1. Institute of Systematic Botany, The New York Botanical Garden, Bronx, NY 10458-5126, U.S.A.
2. Biodiversity Knowledge Integration Center & School of Life Sciences, Arizona State University, P.O. Box 874108, Tempe, AZ 85287-4108, U.S.A.
3. Caleb A. Morse, Biodiversity Institute, R.L. McGregor Herbarium, University of Kansas, 2045 Constant Ave., Lawrence, KS 66047, U.S.A.
4. University of Colorado, Museum Herbarium, Clare Small Building, UCB 350, Boulder, CO 80309, U.S.A.