1. Key Laboratory of Tropical Biological Resources of Ministry of Education, College of Tropical Crops Hainan University Haikou 570228 China
2. Department of Plant and Microbial Biology, College of Biological Sciences University of Minnesota, 140 Gortner Laboratory Saint Paul MN 55108 USA
3. Department of Biology Oberlin College Oberlin OH 44074 USA
4. Department of Botany National Museum of Natural History, MRC‐166, Smithsonian Institution Washington DC 20013‐7012 USA