Approximately 185 species of Lycopodiaceae are known to occur in the Neotropics: ca. 150 belong in the genus Huperzia, ca. 8 in Lycopodium, and ca. 25 in Lycopodiella. The species are enumerated according to assumed relationship, with information of the most important synonyms, a summary of their distribution, comments on their morphology and variability, and reference to selected illustrations. Species delimitation is problematic throughout the family. This is due to the simple morphology and the plasticity of the characters. Morphogenesis seems unstable in many species and may be strongly affected by environmental factors (...)