In order to investigate taxonomic conclusions based upon herbarium studies, 2n = 14 taxa of Petunia have been crossed. Characters identifying hybrids of P. axillaris ssp. axillaris with P. axillaris ssp. parodii, as well as of P. axillaris (s.l.) with P. integrifolia have been established. Length measures show quantitative inheritance, either in subspecies crosses in P. axillaris s.l. or in P. integrifolia s.l. In the latter, the deflexed pedicel inherits as a dominant character with modifiers. It is argued that both species will have inherited several alleles from a common ancestor.