Studying a botanical voucher up close can reveal much about the life of the plant. This project was shaped by the interdisciplinary field of new materialism which foregrounds the vibrancy of matter in order to problematize and unsettle human-centered paradigms that deny matter agency and creativity. The convergence of multiple materialities that continue to act upon one another can be found on each specimen sheet, making their way onto or into the specimens and even human bodies years after they were first collected. "All matter—even the one that we do not see, sense, or suspect—constantly interacts with other matter, whether in human or nonhuman forms."1
At first glance, preserved plants in an herbarium might be perceived as dry, flat figures tucked away in cabinets until viewed in person or online.
However, look closer and you can find that each sheet contains not only a preserved flower or lichen, but a unique array of chemicals, adhesives, dust, tape, labels, seeds, roots, and rhizome. For “what we regularly describe as conservation or preservation can be reinterpreted as the selective unfolding of material possibilities to create a desired assemblage of vibrant matter.”2
Herbaria are ideal places for examining the convergence of different materialities and the effects they have on one another. Herbarium preservation takes into consideration the longevity of materials, the interactions between specimen and adhesives, the ability of preservation materials to withstand damage from bacteria, mold, and insects.3
Insect damage from aptly named herbarium beetles, booklice, and silverfish must be taken into consideration when preserving and maintaining herbarium collections. While specimens coming into the herbarium are placed in a freezer for decontamination before mounting, damage from potential insect damage must be factored in even after specimens are preserved and stored in the herbaria.
Desiccant dust made from diatomaceous earth or silica can be spread around the cabinets to draw moisture from the bodies of insects, thereby killing them before they can damage the specimens. Historically, biocides derived from plants themselves have also been used to prevent insect damage such as camphor, lavender oil-derived linalool, wild rosemary, and cedar oil. Until the 1980s, collections in herbaria were often disinfected using a mix of mercuric chloride and ethanol.4
Starch pastes or polyvinyl acetate glues replaced adhesives made from fish heads, bones, and skins that were found to be susceptible to bacterial attacks. Archer's plastic adhesive, although commonly used in herbaria, experiences textural changes in humid weather and can be negatively affected by the presence of certain insect repellants.
When viewing the items in the Omeka exhibits, zoom in on the images and see what else you can notice when you look closely. What can you notice on the individual vouchers? What material traces emerge?
2. Stuchel, Dani. “Material Provocations in the Archives.” Journal of Critical Library and Information Studies, vol. 3, no. 1, 2020, pp. 1–25, https://doi.org/10.24242/jclis.v3i1.103.
3. For more information on herbarium specimen preservation, see Royal Botanic Gardens, Kew. The Herbarium Handbook. Edited by Diane M Bridson and Leonard Forman, Third edition., Third ed., Royal Botanic Gardens, 2013
4. Known to pose health risks to humans as well as damage the DNA of the specimens, mercury is no longer recommended as studies have found that herbarium specimens can continue to emit metallic mercury decades later.