An introduction to the catalogue of Albert Grunow's 19th century diatom collection at W including a palaeographic aid.

The diatom collection of Albert Grunow (1826-1914) is rich in taxonomic types and important, not only for Grunow's own material (slides, samples) and species, but because it also contains a great deal of historical material collected by early phycologists (e. g. de Brébisson, Kützing, William Smith). The collection is housed at the Department of Botany of the Natural History Museum in Vienna (herbarium W). Grunow's collection is accompanied by a catalogue listing all samples Grunow studied and is organised by ascending sample numbers. The information contained in the catalogue includes species lists, collection localities, the origin of the material (such as marine or fossil), collectors and their collection numbers, cross-references to exsiccata containing the same material, preparation types, or the coordinates of particular valves on his slides, and is therefore important to access for current taxonomists. However, one hurdle is deciphering Grunow's handwriting in German cursive script ('Kurrent'). Hence, the goals of this paper are twofold: 1) to provide insights into Grunow's curation methods and available materials, as laid out in eleven pages of instructions (in German) written by Grunow about the collection and the catalogue and 2) to function as a palaeographic aid, which is provided as an electronic supplement, in order to facilitate reading the instructions and catalogue. The latter is done by pairing Grunow's instructions with their transcription and by providing handwriting samples for each letter of the alphabet. The first is achieved by giving an English translation of the instructions and some comments on the materials and methods he used. We also include two tables listing historical measurement units and their conversions to the metric system, as well as abbreviations used by selected authors. [ABSTRACT FROM AUTHOR]