutions. A two-year project will be conducted to enable the herbarium to work through about two-thirds of the backlog to be accessioned locally. This will entail the standard steps involved in preparing herbarium specimens for permanent archival or distribution: preparation of labels from field notes, filing, sorting duplicates for distribution to herbaria with which the herbarium has an exchange program, packing and shipping.
