Adonis fucensis (A. sect. Adonanthe, Ranunculaceae), a New Species from the Central Apennines (Italy)

SIMPLE SUMMARY: Adonis sect. Adonanthe is characterized by species with strongly gibbous abaxial side of achenes, reticulate-venation on its surface, with short and recurved style and includes four series: ser. Amurenses, ser. Coeruleae, ser. Apenninae, ser. Vernales. In the Euro-Mediterranean area three species belonging to A. sect. Adonanthe are currently recognized: A. apennina (ser. Apenninae), A. volgensis (incl. A. transsilvanica; ser. Vernales), A. vernalis (ser. Vernales). In 2021 was discovered in the Central Apennines (Italy) a yellow-flowered Adonis population belonging to sect. Adonanthe similar to A. volgensis. Following an integrated taxonomic approach, we have shown that the newly discovered population should be regarded as a new species, named A. fucensis, endemic to Abruzzo (Central Apennines, Italy). ABSTRACT: Adonis fucensis is herein described as a new species based on morphological and molecular analyses. It is endemic to one locality of the Central Apennines between Amplero and Fucino plains within the NATURA 2000 network in the SAC IT7110205 (Central Italy). The only discovered population is composed of 65 individuals and is at risk of extinction. The conservation status assessment according to IUCN categories and criteria is proposed and discussed. The new species belongs to A. sect. Adonanthe and is morphologically similar to A. volgensis (incl. A. transsilvanica), a species distributed in Hungary, Romania, Bulgaria, and Turkey as well as eastward to SW Siberia and Central Asia. Adonis fucensis can be distinguished from A. volgensis by larger cauline leaves, pentagonal with lobes lanceolate, larger stipules with more lobes and teeth, and larger flowers. Finally, an analytical key to Adonis species belonging to sect. Adonanthe distributed in Europe is presented.