1. Environmental Science Program, Ramapo College, Mahwah, NJ 07430, USA
2. Department of Botany, University of Wisconsin‐Madison, Madison, WI 53706, USA
3. Department of Biology, Duke University, Durham, NC 27708, USA
4. Systematics and Evolution Group, Section of Natural History, Museum of Natural History and Archaeology, Norwegian University of Science and Technology, N‐7491 Trondheim, Norway