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This Beiheft of Nova Hedwigia features twenty contributions by more than 40 authors, representing the entire range of Prof. Le Cohu´s work and interests. Topics of the contributions range from purely taxonomic papers to articles dealing with diatom biodiversity, ecology, paleoecology and biogeography. The papers apply both traditional and novel techniques. They describe more than 20 new species (high quality SEM images) and three new genera and several taxa are revised. Geographically, the contributions to this volume span a a wide region, from the part of France, where René le Cohu started his research, to the sub-Antarctic Kerguelen Islands from where he has described a great number of species. This Beiheft is dedicated to Prof. Dr. René Le Cohu on the occasion of his 80th birthday, in recognition of his life-long scientific work on the taxonomy and ecology of algae, and diatoms in particular. It addresses phycologists and other researchers working on diatoms and algae.

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