A newly discovered species of Actinostemon (Euphorbiaceae) critically threatened from the Coastal Atlantic Forest of São Paulo State, Brazil

Abstract

A new species of Actinostemon (Euphorbiaceae), restricted to a small area in São Paulo state, Brazil and critically threatened, is described here. The new species, Actinostemon caraguatatubensis is similar to A. concolor, with which it is compared. The new species is a small shrub, representing one of the smallest species of the genus, in addition to presenting the largest leaves ever documented in the genus. Two other characteristics, described here for the first time in the genus, is the presence of auriculate-based leaves and stipules. The new species grows in the understory of Dense Submontane and Lowland areas of the Atlantic Forest, typically near watercourses. Description, diagnosis, distribution map, comparisons with similar species, photographic plates, and preliminary conservation assessment are provided.