Carolus tomentosus, a new species of Malpighiaceae endemic to northeastern Brazil

Carolus currently comprises seven accepted species endemic to seasonally dry forests or rainforests of Central and South America. After unusual populations of Carolus were discovered in the States of Bahia, Minas Gerais and Piauí, we describe it as a new species. This study was based on the analysis of type specimens, protologues, field photographs and herbarium sheets of all its accepted species. As a result, we propose selected specimens as a new species based on differences in leaf, inflorescence and fruit traits. Carolus tomentosus is easily distinguished from C. chasei due to its widely elliptic to ovate (versus narrowly-elliptic to elliptic) and abaxially tomentose (versus abaxially sericeous) leaf blades, petioles frequently 1–2-glandular at apex (versus eglandular), and longer inflorescence main axis (versus shorter inflorescence main axis). We present an identification key to all species of Carolus occurring in Brazil alongside a complete morphological description for the new species, photographic plates, and comments on its conservation, distribution, ecology and taxonomy.