Journal: Taxon
Volume: 63
Pages: 819-830

Abstract:

We performed molecular phylogenetic analyses of the Randia clade of the tribe Gardenieae using both plastid and nuclear DNA data. In the phylogenetic hypotheses presented, the African genera Calochone, Euclinia, Macrosphyra, Oligocodon, Pleiocoryne, and Preussiodora are resolved as a monophyletic group. Support is also found for a clade of the Neotropical genera Casasia, Randia, Rosenbergiodendron, Sphinctanthus, and Tocoyena. This Neotropical clade is resolved as sister group to the African clade in analyses of combined plastid and nuclear data. The genus Euclinia appears polyphyletic. The species described from Madagascar represent an independent lineage, the position of which is moreover found to be incongruent between datasets. Plastid and ribosomal DNA data support a sister-group relationship to the mainland African clade, whereas the low-copy nuclear gene Xdh supports a closer relationship to the Neotropical genera. The phylogenetic reconstructions also indicate that Casasia and Randia are not monophyletic as presently circumscribed. A taxonomic proposal is made for the recognition of the Malagasy taxon at generic level as Melanoxerus.