Phylogeny and classification of the subfamily Rubioideae (Rubiaceae)

We performed phylogenetic analyses of the subfamily Rubioideae (Rubiaceae) based on three different pieces of chloroplast DNA, the protein coding rbcL gene, the spacer sequence between atpB and rbcL (atpB-rbcL), and the recently published (Andersson and Rova 1999) rps16 intron data. New rbcL sequences have been produced for 41 taxa and there are 52 new atpB-rbcL spacer sequences. All analyses gave similar results concerning the phylogeny, but they differ slightly in resolution and support for the various branches. The minor tribes Ophiorrhizeae, Urophylleae, Lasiantheae, and Coussareeae form a grade to the rest of the subfamily, which consists of two well-supported branches, the Psychotrieae alliance and the Spermacoceae alliance, including a majority of all genera and species. Based on the resulting phylogenies we present a revised classification of the Rubioideae. We accent 16 tribes of which 12 more or less correspond to earlier tribal circumscriptions: Anthospermeae, Argostemmateae, Craterispermeae, Gaertnereae, Morindeae, Paederieae, Psychotrieae, Schradereae, Spermacoceae, Rubieae, Theligoneae, and Urophylleae; two tribes have received new and very different circumscriptions: Ophiorrhizeae and Coussareeae; and two are new to science: Lasiantheae and Danaideae.