Critical revision of the nomenclature of Mediterranean therophytic grasslands of the class Stipo-Trachynietea distachyae

In the standard classification of European vegetation, the class Stipo-Trachynietea distachyae is currently recognized as encompassing Mediterranean therophytic swards and basiphilous grasslands along the southern edge of Europe, extending from Portugal to Greece and Crimea. This study provides a critical revision of the nomenclature of this class and its subordinate syntaxonomic units. While these syntaxon names are widely cited in the scientific literature, the present revision reveals that many of them are either invalid, illegitimate, or misapplied. The results have led to the identification of the correct forms of all syntaxon names, along with their nomenclatural types. To promote the stability of phytosociological nomenclature, the orders Ptilostemono stellati-Vulpietalia ciliatae and Stipo capensis-Bupleuretalia semicompositi, the alliance Hypochaeridion achyrophori, and the associations Orlayetum grandiflorae and Erodio neuradifolii-Plantaginetum zwierleinii have been validated. The alliances Omphalodion commutatae and Stipion retortae O. de Bolòs 1958 have been lectotypified, the names Stipo capensis-Trachynietea distachyae and Trachynion distachyae have been mutated to Stipo capensis-Brachypodietea distachyi and Brachypodion distachyi, respectively, and the name Plantagini coronopodis-Catapodion marini has been corrected. Finally, two proposals are announced for the conservation of the names Brachypodietalia distachyi Rivas-Martínez 1978 and Lygeo sparti-Stipetalia Braun-Blanquet et O. de Bolòs 1958 with the aim of stabilising these names in accordance with current usage. These results are essential for ensuring the consistent application of syntaxonomic concepts and for guiding future updates and refinements of the standard classification of European vegetation, for advancing knowledge, disseminating research findings, and ensuring the effective management and conservation of European biodiversity.