Troublesome tropical mints: re-examining generic limits of Vitex and relations (Lamiaceae) in South East Asia

The relationships of Vitex and genera historically placed in Lamiaceae subfamily Viticoideae were investigated. Particular focus was given to some South East Asian genera traditionally allied to Vitex (Paravitex, Tsoongia, Viticigremna, Tejismanniodendron) since progress with South East Asian Floras is being hampered by a lack of clarity in current generic delimitation. On the basis of maximum parsimony and Bayesian phylogenetic analyses of ITS and ndhF sequence data we provide evidence that the Viticoideae is not monophyletic, its members being spread between a number of clades which include genera currently recognised as incertae sedis (Peronema, Hymenopyramis, Petraeovitex, Tectona). The most well Supported clade, the Vitex group, contains Vitex, Paravitex, Tsoongia, Viticipremna, Petitia and Teijsmanniodendron. Morphological similarities of the genera included in this group are also discussed. In light of this evidence Paravitex, Viticipremna and Tsoongia are reduced to synonymy with Vitex, the new combinations being made here. The position of Teijsmanniodendron is not resolved and its generic status is therefore upheld. Similarly, PC-litia is upheld due to a lack of neotropical taxa within the sample.