S. Robbert Gradstein is the former director of the Department of Systematic Botany at G ettingen University, Germany. He serves as Editor-in-Chief of Taxon. Jurgen Homeier is a Senior Lecturer at Albrecht von Haller Institute for Plant Sciences, G ettingen University, Germany. Among his research areas are ecology of tropical forests, tree species composition and diversity, tree regeneration and forest dynamics, factors influencing species composition and productivity of tropical forest ecosystems, and plant databases (www.visualplants.de). Dirk Gansert is a Senior Lecturer at Albrecht von Haller Institute for Plant Sciences, G ettingen University, Germany.