Abstract
A newly discovered species, Lejeunea timokoponenii, from Sandaun Province (formerly West Sepik Province), Papua New Guinea is described and illustrated. Lejeunea timokoponenii is characterized by its upwards-curling leaf margins, large, reniform underleaves, well-developed trigones and conspicuous intermediate thickenings, fully incurved lobule free-margins, and undulate-keeled perianths with a 5–6 cells long beak.