Chromosome numbers and mode of reproduction in Picris hieracioides s.l. (Asteraceae), with notes on some other Picris taxa

(ENG) Chromosome numbers for 88 plants of Picris hieracioides s.l. originating from 32 localities from Austria, Andorra, Croatia, France, Germany, Hungary, Italy, Slovakia and Spain are reported. All analysed plants were diploid, with 2n" 2x"10. In addition to P. hieracioides s.l., we also found diploidy (2n"2x"10) in P. nuristanica from Kirgizia and P. japonica from Japan. Our data confirmed previously published results in the literature. We also studied the mode of reproduction in all three taxa. Picris nuristanica and P. japonica s.l. were able to produce some seeds by selfing, and this is the first record of autogamy in this genus. In P. hieracioides s.l. only strict allogamy was found, demonstrating the presence of a self-incompatibility system in this species. Because apomixis, namely apospory, has previously been reported in P. hieracioides, castration experiments were performed in order to confirm or reject this report. However, no evidence of apomictic seed formation was found within this species. In the light of our results, P. hieracioides should be considered a strictly sexual taxon.