XVI International Botanical Congess

A revised classification of Lamiaceae (Cantino et al. 1992) circumscribes Teucrioideae as a subfamily composed of genera formerly allied with Verbenaceae and Lamiaceae. Among them, Trichostema is a North American genus with the Asian genera Amethystea, Rubiteucris, Schnabelia, and Caryopteris as its closest relatives. A cladistic study of the Caryopteris-Trichostema complex was conducted using ITS sequence data to assess the phylogenetic relationships of these groups. The results suggest that Caryopteris, a genus comprising 16 species distributed from central to northeastern Asia, is polyphyletic while Trichostema is strongly supported as monophyletic. The ITS phylogeny also provides insights into character evolution and the biogeographic history of Trichostema.