Taxonomic synopsis of Euphorbiaceae in the threatened upland forests "Brejos de Altitude" in the Brazilian semi-arid region

Abstract

Abstract The analysis of herbarium collections and field surveys revealed the occurrence of 14 genera and 38 species of Euphorbiaceae in the threatened flora of the Brejos de Altitude of the Pajeú region, a semi-arid area of Pernambuco. Crotonoideae was the most representative subfamily, with Croton (10 spp.), Euphorbia (8 spp.), Dalechampia (3 spp.) and Acalypha (3 spp.) being the genera with the highest number of species. Twelve species are considered endemic to Brazil, five of which are exclusive to the Caatinga domain. The relatively high number of Euphorbiaceae species in the areas studied and the fact that some species are exclusively related to Brejos de Altitude vegetation highlight the need to preserve these forests and to create Conservation Units in these environments. An identification key, photographic plates and comments on the geographical distribution and diagnostic characteristics of the species are presented here. In addition, the presence of Euphorbia ophthalmica in Pernambuco is confirmed, and the typification of Cnidoscolus halteris is clarified and is illustrated.