Revisão taxonômica dos gêneros Dyschoriste Nees e Hygrophila R.Br. (Ruellieae – Acanthaceae) para o Brasil

Abstract

Ruellieae (Acanthaceae) is distributed in the pantropical region, with Brazil as one of the main centers of diversity in the New World, followed by Mexico and Peru. In Flora of Brazil it is represented by 120 species and nine genera, Dyschoriste, belonging to the subtribe Petalidiinae, and Hygrophila, to the subtribe Hygrophilinae, the least studied in the country. Studies developed in the last decades based on morphological and molecular data have been fundamental to clarify its infrafamilial relationships. Thus, studies that aim to assist in the knowledge of the taxonomy and systematics of Ruellieae in Brazil are of great importance, given that there are still gaps in the characterization of the Brazilian Dyschoriste and Hygrophila. In this context, the aim of this work was to carry out a revisional study of the genera Dyschoriste and Hygrophila for Brazil, one of its main centers of diversity, from the combination of morphological and palynological data, aiming to contribute to a better understanding of the relationships between the species of each of these genera, detecting the characteristics for solving taxonomic problems of its species. In addition, to knowing and updating their geographic distribution in the country. As a result, six chapters are presented in this thesis. The first chapter deals with nomenclatural updates in Dyschoriste and Hygrophila, with two lectotypifications, three new synonyms and the proposition of a new name. The second chapter reveals two new species of Dyschoriste for the Brazilian Northeastern, with detailed descriptions of these two taxa, as well as an identification key, illustrations of diagnostic characteristics, maps of geographic distribution and information on conservation status. In chapter 3, we present two new occurrences for the Northeastern region of Brazil and two lectotypifications for the genus Dyschoriste. Chapter 4 deals with the characterization of the pollen morphology of 11 species of Dyschoriste (seven) and Hygrophila (four) in search of characteristics with taxonomic value. Based on the evaluation of several palynological characteristics, together with data on the external morphology of branches, leaves and flowers, a new combination was proposed for a species of Dyschoriste, which was included in the genus Hygrophila. Chapter 5 presents the taxonomic revision of the genus Dyschoriste, in which 13 species were recognized, eight of which are endemic to Brazil. Additionally, descriptions, comments regarding their geographic distributions are provided, including maps, conservation status, flowering and fruiting period, illustrations and photographs and an identification key. In chapter 6 we present the taxonomic revision of the genus Hygrophila, with five species being recognized, three of which are endemic to Brazil. In addition, three lectotypifications and a new synonym are proposed. Additionally, descriptions, comments regarding their geographic distributions are provided, including maps, conservation status, flowering and fruiting period, illustrations and photographs, in addition to an identification key. The results obtained in this research revealed important external and internal morphological characteristics in the separation and recognition of both Dyschoriste and Hygrophila species, in addition to providing updates on flowering, fruiting, conservation status and geographic distribution data for both genera. We hope that our results will contribute to the understanding of the systematic relationships between the groups included in Ruellieae tribe and the Acanthaceae family as a whole.