A survey of the Lejeuneaceae (Hepaticae) was performed at Ferreira Penna Research Station, Melgaço municipality, Pará, where were observed Lejeunea caespitosa Lindenb. ex Gottsche, Lindenb. & Nees, Lejeunea flava (Swartz) Nees, Lejeunea tapajosensis Spruce, Microlejeunea acutifolia Stephani and Microlejeunea epiphylla Bischler. Microlejeunea acutifolia is a new record to Brazil and Microlejeunea epiphylla Bischler is mentioned for the first time to Pará State. The species are described and illustrated and an artificial key is presented to separate them, as well as additional commentaries.