Article

The chromosome number of species belonging to the genus Digitalis L. is mainly 2n = 56, except for D. lutea L. In the latter, distinct counts and ploidy levels have been reported: 2n = 48-56 and 2n = 96-112. Depending on the authors, this taxon is treated either as a single species with two subspecies: D. lutea subsp. lutea and subsp. australis (Ten.) Arcang., or as two distinct species in Italy: D. lutea and D. micrantha Schweigg. However, in S. France and Corsica, classical discriminant characters of these taxa seem less reliable than in Italy. In addition, a phylogenetic study sets plants of subsp. australis from Tuscany and Corsica in two distinct clades. To clarify this situation, flow cytometry, karyological, morphological and pollen studies were carried out on a large sample from different geographical sources. Results confirmed the validity of the two infra-specific taxa, which differ in their ploidy levels (D. lutea subsp. lutea 2n = 112; D. lutea subsp. australis 2n = 56), 2C DNA content and macro- and micro-morphological traits.