1. University of Colorado, Dept. of Ecology & Evolutionary Biology, UCB 334, Boulder, CO 80309, U.S.A.
2. University of Kansas, Biodiversity Institute, R.L. McGregor Herbarium, Lawrence, KS 66047, U.S.A.
3. New York Botanical Garden, 2900 Southern Blvd., Bronx, NY 10458, U.S.A.