Thymus paronychioides (Lamiaceae), a Neglected Species from Sicily Belonging to Thymus sect. Hyphodromi

The taxonomic position of Thymus paronychioides Čelak., a neglected species until recently treated as a synonym of Th. striatus or Th. spinulosus, is reviewed. Karyological and morphological characters were used for comparative analyses with closely related taxa belonging to Th. sect. Hypodromi, such as Th. striatus and Th. spinulosus, occurring in the Mediterranean area (Italy, Balkans and Turkey). Multivariate and univariate morphometric analyses showed that Th. paronychioides is clearly distinct from Th. striatus and Th. spinulosus in the unique features of leaves (elliptical-spathulate, fleshy, with ± curved and prominent lateral veins), in the inflorescence being always capitate with few flowers, and in the larger corolla with the tube usually exceeding the calyx. Furthermore, chromosome counts showed that Th. paronychioides is polyploid (2n = ca. 60), whereas Th. spinulosus and Th. striatus are diploid (2n = 2x = 26). Hence, Th. paronychioides is shown to be an independent taxon, endemic to NW Sicily, placed within Th. sect. Hypodromi subsect. Serpyllastrum. Finally, an identification key to the Italian species of Th. sect. Hypodromi is provided.