Résumé
About the discovery of Potentilla supina L. in Algeria: ecology, taxonomy, biogeography and conservation status. Wetlands of South Constantine high plateaus were recently recognized for their ornithological interest. Potentilla supina L., a paleo-temperate species, was discovered for the first time in Algeria in two of these wetlands. Both stations are located on freshwater overflow areas on salt-affected soils by evaporation. The observed phytocoenose is characteristic of the association Parapholi-Frankenietum pulverulentae Rivas-Martinez ex Castroviejo & Porta 1976 but constitutes a new sub-association pulicarietosum laciniatae described here. Our plant belongs to the subspecies Potentilla supina subsp. tunetica Sojak described decades ago in Tunisia where it was alleged endemic. Its new Algerian-Tunisian endemic status pleads for his long-time native status. Human activities related to the regulation of overflow water and occasional cultivation of dried depressions threaten the sustainability of the main station. Given its geographic and population characteristics and threats on the localities the taxon could be assessed as "critically endangered" for extinction according to the criteria of the IUCN Red List.