Tropical Asian species show that the Old World clade of ‘spiny solanums’ (Solanum subgenus Leptostemonum pro parte: Solanaceae) is not monophyletic

The tropical Asian taxa of the species‐rich genus Solanum (Solanaceae) have been less well studied than their highly diverse New World relatives. Most of these tropical Asian species, including the cultivated brinjal eggplant/aubergine and its wild progenitor, are part of the largest monophyletic Solanum lineage, the ‘spiny solanums’ (subgenus Leptostemonum or the Leptostemonum clade). Here we present the first phylogenetic analysis of spiny solanums that includes broad sampling of the tropical Asian species, with 42 of the 56 currently recognized species represented. Two nuclear and three plastid regions [internal transcribed spacer (ITS), waxy, ndhF‐rpL32, trnS‐trnG and trnT‐trnF] were amplified and used to reconstruct phylogenetic relationships using maximum likelihood and Bayesian methods. Our analyses show that Old World spiny solanums do not resolve in a single clade, but are part of three unrelated lineages, suggesting at least three independent introductions from the New World. We identify and describe several monophyletic groups in Old World solanums that have not been previously recognized. Some of these lineages are coherent in terms of morphology and geography, whereas others show considerable morphological variation and enigmatic distribution patterns. Tropical Asia occupies a key position in the biogeography of Old World spiny solanums, with tropical Asian taxa resolved as the closest relatives of diverse groups of species from Australia and Africa.     

Analysis of eggplant (<Emphasis Type="Italic">Solanum melongena</Emphasis>)-related germplasm: morphological and AFLP data contribute to phylogenetic interpretations and germplasm utilization

A total of 94 Solanum accessions, including eggplants and related species, were morphologically characterized based on greenhouse observations, and molecularly analysed by the AFLP technique. Morphological parameters were helpful in assessing similarities or differences among accessions, and molecular data were used to support morphological conclusions. A dendrogram was computed based on the Dice genetic distances using the neighbour-joining method. The analysis was efficient in the assignment of a species name for eight out of nine accessions that were not previously classified, and revealed that 14 further accessions were misnamed in the collection originally received. The results indicate that the taxonomy of Solanum sections and subgenera including several species should be reconsidered. The AFLP technique was revealed as an efficient tool in determining genetic relationships among species. In general, morphological observations were consistent with molecular data, indicating that both approaches complemented to define the phylogenetic status of a large genus like Solanum. In terms of eggplant breeding, the molecular analysis of the Melongena complex, and of the other sections of the subgenus Leptostemonum, establishes useful germplasm relationships in the gene pool available for the genetic improvement of the cultivated species. The results we have provided highlight an urgent necessity to include molecular parameters in handling and characterizing the genebank-deposited germplasm related to cultivated crops.Communicated by F. Salamini     

The genus Cyrtomium (Pteridophyta: Dryopteridaceae) in Africa and Madagascar

The fern genus Cyrtomium (Dryopteridaceae) in Africa and Madagascar is reviewed. Until now, a single Cyrtomium species ascribed to either C. caryotideum or C. micropterum (the latter often considered to be a variety of the former) was recognized for the region. This study shows that three Cyrtomium species occur in the region. One, C. falcatum, is not native to the African or Madagascan region, but has become naturalized in various parts of South Africa and Réunion. Two, formerly considered as a single taxon and confused with C. caryotideum and Indian forms thereof, are described as new – C. luctuosum from Madagascar, East, West and South Africa and C. pseudocaryotideum from South Africa. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 449–465.     

Phylogenetic analysis of the Brazilian microendemic Paepalanthus subgenus Xeractis (Eriocaulaceae) inferred from morphology

Paepalanthus subgenus Xeractis (Eriocaulaceae) comprises 28 recognized species endemic to the Espinhaço Range, in Minas Gerais state, Brazil. Most species of the subgenus are restricted to small localities and critically endangered, but still in need of systematic study. The monophyly of the subgenus has already been tested, but only with a few species. Our study presents the first phylogenetic hypothesis within the group, based on morphology. A maximum parsimony analysis was conducted on a matrix of 30 characters for 30 terminal taxa, including all species of the subgenus and two outgroups. The biogeographical hypotheses for the subgenus were inferred based on dispersal–vicariance analysis (DIVA). The analysis provided one most‐parsimonious hypothesis that supports most of the latest published subdivisions (sections and series). However, some conflicts remain concerning the position of a few species and the relationships between sections. The distribution and origin(s) of microendemism are also discussed, providing the ground for conservation strategies to be developed in the region. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 137–152.     

Phylogenetics of Eulophiinae (Orchidaceae: Epidendroideae): evolutionary patterns and implications for generic delimitation

Eulophiinae comprise c. 270 species divided into nine genera, with the species‐rich terrestrial genus Eulophia representing 60% of this diversity. Remarkable ecological and morphological variation, and an absence of clear diagnostic characters have led to uncertain generic delimitation in the subtribe. Using a combination of new and previously published DNA sequences, we created a dataset representing 122 taxa and all genera of Eulophiinae and inferred a complete generic‐level phylogeny for the subtribe for the first time. Our sampling focused on analysing Afro‐Madagascan taxa and therefore included representatives of the four mostly epiphytic Madagascan endemic genera, the near Madagascan endemic Oeceoclades and additional sampling of the predominantly African genera Eulophia and Orthochilus. In total, 104 new accessions were collected for this study in Zambia and Madagascar (88 of which represented 36 Eulophia spp. and 12 Oeceoclades spp.). Independent plastid and nuclear phylogenetic trees were inferred using Bayesian and maximum‐likelihood algorithms, which recovered strong support for a monophyletic Eulophiinae, the first‐branching position of the mostly epiphytic Madagascan endemic genera, and increased support for recognition of the terrestrial genera Oeceoclades and Orthochilus. Eulophia, the largest genus in the group, was recovered as polyphyletic, but with implications for its classification and that of Geodorum, that was nested in the main Eulophia clade. Although relationships among several genera were resolved with some confidence, the positions of the South African endemic genus Acrolophia and the epiphytic Madagascan endemic Paralophia require further work. Taxon sampling of Asian Eulophia is a priority for future work on the systematics of this group. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 43–56.     

Phylogenetic position and revised classification of Acacia s.l. (Fabaceae: Mimosoideae) in Africa,including new combinations in Vachellia and Senegalia

Previous phylogenetic studies have indicated that Acacia Miller s.l. is polyphyletic and in need of reclassification. A proposal to conserve the name Acacia for the larger Australian contingent of the genus (formerly subgenus Phyllodineae) resulted in the retypification of the genus with the Australian A. penninervis. However, Acacia s.l. comprises at least four additional distinct clades or genera, some still requiring formal taxonomic transfer of species. These include Vachellia (formerly subgenus Acacia), Senegalia (formerly subgenus Aculeiferum), Acaciella (formerly subgenus Aculeiferum section Filicinae) and Mariosousa (formerly the A. coulteri group). In light of this fragmentation of Acacia s.l., there is a need to assess relationships of the non‐Australian taxa. A molecular phylogenetic study of Acacia s.l and close relatives occurring in Africa was conducted using sequence data from matK/trnK, trnL‐trnF and psbA‐trnH with the aim of determining the placement of the African species in the new generic system. The results reinforce the inevitability of recognizing segregate genera for Acacia s.l. and new combinations for the African species in Senegalia and Vachellia are formalized. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172 , 500–523.     

Phylogeny of the Afro-Madagascan Aristea (Iridaceae) revisited in the light of new data on pollen morphology

Scanning and electron microscopic studies of the pollen grains of several species of the sub-Saharan African and Madagascan genus Aristea of c . 50 species, supplement data from an earlier study and enable us to include these species in a phylogenetic analysis. TEM examination of a range of pollen grains of representative pollen types in Aristea makes it possible to reinterpret past SEM results so that apertures covered with exine masses and previously called sulculate, are now seen to be either zonasulculate or dizonasulculate. Revised and expanded data are combined in a matrix together with new data for seed morphology in the genus, which like the capsules is remarkably diverse, including angular seeds with reticulate sculpturing, lamellate or triangular-columnar seeds with smooth or reticulate surfaces and with smooth or papillate or areolate margins. This new phylogenetic analysis suggests that Aristea should remain treated as comprising three subgenera. In subgenus Eucapsulares we add a new section Latifolieae for A. latifolia , which seems an isolated relic restricted to the mountains of the Cape Region of South Africa, an area of winter rainfall. Species with similar unspecialized capsule and seed morphology occur only in eastern south and tropical Africa and Madagascar, but they have derived pollen morphology whereas the pollen of A. latifolia is plesiomorphic. This species appears to be the closest living ancestor of the genus. In subgenus Aristea we continue to recognize three sections, sect. Racemosae , sect. Singulares and sect. Aristea. Nesting of subgenus Pseudaristea within section Racemosae of subgenus Aristea is probably an artefact of the analysis and does not receive bootstrap support, and hence we continue to recognize this group of species at subgeneric rank.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 41–68.     

Molecular phylogenetic analysis of Tulipa (Liliaceae) based on noncoding plastid and nuclear DNA sequences with an emphasis on Turkey

We investigated the phylogenetic relationships in Tulipa in Turkey using DNA sequences from the plastid trnL‐trnF region and the internal transcribed spacer (ITS) of nuclear ribosomal DNA. We generated trnL‐trnF and nuclear ITS sequences for 11 Tulipa spp. from Turkey and compared the utility of trnL‐trnF and ITS sequences for phylogenetic analysis. Neighbor‐joining, Bayesian and maximum parsimony methods were implemented using the same matrices. Our study of Tulipa based on molecular data revealed congruent results with previous studies. Despite the relatively lower resolution of trnL‐trnF than that of ITS, both sequence matrices generated similar results. Three clades were clearly distinguished, corresponding to subgenera Tulipa, Eriostemones and Orithyia. It is not fully resolved whether Clusianae should be recognized as a separate section of subgenus Tulipa or a distinct subgenus. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172 , 270–279.     

Phylogenetic analysis of eastern Asian and eastern North American disjunct Lespedeza (Fabaceae) inferred from nuclear ribosomal ITS and plastid region sequences

Lespedeza (tribe Desmodieae, Fabaceae) follows a disjunct distribution in eastern Asia and eastern North America. Phylogenetic relationships among its species and related taxa were inferred from nuclear ribosomal internal transcribed spacer (ITS) and plastid sequences (trnH‐psbA, psbK‐psbI, trnK‐matK and rpoC1). We examined 35 species of Lespedeza, two of Kummerowia and one of Campylotropis, the sole constituents of the Lespedeza group. An analysis of these data revealed that the genus Campylotropis is sister to the other two genera. However, we were unable to resolve the relationships between Kummerowia and Lespedeza in the strict consensus trees of parsimony analyses based on plastid and combined DNA data. In the genus Lespedeza, the Old World subgenus Macrolespedeza is monophyletic, whereas the transcontinental subgenus Lespedeza is paraphyletic. Monophyly of eastern Asian species and of North American species is strongly supported. Although inconsistent with the traditional classification, this phylogenetic finding is consistent with seedling morphology. Three subgroups recognized in subgenus Macrolespedeza were unresolved in our phylogenetic trees. An incongruence length difference (ILD) test indicated that the two partitions (nuclear ITS and plastid sequences) were significantly incongruent, perhaps because of hybridization between species in Lespedeza. Most of the primary clades of tribe Desmodieae are Asian, implying that the relatively few New World ones, such as those in Lespedeza, are more recently derived from Asia. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 221–235.     

Phylogenetics,character evolution,and distribution patterns of the greenbriers,Smilacaceae (Liliales), a near‐cosmopolitan family of monocots

Smilacaceae, composed of Smilax and Heterosmilax, are a cosmopolitan family of > 200 species of mostly climbing monocots with alternate leaves characterized by reticulate venation, a pair of petiolar tendrils and usually prickly stems. Although there has been a long history of studying Smilax since Linnaeus named the genus in 1753, the phylogenetic history of this dioecious family remains unclear. Here we present results based on nuclear ribosomal internal transcribed spacer (nrITS) and plastid matK and rpl16 intron DNA sequence data from 125 taxa of Smilacaceae. Our taxon sampling covers all sections of Smilax and Heterosmilax and major distribution zones of the family; species from Ripogonaceae and Philesiaceae are used as outgroups. Our molecular analysis indicates that phylogenetic relationships largely contradict the traditional morphological classification of the family, instead showing a conspicuous geographical pattern among the species clades. The previously recognized genus Heterosmilax was found to be embedded in Smilax. Species in the family are separated into primarily New World and Old World clades, except for a single species lineage, Smilax aspera, that is sister to the remaining species of the family, but with poor statistical support. Ancestral character state reconstructions and examination of distribution patterns among the clades provide important information for future taxonomic revisions and historical biogeography of the group. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 535–548.     

Phylogenetic relationships of Combretaceae inferred from nuclear and plastid DNA sequence data: implications for generic classification

The putative complexity of Combretaceae and lack of information on phylogenetic relationships within the family led us to explore relationships between genera of Combretaceae by means of combined analyses of plastid and nuclear sequences. We collected DNA sequence data from the nuclear ribosomal internal transcribed spacer region and plastid rbcL, psaA‐ycf3 spacer and psbA‐trnH spacer for 14 of the 17 genera of Combretaceae. The current classification of the family into two subfamilies, Strephonematoideae and Combretoideae, is corroborated. Within Combretoideae, division into two tribes, Laguncularieae and Combreteae, is strongly supported. Within Combreteae subtribe Terminaliinae, relationships between genera are largely unresolved. Terminalia is not supported as monophyletic and two groups were identified, one containing mainly African species and another of mostly Asian species. Pteleopsis, Buchenavia and Anogeissus are embedded within Terminalia, and we suggest that all genera of Terminaliinae, with the exception of Conocarpus, should be included in an expanded circumscrition of Terminalia. Within subtribe Combretinae, a clade formed by the two monotypic genera Guiera and Calycopteris is sister to the rest of the subtribe. Groupings in Combretinae are consistent with recent results based on morphological data. Combretum is currently divided into three subgenera: Apethalanthum, Cacoucia and Combretum. The last two were included in this study and supported as monophyletic if Quisqualis is included within subgenus Cacoucia. Meiostemon is sister to subgenus Combretum. We recommend that subgenus Combretum should be expanded to include Meiostemon and subgenus Cacoucia to include Quisqualis. The sectional classification within Combretum proposed in earlier morphological studies is confirmed except for the exclusion of C. imberbe from section Hypocrateropsis in a separate and monotypic section and the inclusion of C. zeyheri (section Spathulipetala) in section Macrostigmatea. In order to accommodate C. imberbe, a new section is suggested. The reinstatement of previously recognized sections Grandiflora and Trichopetala, both of which had been sunk into subgenus Cacoucia section Poivrea, is proposed. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 453–476.     

Adaptive radiation in Coffea subgenus Coffea L. (Rubiaceae) in Africa and Madagascar

Phylogeographic analysis of the Coffea subgenus Coffea was performed using data on plastid DNA sequences and interpreted in relation to biogeographic data on African rain forest flora. Parsimony and Bayesian analyses of trnL-F, trnT-L and atpB-rbcL intergenic spacers from 24 African species revealed two main clades in the Coffea subgenus Coffea whose distribution overlaps in west equatorial Africa. Comparison of trnL-F sequences obtained from GenBank for 45 Coffea species from Cameroon, Madagascar, Grande Comore and the Mascarenes revealed low divergence between African and Madagascan species, suggesting a rapid and radial mode of speciation. A chronological history of the dispersal of the Coffea subgenus Coffea from its centre of origin in Lower Guinea is proposed. No relation was found between phylogenetic topology and the age of emergence of the volcanic islands that Coffea species have colonised in the Indian Ocean, suggesting dispersal from mainland Africa after the emergence of the youngest island, Grande Comore, 500,000 years ago. Additional sequences were obtained from GenBank for 24 species of other Rubiaceae genera, including the Rubia genus whose origin has been dated from the Upper Miocene. Estimates of substitution rates suggested that diversification in Coffea subgenus Coffea occurred about 460,000 years ago or as recently as the last 100,000 years, depending on the cpDNA region considered and calibration. The phylogenetic relationships based on plastid sequences confirmed biogeographic differentiation of coffee species, but they were not congruent with morphological and biochemical classifications, or with the capacity to grow in specific environments. Examples of convergent evolution in the main clades are given using characters of leaf size, caffeine content and reproductive mode.     

Evolutionary history of the burnet moth genus Zygaena Fabricius, 1775 (Lepidoptera: Zygaenidae) inferred from nuclear and mitochondrial sequence data: phylogeny, host–plant association, wing pattern evolution and historical biogeography

Burnet moths of the genus Zygaena are a striking group of primarily diurnal Lepidoptera displaying an exceptional phenotypic plasticity. Previous attempts to elucidate the phylogenetic history of the group had been confounded by a perplexing pattern of characters or insufficient taxon sampling. In the present study, we infer a phylogeny of the genus Zygaena by analysing 5.4 kb of their nuclear and mitochondrial DNA. Eighty‐four of the 98 currently recognized species in this genus are considered, including representatives of all described species groups. RNA coding sequences are aligned with reference to zygaenoid moth specific secondary structure models of corresponding molecules. We conduct phylogenetic analyses within a Bayesian framework applying partition specific substitution parameters; covariation of paired sites in RNA gene sequences is accommodated by using doublet substitution models. The molecular data reveal that a considerable number of currently recognized species groups in Zygaena are not monophyletic. The traditional subgeneric classification proves to be artificial as well; Agrumenia and Zygaena (sensu stricto) are polyphyletic. Only the subgenus Mesembrynus can be confirmed as a monophyletic species cluster. Optimization of larval host–plant associations and forewing patterns on sampled trees of the Bayesian analyses suggest convergent evolution of similar wing pattern types in distantly related species clusters and a shift from cyanogenic to acyanogenic host‐plants. The phylogenetic results challenge the classic assumption that early species diversification in Zygaena took place in the Irano–Turkestanian region. Rather, the molecular data point to the western Mediterranean area as the geographical origin of the group and imply a subsequent colonization of the Middle East and Central Asia. We discuss the apparently convergent evolution of similar wing patterns in context with the chemical defence system of burnet moths and suggest a species group concept for the genus Zygaena that accounts for the recent findings. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92 , 501–520.     

Systematic revision of the genus Aglyptodactylus Boulenger, 1919 (Amphibia: Ranidae), and analysis of its phylogenetic relationships to other Madagascan ranid genera (Tomopterna, Boophis, Mantidactylus, and Mantella)

Recent field studies revealed two new species of the genus Aglyptodactylus (Amphibia: Anura: Ranidae), which was hitherto considered as monotypic and confined to humid eastern Madagascar. Both new species, Aglyptodactylus laticeps sp. n. and Aglyptodactylus securifer sp. n. , occur syntopically in the deciduous dry forest of Kirindy in western Madagascar. In comparison to Aglyptodactylus madagascariensis from eastern rainforests, the new species A. laticeps shows a remarkable morphological divergence, which may be partly due to adaptations to burrowing habits in dry environments. Despite of the morphological differentiation, advertisement calls and osteology indicate that all three species of Aglyptodactylus are closely related. A phylogenetic analysis of the Madagascan ranid genera Aglyptodactylus, Mantella, Mantidactylus, Boophis , and Tomopterna (the latter including species from Madagascar, Africa, and Asia) strongly supports a sister group relationship of Aglyptodactylus with the ranine genus Tomopterna . We therefore transfer Aglyptodactylus from the Rhacophorinae to the Raninae and discuss implications of this rearrangement for ranoid systematics. The existence of the endemic genus Aglyptodactylus in Madagascar as well as its close phylogenetic relationships to Tomopterna confirm that the Raninae were already present on the Madagascan plate before its separation from Africa. The Madagascan Tomopterna labrosa shows several important differences both to Asian and to African species of the genus, and is therefore transferred from the subgenus Sphaerotheca (now restricted to Asia) to a new subgenus Laliostoma subgen. n .     

‘After Africa’: the evolutionary history and systematics of the genus Charaxes Ochsenheimer (Lepidoptera: Nymphalidae) in the Indo‐Pacific region

The predominantly Afrotropical genus Charaxes is represented by 31 known species outside of Africa (excluding subgenus Polyura Billberg). We explored the biogeographic history of the genus using every known non‐African species, with several African species as outgroup taxa. A phylogenetic hypothesis is proposed, based on molecular characters of the mitochondrial genes cytochrome oxidase subunit I (COI) and NADH dehydrogenase 5 (ND5), and the nuclear wingless gene. Phylogenetic analyses based on maximum parsimony and Bayesian inference of the combined dataset implies that the Indo‐Pacific Charaxes form a monophyletic assemblage, with the exception of Charaxes solon Fabricius. Eight major lineages are recognized in the Indo‐Pacific, here designated the solon (+African), elwesi, harmodius, amycus, mars, eurialus, latona, nitebis, and bernardus clades. Species group relationships are concordant with morphology and, based on the phylogeny, we present the first systematic appraisal and classification of all non‐African species. A biogeographical analysis reveals that, after the genus originated in Africa, the evolutionary history of Charaxes in the Indo‐Pacific, in particular Wallacea, may be correlated with the inferred geological and climatic history of the region. We propose that Wallacea was the area of origin of all Charaxes (excluding C. solon) occurring to the east of Wallace's [1863] Line. The earliest Indo‐Pacific lineages appear to have diverged subsequent to the initial fragmentation of a palaeo‐continent approximately 13 million years ago. Further diversification in Indo‐Pacific Charaxes appears primarily related to climatic changes during the Pliocene and possibly as recently as the Pleistocene. Although both dispersal and vicariance have played important roles in the evolution of the genus within the region, the latter has been particularly responsible for diversification of Charaxes in Wallacea. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 457–481.     

The bumblebees of the subgenus Subterraneobombus: integrating evidence from morphology and DNA barcodes (Hymenoptera,Apidae, Bombus)

Although bumblebees have received a lot of attention, some taxonomic problems have persisted for many years. One particularly obdurate case has been the species of the subgenus Subterraneobombus. We revise the bees of this subgenus by integrating evidence from both morphology and, for a 5% subsample, from DNA (cytochrome c oxidase subunit 1, CO1) barcodes from pinned museum specimens. We apply a reciprocal illumination procedure: (1) taxa recognized previously from morphology are used to stratify samples for DNA subsampling; (2) DNA barcodes from these subsamples are used to recognize groups of phylogenetically related specimens; and (3) for these groups, we re‐examine morphological characters in order to recognize and diagnose species. A total of 3854 specimens from 1535 samples from across the geographic range of the subgenus throughout the Holarctic and northern Oriental regions are identified to 11 species. This includes one species newly recognized from Mongolia, Bombus mongolensis Williams sp. nov. Taxon concepts are modified substantially for four species, seven lectotypes are designated, and four new synonyms are recognized. The prevailing usage of Bombus distinguendus is maintained as valid by designating Bombus elegans as a nomen oblitum and designating B. distinguendus as a nomen protectum. Identification keys and colour‐pattern diagrams are provided, and geographic distributions, elevational ranges, and phenological activity periods are described to characterize the species. An estimate of the biogeographic history is reconstructed with dispersal–vicariance analysis. In this study, DNA barcode data have been a cost‐effective source of additional characters for diagnosing groups of specimens. The barcode data contributed directly to recognizing the one new species, of which females remain difficult to identify from morphology alone. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 813–862.     

Revision of the Malagasy species of the genus Tricalysia (Rubiaceae)

The Malagasy representatives of the large African genus Tricalysia (tribe Coffeeae s.l.) are revised. Three Malagasy species were hitherto recognized in the genus, namely T. cryptocalyx , T. madagascariensis , and T. ovalifolia . In this study, two species, T. boiviniana and T. leucocarpa , are transferred from the genus Hypobathrum and seven new species and two new subspecies are described, raising the species number for Tricalysia to a total of 12. This marked increase in species number is a recurring pattern for many Malagasy genera in systematically poorly known families such as Rubiaceae. All the species are described in detail and illustrated, and a list of exsiccatae and a distribution map are provided. Furthermore, the characters of the Malagasy taxa are compared with those of the continental African species, and their infrageneric status is discussed. With the exception of T. ovalifolia , a member of subgenus Empogona , all Malagasy species belong to subgenus Tricalysia . Because of their unisexual flowers, these species cannot be accommodated within one of the four existing sections in subgenus Tricalysia . A new section, Androgyne , is therefore recognized.  © 2007 National Botanic Garden of Belgium. Journal compilation © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 83–126.