Employments:

      1985 - 1987             Research assistant; Rijksherbarium & Hortus Botanicus, Leiden University; biohistorical research on two 17th century herbaria containing plants originating from the Leiden Hortus Botanicus

      1987 - 1988             various short-term occupations:

                                            -      free-lance; translation and modification of two guides to the flowers of north-western Europe

                                            -      Research assistant; Rijksherbarium & Hortus Botanicus, Leiden University; identification and lay-out of the systematic plant collection and historical Clusius garden at the Leiden Hortus Botanicus

                                            -      Research assistant; Rijksherbarium & Hortus Botanicus, Leiden University; pilot study on the application of the Atlas of the Dutch Flora data to study changes in vegetation development and distribution

                                            -      Research assistant; Centre for Environmental Studies, Leiden University; standardization and digitization of vegetation tables

      1988 - 1992             PhD Researcher; Dept. of Plant Taxonomy, Wageningen Agricultural University; project on the taxonomy, phylogeny and biogeography of African Begonia species in relation to glacial rain forest refuges; study including leaf anatomy, ontogeny, bioindicators, historical biogeography and paleoenvironment; supervisors Prof.dr.ir. L.J.G. van der Maesen & Dr.ir. J.J.F.E. de Wilde

      1992 - 1993             idem; part time occupation

      1992 - 1993             Plant Taxonomy Officer, part time occupation; PROSEA (Plant Resources of South-East Asia) project at Dept. of Plant Taxonomy, Wageningen Agricultural University; associate editor for botanical aspects within 2 projects on timber trees, involving scientific editing, literature research, coordination of a large network, fund raising

      1993 - 1994             idem; full time occupation

      1994 - 1998             idem; Editor for Lesser-known timber trees, involving coordination of a large network of contributors, project management, scientific editing, literature research, fund raising

      1999 - 2001             Plant Taxonomy Expert, Ministry of Foreign Affairs, The Netherlands & CENAREST (Centre National de la Recherche Scientifique et Technologique), Gabon, Head of the National Herbarium of Gabon, Libreville, and local management of project “Biodiversité Botanique du Gabon”

      2002 - 2008             Professor in Biosystematics, Wageningen University; Head of the Biosystematics group

      2009 - 2013             Professor in Biosystematics, Wageningen University; Head of the Wageningen branch of the National Herbarium of the Netherlands

      2013 – present       Senior Researcher, Botanic Garden Meise, Belgium; Editor-in-Chief Flore d’Afrique centrale and Flore du Gabon