1. Office of Arid Lands Studies, University of Arizona, 1955 E. Sixth St, Tucson, AZ 85721, USA
2. Department of Soil, Water and Environmental Science, University of Arizona, PO Box 210038, Tucson, AZ 85721‐0038, USA
3. Herbarium, University of Arizona, PO Box 210036, Tucson, AZ 85721‐0036, USA