A floristic analysis and checklist for the northern Santa Rita Mountains, Pima Co., Arizona

The northern Santa Rita Mountains, a chain of low peaks rising to nearly 1,900 m, are situated northeast of the main body of the range, which extends nearly 1,000 m higher in elevation. The study area covered 260 km2, ranged from 1,006 to 1,918 m, and had a flora consisting of 628 native species of vascular plants. Floristic affinities were examined using an indirect Q-mode analysis of the distributions of the species in local floras from throughout the western United States. In the northern Santa Ritas flora, species with widespread distributions in the western United States have affinities with the Sonoran and Colorado Plateau floristic elements; those with more narrow distributions are allied primarily with the Apachian and Chihuahuan floristic elements.