Plants that are used for taxonomic research are generally preserved by drying them out while they are being pressed flat for easy storage. This pressed plant material, is placed in a herbarium, in phylogenetic order, based on the species, genus, family and order designations.
Herbaria are essential for the study and verification of plant classification, the study of geographic distributions, and the standardizing of taxonomic nomenclature. Lately, herbarium materials have been utilized in biochemical and genetic studies. The key to these studies is the state of preservation of the plant material. The preservation of the reproductive and vegetative structures (hairs, stomata, cuticle, etc.), internal anatomy (vascular tissue size and arrangement), biochemistry and genetic material is essential to make accurate observations, to collect representative data and answer pertinent research questions.