What does the „true” Boerhaave herbarium tell us about the practice of collecting plant specimens in the botanical garden Leiden?

Summary

The Dutch physician Herman Boerhaave (1668–1738) was famous for his clinical teaching, but his botanical research was also renowned. Boerhaave (Fig.1) inspired his pupils to set up botanical gardens and devise their own classification systems. His research resulted in the publication of two editions of the garden catalogue of the Leiden Hortus Botanicus, of which the latter (Boerhaave 1720), was deemed important enough to be used extensively as reference by Linnaeus (Linnaeus 1737). Devising a classification system was a major enterprise and must have required a substantial herbarium. Two herbaria were attributed to Boerhaave, but it appears unlikely – even though they have not yet been researched – that they were actually composed by him. From the collection of Naturalis Biodiversity Center, Leiden, we selected 100 specimens that were listed as collected by Boerhaave and verified 88 specimens as having been collected by Boerhaave. However, this small number raises the following questions: What happened to the rest of the herbarium that Boerhaave created? And how can we recognise a Boerhaave specimen?