TAXON 57 (1) • February 2008: 1–17 Khan & al. • Tribal and generic circumscriptions of Sabiceeae Sabiceeae and Virectarieae (Rubiaceae, Ixoroideae): one or two tribes? New tribal and generic circumscriptions of Sabiceeae and biogeography of Sabicea s.l. Saleh A. Khan1,3, Sylvain G. Razafimandimbison2, Birgitta Bremer2 & Sigrid Liede-Schumann1 1 Department of Plant Systematics, University of Bayreuth, Universitätstr. 30, 95440 Bayreuth, Germany.
[email protected] (author for correspondence) 2 Bergius Foundation, Royal Swedish Academy of Sciences; Department of Botany, Stockholm University, 10691, Stockholm, Sweden 3 Department of Botany, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh The results of two recent phylogenetic studies led to the reinstatement of the tribe Sabiceeae, currently clas- sified in the subfamily Ixoroideae s.l. (Rubiaceae) but with conflicting circumscriptions. In the present study, phylogenetic analyses based on nrITS and trnT-F sequence data of 78 taxa are performed to evaluate the dif- ferent circumscriptions of Sabiceeae, the generic limits within Sabiceeae, and the biogeography of Sabicea. The polyphyly of Sabiceeae sensu Andersson is confirmed, and Pentaloncha and Temnopteryx are shown not to belong to Ixoroideae s.l. but to the subfamily Rubioideae. Our results favour a broad circumscription of Sabiceeae that includes Ecpoma, Hekistocarpa, Pseudosabicea, Sabicea, Schizostigma, Stipularia, Tamridaea and Virectaria. Sabicea sensu Wernham is not monophyletic unless Ecpoma, Pseudosabicea, Schizostigma,