A world-level revision is given for the 29 species of Bulbothrix, a generic segregate of Parmelia characterized by marginal bulbate cilia and production of atranorin in the upper cortex. The genus is primarily tropical in distribution and best developed in secondary forests. The main center of speciation is Brazil with 14 species, and the genus is also well represented in Africa. The New World species have a high frequency of depsides and orcinol depsidones, whereas the Old World species usually contain p-orcinol depsidones. One new species, B. klementii Hale, and one new combination, B. goebelii (Zenker) Hale, are proposed.