Fossil leaf cuticle: Best practices for preparation and paleo-CO2 analysis

The cuticle encodes information about a plant's chemistry and leaf epidermal and stomatal cell morphology. Fossil leaf cuticle has been used to determine taxonomic affinities for almost two centuries and recognized in recent decades for its value in reconstructing paleoenvironments and paleoclimates, especially atmospheric CO 2 .

Fossil leaf cuticle preparation techniques are typically reported as single workflows tied to individual studies, starting with finding fossils in the field through the steps of preparing cuticle for chemical and morphological analysis, including decisions about type of microscopy and level of sampling effort at different spatial scales (number of fields-of-view, leaves, and species). The siloed nature of these publications makes finding appropriate methods and workflows for new studies difficult, especially for less experienced researchers.