1995 Volume 45 Issue 2 Pages 95-109
A survey of native habitats of Petunia species over 5 seasons revealed the cooccurrence of two subspecies of P. axillaris sensu lato in Uruguay. Typical subsp. axillaris and subsp. parodii were found in south eastern and north western departments, respectively. Using floral measurements (length of corolla tube, corolla limb, pedicel, and calyx lobes, and the length of corolla tube / length of corolla limb ratio) of specimens collected in these departments, we performed stepwise discriminant analyses. After substituting measurements of 174 specimens collected in the whole of Uruguay into the three discriminant functions thus obtained, we determined them to be either subsp. axillaris or subsp. parodii. Distribution of the two subspecies thus determined by the discriminant functions was roughly delimited by the Rio Negro. A considerable number of doubtful specimens were found in the south western departments, which are on opposite sides of the river de La Plata from the place where secondary intergradation between the two subspecies had been suggested by Wijsman (1982) to have occurred.
