The spirit collection comprises over 7,000 specimens preserved in fluid, stored in glass jars in metal cabinets. This method of preservation is particularly important for fleshy flowers, fruits and fungi that are not suitable for drying, pressing and mounting on a herbarium sheet. More accurate measurements are often possible from spirit-preserved material as the drying process may cause shrinkage; it also allows clear observation of the three-dimensional arrangement of flower parts.
Specimens are stored in Copenhagen Solution: 70% industrial methylated spirit, 28% distilled water and 2% glycerol. The alcohol is a preservative and the glycerol prevents specimens becoming too brittle (formaldehyde solution is no longer used as a preservative due to associated health risks). Rubber seals in the jar lids reduce evaporation, and the fluid level of all specimens is regularly checked. Diatoms are stored in 96% ethanol.
The scope of the spirit collection
The collection is varied, with Flora of Arabia, Zingiberaceae, Orchidaceae, Gesneriaceae and diatoms particularly well-represented. It also includes an extensive collection of mycological specimens from E J H Corner, given to RBGE prior to his death in 1996. Many of his type specimens, particularly in the Boletaceae are preserved in this manner.
The spirit collection is closely linked with the other herbarium collections, with many specimens having associated herbarium sheets, carpological material, photographs and DNA samples. The label information for many specimens has been incorporated onto the searchable Herbarium catalogue.
Use of the collection
The collection is well used by herbarium staff, taxonomists and research visitors. Botanical artists have also utilised the collection, and it provided the inspiration for Turner Prize nominee Christine Borland's installation Spirit Room: Hippocrates.
The spirit collection is open to research visitors by appointment. For further information please contact the Herbarium staff.