A new rheophytic liverwort species, Lejeunea topoensis (Lejeuneaceae), is described from the Andes of Ecuador and southern Brazil. The new species is intermediate between Lejeunea and Neopotamolejeunea, combining short leaf insertions typical of the former genus, and robust stems and pinnate branching with numerous short sexual branches characteristic of the latter. Neopotamolejeunea is therefore reduced to subgeneric status under Lejeunea. The discovery of L. topoensis adds a further species to the growing list of taxa with disjunct distribution in the Andes and the Atlantic coastal region of Brazil. It is postulated that the disjunct range resulted from long-distance dispersal, although it might to some extent reflect under-representation of collections. The new name L. juruana, replacing Neopotamolejeunea uleana, is proposed. Cheilolejeunea rupestris is a new synonym of C. beyrichii.