Species of the complex and diverse genera Psychotria and Palicourea are common but little-known elements in many tropical forest ecosystems. DNA-phylogenetic studies and a re-evaluation of morphological characters have recently shown that species of Psychotria
subg.
Heteropsychotria are nested within Palicourea s.l., which was traditionally separated by exhibiting a bird-pollinated (vs. insect-pollinated) pollination syndrome. In order to render both genera monophyletic groups, species of subg. Heteropsychotria need to be transferred to Palicourea s.l. For Central American species, most of the necessary combinations have already been made. In the course of ongoing research on the phytochemical characterization of species and clades of Costa Rican Palicourea s.l., the nomenclature of Mesoamerican species was revised. As a result, two new combinations and a new name are proposed here: Palicourea
horquetensis (Dwyer & Hayden) A. C. Berger & C. M. Taylor is based on Rudgea
horquetensis Dwyer & Hayden, Palicourea
tonduzii (K. Krause) A. C. Berger is based on Cephaelis
tonduzii K. Kraus and Palicourea
longiinvolucrata A. C. Berger replaces Psychotria
hispidula Standl. In addition, two lectotypes are designated.