A revision of isertia (Isertieae: Rubiaceae)

A revision is presented, of the neotropical genusIsertia Schreber.Cassupa Humb. & Bonpl. is given a new status asIsertia sectionCassupa (Humb. & Bonpl.) B. M. Boom, based on differences in fruit type, number of locules in the ovary, and number of lobes of the stigma. A new combination is made at the species level,I. laevis (Triana) B. M. Boom, and a new species from Panama is described and illustrated,I. scorpioides B. M. Boom. Altogether, fourteen species and one variety are recognized in the genus.