Notes from the Vault: Exsiccatae, Xylotheks, and Lepidochromes—Illustrating Nature with Itself

In the eighteenth and nineteenth centuries, the so-called "golden age" of scientific publication, when many books incorporated beautiful etched, engraved, and lithographed illustrations to augment their scholarly text, there were a small number of books that incorporated actual specimens of the subject matter being discussed. Exsiccatae , which used pressed plants, and lepidochromes , which used the wing scales of moths and butterflies, provided readers with tangible examples of their books' topics, by using specimens collected from nature in lieu of artfully created reproductions as their illustrations. Some books about trees relied on their subject matter to make the books themselves. These "wooden libraries," known as xylotheks , used slabs of wood as their "covers" and bark, sometimes encrusted with lichens, on their spines. Since all of these publications required countless wild specimens and an enormous amount of personal labor to collect and prepare for distribution, very few were ever made. This essay is intended to serve as an introduction to these rare and little-seen publications.