Microscopic characterization is an inherent part of nearly all pharmacopoeias and is one of the primary identification tests required for pharmacopoeial compliance. Thus, these descriptions are generally considered authoritative and should be the first source of microscopic characterizations against which a test sample is compared. In

scopic characterizations is an almost exclusive focus on the characterization of powders rather than whole or partly whole samples. Within the majority of leaves, roots, barks, stems, and seeds, the same structural elements are ubiquitous; leaves contain stomata, roots starch, bark cork, seeds aleurone grains, etc. (Figure 4.1). Therefore, it is relatively easy to have a false positive when conducting an identification of powders. The chance for a positive identification of a species is much greater when the microscopic characteristics of an intact, relatively whole plant part are observed. The individual structural elements are relatively common within the same types of plant parts; however, the unique manner in which the elements are arranged gives a plant its characteristic fingerprint. Therefore, for microscopic characterizations, identification tests that provide a description of the cross or tangential sections of the botanical are optimal.