On the basis of a study of herbarium sheets of the described species Petunia axillaris. P. integrifolia, P. propinqua, P. inflata, P. occidentalis, and P. parodii, it is concluded that only two biological species are involved, the white-flowered P. axillaris (with subspecies axillaris and parodii) and the purple-flowered P. integrifolia (with subspecies integrifolia, inflata comb, nov., and occidentalis comb. nov.). The name P. violacea is rejected as a synonym of P. integrifolia. Possible relations of P. axillaris with an isolated population from Peru of an undescribed species of Petunia are discussed, The geographical distribution of the characters separating the species and subspecies is given.