This work provides a key, illustrations, descriptions, and distribution maps for the 15 species of neotropicalLomariopsis. In the Neotropics, the genus occurs in southern Florida, the Antilles, and Mexico to Bolivia and southern Brazil. Two groups of species can be recognized on the basis of heteroblastic leaf series: one (the “sorbifolia group”) whose leaves become pinnate when 1–2 cm long, and another (the “japurensis group”) whose leaves become pinnate when 15–40 cm long. Three species in the Antilles are unusual because the rachis apex aborts and the distalmost lateral pinna assumes the terminal position.