Revisão taxonômica das espécies de Tabernaemontana L. (Apocynaceae) da Amazônia brasileira, Brasil.

Abstract

The Apocynaceae family stands out as one of the most representative within the angiosperm group, comprising approximately 378 genera and 5,350 species. In the Brazilian context, this family is distributed across 96 genera and 977 species, encompassing all biomes present in the country. Among the five subfamilies that constitute the Apocynaceae family, only three are present in Brazil, namely Rauvolfioideae, Apocynoideae, and Asclepiadoideae. The subfamily Rauvolfioideae consists of 12 tribes, with the Tabernaemontaneae tribe standing out as one of the most diversified. Within this tribe, the genus Tabernaemontana, inserted into the Tabernaemontanenae subtribe, emerges as one of the most diversified, comprising over 120 species. Among these, 46 occur in the neotropics, with 30 recorded in Brazil, and of these, 25 in the Brazilian Amazon region. The taxonomy of the Tabernaemontana genus reveals a complex and extensive history marked by significant changes in its circumscription and species recognition, especially in the Amazonian regions where nomenclature and taxonomy were less explored. Recent phylogenetic studies have recognized the genus as monophyletic, including the neotropical genus Stemmadenia. However, the infrageneric circumscription remained ambiguous, demonstrating monophyly only in the Peschiera and Rejoua sections, while other sections exhibited paraphyly. Despite the abundance of Amazonian species, some were not included in the previous phylogeny. The last taxonomic revision of the genus, conducted in the 1990s, proposed seven sections based exclusively on morphological characters. Among these, only two (Bonafousia and Peschiera) have representatives in Brazil, which were the focus of the present study. The objective of this study was to conduct a systematic approach to Tabernaemontana in the Brazilian context, with an emphasis on species occurring in the Amazon, as well as a nomenclatural revision of the discussed species. To achieve this, a comprehensive taxonomic treatment was developed, including detailed descriptions, identification keys, maps of geographic distribution and diversity, as well as considerations on phenology and conservation status. Samples of the genus were analyzed in the IAN, INPA, MG, UFACPZ, RON herbaria in person, while others were requested on loan or analyzed online through digitized images available in foreign and national herbaria databases. Over 4,000 specimens were analyzed in person, resulting in the development of three thesis chapters, encompassing the treatment of 207 names, of which 25 were accepted, 18 lectotypifications, two neotypifications, one epitypification, the proposition of a new name, the reinstatement of a species, and the description of a new species for science.