Flora de Hypericaceae Juss. (Malpighiales) no Maranhão, Brasil

Abstract

Malpighiales are one of the most diverse orders among angiosperms, with 36 families, 716 genera, and about 16,000 species. The morphological characteristics common to Malpighiales families are scarce, but there is molecular phylogenetic evidence supporting the formation of taxonomic groupings. In this order, the clusioid clade is composed of Bonnetiaceae, Calophyllaceae, Clusiaceae, Hypericaceae, and Podostemaceae. Currently, Hypericaceae has five genera distributed in temperate and tropical regions around the globe. In Brazil, there are two genera, Hypericum L. and Vismia Vand., with confirmed occurrence in all states of the country. Vismia, which has a neotropical distribution from Mexico to southeastern Brazil, is the only genus of the family found in Maranhão. The genus stands out among the Hypericaceae due to its wide distribution in the Americas, diversity, and high phytotherapeutic potential. An important ecological characteristic is that Vismia generally occurs as a pioneer in secondary forests, where it plays a crucial role in ecological succession and the restoration of native vegetation. This dissertation presents i) taxonomic studies on Vismia species occurring in the state of Maranhão and ii) an anatomical study of one of these species, V. guianensis. The dissertation is organized into two chapters: the first presents taxonomic results obtained through collections and analyses of collections, such as descriptions, photographic records, identification keys, and illustrations of the five species that occur in Maranhão, namely Vismia cayennensis, V. gracilis, V. guianensis, V. sandwithii, and V. tenuinervia. The second chapter presents the leaf and flower anatomy of V. guianensis. Therefore, this study contributes to the knowledge of the flora of Maranhão, detailing the taxonomic diversity of species of the genus Vismia occurring in the state, as well as providing an anatomical analysis of Vismia guianensis, contributing to regional botany and elucidating knowledge of the Hypericaceae family.