New revision of Joosia (Rubiaceae-Cinchoneae)

Joosia comprises 11 species, three of which are here described as new: J. longisepala, J. multiflora, and J. obtusa. Joosia pulcherrima Steere is resurrected from synonymy. Joosia is a close relative of Cinchona, Ladenbergia, and Remijia, from all of which it differs in having wilting rather than caducous stipules, an inflorescence of predominantly monochasial cymes, and corolla lobes with marginal showy appendages. It occurs from western Panama along the Andes south to northern Bolivia, with a pronounced center of diversity in Ecuador. On the basis of a cladistic and biogeographical analysis, it is hypothesized that the genus originated in the lowland forest of the westernmost Amazon Basin.