Lejeunea adpressa Nees has ovate and entire-margined leaves, bifid underleaves and 5-keeled perianths, among other typical Lejeunea features. The high variability of the species is demonstrated by the numerous synonyms proposed here, including Lejeunea magnoliae Lindenb. & Gottsche, seven species and one var. of "Lejeunea subg. Eulejeunea" described by Spruce, Eulejeunea setistipa Steph., Lejeunea longifissa Steph. and "L. caespitosa sensu Schuster 1980". Four names are lectotypified. The species is described, illustrated and its geographical distribution in tropical America is documented.