Abstract: This checklist was compiled as part of the Flora of the Sonoran Desert Network Project, a project of the Vegetation Mapping program at the Sonoran Desert Network (http://science.nature.nps.gov/im/units/sodn/index.cfm). It was derived from baseline inventory data, herbarium records, the phylogenetic and ecological literature, and agency study records originating within the park boundary. It is important to note that the Tucson Mountain District (TMD) flora listed here consists of only voucher specimens collected within the boundaries of Saguaro National Park. The TMD is only a portion of the much larger Tucson Mountains range. The Tucson Mountains Flora was completed in 1991 by Rondeau et al. (http://ag.arizona.edu/herbarium/projects/floras/tucson-mountains) and represents a more substantial frame within which to consider the flora of Saguaro National Park.