Petunia axillaris (Solanaceae) includes three allopatric subspecies that present different degrees of self-compatibity and incompatibility. Turchetto et al. study P. axillaris subsp. axillaris, a hawkmoth-pollinated taxon from a sympatric zone, and find a high proportion of self-pollination, indicating a mixed-mating system. The results show that most pollen dispersal in subsp. axillaris occurs within populations and there is a high proportion of inbreeding. This mating system appears to favour species integrity in a secondary contact zone with the congener species P. exserta.