Species diversity is unequally distributed across the globe,with the greatest concentration occurring in the tropics. Even within the tropics, there are significant differences in the numbers of taxa found in each continental region. Manilkara is a pantropical genus of trees in the Sapotaceae comprising c.78 species. Its distribution allows for biogeographic investigation and testing of whether rates of diversification differ amongst tropical regions. The age and geographical origin of Manilkara are inferred to determine whether Gondwanan break-up, boreotropical migration or long distance dispersal have shaped its current disjunct distribution. Diversification rates through time are also analyzed to determine whether the timing and tempo of speciation on each continent coincides with geoclimatic events. Bayesian analyses of nuclear (ITS) and plastid (rpl32-trnL,rps16-trnK,and trnS-trnFM) sequences were used to reconstruct a species level phylogeny of Manilkara and related genera in the tribe Mimusopeae. Analyses of the nuclear data using a fossil-calibrated relaxed molecular clock indicate that Manilkara evolved 32–29 million years ago (Mya) in Africa. Lineages within the genus dispersed to the Neotropics 26–18 Mya and to Asia 28–15 Mya. Higher speciation rates are found in the Neotropical Manilkara clade than in either African or Asian clades. Dating of regional diversification correlates with known palaeoclimatic events. In South America, the divergence between Atlantic coastal forest and Amazonian clades coincides with the formation of drier Cerrado and Caatinga habitats between them. In Africa diversification coincides with Tertiary cycles of aridification an duplif tof the east African plateaux. In South east Asia dispersal may have been limited by the relatively recent emergence of land in New Guinea and islands further east c.10 Mya.

Chiliadenus is a small genus in the Inuleae (Asteraceae), consisting of ten species with allopatric distributions along the southern edge of the Mediterranean Sea. The different species have restricted areas of distribution, with only one being more widely distributed. The first molecular phylogenetic study of the genus with complete sampling, as well as a biogeographic analysis of the origin and biogeographic patterns leading to the current diversity of Chiliadenus is presented. Results confirm Chiliadenus as monophyletic and placed as sister to Dittrichia. The ancestor of Chiliadenus is dated to have diverged from that of Dittrichia around 5.45 Ma ago, coinciding with the Messinian salinity crisis, whereas the Chiliadenus crown group is dated to 2.29 Ma, around 3 million years later. Ancestral area reconstructions show the crown group to likely have originated in the area around Morocco and northwestern Algeria, which is also the area where the early divergences have occurred. Chiliadenus has then later diverged and dispersed over the Mediterranean to its current distribution. The evolution of the Chiliadenus crown group coincides with the onset of the Mediterranean climate, and its evolution may be connected to the subsequent climatic changes.

Apodocephala is a small genus of nine species of shrubs and trees endemic to Madagascar and currently classified in the tribe Astereae (Asteraceae). However, its present tribal position has been questioned, as it lacks some of the salient morphological features of that tribe. This study includes for the first time DNA sequences from Apodocephala (two species including the type of the generic name) to test its phylogenetic position. Phylogenetic analyses based on sequence data from nuclear ribosomal (ETS and ITS) and plastid (ndhF and trnL–trnF) DNA regions, using Bayesian inference and maximum parsimony methods, strongly reject the placement of Apodocephala in the Astereae. Our results, instead, support its position as sister to the Malagasy monospecific genus Lowryanthus within the tribe Athroismeae. Morphological comparison of these sister genera reveal similarities in cypsela morphology, and the inclusion of Apodocephala in the subtribe Lowryanthinae is proposed here. The tribe Athroismeae is now represented by ten genera (Anisochaeta, Anisopappus, Apodocephala, Artemisiopsis, Athroisma, Blepharispermum, Centipeda, Leucoblepharis, Lowryanthus and Symphyllocarpus), six of which occur in Madagascar. The Malagasy Athroismeae occur in all Malagasy terrestrial ecosystems (rainforests, deciduous dry forests, thicket spiny forests and savannas) and are likely the result of multiple independent colonization events mostly from mainland Africa.

Athroismeae is a small tribe of the Asteraceae-Asteroideae, the members of which show considerable variation in morphology. A molecular phylogenetic study of the tribe is presented for the first time, based on plastid (ndhF, trnH-psbA, trnL-trnF) and nuclear data (ETS, ITS). The phylogenetic relationships between the different genera within Athroismeae are discussed, and in addition, three unispecific genera: Anisochaeta, Artemisiopsis and Symphyllocarpus as well as Duhaldea (Inula) stuhlmannii, all earlier placed in other tribes, are here shown to belong within Athroismeae. Symphyllocarpus is sister to Centipeda and the earlier Symphyllocarpinae includes Centipedinae in synonymy. Furthermore, Cardosoa and Philyrophyllum are found to be integrated within Anisopappus and their generic status cannot be maintained. An outline of an amended circumscription of the Athroismeae is presented, with three new combinations and a description of the new subtribe Lowryanthinae.

Aim. The Cape region is known for its exceptional species richness, although much remains unknown regarding the appearance of the modern Cape flora. One explanation is that floral diversification was influenced by the establishment of winter rainfall/summer arid conditions hypothesized to have occurred towards the end of the Miocene. We studied the evolution and diversification of the plant genus Metalasia (Asteraceae–Gnaphalieae), with the aim of testing whether radiation patterns may have been influenced by the climatic changes.

Location. South Africa, with emphasis on the south-west.

Methods. The radiation of Metalasia was investigated using two approaches: a species diffusion approach, which estimated the ancestral areas by means of a relaxed random walk while sampling from extant distributions; and a discrete approach, in which distributions were defined according to the phytogeographical centres of the Cape region. Secondarily derived clock rates from an earlier Gnaphalieae study were used for calibration purposes.

Results. Our analyses date Metalasia to approximately 6.9 Ma, after the Miocene–Pliocene boundary and the establishment of the winter rainfall/summer arid conditions. Metalasia consists of two sister clades: Clade A and Clade B. Clade B, which is endemic to the winter rainfall area, is estimated to have diversified c. 6.4 Ma, whereas Clade A, with a main distribution in the all-year rainfall area, is considerably younger, with a crown group age estimated to 3.3 Ma. Diversification rates suggest an early rapid speciation, with rates decreasing through time both for Metalasia and for clades A and B separately. Ancestral area estimations show a possible scenario for the radiation of Metalasia to its current diversity and distribution, with no conflict between results inferred from diffusion or discrete methods.

Main conclusions. The diversification of Metalasia is estimated to have begun after the establishment of the winter rainfall/summer arid conditions, consistent with its radiation having been influenced by changes in the climatic regime.

Anisopappus (Asteraceae: Athroismeae) is a genus with its main distribution in Africa (one species also in Asia), currently considered to include around 21 species. A molecular phylogenetic study of Anisopappus is presented for the first time, based on plastid (ndhF, trnL-trnF, trnQ-rps16) and nuclear (ETS, ITS) data. Anisopappus is confirmed to be monophyletic, and species interrelationships are resolved. The results differ from earlier treatments based on morphology, and the phylogenetic analyses reveal a need for changes in species circumscriptions as compared to those of the most recent treatment. Consequently, many taxa currently treated as synonyms are here shown to represent separate species indicating that the genus includes well over 40 species. Distribution patterns now emerge where several clades are found to consist of species restricted to a particular geographical region. The Anisopappus of Madagascar, many of which were earlier placed in synonymy with species found on the African continent, are here shown to be endemic, and the results reveal a need for further studies of that group.

The Lucilia group sensu Anderberg and Freire comprises nine South American genera: Belloa, Berroa, Chevreulia, Cuatrecasasiella, Facelis, Gamochaetopsis, Jalcophila, Lucilia and Luciliocline. The aims of this contribution were, using DNA sequences from plastid (rpl32-trnL, trnL-F) and nuclear (ITS and ETS) markers, together with morphological characters, to test the monophyly of the Lucilia group and provide new insight into generic circumscriptions. Our studies, including a broad taxon sampling of Gnaphalieae species, suggest that the Lucilia group is paraphyletic, since Antennaria, Chionolaena, Gamochaeta, Loricaria, Micropsis, Mniodes and Stuckertiella are all nested within the Lucilia group. Morphology and molecular analyses combined showed that the traditional generic circumscription of most of the genera (e.g., Berroa, Chevreulia, Chionolaena, Cuatrecasasiella, Facelis, Jalcophila and Micropsis) correlates with the inferred phylogenetic relationships. Conversely, Lucilia and Luciliocline are non-monophyletic. Lucilia is nested in a clade with Berroa, Facelis and Micropsis. Luciliocline is strongly embedded within the clade Belloa pp + Mniodes. Our results are consistent with Dillon’s study that considered Belloa as a montotypic genus (B. chilensis). Luciliocline and the remaining species of Belloa are accommodated in the genus Mniodes, and the necessary combinations are proposed for the expanded Mniodes. All the analyses showed that the monotypic genera Stuckertiella and Gamochaetopsis are in a well-supported clade nested within Gamochaeta, which implies that taxonomic changes are required also for these genera. Internal relationships in the group and the key morphological characters used in the taxonomy of the group, as well as incongruences found between morphological and molecular analyses, are discussed.

The Inula complex (Asteraceae: Inulinae) is a monophyletic group which comprises eight genera distributed in Eurasia and Africa: Amblyocarpum, Carpesium, Chrysophthalmum, Inula, Pentanema, Rhanteriopsis, Telekia, and Varthemia. With the aim to shed light on the circumscription of these genera, phylogenetic analyses were performed with 293 new DNA sequences (ITS region from nrDNA and three plastid spacers from cpDNA: rps16-trnQ, rpl32-trnL, ndhF-rpl32). It is concluded that both Inula and Pentanema are paraphyletic and that generic delimitations within the Inula complex need to be revised. Based on the results of the analyses, together with morphological and karyological data, we argue that the best solution is a new circumscription of the genus Pentanema including an amended description and 24 new combinations of former Inula species. Resurrection of the names Codonocephalum, Monactinocephalus and Vicoa is proposed to preserve the monophyly of the genera included in the Inula complex. Incongruences between nrDNA and cpDNA are documented and discussed.

Sapotaceae belongs to the heterogeneous order Ericales and exhibits extensive diversity in floral morphology. Although pentamery is widespread and probably the ancestral condition, some clades are extremely variable in merism, with fluctuations between tetramery to hexamery and octomery, affecting different floral organs to different degrees. We assessed the different states of merism in Sapotaceae to determine the evolution of this character among different clades. The floral morphology and development of nine species from eight genera were investigated using scanning electron microscopy (SEM). Furthermore, floral characters related to merism were mapped onto a phylogenetic tree to analyse the distribution and evolutionary significance of merism in the family. Developmental evidence shows that changes in merism are linked to a concerted multiplication of organs among whorls and an increase in whorls through the displacement of organs. Although pentamery is reconstructed as the ancestral condition, a reduction to tetramery or an increase to a higher merism (mainly hexamery or octomery) has evolved at least five times in the family. Fluctuations in merism between different whorls are not random but occur in a coordinated pattern, presenting strong synapomorphies for selected clades. Octomery has evolved at least twice, in Isonandreae from tetramery and in Sapoteae-Mimusopinae from pentamery. Hexamery has evolved at least three times, independently in Northia, the Palaquium clade of Isonandreae and derived from octomery in Sapoteae-Mimusopinae. Three possibilities of merism increase have been identified in Sapotaceae: (1) a concerted increase affecting all organs more or less equally (Palaquium clade of Isonandreae, Sapoteae); (2) a coordinated increase in petals, stamens and mostly carpels without effect on sepals (Labourdonnaisia, Payena–Madhuca clade of Isonandreae); (3) an increase in carpels independently of other organs (Burckella, Letestua, Labramia, etc.). A major shift affecting all Sapotaceae, except Isonandreae, is the sterilization or loss of the antesepalous stamen whorl. The presence of two fertile stamen whorls in Isonandreae indicates a possible reversal or a retained plesiomorphy. In a number of genera, stamens are secondarily increased independently of changes in merism. Descriptions of flowers listing only organ numbers are thus misleading in the inference of evolutionary relationships, as they do not differentiate between changes in merism affecting the number of perianth whorls and other changes affecting the androecium, such as sterilization, loss or occasional doubling of antepetalous stamens.

During the study of Brazilian genera of the Inuleae-Plucheinae (Asteraceae), we have encountered a specimen representing an undescribed species, here described as Tessaria andina. The new species is characterized by having puberulous, tomentose, lanate, or glabrescent indumentum on its branches, a tomentose abaxial leaf surface, leaves with an apically serrate margin, corymbiform inflorescences, a cream to yellowish involucre, erect inner involucral bracts, and the corolla of male flowers with short-stalked glands and trichomes. So far, only one collection of this new species has been made, and that was more than forty years ago. The new species is described, illustrated, and its affinities are discussed. Furthermore, during this investigation we found out that the name Tessaria boliviensis is a nomen nudum, applied to material here shown tobelongto Tessaria fastigiata. An identification key to the species of Tessaria is also presented.

Lactuca indica and Lactuca canadensis have been recorded for the first time in the Americas and in South America, respectively. Lactuca indica is native to Eastern Asia, and L. canadensis to North America. In Brazil, L. indica is used as a substitute for lettuce in some communities. The leaf shape in the Brazilian plants of the two species is less variable than in Asiatic or North American populations. This could possibly be a result of a single introduction to Brazil of each species. Both species are weeds, occurring in disturbed habitats in south and south-eastern Brazil. The two species are described, illustrated and their affinities are discussed. An identification key is provided to the six species of Lactuca (all introduced) in South America.

Phylogenetic relationships in the tribe Inuleae (Asteraceae, sunflower family) are elucidated based on a concatenated set of nuclear (ETS, ITS), and chloroplast data (ndhF, trnL-F, trnH-psbA), analysed by Bayesian and parsimony methods. Extensive sampling of representatives from both subtribes Inuleae-Inulinae and Inuleae-Plucheinae establish their reciprocal monophyly, and result in the first-ever resolved molecular phylogeny of the Inuleae-Plucheinae with new insights into the relationships and morphological character distributions between genera and among species. Of the 31 accepted genera in the Inuleae-Plucheinae, only Pseudoblepharispermum is not represented in this study, 12 monotypic genera are placed in the phylogeny, 13 genera are shown to be monophyletic, and only 5 of the remaining 18 genera are revealed to be polyphyletic. The implications for the nomenclature status of the monotypic and polyphyletic genera are discussed, together with a descriptive review of morphological characters traditionally used to circumscribe the genera in this subtribe.

Reconstructing the biogeographic history of groups present in continuous arid landscapes is challenging dueto the difficulties in defining discrete areas for analyses, and even more so when species largely overlap both in terms ofgeography and habitat preference. In this study, we use a novel approach to estimate ancestral areas for the small plantgenus Centipeda. We apply continuous diffusion of geography by a relaxed random walk where each species is sampledfrom its extant distribution on an empirical distribution of time-calibrated species-trees. Using a distribution of previouslypublished substitution rates of the internal transcribed spacer (ITS) for Asteraceae, we show how the evolution of Centipedacorrelates with the temporal increase of aridity in the arid zone since the Pliocene. Geographic estimates of ancestral speciesshow a consistent pattern of speciation of early lineages in the Lake Eyre region, with a division in more northerly andsoutherly groups since ∼840 ka. Summarizing the geographic slices of species-trees at the time of the latest speciation event(∼20 ka), indicates no presence of the genus in Australia west of the combined desert belt of the Nullabor Plain, the GreatVictoria Desert, the Gibson Desert, and the Great Sandy Desert, or beyond the main continental shelf of Australia. Theresult indicates all western occurrences of the genus to be a result of recent dispersal rather than ancient vicariance. Thisstudy contributes to our understanding of the spatiotemporal processes shaping the flora of the arid zone, and offers asignificant improvement in inference of ancestral areas for any organismal group distributed where it remains difficult todescribe geography in terms of discrete areas.

We investigated the historical biogeography of the Inuleae–Plucheinae (Asteraceae), a group of arid-adapted plants with partly unresolved generic circumscriptions, in order to understand its origin and spatiotemporal evolutionary history in relation to the Cenozoic climate shifts. Location Global, with highest species diversity in the Southern Hemisphere. The spatiotemporal biogeography of the Plucheinae was estimated by both a discrete method using a set of general distribution areas, and a relaxed random walk based on extant species distributions. The topology was time calibrated using a combination of secondary node ages and secondary derived rates for included loci. Our results indicate the median age of the Plucheinae to be approximately 15.4 Ma. The biogeographical analyses infer an ancestral origin in southern Africa, with the relaxed random walk analysis narrowing the uncertainty down to an area reaching from coastal Namibia to the western Kalahari. Africa was colonized in a (south)western–(north)eastern direction following the spread of arid habitats. Ancestral representatives of the Plucheinae colonized South America on at least three separate occasions (13.0–4.0, 4.3–3.1 and 4.1–3.7 Ma), with one subsequent spread to North America. Australia was colonized three times between 3.6 and 0.4 Ma. Madagascar and the Mascarenes were colonized at least seven times. The origin of the Plucheinae is estimated to the Namib region, with early speciations and radiations concurring with the timing of aridification of southern Africa, following the increase in strength of the Antarctic Circumpolar Current and subsequent formation of the Benguela Upwelling at c. 11.8 Ma. The current biogeographical distribution of the Plucheinae is best explained by several Neogene long-distance dispersal events from tropical Africa.

Based on the field and herbarium data, six species of the genus Duhaldea (sensu stricto) are recognized in India. A key to the Indian species, brief descriptions and illustrations are provided along with data on phenology, distribution, ecology, chromosome numbers and ethnobotanical uses.

Previous phylogenetic studies in the Arctotideae-Gorteriinae (Asteraceae) have found support for a Gorteria clade. The results also indicated Hirpicium to be paraphyletic, whereas Gorteria and Gazania were found to be monophyletic. Previous investigations at the genus level on this group have focused only on relationships in Gazania and Gorteria, respectively, with only a few Hirpicium species included. In the present study we include more taxa than in any previous investigation, including all species of Hirpicium, all species of Gorteria and almost all taxa of Gazania. Phylogenetic analyses, based on DNA sequence data from non-coding (rps16, trnL–trnF, and psbA–trnH) as well as coding (ndhF) regions from the plastid genome resolved three major clades, but DNA sequence data from the ribosomal regions (ETS and ITS) from the nuclear genome did not support two of the three clades. The genus Hirpicium, as presently circumscribed, was paraphyletic with one group of four species nested within Gorteria and all remaining species of Hirpicium formed a monophyletic group with two clades, morphologically well-defined. As the name Hirpicium is a synonym of Gorteria, new names for the remaining Hirpicium species are proposed. For one of the Hirpicium clades, comprising Hirpicium echinus, we resurrect the genus Berkheyopsis O. Hoffm., and for the five species belonging to the second clade a new generic name, Roessleria Stångb. & Anderb., is proposed. The necessary new combinations, 12 in total, are made, as well as four lectotypifications and one neotypification. A key to the newly circumscribed genera is presented.

Male and female unisexual flowers have repeatedly evolved from the ancestral bisexual flowers in different lineages of flowering plants. This sex specialization in different flowers often occurs within inflorescences. We hypothesize that inflorescence architecture may impose a constraint on resource availability for late flowers, potentially leading to different optima in floral sex allocation and unisexuality. Under this hypothesis we expect that inflorescence traits increasing the difference in resource availability between early and late flowers would be phylogenetically correlated with a higher level of sexual specialization. To test this hypothesis, we performed a comparative analysis of inflorescence traits (inflorescence size, number of flowers and flower density) in the sunflower family, which displays an extraordinary variation in floral sexual specialization at the inflorescence level, i.e. hermaphroditic, gynomonoecious and monoecious species. We found that species with a complete sex separation in unisexual flowers (monoecy) had significantly denser inflorescences. Furthermore, those species arranging their flowers in denser inflorescences also showed greater differences in the size of early and late fruits, a proxy of resource variation between flowers. Our findings support the idea that floral sexual specialization and consequently sexual segregation may be the consequence of different floral sex allocation optima driven by the sequential development of flowers that results in a persistent resource decline from earlier to later flowers.

Gamochaeta (tribe Gnaphalieae, Asteraceae) is composed of ca. 60 species primarily distributed in tropical and subtropical America. Within the tribe Gnaphalieae, the genus is characterized by capitula arranged in spikes or head-like clusters, few hermaphroditic central florets, truncate style branches with apical sweeping trichomes, pappus bristles connate at the base into a ring falling as a unit, and achenes with globose twin trichomes. Previous molecular phylogenetic studies have suggested the paraphyly of the genus, but have not provided a basis for redefining generic limits due to incomplete taxon sampling. To address this problem, DNA sequences from the plastid (trnL-F) and nuclear (ETS and ITS) genomes were analyzed from a broad taxon sample representing the full range of morphological variation known in the genus. Our results affirm that Gamochaeta is paraphyletic as presently circumscribed. Two clades can be recognized: one clade that includes the majority of the species currently assigned to Gamochaeta and a second clade that includes Gamochaetopsis, Stuckertiella and seven species of Gamochaeta. We present here a new circumscription of Gamochaeta, including two new combinations, Gamochaeta alpina and Gamochaeta peregrina, and the resurrection of Gamochaeta capitata. Our results also show Omalotheca supina, O. norvegica and O. sylvatica, which were placed by some authors in Gamochaeta or in Gnaphalium, form a monophyletic group distantly related to both genera.

What causes the disparity in biodiversity among regions is a fundamental question in bio-geography, ecology, and evolutionary biology. Evolutionary and biogeographic processes(speciation, extinction, dispersal) directly determine species richness patterns, and can bestudied using integrative phylogenetic approaches. However, the strikingly high richness ofEast Asia relative to other Northern Hemisphere regions remains poorly understood from thisperspective. Here, for the first time, we test two general hypotheses (older colonization time,faster diversification rate) to explain this pattern, using the plant tribe Lysimachieae (Primu-laceae) as a model system.We generated a new time-calibrated phylogeny for Lysimachieae (13 genes, 126 species),to estimate colonization times and diversification rates for each region and to test the relativeimportance of these two factors for explaining regional richness patterns.We find that neither time nor diversification rates alone explain richness patterns amongregions in Lysimachieae. Instead, a new index that combines both factors explains global rich-ness patterns in the group and their high East Asian biodiversity.Based on our results from Lysimachieae, we suggest that the high richness of plants in EastAsia may be explained by a combination of older colonization times and faster diversificationrates in this region