Geometric morphometrics as a tool to resolve taxonomic problems: the case of Ophioglossum species (ferns)

Abstract

A modern method, geometric morphometrics, was used to clarify the taxonomic position of the European Ophioglossum species: O. azoricum, O. lusitanicum, and O. vulgatum. The identification of these taxa by traditional methods is rather difficult, due to different taxonomic interpretations. Sterile leaf shapes were investigated using a landmark-based method and the Fourier analysis of outlines. Both methods highlight the shape and the base of the leaf as an important diagnostic character.