Does leaf anatomy aid in species identification of (Arecaceae)?

is a neotropical genus whose identification is based mostly on characters from external morphology, which are sometimes variable or inadequate for species differentiation. We aimed to verify if leaf anatomy of 18 species brings new characters suitable for species identification and if it corroborates the phylogenetic relationship within the genus. Moreover, we propose an anatomical key to assist in species identification. Pinnae were collected and subjected to the usual techniques for light and scanning electron microscopies. The anatomical key was created with the aid of Xper software, based on the importance of characters to distinguish species according to the Jaccard index. All species have isobilateral mirrored mesophyll, amphistomatic leaves and secondary vascular bundles with sclerenchymatic sheath reinforcement connected to the hypodermis. Among the species studied, and showed exclusive characters. For the other species, up to five characters are sufficient for delimitation. Our anatomical key presents relevant characters that allow the identification of the recognized species of . Reliable anatomical characters of easy observation, especially the raphides, are valuable in species distinction. Leaf anatomy, already used to support new taxa in related genera like and , can also be useful to validate questionable species and differentiate between similar species but do not reflect the proposed relationship between species.