Melastomataceae are an easily recognizable family because of their usually opposite leaves with characteristic acrodromous leaf venation, flowers with a well-developed hypanthium, and geniculate, porose, often colorful anthers that frequently have connective appendages. The family has a mostly tropical distribution with 69 % of the species found in the New World, 5 % in continental Africa, 5 % in Madagascar, and 21 % in Asia and northern Australia (Renner, 1993). Melastomataceae comprise close to 5000 species in 150-166 genera, making it one of the ten largest families of flowering plants (Renner, 1993). The circumscription and monophyly of the Melastomataceae have generated little or no controversy, with the only debatable issue being whether the Memecylaceae should be considered to be part of the Melastomataceae or as a sister family (Renner, 1993; Conti et al., 1997). However, intrafamilial relationships have been controversial, as reflected in the various classifications proposed in the last 130 years (Triana, 1871; Cogniaux, 1891; van Vliet et al., 1981; Renner, 1993), and in the fact that traditional as well as modern classifications based on morphology differ from those that can be derived from molecular data (Renner, 1993; Clausing & Renner, 2001; Renner & Meyer, 2001). Recent molecular phylogenetic analyses (Clausing & Renner, 2001) suggest that at least 10 tribes should be recognized in the Melastomataceae (in addition to the Memecyleae if they are considered to be part of the family): Melastomeae, Kibessieae, Astronieae, Merianieae, Miconieae, Bertolonieae, Blakeeae, Sonerileae, Dissochaeteae, and Microlicieae.
The circumscription of Miconieae has varied, and the tribe at times has included Old and New World taxa, and/or taxa with dry and fleshy fruits. Based on a morphological and anatomical cladistic analysis, Renner (1993) defined the Miconieae as those genera with inferior ovaries, no pedoconectives and non-cochleate seeds. Additionally, most of these genera have ovaries that develop into berries. However, later molecular analyses showed that the Old World genera are part of an expanded tribe Melastomeae (Clausing & Renner, 2001; Renner et al., 2001; Renner & Meyer, 2001). Some of the New World genera traditionally considered Miconieae have also been excluded based on recent analyses.Henriettea DC. and five other cauliflorous genera traditionally placed in the Miconieae have been excluded because they form a distinct and more distantly related clade (Michelangeli et al., 2004; Penneys et al., 2004b), while Huilaea Wurdack and ChalybeaNaudin have been found to belong to the tribe Blakeeae (Penneys et al., 2004a; Penneys, 2007). The capsular-fruited genera Allomaieta Gleason, Alloneuron Pilg., and WurdastomWallnofer, which were placed in the Miconieae (Renner, 1993) or in their own tribe Cyphostyleae form a monophyletic group not closely related to Miconieae, while the capsular-fruited Eriocnema Naudin, traditionally placed in the tribe Microliceae, has been found to be sister to the Miconieae (Fritsch et al., 2004; Martin et al., in press). With these new insights, the Miconieae now comprise approximately 1800 species in 19-23 genera, forming a large and exclusively Neotropical clade characterized by flowers with inferior or partly inferior ovaries that develop into baccate fruits, stamens with no or only poorly developed connective appendages, and the absence of megastyloids and imbricate bracts at the base of the flowers.
It has long been known that genera within the tribe are poorly characterized, often difficult to discern, or even arbitrarily defined (Baillon, 1880; Cogniaux, 1891; Gleason, 1925a, 1932a, 1958; Macbride, 1941; Wurdack, 1972, 1980; Judd, 1986, 1989; Judd and Skean, 1991). Thus, most botanists working on the tribe have agreed with Cogniaux (1891) who stated that within the Miconieae “the delimitation of genera is rather arbitrary; one could easily distinguish more of them; at the same time one could justify the union of many of those which are generally recognized today”. Phylogenetic analyses have shown that the large genus Miconia (with over 1000 species) is clearly paraphyletic, with all other genera embedded within it. During the present project, we will continue working on the phylogenetic relationships within the tribe, in order to produce a natural and character based classification. For the time being, species will be treated under their current accepted name.