Józef Rostafiński (1850-1928) was an eminent Polish naturalist of his time. Although his initial interest was in slime-moulds and algae, he soon turned his attention to the history of botany, to which he devoted most of his scientific work, eventually becoming one of its foremost authorities in Polish science. Among his many achievements, comprising 573 publications, some of them are devoted to folk knowledge of plants while some others to what these days would be classified as ethnobotany, i.e., research into the history of cultivated plants, the history of Polish vernacular botanical nomenclature and the origins of certain folk customs.