1. Alaska Geobotany Center, Institute of Arctic Biology, University of Alaska Fairbanks, 311 Irving, P.O. Box 757000 Fairbanks, AK 99775, USA
2. Institute für Botanik und Botanischer Garten, Westfälische Wilhelms‐Universität Schloßgarten 3, D‐48149 Münster, Germany; E‐mail
3. Icelandic Museum of Natural History P.O. Box 5320, Reykjavik, Iceland; E‐mail
4. Institute of Biology and Geology, University of Tromsø N‐9037 Tromsø, Norway; E‐mail
5. International Institute for Tropical Forestry, USDA Forest Service 1201 Calle Ceiba, San Juan, Puerto Rico, PR 00927‐1119, USA; E‐mail
6. Department of Far North Vegetation, Komarov Botanical Institute RAS, Prof. Popov str. 2, 197376 St. Petersburg Russia; E‐mail
7. E‐mail
8. USGS Alaska Geographic Science Office 4230 University Dr., Anchorage, AK 99508‐4664 USA; E‐mail 8 Earth Cryosphere Institute SB RAS Vavilov str. 30/6, r. 85, Moscow 119991, Russia
9. US Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, AK 99503, USA; E‐mail
10. see footnote