This note follows from an earlier Commentary published in Journal of Biogeography (Carrión & Fernández, 2009, 36, 2202–2203), which provided palaeoecological data, and two replies in the form of Correspondence (Loidi et al., 2010, 37, 2209–2211; Farris et al., 2010, 37, 2211–2213). The latter papers attempt to invalidate the palaeoecological database as a source of comparison with the maps of potential vegetation. Here, some of the different interpretations of the term ‘potential natural vegetation’ (PNV), as used by the floristic phytosociological school, are discussed. It is suggested that there is a conceptual impasse that will not have a solution until a terminological consensus is reached. This terminology will open new methodological avenues that will facilitate the entry of new information derived from historical biogeography, palaeoecology, ecology, phylogeography, and niche and community modelling. One of the main sources of conflict arises from the link made between habitats and floristically-determined associations, a confusion that has crucial repercussions in biological conservation, including in respect of the EU Habitats Directive.