Molecular support of the classification of Greeniopsis Merr. in Aleisanthieae (Rubiaceae), with a revision of the genus
Résumé
Greeniopsis Merr. is a small genus of Rubiaceae endemic to the Philippines. Previously, no molecular data have been available for Greeniopsis and its taxonomic position has remained controversial. Based on morphology, the genus was tentatively included in the tribe Aleisanthieae (Ixoroideae) along with the Southeast Asian genera Aleisanthia and Aleisanthiopsis. To determine the taxonomic position of Greeniopsis and evaluate the monophyly of the genus, sequences of the rps16 and trnT-F regions of cpDNA of all seven Greeniopsis species were generated. Parsimony and Bayesian analyses of the combined plastid dataset strongly support the inclusion of Greeniopsis in Aleisanthieae as well as its monophyly. Woolly hairs on the abaxial leaf surface occur in only one Greeniopsis species and can no longer be regarded a synapomorphy of the tribe. The generic status of Aleisanthia, Aleisanthiopsis, and Greeniopsis is maintained. A revision of Greeniopsis, including a key to species, descriptions, distribution maps, and illustrations, is provided.