The four W's of two 18th century Dutch herbaria: the 'Zierikzee Herbarium' and the herbarium of Simon D'Oignies

One of the objects of the Municipal Museum Zierikzee (Province of Zealand, The Netherlands) is a historical herbarium referred to by the name the 'Zierikzee Herbarium'. The characteristics of the specimens in the Zierikzee Herbarium are so similar to those in a herbarium at Naturalis Biodiversity Center, Leiden(L), that both must originate from the same place and time. About the latter herbarium little is known, except that it was once owned by the army-surgeon Simon(e) d'Oignies (1740–1782). The Zierikzee Herbarium was recently described and analysed in detail by Offerhaus et al. (2021). It is hypothesised that the Zierikzee Herbarium is part of a herbarium made by Professor Martinus Wilhelmus Schwencke (1707–1785) and was used during his lectures for future pharmacists in his botanical garden in The Hague in the 1750s, and auctioned in Leiden in 1785. The presence in the Zierikzee Herbarium of a virtually complete set of medicinal plants mentioned in the 'Pharmacopoea Hagana' (Anonymous 1738) eventually led to the conclusion that these could not have been assembled before 1730. Based on the printed ornaments that are used to mount the plants in these, and the major Dutch herbaria of the 18th century, I argue that the plants in the Zierikzee Herbarium and the herbarium of D'Oignies were remounted at a later date. The hypothesis by Offerhaus et al. (2021: 12) that the Zierikzee Herbarium was started between 1710 and 1720 is rejected. Arguments are given why it is unlikely that the Zierikzee Herbarium, as is suggested by Offerhaus et al. (2021: 12), is the herbarium of the head gardener of the Leiden botanic garden, Jacob Ligtvoet (1684–1752) and was auctioned in 1752.