1. Institute of Botany and Microbiology; Laboratory of Plant Systematics; Kasteelpark Arenberg 31, P.O. Box 2437, 3001 Leuven Belgium
2. Leiden University; Netherlands Centre for Biodiversity Naturalis (section NHN); P.O. Box 9514, 2300 RA Leiden The Netherlands
3. Royal Botanic Gardens; Jodrell Laboratory; Kew, Richmond, Surrey TW9 3DS U.K
4. Institute of Systematic Botany and Ecology; Jodrell Laboratory; Albert-Einstein-Allee 11, Ulm 89081 Germany