The “true Boerhaave herbarium”: an analysis of the specimens of Herman Boerhaave (1668–1738) contained in the Van Royen collection at naturalis

Collecting plants and making herbarium specimens was quintessential for an eighteenth century botanist. Studying the extant plant specimens from this period can give us valuable insights into how scholars approached the science of botany. Several dried plant specimens in the 18th-century Van Royen collection kept at Naturalis, Leiden, have at one time been recognised as originating from Herman Boerhaave (1668–1738). The aim of this study is to establish which specimens come from Boerhaave and try to answer the question why relatively few of these survived. We verified which specimens came from Boerhaave and updated the existing identifications of 88 specimens. We studied the way the specimens were mounted, the handwritings on the various labels and the use of decorations. We taxonomically identified them and linked the accompanying labels to the seed register of the Leiden Hortus Botanicus, where these specimens originated from. The transcription of the labels provided us with valuable information about the introduction and cultivation of indigenous and exotic, predominantly Mediterranean, plant species. Little effort has been put into connecting the contribution by Boerhaave with the living collection of the Leiden Hortus botanicus at the time, that is, the herbarium specimens we now know to have been described by Boerhaave. By studying these specimens we made his contribution visible.