1. Universidad Nacional Autónoma de México, Instituto de Biología, Departamento de Botánica, Apartado Postal 70‐233 04510 México, Distrito Federal, Mexico
2. Department of Systematic Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE‐75236 Uppsala, Sweden
3. L'Institut de recherche pour le développment, International Center of Physiology and Ecology, P.O. Box 30772 Nairobi, Kenya
4. Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman 59717 USA