Recent Neotropical exploration and floristic studies have continued the discovery of species of Rubiaceae new to science, including the six species described here: Bouvardia costaricensis C. M. Taylor of central Costa Rica is distinguished by its foliaceous enlarged calyx lobes and long white salverform corollas; Hillia pumila C. M. Taylor of dwarf montane forests in central Peru is distinguished by its quite small leaves and stipules; Joosia antioquiana C. M. Taylor of northwestern Colombia is distinguished by its long stipules, leaves with numerous secondary veins, and four entire (i.e., unornamented) corolla lobes; Ladenbergia franciscana C. M. Taylor of southern Ecuador is distinguished by its calyptrate stipules, small, mostly obtuse leaves, and shallowly lobed calyx limb; Pentagonia osaensis C. M. Taylor of southern Costa Rica is distinguished by its dense pilosulose to velutinous pubescence and its subtruncate to very shallowly lobed calyx limb; and Posoqueria laevis C. M. Taylor of Panama is distinguished by its leaves with the secondary and higher-order venation not visible.