Nomenclatural and taxonomic remarks on Prunus cupaniana (Rosaceae) from Sicily

“Prunus cupaniana” is a nomen nudum doubtfully given by Gussone (1842) to some Sicilian populations close to Prunus mahaleb L. from which they are distinct by both biological and ecological characters. This name was later cited by Nyman (1878) which did not provide its validation, contrary to the erroneous IPNI report “Prunus cupaniana Guss. ex Nyman -- Consp. Fl. Eur. 1: 213. 1878 [Sep 1878]“. Fiori (1926) applied the Gussone’s epithet to the infraspecific combination “Prunus mahaleb cupaniana(Guss.)”, which is invalid being based on a nomen nudum. Before Fiori, Lojacono (1891) treated the same populations under P. mahaleb var. prostrata. Recently Raimondo & Spadaro [in Fl. Medit. 19: 309 (2009)] treated the population of “Prunus cupaniana” as Prunus mahaleb subsp. cupaniana. This latter name is invalid too. In order to maintain the subspecific rank, the examined taxon is here treated as: Prunus mahaleb subsp. prostrata (Lojac.) Raimondo & Spadaro st. nov. [Bas. Prunus mahaleb var. prostrata Lojac., Fl. Sic. 1(2): 164 (1891); Prunus mahaleb subsp. cupaniana(Guss.) Raimondo & Spadaro, nom. inval.] This subspecies differs from P. mahaleb subsp. mahaleb by its characteristic prostrate or ascending many-stemmed bushy habit; leaves cordate, coriaceous; corymb poor with small flowers; fruits small, ovoid, slightly flattened, black when ripened. It is also ecologically distinct.