Diversity of arborescent lineages of Crotoneae (Euphorbiaceae) in the Brazilian Atlantic Rain Forest

Abstract

We conducted fieldwork and herbarium research to investigate the morphological diversity, taxonomy, and geographic distribution of arborescent lineages of tribe Crotoneae (Euphorbiaceae) in the Brazilian Atlantic Rain Forest domain, a neotropical region considered one of the world's hot spots of biodiversity. We found that arborescent lineages of Crotoneae are represented in the Atlantic Rain Forest by two genera (Croton and Brasiliocroton) and 23 species. Of this total, 70% of the species are endemic to the Atlantic Rain Forest. The genus Brasiliocroton, which is endemic to Brazil, includes two species, and Croton is represented by 21 species. We provide identification keys, update morphological description of key characters, include pertinent taxonomic comments, and illustrate most of the studied species with live photographs to facilitate taxonomic identification. The conservation status of each species is also evaluated. We establish five new synonyms, one superfluous name, and nine lectotypifications.