Novelties in the genus Persicaria (Polygonaceae) in Brazil: a new species, a new combination, and a diagnostic key to all species

This work presents novelties in the genus Persicaria in Brazil. More specifically, we describe P. sylvestris, a new species from the Atlantic rainforest in subtropical Brazil, propose the new combination P. diospyrifolium and designate a lectotype for its basionym, Polygonum diospyrifolium. The new species has until now been identified as P. acuminata, from which it differs by morphological characters as well as ecological aspects. We also provide photographs of the new species and of similar species along with a distribution map and a key to the species of Persicaria in Brazil.