Data on species plasticity and stable characters have an overall importance in identification keys: comments on Brullo et al. (2022) article

The paper of Brullo et al. (2022) aimed to lectotypify _Elatine macropoda_ Guss. and _E. gussonei_ (Sommier) Brullo et al., two enigmatic members of the genus. They gave an overview of the taxonomic issue of these species, identified the type specimens, and gave a comprehensive description of both species, as well as aimed to clarify open questions in the nomenclature of these taxa. However, some of the points raised by Brullo et al. (2022) are in contrast to previously published scientific evidence, leading them to reach different taxonomic conclusions. This contrast is the result of (i) misinterpreted some key findings published in other works, and (ii) stitching to preconceptions on the distribution and specific characteristics of these species. Given the importance of scientific discussion, authors here attempt to shed light on contested points to help the better understanding of the taxonomy of this genus in Europe.