Sinopse taxonômica das espécies pertencentes a tribo Hippomaneae A. Juss. ex Spach. (Euphorbiaceae Juss.) no Nordeste do Brasil

Abstract

The tribe Hippomaneae is one of the largest taxa of the subfamily Euphorbioideae (Euphorbiaceae) with about 300 species distributed throughout the Pantropical region. In Brazil, 106 species are referred, among which almost half (48%) occur in the Northeast, making this region an important center of diversity for the taxon in the country. In order to reduce the taxonomic impediment in the region and improve knowledge about the tribe in a region with outdated information for most Hippomaneae genera, a taxonomic survey of the representatives of the tribe in this locality was carried out. 50 species included in 10 genera (Actinostemon, Gymnanthes, Gradyana, Mabea, Maprounea, Microstachys, Sapium, Sebastiania, Senefeldera and Stillingia) were recorded. Microstachys proved to be the most diverse of all genera with 13 species, followed by Actinostemon, Mabea, Sapium, Sebastiania (6 spp.), Gymnanthes (5), Stillingia (4), Maprounea (2) and Gradyana and Senefeldera with a species each. In fact, M. corniculata emerges as the species with the widest range of distribution in the region and in Brazil as a whole. On the other hand, almost 20 species of the tribe are known for, at most, two northeastern states, among these: Gymnanthes multiramea, Mabea taquari, Microstachys ditassoides, M. marginata, M. uleana, Sapium pallidum, Stillingia trinervia, S. argutedentata and S. loranthacea. Bahia is the state with the highest representation of the tribe comprising 43 of the 50 species, followed by Pernambuco (24) Ceará (21) and Sergipe (19) and in these locations the Atlantic Forest stands out with 11 species, followed by the Caatinga (7) and Cerrado (6). New records are reported for 17 species, expanding the known geographical distribution for them in the region. Therefore, the present work fills an important gap in the knowledge of the tribe in the Northeast and in Brazil, updating the species list and the distribution of species in the region and providing subsidies for future protective measures, especially for the more restricted and rare species.