1. Institute of Arctic Biology, 311 Irving I Building, 902 N. Koyukuk Drive, P.O. Box 757000, University of Alaska Fairbanks, Fairbanks, AK 99775‐7000, USA
2. Present address: National Herbarium of the Netherlands, Netherlands Centre for Biodiversity Naturalis, Leiden University, Einsteinweg 2, P.O. Box 9514, 2300 RA Leiden, the Netherlands
3. Sequence and Analysis Program, Broad Institute of MIT and Harvard, Cambridge, MA 02141, USA