The Neotropical genus Borojoa Cuatrec. (Rubiaceae) is now considered a synonym of Alibertia A. Rich. ex DC. Consequently, three species named in Borojoa and found in Costa Rica and Panama are transferred to Alibertia with these corresponding nomenclatural changes: the new combination A. atlantica (Dwyer) Delprete & C. H. Perss. is based on B. atlantica Dwyer, the new name A. dwyeri Delprete & C. H. Perss. is provided for B. panamensis Dwyer, and the new combination A. patinoi (Cuatrec.) Delprete & C. H. Perss. is provided for B. patinoi Cuatrec. Additionally, the species A. premontana C. M. Taylor is reduced to a variety of A. edulis (Rich.) A. Rich. ex DC., as A. edulis var. premontana (C. M. Taylor) Delprete & C. H. Perss. A lectotype is selected for A. edulis. The recent publication of Arachnothryx chimalaparum Lorence ex Borhidi designated a holotype deposited at MO, but no such specimen has been located; a lectotype is here chosen based on a duplicate of the holotype deposited at MEXU. The new species Notopleura recondita Hammel & C. M. Taylor of the Osa Peninsula of Costa Rica can be distinguished from N. polyphlebia (Donn. Sm.) C. M. Taylor by its leaf blades with the secondary veins plane on the adaxial surface and its short cymose or paniculiform inflorescences. The new species Palicourea matamana C. M. Taylor of premontane forests of central-eastern Costa Rica can be separated from P. orosiana C. M. Taylor by its larger stipules, longer calyx lobes, and hirsute pubescence. The new species P. providenciana J. Sánchez-Gonz. & C. M. Taylor of montane forests in south-central Costa Rica can be separated from P. hammelii C. M. Taylor by its longer lanceolate stipule lobes, dark purple or yellow-flushed inflorescences, and shorter calyx lobes. The Panamanian plants treated previously as Psychotria acuminata subsp. boraginoides Dwyer are here considered to differ at the species level from P. acuminata Benth., and accordingly the new combination P. boraginoides (Dwyer) C. M. Taylor is here published for this species. Clarification of the identity of Cephaelis croatii Dwyer shows that it is a distinct species of Psychotria, and the new combination P. croatii (Dwyer) C. M. Taylor is published here for this species. The new species P. herrerana C. M. Taylor of central Costa Rica can be recognized by its combination of large, sessile, elliptic leaves, its large paniculiform inflorescences, and its relatively small corollas. Study of the Costa Rican plants previously called Rudgea thyrsiflora Donn. Sm. shows that these do not have the characters of Rudgea, but are similar to Psychotria racemosa Rich. and better included in this latter genus; the new name P. tsakiana C. M. Taylor is here published for this species. The new combination Simira panamensis (Dwyer) C. M. Taylor is published here based on the name Bathysa panamensis Dwyer, which has priority over the name S. darienensis Dwyer; both of the names Dwyer published are based on the same type specimen, thus the later name S. darienensis is illegitimate.