Peter Hovenkamp

Peter Hovenkamp at work at Gunung Halimun Nature Reserve, Java

I am first and foremost a systematist, and I want to find out what is really there.

I am convinced that we can only find meaningful answers if we ask meaningful questions. I think that we need to know what species are out there, and what their variability and distribution is, before we can investigate their evolution and interactions. This attitude has also led me to consider some questions in the fields of phylogenetic reconstruction, biogeography and biodiversity informatics. It is fascinating to find time and again that answers to difficult questions suddenly become much easier when the questions are formulated clearly and carefully.


Polypodiaceae, Diplazium, Nephrolepis, biogeography, phylogenetics, morphology and anatomy, taxonomy, Oleandra, Flora's

Peter Hovenkamp

Researcher, Pteridology
Biodiversity discovery
+31 (0)71 751 7213
websites: Diplazium in MalesiaFerns of Sulawesi


I study systematics and taxonomy of ferns, always with the goal to search for orderliness in the patterns displayed by the species. My main sources are the herbarium specimens that a multitude of explorers and collectors over the last centuries have deposited in natural history collections. Not only are these specimens  an important scientific and cultural legacy, but they are often the only reliable evidence of the occurrence of species. And only well-documented and permanently preserved specimens provide reliable links to other studies.

Most of my studies on  ferns have focused on the species occurring in Southeast Asia (a.o. the genera Pyrrosia, Selliguea, Nephrolepis, Oleandra). This has resulted in contributions to flora's ofSri Lanka, Peninsular Malaysia, Singapore, China and the Malesian region (the region encompassing Malaysia, the Philippines, Indonesia, Brunei, Timor-Leste and Papua New Guinea), and in several new species. But I also am interested in the ferns of The Netherlands, and have contributed to the Heukels' Flora.

In the course of these studies, I also was excited to find that it is still possible to discover entirely new structures or phenomena. I studied the diversity of rhizome morphology in the Polypodiaceae, the curious way in which spores are ejected from the sporangia of Angiopteris (Marattiaceae) and the role of shape and structure of the spores in that process, and the periodicity in starch metabolism in Matteuccia struthiopteris.

In a more theoretical mood, I have tried to elucidate the meaning of permutation branch supports in phylogenetics, and the role of phylogeny in the reconstruction of the biogeographic history of taxa.

Oleandra neriifolia - one of the few ferns that have a shrubby habit
Lemmaphyllum microphyllum


My current work focuses on the species of Diplazium ("twinsorus ferns") in the Malesian area. Diplazium is a worldwide genus of ferns with an estimated 350 species. Despite recent work on the phylogeny and biogeography of the genus, the number of species and their distribution in the Malesian region is largely unknown. I am working towards an annotated checklist of the species, as a first approximation of the total diversity in this genus in the area. 


  • Hovenkamp, P. H. (1986). "A monograph of the fern genus Pyrrosia." Leiden Bot.Series 9: 1-280.
  • Hovenkamp, P. (1997). "Vicariance events, not areas, should be used in biogeographical analysis." Cladistics 13(1-2): 67-79.
  • Hovenkamp, P. H. (1998). Polypodiaceae. Flora Malesiana II. Leiden. 3: 1-234.
  • Hovenkamp, P. (2006). "Can taxon-sampling effects be minimized by using branch supports?" Cladistics 22(3): 264-275.
  • Hovenkamp, P. (2011). "Syncretism and Corroboration." Cladistics 28(2): 115-116.
  • Hovenkamp, P. H., R. van der Ham, G. A. van Uffelen, M. van Hecke, J. A. Dijksman and W. Star (2009). "Spore movement driven by the spore wall in an eusporangiate fern." Grana 48(2): 122-127.
  • Hovenkamp, P. and B.-C. Ho (2012). "A revision of the fern genus Oleandra (Oleandraceae) in Asia." PhytoKeys 11: 1-37.
  • Hovenkamp, P., S.-K. Yan and H.-C. Young (2016). "Seasonal changes in starch content in trophopods of Matteuccia struthiopteris (L) Todaro." American Fern Journal 16(3): 153-160.
  • PPG1 (2016). "A community-derived classification for extant lycophytes and ferns." Journal of Systematics and Evolution 54(6): 563-603.
  • Yahaya, N. H., M. Stech, B. J. M. Zonneveld and P. H. Hovenkamp (2016). "What is Nephrolepis ‘bostoniensis’?: Unravelling the origin of Nephrolepis hybrids and cultivars with molecular data." Scientia Horticulturae 204: 153-160.

A full list of my publications is available at my ORCID page.




    Picture of student holding a frond of Pteris holttumii


    • BSc Course Evolutionary Biology and MSc course Integrative Taxonomy: Theory and methods of phylogenetic reconstruction
    • Flora of The Netherlands