Four genera and 13 species of Lemnaceae are currently known to occure in Colombia. The presence of Wolffiella oblonga (Phil.) Hegelm. in Colombia is confirmed for the first time. Descriptions of the family and genera are given, as also keys to species, illustrations, information about the distribution of the species. A short explanatory glossary is also provided. Nomenclature follows the recent monograph of the family (Landolt, 1986).
