I am a retired professor of ecology. I have been working in vegetation, restoration and aquatic ecology, respectively. My interest in aquatic plant taxonomy arose during my works on river ecology. I realized that the taxonomic treatment of many aquatic plant groups is insufficient and does not allow species identification. Growth form, life form, and life cycle of aquatic plants are often described in terminologies developed for terrestrial plants. Morphological descriptions are often lacking the necessary precision and are underestimating phenotypic variability. Precise and complete descriptions are the necessary basis for functioning keys. I have co-authored a worldwide account of Potamogeton (1998) and of Ranunculus sect. Batrachium (2017), both based on extensive field and herbarium studies. I worked on identification of Callitriche, Myriophyllum, Sparganium, Typha, Mentha as well as submerged forms of semi-aquatic species , Recently I co-authored a book on Aquatic Plants of Northern and Central Europe including Britain and Ireland (2023).