Luziola is a small genus from aquatic environments of the New World. The most widespread species in the genus is L. peruviana. Morphological variation has been documented for this species throughout its entire range of distribution, however this variation has been difficult to characterize. A population aggregation analysis was performed in order to determine how many species can be identified when analyzing characters from the individuals of this taxon as well as with individuals from closely related taxa such as L. divergens, L. doelliana, and L. pittieri. Multivariate analysis, ANOVA and ANCOVA analyses were also performed to detect if quantitative morphological variation is related to altitude and latitude. Results indicate that within this complex only one species should be recognized, referable to L. peruviana, and that plants near the equator are larger, and have larger lemmas and paleas in both female and male flowers. An identification key for the nine species now recognized in Luziola is included.