Dr Walter Bock was a German diatomist active in the middle of the 20th century, primarily working in the regions of Würzburg and Aschaffenburg, Bavaria, Germany. There is only very sparse information available regarding his personal life and scientific ca-reer. He was employed at the Wirsberg Gymnasium in Würzburg as a teacher (in German: Studienprofessor, meaning that he was also responsible for the educational training of teachers). As a di-atomist, Bock published a number of significant contributions, particularly on the diatom flora and other algal groups from Cen-tral European lakes. Much of this work was conducted in collab-oration with his brother and fellow German phycologist Dr Otto Bock.
Importantly, Dr Bock also made substantial contributions to the study of the terrestrial diatom flora living on rocks, walls and dry soils (Bock 1963, 1970). Throughout his research, Bock described a total of 20 new diatom species. While a few of these species are observed regularly, the majority remain rarely seen. Taxa such as Navicula umida W.Bock, Navicula nolensoides W.Bock, and Na-vicula muralibionta W.Bock are most likely largely unfamiliar to most contemporary diatomists. Several of Bock's species have since been transferred to different genera. For example, Navicula dolomitica W.Bock is now recognised under the genus Geissleria as G. dolomitica (W.Bock) Lange-Bertalot & Metzeltin, while Na-vicula spinifera W.Bock and N. pseudonivalis W.Bock were both transferred to the genus Luticola. Similarly, Achnanthes nollii O.Bock & W.Bock was transferred to Achnanthidium in 2021.
The complete collection of Walter Bock’s microscopic slides, along with his original notes, was donated to Meise Botanic Gar-den by Prof. dr Horst Lange-Bertalot. This valuable addition to the diatom collection in Meise has triggered a renewed interest in Walter Bock and his diatom species. Through careful analysation of the accompanying notes and slides, we were able to find and verify all described taxa. Unfortunately, the unmounted material is no longer present so we could only use light microscopy (LM) observations to document the species. Nevertheless, the observations allowed for a more detailed assessment of the morphological characteristics of nearly all species.