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The internal and external transcribed spacers of nuclear ribosomal DNA were sequenced in 167 samples of Memecylon s.str. and 22 outgroup samples of Lijndenia, Mouriri, Spathandra, Votomita, and Warneckea. Maximum‐likelihood analyses of ETS, ITS1, 5.8S and ITS2 alignments yielded tree topologies that are not significantly incongruent, with one exception involving the Tanzanian sample Luke 9741. Monophyly of Memecylon s.str. is strongly supported in the separate ETS and the combined ETS + ITS1 + 5.8S + ITS2 analyses. Also supported in all analyses except 5.8S is a sister‐group relationship between a small species‐group from western and central Africa (Memecylon subg. Mouririoidea, ovary 4‐loculed) and the remaining taxa (M. subg. Memecylon, ovary unilocular). In the combined analysis, internal branches at the base of M. subg. Memecylon are short and weakly supported, yet within this large subgenus one finds a series of monophyletic groups representing different parts of the widespread paleotropical distribution (one group in western and central Africa; two separate groups in East Africa, one of these extending to southern Africa and disjunctly to western and northern Madagascar; one species‐rich group occurring exclusively on Madagascar and the neighboring Comoro and Mascarene islands; and three distinct groups in Indo‐Malesia, one of these also including the Seychelles endemic M. elaeagni). Within the western and central African clade, M. sect. Polyanthema sensu Jacques‐Félix is paraphyletic with respect to M. sect. Afzeliana, and at the morphological level it seems to be a group defined by symplesiomorphies (ovary unilocular, fruit globose). Three East African species (M. fragrans, M. greenwayi, M. semseii) are returned to Memecylon s.str. after being erroneously transferred to Lijndenia by Borhidi. The Madagascan endemic M. mocquerysii is no longer considered a taxonomic synonym of the distantly related, Tanzanian M. cogniauxii. In addition to elevating M. sect. Mouririoidea to subgeneric rank, the following changes are proposed in the infrageneric classification of African Memecylon: (1) the circumscription of sect. Polyanthema is narrowed to comprise only the members of the “M. polyanthemos complex” sensu Jacques‐Félix; (2) Engler's sections Tenuipedunculata, Cauliflora, and Obtusifolia are re‐instated with emended descriptions (in the case of sect. Cauliflora with an expanded circumscription); (3) seven new sections, Buxifolia, Diluviana, Felixiocylon, Germainiocylon, Magnifoliata, Montana, and Sitacylon, are described; (4) the purported occurrence of M. sect. Pseudonaxiandra in East Africa is rejected. A key is provided to the two subgenera and twelve sections currently recognized in African Memecylon. Further study is needed toward a sectional classification of Indo‐Malesian Memecylon, and for revision of the seven Madagascan sections recognized by Jacques‐Félix.

Aim: African Melastomateae (Melastomataceae) comprise c. 185 species occurringin closed or open habitats throughout sub-Saharan Africa. We sought to reconstruct biogeographical and habitat history, and shifts in diversification rates of African Melastomateae using a well-sampled, dated molecular phylogeny.Location: Americas, sub-Saharan Africa, Madagascar, SE Asia.Taxon: Angiosperms, Melastomataceae, African Melastomateae.Methods: Phylogenetic relationships were estimated based on an extensive sampling of New and Old World Melastomateae, using two nuclear and three plastid markers. Divergence times were estimated in BEAST based on three calibration priors under Bayesian uncorrelated lognormal relaxed clock and birth-death speciation process. The dated phylogeny was used to infer the biogeographical history under a dispersal-extinction-cladogenesis model in "BioGeoBEARS". The ancestral habitat of African Melastomateae was estimated using maximum likelihood and stochastic character mapping in "Phytools" and "ape" respectively. Finally, shifts in diversification rates were tested using BAMM.

Melastomateae are the most species-rich (185 spp./13 gen.) and morphologically diverse tribe within the African Melastomataceae. In this study we present the first in-depth phylogenetic analysis of African Melastomateae using sequences generated from one nuclear (nrITS) and two plastid spacers (accD-psaI, psbK-psbL) sampling 183 accessions representing 75 African, 10 Madagascan and 7 Asian species and a broad outgroup sampling. We infer phylogenetic relationships using maximum likelihood, maximum parsimony and Bayesian approaches and propose a revised generic classification of African Melastomateae based on our molecular trees in combination with a careful reassessment of morphological variation. Our phylogenetic analyses support the monophyly of Old World Melastomateae except Dinophora which clearly falls outside Melastomateae. Asian and Madagascan endemic genera of Melastomateae are nested among the African genera. Of the African genera only two monophyletic groups, Dichaetanthera and Tristemma, are recovered in addition to the monospecific Pseudosbeckia lineage, while Antherotoma, Dissotis and Heterotis as currently circumscribed are polyphyletic. However, the subgenera and sections of these genera are mostly recovered as morphologically distinct and molecularly well-supported clades. Isomorphism versus dimorphism of the stamens is found to be an unreliable character when delimiting genera in Melastomateae. We propose the reinstatement of Argyrella and Dupineta, a new status at generic rank for Dissotis subg. Dissotidendron, a broadened circumscription of Guyonia (to include the species previously placed in Heterotis sect. Cyclostemma), and description of a new, monospecific genus Anaheterotis for the Heterotis pobeguinii lineage. Heterotis is maintained at generic rank but with a narrower circumscription in comparison to earlier treatments. We accommodate the rare Osbeckia porteresii lineage from Mt. Nimba (Guinea) within an expanded Melastomastrum. To complete our generic realignment, a total of 42 new combinations are effected at the species level and below, and a key is provided for the 12 genera presently recognised in African Melastomateae. Denser taxonomic sampling and sequencing of more loci will be needed to resolve relationships within the large clade of Dissotis s.str. and allies (including Antherotoma as well as three West African species erroneously placed in the otherwise Asian Osbeckia).

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