[in French with additional Esperanto and English abstract: ] Detailed description of Psora gresinonis s.s. (proxilittoral in the Mediterranean region) and two new related species, P. bellilensis Brien and Cl. Roux sp. nov. (proxilittoral, at Belle–Île, southern Brittany) and P. cravenis Cl. Roux and Poumarat sp. nov. (proxilittoral or not in Provence and Languedoc, at the mesomediterranean zone). Identification key for these three species and for P. vallesiaca which had previously been confused with P. bellilensis by Monnat in Esnault et coll. (2020).