Why are plants named after witches and devils in north-western Europe?

Ethnopharmacological relevance: Witches in Western Europe are associated with the use of medicinal, abortifacient, hallucinogenic, and toxic plants. Curiously, these associations are not backed up by first-hand evidence and historians are unconvinced that people convicted as witches were herbalists. Local plant names provide an untapped source for analysing witchcraft-plant relationships. Aim of the study: We analysed vernacular plant names indicating an association with witches and devils to find out why these species and witchcraft were linked. Materials and methods: We constructed a database with vernacular names containing the terms witch and devil in related north-west European languages. The devil was added because of its association with witchcraft. The plant species' characteristics (e.g., medicinal use, toxicity) were assessed to determine if there were non-random associations between these traits and their names. Results: We encountered 1263 unique vernacular name-taxa combinations (425 plant taxa; 97 families). Most species named after witches and/or devils were found within the Asteraceae, Ranunculaceae, and Rosaceae. For Dutch, German and English we confirmed associations between witchcraft names and toxicity. Hallucinogenic plants do not appear to be associated with witch-names. For Dutch, we found significant associations between plant names and medicinal and apotropaic uses, although we did not find any association with abortifacient qualities. Conclusions: This study demonstrates that there is a wide variety of plants associated with witches and the devil in north-western Europe. Plant names with the terms witch and devil were likely used in a pejorative manner to name toxic and weedy plants, and functioned as a warning for their harmful properties. Our study provides novel insights for research into the history of witchcraft and its associated plant species.