The classification of the Catesbaeeae and Chiococceae tribes, along with the entire Rubiaceae, has been intensely debated in recent years. This debate has focused on a few key morphological characters (corolla shape and aestivation, anther shape and position, fruit placentation, and number and position of ovules) and one set of molecular data (rbcL). Several phylogenetic analyses in the Rubiaceae based on nucleotide sequences of the trnL-F and rps16 regions of the plastid genome and the nuclear ribosomal internal transcribed spacers (ITS1&2) suggest that none of the previously proposed classifications are entirely correct. Molecular data suggest that the traditionally defining flower and fruit features of the Catesbaeeae and Chiococceae are actually phylogenetically homoplastic, leaving present generic boundaries and relationships within the Catesbaeeae-Chiococceae Complex in doubt. The Catesbaeeae-Chiococceae Complex is a group that includes approximately 27 genera and 196 species primarily concentrated in the Greater Antilles (nearly 70% of the taxa) but also occurring in Malesia and the South Pacific (3 genera). Phylogenies using trnL-F and rps16 have identified one major monophyletic group. However, the ITS data provides more resolution and additional taxa have been surveyed. Presently the ITS data is not congruent with the other data sets and does not support the monophyly of the Catesbaeeae-Chiococceae Complex. Additionally, Pacific genera which have been absent in previous molecular studies have been sampled and included in the analyses in the hope to better understand the disjunct biogeographic distribution of these Caribbean and Pacific taxa. Based on ITS data some genera, i.e. Exostema and Bikkia, do not appear to be monophyletic. The Pacific taxa form two distinct clades, suggesting that there have been apparently two separate introductions of the Catesbaeeae-Chiococceae Complex into the Pacific basin.

Key words: Biogeography, Caribbean, Evolution, ITS, Pacific, Rubiaceae