Allopolyploid origin of highly invasive Centaurea stoebe s.l. (Asteraceae)

► The pattern of cloned ITS region suggests allopolyploid origin of invasive Centaurea stoebe. ► The hybridization might have triggered shift from monocarpic to polycarpic life cycle. ► This in turn may explain the colonization success of the tetraploids. ► The results show deep split of the C. paniculata and C. stoebe groups. ► Molecular dating indicates a young diversification within the C. stoebe group.