Evolutionary analysis of angiosperm dehydrin gene family reveals three orthologues groups associated to specific protein domains.

Dehydrins (DHNs) are a family of plant proteins that play important roles on abiotic stress tolerance and seed development. They are classified into five structural subgroups: K-, SK-, YK-, YSK-, and KS-DHNs, according to the presence of conserved motifs named K-, Y- and S- segments. We carried out a comparative structural and phylogenetic analysis of these proteins, focusing on the less-studied KS-type DHNs. A search for conserved motifs in DHNs from 56 plant genomes revealed that KS-DHNs possess a unique and highly conserved N-terminal, 15-residue amino acid motif, not previously described. This novel motif, that we named H-segment, is present in DHNs of angiosperms, gymnosperms and lycophytes, suggesting that HKS-DHNs were present in the first vascular plants. Phylogenetic and microsynteny analyses indicate that the five structural subgroups of angiosperm DHNs can be assigned to three groups of orthologue genes, characterized by the presence of the H-, F- or Y- segments. Importantly, the hydrophilin character of DHNs correlate with the phylogenetic origin of the DHNs rather than to the traditional structural subgroups. We propose that angiosperm DHNs can be ultimately subdivided into three orthologous groups, a phylogenetic framework that should help future studies on the evolution and function of this protein family.

Evaluation of conservation status of plants in Brazil's Atlantic forest: An ethnoecological approach with Quilombola communities in Serra do Mar State Park.

The Atlantic Forest is considered the fourth most important biodiversity hotspot. Although almost 96% of its original area has been devastated, a large part of its remaining conserved area is inhabited by traditional communities. This research focused on two Quilombola communities who reside within the Núcleo Picinguaba of the Serra do Mar State Park, State of São Paulo, Brazil. The objective was to use a combination of ethnoecological and ecological approaches to select priority species for which to develop participatory conservation and sustainable management plans in protected areas in Brazil. We collaborated with community members to collect ethnobotanical and ethnoecological data and then measured the abundance of native species in local forests through phytosociological sampling. We used this information to assess the degree of threat to useful species using the Conservation Priority Index, adding an additional layer of analysis based on habitat successional categories. We then overlayed those useful species identified as highest risk locally with those federally listed as threatened or endangered. Based on this, we identified three species as priority for the development of sustainable management plans: Virola bicuhyba, Cedrella fissilis and Plinia edulis.

The breadth of the Mexican Transition Zone as defined by its flowering plant generic flora.

Biogeographic regions are defined by taxa with similar distribution patterns. Flowering plants have been widely used to propose biogeographic regionalization schemes because of shared historical or ecological factors that determine their distribution. The Mexican Transition Zone represents the boundary between the Nearctic and Neotropical kingdoms; however, there is no general agreement about the limits and extent of this region. Despite the significance of its role in the history of Mexican biota, no study involving a set of relevant plant taxa validates the magnitude of the Mexican Transition Zone. This work attempts to determine the proportion of flowering plant families and genera that characterize the biogeographic kingdoms and the Mexican Transition Zone. Through identification of distinctive genera it is shown that the Mexican Transition Zone includes the mountains of Mexico, from Oaxaca northwards. The results provide a broad view of the distribution patterns of the flora of Mexico and allow the evaluation of relationships and floristic affinities.

Major lineages of Loasaceae subfam. Loasoideae diversified during the Andean uplift.

The Loasoideae is the largest clade in the Loasaceae. This subfamily is widespread throughout the Neotropics and centered in the Andes, presenting an excellent opportunity to study diversification across much of temperate and mid to high-elevation areas of South America. Despite that, no studies have addressed the historical biogeography of the Loasoideae to date, leaving an important knowledge gap in this plant group. Here, we used four plastid markers (i.e., trnL-trnF, matK, trnS-trnG, and rps16) and sequenced 170 accessions (134 ingroup taxa) to infer the phylogeny of Loasoideae. We then used this phylogeny as basis to estimate divergence times using an uncorrelated relaxed molecular clock approach and seven fossils as primary calibration points. We employed the Dispersal-Extinction-Cladogenesis (DEC) approach to reconstruct the ancestral ranges of the subfamily. Our results indicate that stem Loasoideae diverged from its sister group in the Late Cretaceous to Early Paleocene (ca. 83-62 Ma). The crown node of the whole clade goes back to the Middle Paleocene to Middle Eocene (ca. 60-45 Ma), corresponding to the earliest diversification events of the extant groups, prior to most of the Andean orogeny and roughly coinciding with the Paleocene-Eocene Thermal Maximum. On the other hand, the crown nodes of most genera appear to have originated in the Oligocene and Miocene (median ages: 28-10 Ma). The diversification of some extant lineages appears to have happened in parallel to Andean uplift pulses that seem to have had an effect on the orogeny and concomitant establishment of new habitats and latitudinal corridors. The most likely ancestral areas retrieved for crown Loasoideae, are the tropical Andes and Pacific arid coast. Most of the extant clades have remained restricted to their ancestral areas. Transoceanic Long Distance Dispersal appears to have been involved in the arrival of Loasoid ancestors to South America, and in the distribution of the small clades Kissenia in Africa and Plakothira on the Marquesas Archipelago. The results presented here suggest that the historical biogeography of the continental scale radiation of Loasoideae, follows the sequence and timing of the development of temperate and mid to high-elevation habitats across South America during the Tertiary.

Are we close to knowing the plant diversity of the Amazon?

Amazonia is often cited as having the most diverse flora on the planet. However, the total number of species of higher plants in the region has been largely a matter of guesswork. Some recent publications have estimated the total number of species present, which indicate a lower overall diversity than was estimated in the past. However, analysis of the sampling density across the region, and data from various sources suggest that there may be reason why the recent figures may be considerable underestimates. I believe that much more investment in extensive collecting of quality plant specimens is needed to encounter the very large number of rare and local species that might never have been collected. Unfortunately the tendencies of investment in botany, in terms of geography and types of project, suggest that we will probably not be able to accurately assess the real diversity of the region.

Perceptions of the local beekeepers on the diversity and flowering phenology of the melliferous flora in the community of Xmabén, Hopelchén, Campeche, Mexico.

BACKGROUND: The knowledge of native melliferous flora (MF) may contribute to identify the diversity of species available for beekeeping activities during the dry and rainy seasons of the year in the Yucatan Peninsula (YP) region. The acute shortage of food resources considerably reduce local honey production and needs to be addressed appropriately. The objective of this study has been identifying the local MF, their nectar and pollen contribution, their flowering patterns, and the criteria of the vegetation to be established adjacent to local apiaries for stable production of quality honey. The study also investigates how this approach helps to complete the annual flowering cycle required to maintain the honeybee colonies, thereby preventing swarm escapes during periods of acute food stress in the community of Xmabén, Hopelchén, Campeche, Mexico. METHODOLOGY: We conducted a comprehensive survey based on interviews with 40 local beekeepers and a review of herbarium specimens (CICY) of the database of the global information network on the native MF biodiversity with high apiculture potential, the contribution of nectar and pollen they provide, and their flowering patterns. Furthermore, we documented interviews with the same beekeepers on the necessary conditions for establishing the ideal components of vegetation in areas adjacent to apiaries for high-quality honey production in the Xmabén community of Hopelchén, Campeche, Mexico. RESULTS: We have identified 56 native MF species with apiculture potential, that need to be planted around the apiaries for assisting honeybees in successfully running the beekeeping production cycle. Hence, the MF diversity of Xmabén community constitutes a valuable resource for successful beekeeping in the region and adjoining localities. We found that 22.5% of local beekeepers are dedicated exclusively to apilcilture, while 77.5% practice it as a secondary activity due to better sources of income in agriculture (60%), masonry (10%), and livestock management (7.5%). The data generated can help in further expansion of the local apiaries, beekeeping business, and in building future opportunities for the local apiculture industry. Indigenous knowledge of the beekeepers was comprehensive and corroborated the technical information on MF collected from the herbarium, further emphasizing the value of indigenous knowledge on traditional beekeeping practices. CONCLUSION: From the perspective of human ecology, our study reveals the need of collecting, analyzing, and interpreting indigenous knowledge to facilitate traditional beekeeping practices of the region without using expensive, modern technology to solve ecosystem-based problems through long-term, sustainable, traditional, and environment friendly approaches.

The Latitudinal Distribution of Morphological Diversity among Holocene Angiosperm Pollen Grains from Eastern North America and the Neotropics.

Current knowledge about the biogeographic patterns of biodiversity is based mostly on taxonomic diversity, which is typically measured as the number of species or higher taxa. In this paper I analyze 26 previously published Holocene lake core pollen records in order to assess how the morphological diversity of angiosperm pollen grains varies with latitude on a transect that includes eastern North America and the Neotropics. This represents a step toward understanding the evolution of plant morphology in a biogeographical context. I employ a system of eight discrete characters to describe first-order features of angiosperm pollen morphology and use algorithms written in the Python programming language to assess their morphological diversity. There is no statistically significant relationship between taxonomic diversity and morphological diversity in the samples of Holocene angiosperm pollen investigated here. The number of pollen morphotypes in the sediment samples investigated here increases from high latitudes to the tropics, but the highest morphological diversity occurs at high latitudes, and the lowest morphological diversity occurs at mid-latitudes around 40-50°N. At the biome level, there are peaks in morphological diversity at low and high latitudes with a trough in mid latitudes. There is evidence of high levels of pollen morphotype endemism in the tropical biome, and further work on how the volume of morphological space varies with latitude is needed in order to understand whether taxa in species-rich tropical ecosystems are more densely packed into morphological space.

Silica bodies in leaves of neotropical Podostemaceae: taxonomic and phylogenetic perspectives.

Background and Aims: The presence, location and morphology of silica bodies are informative anatomical characters in angiosperms, mainly in Poales. In Podostemaceae, a strictly aquatic family, these structures are mentioned frequently, but there is limited insight into their location and morphological features. In the present study we focused on describing and analysing the morphological diversity of silica bodies in leaves of neotropical Podostemaceae at the intra- and interspecific levels to determine their taxonomic and phylogenetic relevance. Methods: We studied 103 specimens distributed across 40 species. Silica body morphological traits were analysed under light and scanning electron microscopy. Additionally, data from three species of Hypericaceae (sister group) were retrieved from the literature. A phylogenetic framework based on four molecular markers was built in order to reconstruct ancestral character states related to silica bodies in neotropical Podostemaceae. Key Results: Silica bodies were detected in epidermal, subepidermal and perivascular cells, presenting different shapes and surface morphology. Presence and location were used for primary differentiation while surface morphology and lumen (presence and shape) were used for finer distinctions. Intraspecific comparisons among samples showed that the length and width of these structures were highly variable. Maximum parsimony and maximum likelihood analyses for ancestral character reconstruction were congruent. Three out of five characters showed a statistically strong phylogenetic signal. Conclusions: Silica bodies were reported for the first time for 19 taxa, and their morphological diversity is greater than reported in previous studies. Their presence can be considered an apomorphy in Podostemaceae. Although some significant differences were detected in length and width, qualitative characters are more informative at both specific and generic ranks.

Comparative genomic analysis of Genlisea (corkscrew plants-Lentibulariaceae) chloroplast genomes reveals an increasing loss of the ndh genes.

In the carnivorous plant family Lentibulariaceae, all three genome compartments (nuclear, chloroplast, and mitochondria) have some of the highest rates of nucleotide substitutions across angiosperms. While the genera Genlisea and Utricularia have the smallest known flowering plant nuclear genomes, the chloroplast genomes (cpDNA) are mostly structurally conserved except for deletion and/or pseudogenization of the NAD(P)H-dehydrogenase complex (ndh) genes known to be involved in stress conditions of low light or CO2 concentrations. In order to determine how the cpDNA are changing, and to better understand the evolutionary history within the Genlisea genus, we sequenced, assembled and analyzed complete cpDNA from six species (G. aurea, G. filiformis, G. pygmaea, G. repens, G. tuberosa and G. violacea) together with the publicly available G. margaretae cpDNA. In general, the cpDNA structure among the analyzed Genlisea species is highly similar. However, we found that the plastidial ndh genes underwent a progressive process of degradation similar to the other terrestrial Lentibulariaceae cpDNA analyzed to date, but in contrast to the aquatic species. Contrary to current thinking that the terrestrial environment is a more stressful environment and thus requiring the ndh genes, we provide evidence that in the Lentibulariaceae the terrestrial forms have progressive loss while the aquatic forms have the eleven plastidial ndh genes intact. Therefore, the Lentibulariaceae system provides an important opportunity to understand the evolutionary forces that govern the transition to an aquatic environment and may provide insight into how plants manage water stress at a genome scale.

Antimycobacterial and antimalarial activities of endophytic fungi associated with the ancient and narrowly endemic neotropical plant Vellozia gigantea from Brazil

BACKGROUND Endophytic fungi, present mainly in the Ascomycota and Basidiomycota phyla, are associated with different plants and represent important producers of bioactive natural products. Brazil has a rich biodiversity of plant species, including those reported as being endemic. Among the endemic Brazilian plant species, Vellozia gigantea (Velloziaceae) is threatened by extinction and is a promising target to recover endophytic fungi. OBJECTIVE The present study focused on bioprospecting of bioactive compounds of the endophytic fungi associated with V. gigantea, an endemic, ancient, and endangered plant species that occurs only in the rupestrian grasslands of Brazil. METHODS The capability of 285 fungal isolates to produce antimicrobial and antimalarial activities was examined. Fungi were grown at solid-state fermentation to recover their crude extracts in dichloromethane. Bioactive extracts were analysed by chromatographic fractionation and NMR and displayed compounds with antimicrobial, antimycobacterial, and antimalarial activities. FINDINGS Five fungi produced antimicrobial and antimalarial compounds. Extracts of Diaporthe miriciae showed antifungal, antibacterial, and antimalarial activities; Trichoderma effusum displayed selective antibacterial activity against methicillin-resistant Staphylococcus aureus and Mycobacterium intracellulare; and three Penicillium species showed antibacterial activity. D. miriciae extract contained highly functionalised secondary metabolites, yielding the compound epoxycytochalasin H with high antimalarial activity against the chloroquine-resistant strain of Plasmodium falciparum, with an IC50 approximately 3.5-fold lower than that with chloroquine. MAIN CONCLUSION Our results indicate that V. gigantea may represent a microhabitat repository hotspot of potential fungi producers of bioactive compounds and suggest that endophytic fungal communities might be an important biological component contributing to the fitness of the plants living in the rupestrian grassland.

Antimycobacterial and antimalarial activities of endophytic fungi associated with the ancient and narrowly endemic neotropical plant Vellozia gigantea from Brazil.

BACKGROUND: Endophytic fungi, present mainly in the Ascomycota and Basidiomycota phyla, are associated with different plants and represent important producers of bioactive natural products. Brazil has a rich biodiversity of plant species, including those reported as being endemic. Among the endemic Brazilian plant species, Vellozia gigantea (Velloziaceae) is threatened by extinction and is a promising target to recover endophytic fungi. OBJECTIVE: The present study focused on bioprospecting of bioactive compounds of the endophytic fungi associated with V. gigantea, an endemic, ancient, and endangered plant species that occurs only in the rupestrian grasslands of Brazil. METHODS: The capability of 285 fungal isolates to produce antimicrobial and antimalarial activities was examined. Fungi were grown at solid-state fermentation to recover their crude extracts in dichloromethane. Bioactive extracts were analysed by chromatographic fractionation and NMR and displayed compounds with antimicrobial, antimycobacterial, and antimalarial activities. FINDINGS: Five fungi produced antimicrobial and antimalarial compounds. Extracts of Diaporthe miriciae showed antifungal, antibacterial, and antimalarial activities; Trichoderma effusum displayed selective antibacterial activity against methicillin-resistant Staphylococcus aureus and Mycobacterium intracellulare; and three Penicillium species showed antibacterial activity. D. miriciae extract contained highly functionalised secondary metabolites, yielding the compound epoxycytochalasin H with high antimalarial activity against the chloroquine-resistant strain of Plasmodium falciparum, with an IC50 approximately 3.5-fold lower than that with chloroquine. MAIN CONCLUSION: Our results indicate that V. gigantea may represent a microhabitat repository hotspot of potential fungi producers of bioactive compounds and suggest that endophytic fungal communities might be an important biological component contributing to the fitness of the plants living in the rupestrian grassland.

Biodiversity conservation gaps in the Brazilian protected areas.

Although Brazil is a megadiverse country and thus a conservation priority, no study has yet quantified conservation gaps in the Brazilian protected areas (PAs) using extensive empirical data. Here, we evaluate the degree of biodiversity protection and knowledge within all the Brazilian PAs through a gap analysis of vertebrate, arthropod and angiosperm occurrences and phylogenetic data. Our results show that the knowledge on biodiversity in most Brazilian PAs remain scant as 71% of PAs have less than 0.01 species records per km2. Almost 55% of Brazilian species and about 40% of evolutionary lineages are not found in PAs, while most species have less than 30% of their geographic distribution within PAs. Moreover, the current PA network fails to protect the majority of endemic species. Most importantly, these results are similar for all taxonomic groups analysed here. The methods and results of our countrywide assessment are suggested to help design further inventories in order to map and secure the key biodiversity of the Brazilian PAs. In addition, our study illustrates the most common biodiversity knowledge shortfalls in the tropics.

Hummingbird pollination and the diversification of angiosperms: an old and successful association in Gesneriaceae.

The effects of specific functional groups of pollinators in the diversification of angiosperms are still to be elucidated. We investigated whether the pollination shifts or the specific association with hummingbirds affected the diversification of a highly diverse angiosperm lineage in the Neotropics. We reconstructed a phylogeny of 583 species from the Gesneriaceae family and detected diversification shifts through time, inferred the timing and amount of transitions among pollinator functional groups, and tested the association between hummingbird pollination and speciation and extinction rates. We identified a high frequency of pollinator transitions, including reversals to insect pollination. Diversification rates of the group increased through time since 25 Ma, coinciding with the evolution of hummingbird-adapted flowers and the arrival of hummingbirds in South America. We showed that plants pollinated by hummingbirds have a twofold higher speciation rate compared with plants pollinated by insects, and that transitions among functional groups of pollinators had little impact on the diversification process. We demonstrated that floral specialization on hummingbirds for pollination has triggered rapid diversification in the Gesneriaceae family since the Early Miocene, and that it represents one of the oldest identified plant-hummingbird associations. Biotic drivers of plant diversification in the Neotropics could be more related to this specific type of pollinator (hummingbirds) than to shifts among different functional groups of pollinators.

Spatial phylogenetics of the vascular flora of Chile.

Current geographic patterns of biodiversity are a consequence of the evolutionary history of the lineages that comprise them. This study was aimed at exploring how evolutionary features of the vascular flora of Chile are distributed across the landscape. Using a phylogeny at the genus level for 87% of the Chilean vascular flora, and a geographic database of sample localities, we calculated phylogenetic diversity (PD), phylogenetic endemism (PE), relative PD (RPD), and relative PE (RPE). Categorical Analyses of Neo- and Paleo-Endemism (CANAPE) were also performed, using a spatial randomization to assess statistical significance. A cluster analysis using range-weighted phylogenetic turnover was used to compare among grid cells, and with known Chilean bioclimates. PD patterns were concordant with known centers of high taxon richness and the Chilean biodiversity hotspot. In addition, several other interesting areas of concentration of evolutionary history were revealed as potential conservation targets. The south of the country shows areas of significantly high RPD and a concentration of paleo-endemism, and the north shows areas of significantly low PD and RPD, and a concentration of neo-endemism. Range-weighted phylogenetic turnover shows high congruence with the main macrobioclimates of Chile. Even though the study was done at the genus level, the outcome provides an accurate outline of phylogenetic patterns that can be filled in as more fine-scaled information becomes available.

Foreign Plastid Sequences in Plant Mitochondria are Frequently Acquired Via Mitochondrion-to-Mitochondrion Horizontal Transfer.

Angiosperm mitochondrial genomes (mtDNA) exhibit variable quantities of alien sequences. Many of these sequences are acquired by intracellular gene transfer (IGT) from the plastid. In addition, frequent events of horizontal gene transfer (HGT) between mitochondria of different species also contribute to their expanded genomes. In contrast, alien sequences are rarely found in plastid genomes. Most of the plant-to-plant HGT events involve mitochondrion-to-mitochondrion transfers. Occasionally, foreign sequences in mtDNAs are plastid-derived (MTPT), raising questions about their origin, frequency, and mechanism of transfer. The rising number of complete mtDNAs allowed us to address these questions. We identified 15 new foreign MTPTs, increasing significantly the number of those previously reported. One out of five of the angiosperm species analyzed contained at least one foreign MTPT, suggesting a remarkable frequency of HGT among plants. By analyzing the flanking regions of the foreign MTPTs, we found strong evidence for mt-to-mt transfers in 65% of the cases. We hypothesize that plastid sequences were initially acquired by the native mtDNA via IGT and then transferred to a distantly-related plant via mitochondrial HGT, rather than directly from a foreign plastid to the mitochondrial genome. Finally, we describe three novel putative cases of mitochondrial-derived sequences among angiosperm plastomes.

Morphological analysis of vessel elements for systematic study of three Zingiberaceae tribes.

Zingiberaceae containing over 1,000 species that are divided into four subfamilies and six tribes. In recent decades, there has been an increase in the number of studies about vessel elements in families of monocotyledon. However, there are still few studies of Zingiberaceae tribes. This study aims to establish systematic significance of studying vessel elements in two subfamilies and three tribes of Zingiberaceae. The vegetative organs of 33 species processed were analysed by light and scanning electron microscopy and Principal Component Analysis was used to elucidate genera boundaries. Characteristics of vessel elements, such as the type of perforation plate, the number of bars and type of parietal thickening, are proved to be important for establishing the relationship among taxa. Scalariform perforation plate and the scalariform parietal thickening are frequent in Zingiberaceae and may be a plesiomorphic condition for this taxon. In the Principal Component Analysis, the most significant characters of the vessel elements were: simple perforation plates and partially pitted parietal thickening, found only in Alpinieae tribe, and 40 or more bars composing the plate in Elettariopsis curtisii, Renealmia chrysotricha, Zingiber spectabile, Z. officinale, Curcuma and Globba species. Vessel elements characters of 18 species of Alpinieae, Zingibereae and Globbeae were first described in this work.

Embryology of Pera (Peraceae, Malpighiales): systematics and evolutionary implications.

Pera is a neotropical genus that currently belongs to the family Peraceae. This circumscription resulted from an inclusion of the Rafflesiaceae between the old tribe Pereae and all other Euphorbiaceae, and wherein Pereae was elevated to family rank making Euphorbiaceae monophyletic again. These changes are necessary although Rafflesiaceae are holoparasitic with extremely reduced vegetative bodies and large flowers while Peraceae and Euphorbiaceae have well developed vegetative parts and reduced flowers. As the embryology of Peraceae was poorly known, and embryological processes are conservative, we studied the embryology of Pera glabrata, searching for similarities between Peraceae, Rafflesiaceae, and Euphorbiaceae that could support this grouping. Usual methods of light microscopy and scanning electron microscopy were utilised. The results show endothecium with reversed-T-shaped cells, prismatic crystals in the tapetum, and disintegrated aerenchymatous septum in the mature fruit as unique features for Peraceae and possibly apomorphies for the family. In addition to the unisexual flowers, porogamous fertilization is present and one ovule per carpel which may support the Peraceae-Rafflesiaceae-Euphorbiaceae clade. The comparative approach also suggests possible (syn-)apomorphies for linoids and phyllanthoids, only linoids, Rafflesiaceae, Euphorbiaceae, and Ixonanthaceae. The presence of a placental obturator found previously unknown in Peraceae emerged as a possible synapomorphy for the euphorbioids (including Ixonanthaceae, Linaceae, Phyllanthaceae, Picrodendraceae, Peraceae, Rafflesiaceae, and Euphorbiaceae), which appeared in a common ancestor of the group and has been lost in Rafflesiaceae.

Comparative inflorescence development in selected Andean Santalales.

PREMISE OF THE STUDY: Loranthaceae, Santalaceae, and Viscaceae are the most diversified hemiparasitic families of Santalales in the Andes. Their partial inflorescences (PIs) vary from solitary flowers, or dichasia in most Santalales, to congested floral groups along articles in most Viscaceae. The atypical articled inflorescences in Phoradendreae (Viscaceae), a phylogenetic novelty restricted to this tribe, have been variously described as racemes, spikes, fascicles, or as intercalary inflorescences, but no developmental studies have been performed to compare them with the construction of PIs across Santalales. METHODS: We used standard light microscopy and scanning electron microscopy to record the inflorescence development in members of Phoradendreae (Viscaceae) in comparison to those in species of Aetanthus, Gaiadendron, Oryctanthus, Passovia, and Peristethium (Loranthaceae) and Antidaphne (Santalaceae). KEY RESULTS: Morphological and developmental comparisons as well as optimization onto a phylogenetic framework indicate that individual inflorescences in Santalales are indeterminate and are formed by axillary cymose PIs. The latter correspond to dichasia, either simple, compound, or variously reduced by abortion of lateral flowers, abortion of the terminal flower, or loss of bracteoles. CONCLUSIONS: Dichasia are plesiomorphic in Santalales. These results favor the interpretation that inflorescences in Phoradendreae are formed by the fusion of serial dichasia (=floral rows) with the main inflorescence axis via syndesmy. We compared this interpretation with the competing one based on the co-occurrence of collateral and serial floral buds.

Influence of biological and social-historical variables on the time taken to describe an angiosperm.

PREMISE OF THE STUDY: By convention, scientific naming of angiosperm species began in 1753; it is estimated that 10-20% of species remain undescribed. To complete this task before rare, undescribed species go extinct, a better understanding of the description process is needed. The South American Cerrado biodiversity hotspot was considered a suitable model due to a high diversity of plants, habitats, and social history of species description. METHODS: A randomized sample of 214 species (2% of the angiosperm flora) and 22 variables were analyzed using multivariate analyses and analysis of variance. KEY RESULTS: Plants with wide global distributions, recorded from many areas, and above 2.6 m were described significantly earlier than narrowly distributed, uncommon species of smaller stature. The beginning of the career of the botanist who first collected the species was highly significant, with an average delay between first collection and description of 29 yr, and between type collection and description 19 yr; standard deviations were high and rose over time. Over a third of first collections were not cited in descriptions. Trends such as scientific specialization and decline of undescribed species were highlighted. Descriptions that involved potential collaboration between collectors and authors were significantly slower than those that did not. CONCLUSIONS: Results support four recommendations to hasten discovery of new species: (1) preferential collecting of plants below 2.6 m, at least in the Cerrado; (2) access to undetermined material in herbaria; (3) fieldwork in areas where narrow-endemic species occur; (4) fieldwork by knowledgeable botanists followed by descriptive activity by the same.