Nine new species of Piper sect. Isophyllon Miq. (Piperaceae) from Brazil

Piper section Isophyllon comprised about 120 species with a Neotropical distribution, with the greatest diversity occurring in Central America and the Brazilian Atlantic Forest. Based on analysis of the largest Brazilian herbaria, we describe nine new species of Piper sect. Isophyllon: P. arianeae G.A. Queiroz, Sarnaglia & E.F. Guim.; P. forzzae G.A. Queiroz & E.F. Guim.; P. jaramilloae G.A. Queiroz & E.F. Guim.; P. marquetii G.A. Queiroz, E.F. Guim. & Sarnaglia; P. martinellii G.A. Queiroz & E.F. Guim.; P. michelineae G.A. Queiroz & E.F. Guim.; P. moreiranum G.A. Queiroz & E.F. Guim.; P. rizzinii G.A. Queiroz & E.F. Guim.; and P. sucreanum G.A. Queiroz & E.F. Guim. In addition to the taxonomical descriptions, illustrations, maps, and comments, we provide an identification key for the Brazilian species of this group.