1. Institute of Systematic Botany University of Zurich Zollikerstrasse 107 8008 Zürich Switzerland
2. Biosystematics Group Wageningen University Droevendaalsesteeg 1 6708 PB Wageningen the Netherlands
3. Molecular Systematics Section Jodrell Laboratory Royal Botanic Gardens, Kew Richmond Surrey TW9 3DS UK
4. Herbarium, Library, Art & Archives Royal Botanic Gardens, Kew Richmond Surrey TW9 3AB UK