1. Laboratory of Plant Systematics; K.U. Leuven, Kasteelpark Arenberg 31, P.O. Box 2437, Leuven 3001 Belgium
2. Instituto de Biología; Universidad Nacional Autónoma de México; Postal 70-367, CP 04510 Mexico
3. National Herbarium of the Netherlands; Leiden University Branch; P.O. Box 9514, RA Leiden 2300 The Netherlands
4. National Botanic Garden of Belgium; Domein van Bouchout, Meise 1860 Belgium