Collapse of Isertieae, re-establishment of Mussaendeae, and a new genus of Sabiceeae (Rubiaceae); phylogenetic relationships based on rbcL data

The circumscription of the Isertieae has been under debate for a long time and recently a phylogeny based on morphological data has been presented (ANDERSSON 1996), contradicting the classification of ROBBRECHT (1988, 1993). Our investigation of molecular data neither supports the phylogeny of ANDERSSON nor the classification of ROBBRECHT, but instead indicates totally new relationships of Isertieae, Mussaendeae, and Sabiceeae. The Isertieae are a bigeneric tribe of subfam. Cinchonoideae, while Mussaendeae and Sabiceeae are two separate tribes of subfam. Ixoroideae. We have also referred a species from Socotra (Yemen) with disputed position to the tribe Sabiceeae and we place it in a new genus, Tamridaea, with the single species T. capsulifera comb. nov. New rbcL sequences of 20 taxa are presented and analysed, from Gentianaceae: Gentianella; from Loganiaceae: Spigelia; and from Rubiaceae: Amphidasya, Aoranthe, Chomelia, Coussarea, Gonzalagunia, Heinsia, Hippotis, Isertia (three taxa), Mussaenda, Pseudomussaenda, Pseudosabicea, Rondeletia, Sabicea, Schraclera, Tamridaea, and Virectaria.