Data from: Geometric morphometrics dismiss the polymorphic Hydrocotyle quinqueloba (Araliaceae) from the neotropics

Hydrocotyle taxonomy is poorly resolved due the traditional assessment of leaf morphology that has imposed difficulties to species delimitation and prompted the recognition of several infraspecific taxa. Hydrocotyle quinqueloba comprises ten infraspecific taxa that differ mainly by the shape of their leaf blade. The species occurs in montane forests of the Andes and eastern Brazil, along the Atlantic forest and Cerrado domains. However, the geographic distribution of the taxa under H. quinqueloba is poorly known, and their supposedly continuous morphological variation remains unverified. Here we analyze the morphological variation and documented correlated differences in geographic distribution of H. quinqueloba to assess whether they support the delimitation of distinct species or the recognition of infraspecific taxa. For this task, we applied landmark-based geometric morphometrics (GM) to leaves and traditional morphometrics to other structures of specimens of H. quinqueloba. Procrustes analysis of variance (Procrustes ANOVA) indicated that variation of leaf blade shape was weakly associated with geography and was mainly explained by taxa themselves. In contrast, variation of leaf blade size was significantly (p < 0.001) associated with geography, but variation at the specimen level could account for it. Principal component analysis (PCA) of leaf blade shape indicated that taxa differed mainly by the angle and relative size between median and lateral primary veins, by the space between the petiole insertion and middle lobe’s sinuses, and by the width of middle lobe’s base. Canonical variate analysis (CVA) indicated significant (p < 0.01) differences among seven infraspecific taxa that formed groups defined by leaf blade shape. Linear discriminant analysis (LDA) of 11 morphological characters separated five groups of taxa, which displayed significant (p < 0.001) differences among each other. Based on that, we propose an updated taxonomic treatment that restricts the circumscription of H. quinqueloba to plants from the Andes and accepts four species from eastern Brazil