Format: ORAL

Fainelli Federico1; Giacomo Baldesi1; Giulia Ginelli1; Carla Lambertini2; Orsenigo Simone1

1 University of Pavia, Pavia, Italy 2 University of Milan, Milan, Italy

Hieracium L. has extreme morphological variation caused by complex reproductive strategies, interspecific hybridization and polyploidization. The genus includes few sexual diploids and numerous apomictic polyploids1. Taxonomy and systematics of this group are extremely complex and poorly investigated. Hieracium. tenuiflorum Arv.-Touv. belongs to H. murorum L. group (sect. Hieracium), and occurs in Alps and Apennines, where it grows in forest margins and along roadsides between 200-1800 m a.s.l. Currently, there are 6 subspecies ascribed to H. tenuiflorum. Most of them were originally described for Italian localities across the Alps. However, the current classification for these taxa is based only on morphology and information on current distribution, ploidy level or genetic diversity is lacking. To disentangle the taxonomic diversity of the species, we used an integrated taxonomic approach, including nomenclatural investigation on herbarium specimens, morphometry, chromosome counts, genome size estimation and molecular systematics. Recently collected plants from loci classici of H. tenuiflorum subspecies and from different localities in Alps and Apeninnes were investigated. These studies revealed a high variability in ploidy level in H. tenuiflorum. For the first time, at least three diploid H. tenuiflorum populations were reported in the Southern Alps. Morphometric analyses showed morphological differences between subspecies despite morphological clusters mainly overlapped, suggesting high morphological similarity. Finally, we performed molecular investigations using three plastid intergenic spacers (trnH-psbA, trnT-trnL, and trnV-ndhC) and ten nuclear microsatellites to evaluate the phylogenetic relationship between sampled populations. 1) Mraz, P., Zdvork, P., (2019) Ann. Bot., 123(2), 391-403.