Morphoanatomical and histochemical investigation of Monteverdia evonymoides (Reissek) Biral

Monteverdia species are known for their medicinal properties. However, due to similarities between species, the accurate identification of different species can be cumbersome. The study of morphoanatomy can contribute to the authentication of the species by providing additional information and contributing to the species characterization. Therefore, this work presents the morphoanatomy of the leaves and stems of Monteverdia evonymoides (Reissek) Biral analyzed by optical microscopy, scanning electron microscopy, and histochemical approaches. Through these methods, we were able to determine, morphologically, the analyzed species features large and woody trees; its leaves are simple, distichous, and entire; the leaf margins are fringed; the stipules are caducous, triangular, and rarely persistent; the apex can vary from acute to obtuse, and the leaf blade has no trichomes. The frontal view presents polygonal epidermal cells, anomocytic, anisocytic, and tetracytic stomata that are found on the abaxial surface and are positioned at the same level as the ordinary epidermal cells; the epidermis is uniseriate and covered with a thick cuticle; the mesophyll is dorsiventral; the midrib is biconvex, and below the epidermis is the angular collenchyma, with one collateral bundle in an open arc and two dorsal bundles; in the ground parenchyma, there is a small collateral vascular bundle, with fibers juxtaposed to the phloem. Histochemical reactions were positive for lipophilic, phenolic, and lignified compounds. Among the observed characteristics, the stomatal classification of the leaf and the prominence of the midrib (adaxial surface) in this study help to identify M. evonymoides and may contribute to species taxonomy by comparing it with other species of the genus and quality control studies.