The type material of Jungermannia obscura Sw., collected by Olof Swartz in Jamaica between 1783 and 1786, is a mixture of three common tropical species of Frullania: F. arecae (Spreng.) Gottsche, F. gibbosa Nees and F. riojaneirensis (Raddi) Aongstr. The material of F. arecae fits the protologue best and is therefore chosen as the lectotype of J. obscura Sw. As a consequence, the name Frullania arecae (Spreng.) Gottsche is replaced by the older name Frullania obscura (Sw.) Dumort.