Micrografía foliar de arbustos y peque？os árboles medicinales de la Provincia Biogeográfica de las Yungas (Argentina)

fifty five species of shrubs and small trees belonging to 24 families which inhabit the biogeographic province of the yungas (argentina) have been cited with medicinal properties. the aim of this study is to provide leaf micrographic parameters to recognize these taxa as a tool to allow quality control. fresh material and hydrated herbarium specimens fixed in faa were surveyed. the main differential traits are: trichome and stomata types; presence of striate cuticle, papillose epidermis and/or presence of hypodermis; vascular bundle types; crystal and secretory structures types. as a result, we offer a dichotomic key to distinguish these 55 species and illustrations to clarify it. an ecological interpretation of leaf structures is also given. predominantly, meso-hygromorphic traits are found in shrubs, while meso-xeromorphic traits are found in small trees due to the presence of some sclerophyllous and xeromorphic features.