Hibiscus section Furcaria (Malvaceae) includes 100+ species distributed pantropically, with major centers of diversity in Africa, Australia, and the New World. The section includes ten extant diploid (n = 18) species, nine of which are primarily African, and one New World species (H. costatus). In addition to the diploid species there are several allopolyploid lineages ranging from tetraploid to decaploid. Most of the extant diploid species, and several allopolyploid species have previously been cytogenetically characterized and placed into "genome groups" based on chromosome pairing behavior in F1 hybrids. Despite these strong foundational data, however, no phylogenetic studies have been performed in this group. Accordingly, the monophyly of the diploid genome groups and the relationships among them are currently unknown. Further, the affiliation of two of the diploid species, H. berberidifolius and H. costatus, are unclear. Finally, the origins of, and relationships within and among groups of allopolyploid species have yet to be extensively analyzed. To begin to address these questions DNA sequence data has been generated from several nuclear single-copy alcohol dehydrogenase (Adh) genes, as well as from the ITS region of nuclear ribosomal DNA. Preliminary results suggest that at least one of the genome groups may not be monophyletic. Further, the placement of the sole New World diploid, H. costatus, indicates that it is most closely related to the African G-genome diploid, H. sudanensis. The relative utilities of Adh and ITS sequences will be discussed, as will the origins and relationships of selected allopolyploid species.

Key words: Adh, allopolyploidy, Hibiscus, ITS, Malvaceae, phylogenetics