Leaf anatomy of seven endemic species of Glicophyllum (Malpighiaceae) in Brazil.

Glicophyllum is well supported, presenting four homoplasies, easily differentiated from the other genera of the clade due to characteristics related to the reproductive organs, which can make the identification of their species difficult when they are not in the reproductive phase. Therefore, there are provided the leaf anatomical and morphological description of the leaf glands of seven species of Glicophyllum to assist in the identification of their species. The samples for the study were obtained from several national and international herbaria, sectioned freehand, stained with basic fuchsin - astra blue and compared through a binary matrix using the Sorensen's coefficient in the MVSP software. Among the leaf anatomical characters found, the following stand out: presence/absence of trichomes; petiole contour; contour of the main vein; organization of the mesophyll, presence/absence of bundle sheath extension and the surface of the glands. In this study, an identification key with leaf anatomical data is presented for the first time, demonstrating the applicability of leaf anatomy for the taxonomy of Glicophyllum. In the multivariate analysis, it is observed that the characteristics of leaf venation and topology of the glands are more representative to differentiate the taxa. Therefore, the data obtained can support future taxonomic and phylogenetic studies of the genus.

Chloroplast genomes of Byrsonima species (Malpighiaceae): comparative analysis and screening of high divergence sequences.

Byrsonima is the third largest genus (about 200 species) in the Malpighiaceae family, and one of the most common in Brazilian savannas. However, there is no molecular phylogeny available for the genus and taxonomic uncertainties at the generic and family level still remain. Herein, we sequenced the complete chloroplast genome of B. coccolobifolia and B. crassifolia, the first ones described for Malpighiaceae, and performed comparative analyses with sequences previously published for other families in the order Malpighiales. The chloroplast genomes assembled had a similar structure, gene content and organization, even when compared with species from other families. Chloroplast genomes ranged between 160,212 bp in B. crassifolia and 160,329 bp in B. coccolobifolia, both containing 115 genes (four ribosomal RNA genes, 28 tRNA genes and 83 protein-coding genes). We also identified sequences with high divergence that might be informative for phylogenetic inferences in the Malpighiales order, Malpighiaceae family and within the genus Byrsonima. The phylogenetic reconstruction of Malpighiales with these regions highlighted their utility for phylogenetic studies. The comparative analyses among species in Malpighiales provided insights into the chloroplast genome evolution in this order, including the presence/absence of three genes (infA, rpl32 and rps16) and two pseudogenes (ycf1 and rps19).

Chemical Composition and Antioxidant, Antinociceptive, and Anti-inflammatory Activities of Four Amazonian Byrsonima Species.

Species of the Byrsonima genus are widely used in Brazil, especially for the treatment of gastrointestinal disorders. However, species from the Amazonian region are still poorly studied. Thus, we studied the antioxidant, antinociceptive, and anti-inflammatory activities of for Amazonian species, Byrsonima crispa, Byrsonima duckeana, Byrsonima garcibarrigae, and Byrsonima incarnata. Phenolic composition was determined by chemical and chromatographic methods. The aqueous extracts were evaluated in DPPH• , ABTS+• , and superoxide (O2•- ) tests, LPS-activated macrophage assay, and formalin test. All species contained a high phenolic and flavonoid content. We identified 15 phenolic compounds, including phenolic acids, hydroxycinnamic acids, flavonoids, and catechins. The extracts showed high antioxidant activity and were more active than quercetin at inhibiting nitric oxide release in the LPS-activated macrophage assay. B. duckeana and B. garcibarrigae showed higher in vivo antinociceptive and anti-inflammatory activities. B. garcibarrigae presented significant effect on the early phase of the formalin test, pointing to an antinociceptive mechanism distinct from traditional anti-inflammatory medicines. In conclusion, the pharmacological potential of these species is closely related to their flavonoid-rich chemical composition, which seems to act through antioxidant mechanisms. Copyright © 2017 John Wiley & Sons, Ltd.

Oil collecting bees and Byrsonima cydoniifolia A. Juss. (Malpighiaceae) interactions: the prevalence of long-distance cross pollination driving reproductive success.

Oil-collecting bees are the natural pollinators of oil-flower plants, but little is known about the pollination process and the effectiveness of their pollination service to the reproductive success of their host plants. In species of Byrsonima the reproductive system have been described as auto-compatible or self-incompatible. We studied the reproductive system of Byrsonima cydoniifolia, the fructification by means of short, medium and long-distance cross pollinations, the morphology and floral biology and the pollination interactions with species of oil-collecting bees. By means of controlled pollinations we found self-incompatibility caused by abortion of most self-pollinated flowers and demonstrated that the prevailing cross pollination ensuring the reproductive success of B. cydoniifolia is the long-distance cross pollination and Centridini bees; Epicharis nigrita, particularly, are the pollinators promoting the gene flow between genetically distinct populations.

Genetic variability in accessions of the acerola germplasm bank of Universidade Federal Rural de Pernambuco, Brazil.

Brazil is the world's largest producer of acerola, Malpighia emarginata (Malpighiaceae); the Northeast is responsible for 60% of the national production. The culture of acerola in Brazil has great genetic variability; plantings have high phenotypic diversity and are not very productive, often originating from propagation by seed. We evaluated the genetic diversity of 42 accessions from the Acerola Active Germplasm Bank of Universidade Federal de Pernambuco. Using 15 RAPD primers, 182 markers were obtained, of which 166 were polymorphic and 16 were monomorphic. We found high genetic variability among the accessions (HE = 0.29), with no redundancy. Considering the accessions from the states of Pernambuco, Bahia and Pará as distinct groups, there was greater diversity in accessions from Bahia than from the other two states.

Heteropterys cotinifolia: a neuropharmacological and phytochemical approach with possible taxonomic implications.

Heteropterys cotinifolia (Malpighiaceae) has been used in traditional Mexican medicine mainly for the treatment of nervous disorders. However, the specific neuropharmacological activities responsible for this use remain to be defined. The present study evaluates the antidepressant and anxiolytic effects produced by the methanolic extract of Heteropterys cotinifolia and the influence of such effects on motor activity in ICR mice. Our results show that the methanolic extract of Heteropterys cotinifolia produces a dose-dependent antidepressant effect in the forced swimming test in mice at doses from 31 to 310 mg/kg, with no reduction of mice locomotion. However, no anxiolytic properties were observed. Our findings suggest that the main extract compounds identified as chlorogenic acid and rutin may be involved in the antidepressant effects. To our knowledge, the present study constitutes the first report of pharmacological and phytochemical data of Heteropterys cotinifolia. The presence of flavonoids in the methanolic extract of Heteropterys cotinifolia may also provide further data to characterize taxonomically this species in order to be distinguished from others species closely related and belonging to the same genus.

Phylogenomics and a posteriori data partitioning resolve the Cretaceous angiosperm radiation Malpighiales.

The angiosperm order Malpighiales includes ~16,000 species and constitutes up to 40% of the understory tree diversity in tropical rain forests. Despite remarkable progress in angiosperm systematics during the last 20 y, relationships within Malpighiales remain poorly resolved, possibly owing to its rapid rise during the mid-Cretaceous. Using phylogenomic approaches, including analyses of 82 plastid genes from 58 species, we identified 12 additional clades in Malpighiales and substantially increased resolution along the backbone. This greatly improved phylogeny revealed a dynamic history of shifts in net diversification rates across Malpighiales, with bursts of diversification noted in the Barbados cherries (Malpighiaceae), cocas (Erythroxylaceae), and passion flowers (Passifloraceae). We found that commonly used a priori approaches for partitioning concatenated data in maximum likelihood analyses, by gene or by codon position, performed poorly relative to the use of partitions identified a posteriori using a Bayesian mixture model. We also found better branch support in trees inferred from a taxon-rich, data-sparse matrix, which deeply sampled only the phylogenetically critical placeholders, than in trees inferred from a taxon-sparse matrix with little missing data. Although this matrix has more missing data, our a posteriori partitioning strategy reduced the possibility of producing multiple distinct but equally optimal topologies and increased phylogenetic decisiveness, compared with the strategy of partitioning by gene. These approaches are likely to help improve phylogenetic resolution in other poorly resolved major clades of angiosperms and to be more broadly useful in studies across the Tree of Life.

Pollination of Byrsonima coccolobifolia: short-distance isolation and possible causes for low fruit production.

Byrsonima coccolobifolia is a tropical plant from the Malpighiaceae family, distributed in the neotropical savanna fields and pollinated by bees known as "collecting-oil bees". In this study, conducted in a Cerrado area located on a farm in the city of Silvânia, GO, the following hypothesis was tested: the greater the isolation degree of a plant, the lower its fruit production due to access difficulties for pollinators. Using a linear regression analysis, it was possible to relate the fruiting rate with the degree of isolation of each B. coccolobifolia individual and consequently it was found that the isolation had no influence on the pollination rate, an unexpected event that can be explained by the distance amongst individuals not being large enough to limit the movement of pollinators, or because cross-pollination was not the predominant form of reproduction, since the rate of cross-pollination was similar to self-pollination. It was also found that the proportion of fruits produced was lower than expected, a factor which may also have influenced the results.

Pollination of Byrsonima coccolobifolia: short-distance isolation and possible causes for low fruit production / Polinização de Byrsonima cocolobifolia: isolamento de curta distância e as possíveis causas para baixa produção de frutos

Byrsonima coccolobifolia is a tropical plant from the Malpighiaceae family, distributed in the neotropical savanna fields and pollinated by bees known as "collecting-oil bees". In this study, conducted in a Cerrado area located on a farm in the city of Silvânia, GO, the following hypothesis was tested: the greater the isolation degree of a plant, the lower its fruit production due to access difficulties for pollinators. Using a linear regression analysis, it was possible to relate the fruiting rate with the degree of isolation of each B. coccolobifolia individual and consequently it was found that the isolation had no influence on the pollination rate, an unexpected event that can be explained by the distance amongst individuals not being large enough to limit the movement of pollinators, or because cross-pollination was not the predominant form of reproduction, since the rate of cross-pollination was similar to self-pollination. It was also found that the proportion of fruits produced was lower than expected, a factor which may also have influenced the results.

Byrsonima coccolobifolia é uma planta tropical da família Malpighiaceae, distribuída no Cerrado e polinizada por abelhas conhecidas como "abelhas coletoras-de-óleo". No presente estudo, realizado em área de cerrado localizada em uma fazenda no município de Silvânia, GO, foi testada a hipótese de que quanto maior o grau de isolamento de uma planta, menor sua produção de frutos, devido à dificuldade de acesso dos polinizadores. Através de uma análise de regressão linear foi possível relacionar a taxa de frutificação ao grau de isolamento de cada indivíduo de B. coccolobifolia, e verificou-se que o isolamento não exerceu influência alguma na produção de frutos, fato inesperado que pode ser explicado pela distância entre os indivíduos não ser suficientemente grande a ponto de limitar o trânsito de polinizadores, ou pelo fato da polinização cruzada não ser a forma predominante de reprodução, uma vez que a taxa de polinização cruzada foi semelhante à de autopolinização. Verificou-se ainda que a proporção de frutos produzidos foi abaixo do esperado, fator que também pode ter influenciado os resultados.

New species of Chelonus (Microchelonus) Szépligeti, 1908 (Hymenoptera: Braconidae: Cheloninae) from Brazil.

Chelonus (Microchelonus) murici sp. nov. (Hymenoptera: Braconidae: Cheloninae) is described in this work. It was reared from an unknown host in murici fruits, Byrsonima verbascifolia (L.) Rich. ex A. L. Juss. (Malpighiaceae), a species from the Brazilian savannah whose fruits are widely consumed by the population in northern Brazil. The adult of this new species is illustrated.

New species of Chelonus (Microchelonus) Szépligeti, 1908 (Hymenoptera: Braconidae: Cheloninae) from Brazil / Nova espécie de Chelonus (Microchelonus) Szépligeti, 1908 (Hymenoptera: Braconidae: Cheloninae) do Brasil

Chelonus (Microchelonus) murici sp. nov. (Hymenoptera: Braconidae: Cheloninae) is described in this work. It was reared from an unknown host in murici fruits, Byrsonima verbascifolia (L.) Rich. ex A. L. Juss. (Malpighiaceae), a species from the Brazilian savannah whose fruits are widely consumed by the population in northern Brazil. The adult of this new species is illustrated.

Chelonus (Microchelonus) murici sp. nov. (Hymenoptera: Braconidae: Cheloninae) é descrita neste trabalho. Os espécimes foram obtidos de hospedeiros não conhecidos em frutos de murici, Byrsonima verbascifolia (L.) Rich. ex A. L. Juss. (Malpighiaceae), uma espécie vegetal do cerrado brasileiro, cujo fruto é muito consumido pelo povo do nordeste do Brasil. O adulto desta nova espécie é ilustrado.

Botanical aspects of Heteropterys umbellata (Malpighiaceae): a cytological and palynological approach.

The genus Heteropterys is one of the major genera in Malpighiaceae. However, few cytological and palynological studies were reported. The present work described for the first time the chromosome number, heterochromatin pattern, meiotic behavior, pollen viability and palynological aspects of Heteropterys ubellata, a very spread species. One large Brazilian population was evaluated using conventional techniques for meiotic studies and acetolyse to access the pollen morphology. The species showed 2n = 20 chromosomes, normal meiotic development and viable pollens. Great blocks of heterochromatin were observed around the centromers. DAPI staining was positive for centroeric heterochroatin, hile CMA3 ark as observed just at terinal regions of one pair of hoologues chromosomes. This result and the presence of one chromosome pair attached to the nucleoli during the pachytene and diakinesis suggested the presence of only one pair of NORs. Palynological analysis revealed that pollen grains are apolar, 6 porate and with colpoids associated to all pores. The pollen content was positive for the starch test, and the exine was rugulate with little psilate regions.

Botanical aspects of Heteropterys umbellata (Malpighiaceae): a cytological and palynological approach

The genus Heteropterys is one of the major genera in Malpighiaceae. However, few cytological and palynological studies were reported. The present work described for the first time the chromosome number, heterochromatin pattern, meiotic behavior, pollen viability and palynological aspects of Heteropterys ubellata, a very spread species. One large Brazilian population was evaluated using conventional techniques for meiotic studies and acetolyse to access the pollen morphology. The species showed 2n = 20 chromosomes, normal meiotic development and viable pollens. Great blocks of heterochromatin were observed around the centromers. DAPI staining was positive for centroeric heterochroatin, hile CMA3 ark as observed just at terinal regions of one pair of hoologues chromosomes. This result and the presence of one chromosome pair attached to the nucleoli during the pachytene and diakinesis suggested the presence of only one pair of NORs. Palynological analysis revealed that pollen grains are apolar, 6 porate and with colpoids associated to all pores. The pollen content was positive for the starch test, and the exine was rugulate with little psilate regions.

O gênero Heteropterys é um dos maiores gêneros entre as Malpighiaceae. Entretanto, poucos estudos citológicos e palinológicos foram relatados. O presente trabalho descreveu pela primeira vez o número cromossômico, o padrão heterocromático, o comportamento meiótico, a viabilidade polínica e aspectos palinológicos de Heteropterys umbellata, uma espécie muito disseminada. Uma grande população brasileira foi estudada utilizando técnicas convencionais para o estudo de cromossomos meióticos e acetólise para acessar a morfologia polínica. A espécie apresentou 2n = 20 cromossomos, desenvolvimento meiótico normal e pólens viáveis. Grandes blocos de heterocromatina foram observados ao redor dos cen-trômeros. A coloração com DAPI foi positiva para a hetero-cromatina centromérica, enquanto marcas com CMA3 foram observadas somente em um sítio terminal de um par de cromossomos homólogos. Este resultado e a presença de um par de cromossomos associados a um nucléolo durante o paquíteno e diacinese sugerem a presença de somente um par de RONs. A análise palinológica revelou que os grãos de pólen são apolar, com 6 poros e colpóides associados a todos eles. O conteúdo polínico foi positivo para o teste de amido e a exina mostrou-se rugulada com poucas regiões psiladas.

Frugivory in Lacistema hasslerianum Chodat (Lacistemaceae), a gallery forest understory treelet in Central Brazil.

The objectives of this study were to know and to characterize the behavioural patterns of frugivorous birds in Lacistema hasslerianum. The study was carried out in the Panga Ecological Station (Uberlândia, Minas Gerais State). During the frutification time (September-October), L. hasslerianum was observed for 31.25 hours and received 58 visits by five species of birds. Tyrannidae was the best represented family (2 species). Pipridae was the most frequent visitor in L. hasslerianum (68.97% of visits). The number of consumed fruits was correlated with the time of permanence on the plant. The main foraging tactic was 'Stalling' (58.62%) and the most frequent fruit consumption strategy was 'swallower' (45.25%), which indicates a high seed dispersal potential. Antilophia galeata (Pipridae), although a territorial bird, presented the best dispersal efficiency for Lacistema hasslerianum, because of its consumption rate (2.82 whole fruits consumed/minute).

Frugivory in Lacistema hasslerianum Chodat (Lacistemaceae), a gallery forest understory treelet in Central Brazil / Frugivoria em Lacistema hasslerianum Chodat (Lacistemaceae), uma arvoreta de subbosque de Mata de Galeria no Brasil Central

The objectives of this study were to know and to characterize the behavioural patterns of frugivorous birds in Lacistema hasslerianum. The study was carried out in the Panga Ecological Station (Uberlândia, Minas Gerais State). During the frutification time (September-October), L. hasslerianum was observed for 31.25 hours and received 58 visits by five species of birds. Tyrannidae was the best represented family (2 species). Pipridae was the most frequent visitor in L. hasslerianum (68.97 percent of visits). The number of consumed fruits was correlated with the time of permanence on the plant. The main foraging tactic was "Stalling" (58.62 percent) and the most frequent fruit consumption strategy was "swallower" (45.25 percent), which indicates a high seed dispersal potential. Antilophia galeata (Pipridae), although a territorial bird, presented the best dispersal efficiency for Lacistema hasslerianum, because of its consumption rate (2.82 whole fruits consumed/minute).

Os objetivos deste estudo foram conhecer e caracterizar o padrão comportamental das aves frugívoras em Lacistema hasslerianum. O estudo foi realizado na Estação Ecológica do Panga (Uberlândia-MG). Durante a época de frutificação (setembro-outubro), L. hasslerianum foi observada por 31 horas e 15 minutos e recebeu 58 visitas de cinco espécies de aves. Tyrannidae foi a família mais representativa (2 espécies), Pipridae, a família mais frequente (68,97 por cento). O número de frutos consumidos foi correlacionado com o tempo de permanência na planta. A principal tática de forrageamento utilizada pelos visitantes de L. hasslerianum foi "vôo" (58,62 por cento) e a estratégia de consumo do fruto predominante foi "engolidor" (45,25 por cento), o que indica um elevado potencial de dispersão. Antilophia galeata (Pipridae), apesar de territorialista, apresentou a maior eficiência de dispersão para L. hasslerianum devido à sua taxa de consumo (2,82 frutos consumidos inteiros/minuto).

[The acerola fruit: composition, productive characteristics and economic importance]. / El fruto de la acerola: composición, características productivas e importancia económica.

The acerola (Malpighia emarginata Sessé y Mociño ex DC) is a wild plant grown in zones of tropical and subtropical climate. Acerola is origin from South of Mexico, Central America and Septentrional area of South America. Its scientific name was adopted in 1986 by the International Council of Vegetable Genetic Resources. Malpighia emarginata has a subglobulose drupa fruit with three seeds which account between the 19 - 25% of the total weight. The diameter and weight of the fruit varies between 1 - 4 cm and 2 - 15 g, respectively. The fruit shows green color when it is developing, which changes to yellow and red tones when it is mature. Each plant produces annually 20 - 30 kg of fruits. This fruit contents macro and micronutrients: proteins (0.21-0.80 g/100 g), fats (0.23-0.80 g/100 g), carbohydrates (3.6-7.80 g/100 g), mineral salts (iron 0.24, calcium 11.7, phosphorus 17.1 mg/100 g) and vitamins (thiamine 0.02, riboflavine 0.07, piridoxine 8.7 mg/100 g). Its high content in vitamin C (695 a 4827 mg/100 g) is remarkable, therefore acerola has an increasing economic value by its great consume during last years. Acerola also presents carotenoids and bioflavonoids which provide important nutritive value and its potential use as antioxidant. Brazil has a climate and soil appropriate for the culture of acerola, thus this country is the main mundial productor. Acerola is commercialised as juices, jams, ices, gelatins, sweets or liquors. Bibliographical data have been mainly supplied by Electronic Resources of the University of Seville and the University do Vale do Itajaí (Santa Catarina, Brazil).

Anatomía de la madera de 17 especies de la familia malpighiaceae juss / Wood anatomy of 17 species from malpighiaceae juss family

Se presenta el estudio anatómico de la madera de 17 especies leñosas de la familia Malpighiaceae: Banisteriopsisacapulcensis, Bunchosia argentea, B. mollis, Byrsonima aerugo, B. arthropoda, B. chalcophylla, B. chrysophylla, B. coriacea, B. crassifolia, B. densa, B. frondosa, B. japurensis, B. ligustrifolia, B. rugosa, B. spicata, B. stipulacea y Malpighia glabra. Entre especies de un mismo género se observa una estructura homogénea; pero entre géneros existen diferencias en cuanto a tipo de parénquima, platinas de perforación, fibras septadas y ubicación de cristales. La presencia de células radiales perforadas y cristales en las fibras se reporta por primera vez para la familia Malpighiaceae. El desarrollo de platinas de perforación foraminadas se observó en, aproximadamente, el 70 por ciento de las especies estudiadas del género Byrsonima; siendo reportadas por primera vez para las especies Byrsonima aerugo, B. chalcophylla, B. crassifolia, B. densa, B. japurensis, B. ligustrifolia y B. spicata.

This paper deals about the wood anatomy of 17 woody species from Malpighiaceae family: Banisteriopsisacapulcensis, Bunchosia argentea, B. mollis, Byrsonima aerugo, B. arthropoda, B. chalcophylla, B. chrysophylla, B. coriacea, B. crassifolia, B. densa, B. frondosa, B. japurensis, B. ligustrifolia, B. rugosa, B. spicata, B. stipulacea and Malpighia glabra. In species from a same genus, the wood anatomy is very homogeneus; but between genus we can found differences in some features like parenchyma type, perforations plates, septate fibres and crystals ubication. The presence of perforated ray cells and prismatic crystals in fibres could be the first report about it in Malpighiaceae family. Foraminate perforations plates were observed in 70 percent of Byrsonima species and this could be the first report about this perforation type for Byrsonima aerugo, B. chalcophylla, B. crassifolia, B. densa, B. japurensis, B. ligustrifolia and B. spicata.

Pollination and reproductive biology of twelve species of neotropical Malpighiaceae: stigma morphology and its implications for the breeding system.

BACKGROUND AND AIMS: This study on reproductive biology examines the stigmatic morphology of 12 Brazilian Malpighiaceae species with regard to their pollination and breeding system. METHODS: The species were studied in natural populations of a semi-deciduous forest fragment. Style tips were processed for observation by SEM and pollen-tube growth was analyzed under fluorescence microscopy. The breeding system was investigated by isolating flowers within waterproof bags. Floral visitors were recorded through notes and photographs. KEY RESULTS: Flowers are yellow, pink or white, protogynous, herkogamous and sometimes lack oil glands. While Banisteriopsis pubipetala has functional female flowers (with indehiscent anthers), 11 species present hermaphrodite flowers. Stigmas of these species may be terminal, with a slightly concave surface, or internal, consisting of a circular cavity with a large orifice, and are covered with a thin, impermeable cuticle that prevents pollen from adhering, hydrating, or germinating. Malpighiaceae have a special type of 'wet' stigma, where a secretion accumulates under the cuticle and is released by mechanical means-mainly rupture by pollinators. Even though six species show a certain degree of self-compatibility, four of them present a form of late-acting self-incompatibility, and the individual of B. pubipetala is agamospermous. Species of Centris, Epicharis and Monoeca bees pollinate these flowers, mainly collecting oil. Some Epicharis and Monoeca species collected pollen by vibration. Paratetrapedia and Tetrapedia bees are pollen and oil thieves. CONCLUSIONS: The Malpiguiaceae species studied are pollinator-dependent, as spontaneous self-pollination is limited by herkogamy, protogyny and the stigmatic cuticle. Both the oil- and pollen-collecting behaviours of the pollinators favour the rupture of the stigmatic cuticle and the deposition of pollen on or inside the stigmas. As fruit-set rates in natural conditions are low, population fragmentation may have limited the sexual reproduction of these species.

Laurasian migration explains Gondwanan disjunctions: evidence from Malpighiaceae.

Explanations for biogeographic disjunctions involving South America and Africa typically invoke vicariance of western Gondwanan biotas or long distance dispersal. These hypotheses are problematical because many groups originated and diversified well after the last known connection between Africa and South America (approximately 105 million years ago), and it is unlikely that "sweepstakes" dispersal accounts for many of these disjunctions. Phylogenetic analyses of the angiosperm clade Malpighiaceae, combined with fossil evidence and molecular divergence-time estimates, suggest an alternative hypothesis to account for such distributions. We propose that Malpighiaceae originated in northern South America, and that members of several clades repeatedly migrated into North America and subsequently moved via North Atlantic land connections into the Old World during episodes starting in the Eocene, when climates supported tropical forests. This Laurasian migration route may explain many other extant lineages that exhibit western Gondwanan distributions.

Phylogeny of Acridocarpus-Brachylophon (Malpighiaceae): implications for tertiary tropical floras and Afroasian biogeography.

A major tenet of African Tertiary biogeography posits that lowland rainforest dominated much of Africa in the late Cretaceous and was replaced by xeric vegetation as a response to continental uplift and consequent widespread aridification beginning in the late Paleogene. The aridification of Africa is thought to have been a major factor in the extinction of many African humid-tropical lineages, and in the present-day disparity of species diversity between Africa and other tropical regions. This primarily geologically based model can be tested with independent phylogenetic evidence from widespread African plant groups containing both humid- and xeric-adapted species. We estimated the phylogeny and lineage divergence times within one such angiosperm group, the acridocarpoid clade (Malpighiaceae), with combined ITS, ndhF, and trnL-F data from 15 species that encompass the range of morphological and geographic variation within the group. Dispersal-vicariance analysis and divergence-time estimates suggest that the basal acridocarpoid divergence occurred between African and Southeast Asian lineages approximately 50 million years ago (mya), perhaps after a southward ancestral retreat from high-latitude tropical forests in response to intermittent Eocene cooling. Dispersion of Aeridocarpus from Africa to Madagascar is inferred between approximately 50 and 35 mya, when lowland humid tropical forest was nearly continuous between these landmasses. A single dispersal event within Acridocarpus is inferred from western Africa to eastern Africa between approximately 23 and 17 mya, coincident with the widespread replacement of humid forests by savannas in eastern Africa. Although the spread of xeric environments resulted in the extinction of many African plant groups, our data suggest that for others it provided an opportunity for further diversification.