Erik Smets

Erik Smets

I am fascinated by flowering plants. More specifically, I am very interested in defining good characteristics - morphological, anatomical as well as phytochemical and molecular - to order flowering plants in predictive groups reflecting their phylogeny. My MSc project was about the definition of placentation types, seed types and nectaries, and in my PhD thesis I continued studying the floral nectaries of the flowering plants. Both degrees were obtained at the KU Leuven (Belgium). From the early start of my career I had many managerial tasks and a huge teaching load, two aspects of my professional life that I found very rewarding, also from a research perspective.


Floral development, Morphology and Anatomy, Nectaries, Phylogeny, Systematics
Dioscoreales, Ericales, Gentianales, Poales

Prof. dr. E. F. (Erik) Smets
+31 (0)71 751 92 59



Former and present positions

  • 1-1-2022 - present: Guest researcher Naturalis Biodiversity Center
  • 1-10-2020 - present: Emeritus professor with formal duties (KU Leuven)
  • 1-9-2005 - present: Full professor (Chair of Systematic botany), Leiden University
  • 1-7-2010 - 31-12-2021: Scientific director of Naturalis Biodiversity Center
  • 1-4-2009 – 30-6-2010: Research program director (40%) of the National Natural History Museum Naturalis
  • 1-9-2005 - 31-12-2021: Director of the National Herbarium of the Netherlands (NHN)
  • 1-9-2005 - 30-9-2020: Professor by Special Appointment (Chair of Systematic botany), KU Leuven
  • 1-9-2005 - 1-2-2016: Scientific director of the Hortus botanicus Leiden
  • 1-5-2005 - 31-8-2005: Full professor (20%), Leiden University
  • 1-8-2000 - 31-7-2005: Head of the Department of Biology, KU Leuven
  • 1-10-1989 - 30-11-2008: Professor and Head of the Laboratory of Plant Systematics, KU Leuven


  • Member of the Royal Flemish Academy of Belgium for Science and the Arts (2012)
  • Member of The Royal Holland Society of Sciences and Humanities (2010)
  • Foreign Member of the Linnean Society (2005) 

Other past and current academic activities

Ongoing activities:

  • Member of the Digitisation Project Board, RBG Kew, since 2022.
  • Chair of the Board of the Fonds Pontium Foundation, since 2020.
  • Treasurer of the Executive Committee of the Consortium of European Taxonomic Facilities (CETAF), since 2016
  • Member of the Scientific Advisory Board of the Natural History Museum Stuttgart (SMNS), since 2012.
  • Member of the Leopold III-Fund for Nature Research and Nature Conservation, since 2009.
  • Member and Chair (since 10-2020) of the Board of the Alberta Mennega Foundation, since 2007.
  • Chair of the Professor Lam Fund, since 2007.
  • Vice-Chair of the Board of the Flora Malesiana Foundation, since 2006.
  • Board of Directors of the Consortium of European Taxonomic Facilities (CETAF), since 2005.
  • Chair of the Dr. E. Kits van Waveren Foundation, since 2005.
  • Member of the Scientific Advisory Board of Botanic Garden Meise, since 1997.
  • Member and Chair (1997-2005) of the Board of the Alumni Society PDL (“Vereniging van Afgestudeerden in de Plantkunde en de Dierkunde van de Universiteit te Leuven”), since 1991.

Past activities:

  • Member of the Board of the C.T. De Wit Graduate School for Production Ecology and Resource Conservation (PE&RC); 2012-2021.
  • Member of the Scientific Advisory Board of the Fungal Biodiversity Centre (CBS-KNAW); 2011-2021.
  • Member of the Scientific Advisory Board of the Natural History Museum Karlsruhe (SMNK); 2012-2018.
  • Member of the Committee of Scientific Advisors of the National Authority for Data concerning Nature (GAN); 2012-2015.
  • Member of the Board of ETI Bioinformatics; 2008-2013.
  • Board of Directors of the EU Network of Excellence “European Distributed Institute of Taxonomy”; 2006-2011.
  • Member, Vice-Chair (2008) and Chair (2009) of the Expert Panel Biodiversity and Ecology of The Research Foundation Flanders; 2000-2009.
  • Member of the Board of the Research School Biodiversity; 2005-2012.


Initially, I was fascinated by the huge diversity in floral morphology. Later, my research interests expanded into floral development, pollen morphology, fruit and seed morphology, and wood anatomy. Monographic studies, still crucial for the inventory of Earth’s biodiversity, also became a major topic in my research group. The introduction of molecular systematics provided a new framework to comprehend the evolutionary relationships of plants.

I strongly favor a multidisciplinary approach in which morphological features are combined with DNA sequence data and evolutionary developmental genetics (which I like to call molecular morphology) because integrative systematics will ultimately lead to better insights in the evolution of characters and in understanding the evolutionary history of flowering plants. 

Diffuusporig hout


As scientific director and member of the management team of Naturalis one of my main duties is to make our motivated group of scientist more effective. Since a few years my direct participation in research is limited, and therefore all my PhD candidates are supervised by a very dedicated daily supervisor (co-promotor). It is very rewarding though to be involved in the PhD projects mentioned below because it enables me to stay connected with current research.

Ongoing PhD projects (preliminary titles)

  • Phylogeny and morphological evolution of Leucobryaceae Schimp. (Bryophyta, Dicranales). (Bonfim Santos, M.; co-promotor Stech, M.)
  • Patterns of epiphytic bryophyte diversity in Gede-Pangrango National Park, Java, Indonesia. (Iskander, E.; co-promotors Stech, M. & Mota de Oliveira, S.)
  • Genomic barcoding as a tool to trace and identify illegal logged African trees. (Mascarello, M.; co-promotor Janssens, S.)
  • The Evolution and development of orchid flowers and fruits. (Pramanik, D.; co-promotor Gravendeel, B.)
  • Herb hydraulics: testing the role of root pressure to unravel the dynamics of drought-induced vascular dysfunction in stems. (Thonglim, A.; co-promotor Lens, F.)
  • Unraveling evolutionary patterns in the microscopic wood anatomy of two tropical clades. (Beckers, V.; co-promotor Lens, F.)
  • Bina Swadaya in Klaten Regency: Knowledge and Use of a Community-Based Organisation for Sustainable Development in the Central Java Province, Indonesia. (Ismawan, B.; co-promotor Slikkerveer, J.)
  • Knowledge and Use of Traditional Food Plants among the Kitui People of Kenya: An Ethno-Agricultural Study in East Africa. (Maundu, P.; co-promotor Slikkerveer, J.)
  • Ijon in the Sunda Region of West Java: The Role of an Indigenous Agricultural Institution in Sustainable Community Development in Indonesia. (Dimas Isjwara, H.; co-promotor Slikkerveer, J.)


  • Beckers, V., Rapini, A., Smets, E. & F. Lens. 2022. Comparative wood anatomy and origin of woodiness in subfamilies Secamonoideae and Asclepiadoideae (Apocynaceae). Taxon 71, 6: 1230-1250.
  • Vrijdaghs, A., De Block, P., De Toni, K., Smets, E. & E. Robbrecht. 2022. Floral ontogeny links Dialypetalanthus (Condamineeae) with the floral developmental morphology of other Rubiaceae. Plant Ecology and Evolution 155, 3: 394-403.
  • Ruchisansakun, S., Mertens, A., Janssens, S., Smets, E. & T. van der Niet. 2021. Evolution of pollination syndromes and corolla symmetry in Balsaminaceae reconstructed using phylogenetic comparative analyses. Annals of Botany 127, 2: 267–280.
  • Vrijdaghs, A., Smets, E. & P. De Block. 2020. Different ways to obtain similar results: the development of the corolla and epipetaly in Rubieae (Rubioideae, Rubiaceae). Plant Ecology and Evolution 153, 3: 466-486.
  • Ochoterena, H., Vrijdaghs, A., Smets, E. & R. Claßen-Bockhoff. 2019. The search for common origin: homology revisited. Systematic Biology 68, 5: 767–780.
  • Hoekstra, P., Wieringa, J., Smets, E. & L. Chatrou. 2018. Floral evolution by simplification in Monanthotaxis (Annonaceae) and hypotheses for pollination system shifts. Scientific Reports 8: 12066 DOI:10.1038/s41598-018-30607.
  • Dirks-Mulder, A., Butôt, R., van Schaik, P., Wijnands, J.-W., van den Berg, R., Krol, L., Doebar, S., van Kooperen, K., de Boer, H., Kramer, E., Smets, E., Vos, R., Vrijdaghs, A. & B. Gravendeel. 2017. Exploring the evolutionary origin of floral organs of Erycina pusilla, an emerging orchid model system. BMC Evolutionary Biology 17, 89 (18 pages, 11 figs.).
  • Jeiter, J., Hilger, H., Smets, E. & M. Weigend. 2017. The relationship between nectaries and floral architecture: a case study in Geraniaceae and Hypseocharitaceae. Annals of Botany 120, 5: 791-803.

For a list of all my publications, see below.


Naturalis aims to be a breeding ground for international scientific talent. Therefore, PhD's have a special position in our organisation.
I acted as promotor (*co-promotor) of the following successfully defended PhD projects:

  • Atria, M. 2023. Systematics and biogeography of the rattan Calamus javensis complex (Arecaceae, Calamoideae) in Malesia. PhD thesis Leiden University.
  • Hoekstra, P.H. 2022.  Disentangling lianas. The systematics of Monanthotaxis (Annonaceae). PhD thesis Wageningen University.
  • Wati, R.K. 2021. Systematics, epidermal defense and bioprospecting of wild orchids. PhD thesis Leiden University.
  • Sinnesael, A. 2020. Bacterial leaf symbiosis. Origin, function, evolutionary gain, and transmission mode of bacteriophilous Rubiaceae. PhD thesis KU Leuven. 
  • Dirks-Mulder, A. 2020. Evolution and development of orchid flowers and fruits. PhD thesis Leiden University.
  • *Jeiter, J. 2020. Evolution of floral organisation and architecture in Boraginales and Geraniales. PhD thesis University of Bonn.
  • de Bekker, J.C.M. 2020. Transcultural Health Care Utilisation in Serengeti of Tanzania: Towards Applied Ethnoscience in Public Health Management. PhD thesis Leiden University.
  • Dória, L.C. 2019. Functional xylem anatomy. Intra and interspecific variation in stems of herbaceous and woody species. PhD thesis Leiden University.
  • Bogarín Chaves, D. 2019. Evolutionary diversification and historical biogeography of Orchidaceae in Central America with emphasis on Costa Rica and Panama. PhD thesis Leiden University.
  • Saefullah, K. 2019. Gintingan in Subang: An indigenous institution for sustainable community-based development in the Sunda Region of West Java, Indonesia. PhD thesis Leiden University.
  • Erwina, W. 2019. Iber Kasehatan in Sukamiskin: Utilisation of the plural health information & communication system in the Sunda Region of West Java, Indonesia. PhD thesis Leiden University.
  • Ruchisansakun, S. 2018. Balsaminaceae in Southeast Asia. Systematics, Evolution, and Pollination Biology. PhD thesis Leiden University.
  • Schwallier, R. 2016. Evolutionary diversification of Nepenthes. PhD thesis Leiden University.
  • Semenova-Nelsen, T. 2016. Fungi of the greening Arctic: compositional and functional shifts in response to climatic changes. PhD thesis Leiden University.
  • Morgado, L. 2016. Peeking into the future: Fungi in the Greening Arctic. PhD thesis Leiden University.
  • Karremans, A. 2015. Systematic, phylogenetic and pollination studies of Specklinia (Orchidaceae). PhD thesis Leiden University.
  • Mennes, C. 2015. Antiquities of the rainforest. Evolution of mycoheterotrophic angiosperms on Glomeromycota. PhD thesis Leiden University.
  • Lang, A. 2014. Phylogeny and species delimitation within the moss genus Dicranum Hedw.PhD thesis Leiden University.
  • Towns, A. 2014. Fertility and Fontanels. Women’s knowledge of medicinal platns for reproductive health and childcare in western AfricaPhD thesis Leiden University.
  • Chaowasku, T. 2014. The Miliuseae revisited. Phylogenetic, taxonomic, and palynological studies in a major clade of Annonaceae. PhD thesis Leiden University.
  • Verstraete, B. 2013. Bacterial leaf endophytes in African Rubiaceae. PhD thesis KU Leuven.
  • Caris, P. 2013. Bloemontogenetische patronen in de Ericales sensu lato. PhD thesis KU Leuven.
  • Kok, P. 2013. Islands in the Sky: Species Diversity, Evolutionary History, and Patterns of Endemism of the Pantepui Herpetofauna. PhD thesis Leiden University.
  • *Vekemans, D. 2012. Diversification of MADS-box genes in flowering plants. PhD thesis KU Leuven.
  • Rabaey, D. 2012. Micromorphological study of pits in tracheary elements of woody angiosperms. PhD thesis KU Leuven. 
  • Appelhans, M. 2011. Phylogeny and biogeography of Spathelioideae (Rutaceae). PhD thesis Leiden University.
  • Lemaire, B. 2011. Diversity and Evolution of Bacterial Endosymbionts in Leaf Nodulated Angiosperms. PhD thesis KU Leuven. 
  • Subedi, A. 2011. New species, pollinator interactions and pharmaceutical potential of Himalayan orchids. PhD thesis Leiden University.
  • Boedeker, C. 2010. Phylogenetic, taxonomic and biogeographical studies in the Pithophoraceae (Cladophorales, Chlorophyta). PhD thesis Leiden University. 
  • Pruesapan, K. 2010. The rise and fall of Sauropus (Phyllanthaceae). A molecular phylogenetic analysis of Sauropus and allies. PhD thesis Leiden University.
  • Van den Hof, K. 2010. Evolution of Viola stagnina and its sisterspecies by hybridization and polyploidization. PhD thesis Leiden University.
  • *Viaene, T. 2010. Evolution of ancient MADS-gene functions. PhD thesis KU Leuven.
  • Jacobs, B. 2010. Fruits and seeds of Dipsacales. Morphology and evolution. PhD thesis KU Leuven.
  • Tosh, J. 2009. Biogeography of Madagascan Rubiaceae: Case studies from the Afro-Madagascan genus Tricalysia and the pantropical genus Ixora. PhD thesis KU Leuven.
  • Geeraerts, A. 2009. Phylogenetic reconstructions, morphological diversity and historical biogeography of Ebenaceae. PhD thesis KU Leuven.
  • Groeninckx, I. 2009. Integrated study of the herbaceous Spermacoceae (Rubiaceae). Systematics & Evolution. PhD thesis KU Leuven.
  • Moon, H.-K. 2008. Systematic studies in Mentheae (Lamiaceae). Morphology, evolutionary aspects, phylogeny. PhD thesis KU Leuven.
  • Merckx, V. 2008. Myco-heterotrophy in Dioscoreales. Systematics and evolution. PhD thesis KU Leuven.
  • Janssens, S. 2008. Evolutionary studies in Balsaminaceae: integration of evidence from molecular and morphological data. PhD thesis KU Leuven.
  • Vrijdaghs, A. 2006. A floral ontogenetic approach to homology questions in non-mapanioid Cyperaceae. PhD thesis KU Leuven.
  • Geuten, K. 2006. Bayesian phylogenetics and perianth evolutionary developmental genetics of the balsaminoid Ericales. PhD thesis KU Leuven.
  • Lens, F. 2005. Systematic significance of wood anatomical characters in Ericales. PhD thesis KU Leuven.
  • Ntore, S. 2004. Contribution à la connaissance systématique du genre afrotropical Pauridiantha (Rubiaceae). PhD thesis KU Leuven.
  • Schols, P. 2004. Contributions to the palynology and phylogeny of Dioscorea (Dioscoreaceae). PhD thesis KU Leuven.
  • Dessein, S. 2003. Systematic studies in the Spermacoceae (Rubiaceae). PhD thesis KU Leuven.
  • Vinckier, S. 2003. Orbicules: morphology, ultrastructure, and development in Gentianales and their possible role as vector of allergens. PhD thesis KU Leuven.
  • Vermoere, M. 2002. Holocene vegetation history in the territory of Sagalassos (southwest Turkey). A palynological approach. PhD thesis KU Leuven.
  • Pyck, N. 2001. Phylogenetic relations within Dipsacales. A combined molecular and morphological approach. PhD thesis KU Leuven.
  • Jansen, S. 2001. Comparative wood anatomy of the Rubiaceae and phylogenetic implications of aluminium hyperaccumulation and vestured pits in angiosperms. PhD thesis KU Leuven.
  • Piesschaert, F. 2001 Carpology and pollen morphology of the Psychotrieae (Rubiaceae-Rubioideae). Towards a new tribal and generic delimitation. PhD thesis KU Leuven.
  • Huysmans, S. 1998. Palynology of the Cinchonoideae (Rubiaceae). Morphology and development of pollen and orbicules. PhD thesis KU Leuven.
  • Roels, P. 1998. Phylogenetic position and delimitation of the order Dipsacales. A multidisciplinary approach. PhD thesis KU Leuven.
  • Stoffelen, P. 1998. Coffea and Psilanthus (Rubiaceae) in tropical Africa: a systematic and palynological study, including a revision of the West and Central African species. PhD thesis KU Leuven.
  • De Laet, J. 1997. A reconsideration of three-item analysis, the use of implied weights in cladistics, and a practical application in Gentianaceae. PhD thesis KU Leuven.
  • Ronse Decraene, L.-P. 1992. The androecium of the Magnoliophytina: characterisation and systematic importance. PhD thesis KU Leuven.


    In 1999 I received a Teaching Certificate at the KU Leuven (Onderwijskundige Vorming Docenten), and in 2012 I obtained the Certificate Basic Teaching Qualification (BKO) from Leiden University).

    Apart from some guest lectures, for example in the courses ‘Diversity of Algae, Fungi and Plants‘ (3rd Year Biology, KU Leuven) and ‘Plant Families of the Tropics’ (Masters Biology, Leiden University) I taught  ‘Anatomy’ in the course ‘Tree of Life’ (1st Year Biology, Leiden University) and ‘Evolutionary Developments’ in the minor ‘Biodiversity and Natural Environment’ (3rd Year Biology, Leiden University).


    On a regular basis I am invited to talk about Plant systematics, The classification of Flowering plants, or to introduce Naturalis Biodiversity Center. Examples of recent talks are:

    • Naturalis Biodiversity Center: Museum, Collection Infrastructure and Research Institute. Chiang Mai University, Thailand (2016).
    • Naturalis: More than a Museum. Visit Bachelor students of Wageningen University (2015)
    • Naturalis: Museum, Natural History Collection, and Research Institute. Leidse Kennisdag, Leiden (2015).