Phylogenetic Relationships ofAllomaieta,Alloneuron,Cyphostyla, andWurdastom(Melastomataceae) and the Resurrection of the Tribe Cyphostyleae

Abstract

In the Melastomataceae, flowers with superior ovaries usually develop into capsular fruits, while flowers with inferior or partially inferior ovaries develop into berries. The phylogenetic position and affinities of four enigmatic genera with inferior ovaries and capsular fruits, Allomaieta, Alloneuron, Cyphostyla, and Wurdastom, were investigated using three plastid loci (rbcL, ndhF, and rpl16) and morphological characters. These four genera have been placed at times in their own tribe, the Cyphostyleae, but they have also been placed in the Miconieae, and whether they form a group at all has also been the subject of debate. We find that these four genera form a well-supported group that can be diagnosed by the unique character combination of haplostemonous flowers (same number of anthers and petals), inferior ovaries, and capsular fruits. Most members of the tribe also have a calyptrate calyx, but the mode of dehiscing of the calyx varies across species. This character combination and the phylogenetic position of this clade within the family warrant the recognition of the tribe Cyphostyleae. The previously proposed synonymy of Cyphostyla under Allomaieta is maintained, and a key to the genera in the tribe and a list of all species, with nomenclatural and taxonomic information, are provided. Lectotypifications for two species are also included.