Lejeunea huctumalcensis (Lejeuneaceae), a species widely distributed in the Neotropics, is characterized by the presence of ocelli in leaf lobes, innovations of lejeuneoid- and pycnolejeuneoid-type, perianths with five entire to ramified laciniae and vegetative reproduction via regenerants and caducous leaves. The species is a member of Lejeunea subgenus Otigoniolejeunea. Lejeunea acanthotis, L. schizotis, L. xiphotis and Ceratolejeunea dussiana are proposed as new synonyms of L. huctumalcensis. The relation of this species to Ceratolejeunea and other genera is discussed. Lejeunea huctumalcensis is described and illustrated.