Contributions of trichome micromorphology to the characterization of species traded as 'BOLDO'

Traditional uses, common names, adulterations and substitutions of medicinal plants are some of the considerations that require qualitative analysis for effective quality control. Microscopy studies of selected “boldo” species using light and scanning electron microscopy reveled key diagnostic traits that can help species identification. These traits can contribute to the quality control of the botanical traded in the form of whole, fragmented or powdered leaves. The studied species exhibited different features in their leaf trichome micro-morphology; Peumus boldus has stellate non-glandular trichomes, Plectranthus neochilus possesses simple non-glandular trichomes with warty cuticle, and short-stalked capitate and peltate glandular trichomes, and Plectranthus barbatus has simple non-glandular with smooth cuticle, short- and long-stalked capitate, as well as peltate glandular trichomes. These differences prove to be helpful in the species identification and quality control of products containing “boldo” species.