A preliminary cladistic study of the families of the superorder Lamiiflorae

Abstract

A preliminary cladistic analysis was undertaken to evaluate the relationships between families of the superorder Lamiiflorae sensu Dahlgren. Several character complexes were surveyed, and ultimately 29 informative characters were used for the study. Three families, Clethraceae, Oleaceae and Solanaceae were selected for outgroup comparison and polarization of the characters. A data matrix was constructed for the 23 ingroup families. The data matrix was analysed with the cladistic parsimony program Hennig86. Three equally parsimonious cladograms were found. Many family interrelationships could not be resolved, although several groups were common to all three cladograms, as shown by a strict consensus tree. The Retziaceae emerged as the sister group to the remaining families. About half of those appeared in a large polytomy in the consensus tree. There was also one possibly monophyletic complex of families involving the Lamiales with the families Verbenaceae, Lamiaceae, Phrymaceae and Callitrichaceae as well as the three isolated families Trapellaceae, Hippuridaceae, and Hydrostachyaceae. Within this complex, Verbenaceae and Lamiaceae came out as sister groups, as did Callitrichaceae and Hydrostachyaceae, with Hippuridaceae as sister group to them. However, the results must be regarded as tentative.