Adhesives used in herbaria: Current practice with regard to what we know from written sources on mounting herbarium specimens and conservation

Herbaria are important sources of information concerning biodiversity, climate change and ecology, migration and evolution of plants, and extinct or invasive species. The development of genetic sampling enables retrieval of genetic material even from historical records, extending potential uses of herbarium collections. However, the use of adhesives might be detrimental to dried plant specimens, contributing to their degradation on many levels. The use of the appropriate adhesive has always been the subject of discussion and one of the important issues concerning herbarium making. This paper discusses current practices of the use of adhesives in herbaria collections, regarding their long‐term quality in terms of aging behaviour and appropriateness for the use with herbarium material. Health and safety of herbarium staff are also addressed. Results of a survey consisting of open‐ended questions are presented, showing various approaches to the mounting of specimens and differences in assessing particular adhesives. The goal of the enquiry was to gather information about the most popular current practices of herbarium conservators. A list of adhesives extracted from an extensive review of herbarium‐related literature is also provided, including conservation treatment reports.