The genus Festuca s.l. (Poaceae): taxonomic and distributional studies, with special reference to the F. circummediterranea group

Festuca L. (Poaceae, Loliinae) and allied genera represent one of the most problematic taxonomic critical groups of worldwide interest, for combination of intrinsic high phenotypic variability and nomenclatural complexity, produced by two centuries of heterogeneous and, to some extent, conflicting taxonomic interpretations. The present PhD thesis, through the examination of three main ISI papers and further “satellite” contributions (both ISI and non-ISI) published during the PhD course, fills some relevant gaps in the knowledge of Festuca s.l., with special regards to three research topics: (1) Nomenclature: the name Festuca apennina De Not., still lacking a formally designated type, is lectotypified and a new combination, shifting this taxon from Festuca to Lolium L. at species rank, is proposed: L. apenninum (De Not.) Ardenghi & Foggi; (2) Taxonomy: the first comprehensive karyological overview of the group of Festuca circummediterranea Patzke, comprising 10 Euro-Mediterranean taxa, is provided. The first chromosome counts for F. jeanpertii (St.-Yves) Markgr. subsp. jeanpertii, subsp. achaica Markgr.-Dann., and subsp. gracilis (Hack.) Raus are reported. All the taxa were found to be diploid (2n=14) and have a similar karyotype. These data clarify the relationships between each taxon and represent a valuable support to a future multidisciplinar systematic revision of the whole aggregate; (3) Applied Plant Taxonomy: the application of the current taxonomic knowledge in Festuca s.l. improved scientific fields more or less connected with taxonomy, such as: (a) Phytogeography: the new treatment of Festuca s.l. within the new edition of Sandro Pignatti’s Flora d’Italia (in press) has been fulfilled; along with floristic novelties at regional scale, the distributional scenario of this critical group has been enhanced in both southern Europe and Italy; (b) Crop wild relatives (CWR): taking into account the commercial value of fescues as cultivated grasses, the first taxonomically based priority list of Italian CWRs of Festuca s.l. has been compiled.