1. Department of Ecology, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 44, Czech Republic
2. Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-University of Göttingen, Untere Karspüle 2, Göttingen, 37073, Germany
3. The Czech Academy of Sciences, Institute of Botany, Dukelská 135, Třeboň, 379 82, Czech Republic
4. Centre for Polar Ecology, University of South Bohemia, Na Zlaté stoce 3, České Budějovice, 370 05, Czech Republic