Taxonomical, morphological and geobotanical considerations on Seseli tortuosum L. (Apiaceae) from Sicily

Seseli tortuosum L. is represented in Sicily by populations occurring in two distinct habitats, i. e. on sandy coasts and inland rocky substrata. In-depth morphological analyses have stressed that these populations differ also in habit, leaves, inflorescences, flowers and fruits. Apart from their morphology and ecology, they show a different chromosome complement, tetraploid (2n = 44) and diploid (2n = 22), respectively. From the taxonomic judgement, the inland populations can be attributed to the Linnean type, while the psammophilous ones relate to a well distinct taxon, previously described as S. tortuosum var. maritimum Guss. Based on these outcomes, the latter populations should be treated at subspecific level, and thus we propose to refer them to S. tortuosum L. subsp. tortuosum and subsp. maritimum (Guss.) C. BRULLO, S. BRULLO, Guisso & SCIANDRELLO stat. nov., respectively.