Is DNA barcoding child's play? Science education and the utility of DNA barcoding for the discrimination of UK tree species

We present the findings of a DNA barcoding study of the UK tree flora, implemented as part of an innovative, research‐based science education programme called ‘Tree School’. The UK tree flora comprises native and introduced species, and is a taxonomically diverse study group for the exploration of the potential and limitations of DNA barcoding. The children participating in the project collected voucher specimens and generated DNA barcode sequences from trees and shrubs found in the grounds and surrounding woodlands of a residential field centre in Dorset, UK. We assessed the potential of rbcL and matK markers for amplification and DNA sequencing success and for species discrimination among the 67 tree and shrub species included in this study. Although we achieved 100% PCR amplification and sequencing success for rbcL and matK, mononucleotide repeats affected sequence quality in matK for some taxonomic groups (e.g. Rosaceae). Species discrimination success ranged from 65% to 71% using tree‐based methods to 86% using BLASTN. The occurrence of known hybrids (diploid and polyploid) and their progenitors on the study site reduced the overall species discrimination success for both loci. This study demonstrates that, even in a floristic context, rbcL and matK alone are insufficient for the discrimination of UK tree species, especially where taxonomically complex groups are present. From a science education perspective, DNA barcoding represents a compelling and accessible platform for the engagement of non‐experts in ongoing research, providing an opportunity for them to contribute authentic scientific data to an international research campaign.     

Species discrimination in Sisyrinchium (Iridaceae): assessment of DNA barcodes in a taxonomically challenging genus

DNA barcoding aims to develop an efficient tool for species identification based on short and standardized DNA sequences. In this study, the DNA barcode paradigm was tested among the genera of the tribe Sisyrinchieae (Iridoideae). Sisyrinchium, with more than 77% of the species richness in the tribe, is a taxonomically complex genus. A total of 185 samples belonging to 98 species of Sisyrinchium, Olsynium, Orthrosanthus and Solenomelus were tested using matK, trnH‐psbA and internal transcribed spacer (ITS). Candidate DNA barcodes were analysed either as single markers or in combination. Detection of a barcoding gap, similarity‐based methods and tree‐based analyses were used to assess the discrimination efficiency of DNA barcodes. The levels of species identification obtained from plastid barcodes were low and ranged from 17.35% to 20.41% for matK and 5.11% to 7.14% for trnH‐psbA. The ITS provided better results with 30.61–38.78% of species identified. The analyses of the combined data sets did not result in a significant improvement in the discrimination rate. Among the tree‐based methods, the best taxonomic resolution was obtained with Bayesian inference, particularly when the three data sets were combined. The study illustrates the difficulties for DNA barcoding to identify species in evolutionary complex lineages. Plastid markers are not recommended for barcoding Sisyrinchium due to the low discrimination power observed. ITS gave better results and may be used as a starting point for species identification.     

Phylogenetic and mixed Yule‐coalescent analyses reveal cryptic lineages within two South American marine snails of the genus Crepipatella (Gastropoda: Calyptraeidae)

The presence of sibling species within the marine gastropod genus Crepipatella has complicated the taxonomy of members of the group. Since the establishment of the genus, 15 species have been described, but recent studies have indicated that there are only five valid species, two of which inhabit the coasts of Chile, namely C. dilatata and C. fecunda. The two species are morphologically indistinguishable as adults, but can be differentiated on the basis of their encapsulated developmental stages. The primary aim of this study was to reconstruct phylogeny within the genus, and to establish species limits of C. dilatata and C. fecunda, using mitochondrial DNA data. To this end, we used maximum parsimony, maximum likelihood, and Bayesian inference to reconstruct phylogenies using 589 bp of the cytochrome oxidase I (COI) gene. The mtDNA phylogenies were then used as input in a general mixed Yule‐coalescent (GMYC) analysis to estimate species boundaries. In addition, quarter likelihood mapping was used to test a posteriori the confidence of inner branch patterns in the phylogenetic tree. Both DNA tree‐based and GMYC methods provide support for five isolated lineages within this species complex. Our data also suggest that Late Pleistocene and Holocene fragmentation and subsequent range expansion events may have shaped contemporary genetic patterns of Crepipatella in South America.     

Diet selection at three spatial scales: Implications for conservation of an endangered Hawaiian tree snail

Several recent studies suggest local adaptation in multiple taxa across Hawaii's steep environmental gradients. Restoration efforts in devastated tropical island ecosystems may be deficient if we lack an understanding of the interactions and dependencies in communities that occur along these gradients. Endangered Hawaiian tree snails are part of a snail–epiphyte–plant system where they graze fungi and other microbes on the leaf surface, a process difficult to observe using conventional techniques. Tree snails have undergone catastrophic decline due to introduced predators, removal by shell collectors, and human‐influenced habitat degradation. Prior to this study, little was known about the relationship among tree‐snails, their host plants, and the epiphytic microbes on which they feed. In this study, we identified scale‐dependent selection of substrates in Achatinella sowerbyana and Achatinella lila across the species’ ranges. We assessed: (1) within‐plant diet selection using high‐throughput DNA sequencing (micro‐scale); (2) among‐plant selection of tree host species (small‐scale); (3) and the influence of climate on this system (macro‐scale). Selection of substrates occurred at two scales: fungal communities in fecal samples differed in composition from those available on leaf surfaces; and at all sites, snail occurrence on Metrosideros polymorpha, a foundational forest plant, was significantly higher than expected based on availability. Habitat restoration efforts should focus on out‐planting of M. polymorpha, the preferred snail host tree, in degraded habitat. Fungal differences across sites suggest relocation efforts to predator‐free enclosures may be hindered by microbial shifts associated with geographic distance or differing environments.     

DNA barcoding of Corydalis,the most taxonomically complicated genus of Papaveraceae

The genus Corydalis is recognized as one of the most taxonomically challenging plant taxa. It is mainly distributed in the Himalaya–Hengduan Mountains, a global biodiversity hotspot. To date, no effective solution for species discrimination and taxonomic assignment in Corydalis has been developed. In this study, five nuclear and chloroplast DNA regions, ITS, ITS2, matK, rbcL, and psbA‐trnH, were preliminarily assessed based on their ability to discriminate Corydalis to eliminate inefficient regions, and the three regions showing good performance (ITS, ITS2 and matK) were then evaluated in 131 samples representing 28 species of 11 sections of four subgenera in Corydalis using three analytical methods (NJ, ML, MP tree; K2P‐distance and BLAST). The results showed that the various approaches exhibit different species identification power and that BLAST shows the best performance among the tested approaches. A comparison of different barcodes indicated that among the single barcodes, ITS (65.2%) exhibited the highest identification success rate and that the combination of ITS + matK (69.6%) provided the highest species resolution among all single barcodes and their combinations. Three Pharmacopoeia‐recorded medicinal plants and their materia medica were identified successfully based on the ITS and ITS2 regions. In the phylogenetic analysis, the sections Thalictrifoliae, Sophorocapnos, Racemosae, Aulacostigma, and Corydalis formed well‐supported separate lineages. We thus hypothesize that the five sections should be classified as an independent subgenus and that the genus should be divided into three subgenera. In this study, DNA barcoding provided relatively high species discrimination power, indicating that it can be used for species discrimination in this taxonomically complicated genus and as a potential tool for the authentication of materia medica belonging to Corydalis.     

Evaluating the capacity of plant DNA barcodes to discriminate species of cotton (Gossypium: Malvaceae)

Although two plastid regions have been adopted as the standard markers for plant DNA barcoding, their limited resolution has provoked the consideration of other gene regions, especially in taxonomically diverse genera. The genus Gossypium (cotton) includes eight diploid genome groups (A–G, and K) and five allotetraploid species which are difficult to discriminate morphologically. In this study, we tested the effectiveness of three widely used markers (matK, rbcL, and ITS2) in the discrimination of 20 diploid and five tetraploid species of cotton. Sequences were analysed locus‐wise and in combinations to determine the most effective strategy for species identification. Sequence recovery was high, ranging from 92% to 100% with mean pairwise interspecific distance highest for ITS2 (3.68%) and lowest for rbcL (0.43%). At a 0.5% threshold, the combination of matK+ITS2 produced the greatest number of species clusters. Based on ‘best match’ analysis, the combination of matK+ITS2 was best, while based on ‘all species barcodes’ analysis, ITS2 gave the highest percentage of correct species identifications (98.93%). The combination of sequences for all three markers produced the best resolved tree. The disparity index test based on matK+rbcL+ITS2 was significant (P < 0.05) for a higher number of species pairs than the individual gene sequences. Although all three barcodes separated the species with respect to their genome type, no single combination of barcodes could differentiate all the Gossypium species, and tetraploid species were particularly difficult.     

Species‐Specific Barriers to Tree Regeneration in High Elevation Habitats of West Virginia

Herbaceous competition and herbivory have been identified as critical barriers to restoration of native tree species in degraded landscapes around the world; however, the combined effects of competition and herbivory are poorly understood. We experimentally manipulated levels of herbivory and herbaceous competition and analyzed the response of tree seedling performance over three growing seasons as a function of species and habitat in north‐central West Virginia. Four native tree species were planted in old field and forest experimental plots: Castanea dentata (American chestnut), Quercus rubra (red oak), Acer saccharum (sugar maple), and Picea rubens (red spruce). Red spruce demonstrated the highest growth increment and greatest survival (64%) and most consistent results among treatments and habitats. Red spruce survival was not reduced in the presence of Odocoileus virginianus (white‐tailed deer) browse and herbaceous competition; however, growth was improved by suppression of herbaceous competition. We suspect that this deciduous forest landscape would regenerate to a red spruce dominated forest if seed source was available. In contrast, the other three species tested had very low survival when exposed to deer and were more responsive to competing vegetation and habitat type. American chestnut had low survival and growth across all treatments, suggesting basic climate limitations. Vigorous natural regeneration of Prunus serotina (black cherry) occurred in forest plots where both competing herbs and deer were excluded. Our results demonstrated the importance of testing multiple potential recruitment barriers and species at once and the need for species and habitat‐specific restoration treatments.     

Identification of species and materia medica within Angelica L. (Umbelliferae) based on phylogeny inferred from DNA barcodes

DNA barcodes have been increasingly used in authentication of medicinal plants, while their wide application in materia medica is limited in their accuracy due to incomplete sampling of species and absence of identification for materia medica. In this study, 95 leaf accessions of 23 species (including one variety) and materia medica of three Pharmacopoeia‐recorded species of Angelica in China were collected to evaluate the effectiveness of four DNA barcodes (rbcL, matK, trnH‐psbA and ITS). Our results showed that ITS provided the best discriminatory power by resolving 17 species as monophyletic lineages without shared alleles and exhibited the largest barcoding gap among the four single barcodes. The phylogenetic analysis of ITS showed that Levisticum officinale and Angelica sinensis were sister taxa, which indicates that L. officinale should be considered as a species of Angelica. The combination of ITS + rbcL + matK + trnH‐psbA performed slight better discriminatory power than ITS, recovering 23 species without shared alleles and 19 species as monophyletic clades in ML tree. Authentication of materia medica using ITS revealed that the decoction pieces of A. sinensis and A. biserrata were partially adulterated with those of L. officinale, and the temperature around 80 °C processing A. dahurica decoction pieces obviously reduced the efficiency of PCR and sequencing. The examination of two cultivated varieties of A. dahurica from different localities indicated that the four DNA barcodes are inefficient for discriminating geographical authenticity of conspecific materia medica. This study provides an empirical paradigm in identification of medicinal plants and their materia medica using DNA barcodes.     

Geographical origin of Leucobryum boninense Sull. & Lesq. (Leucobryaceae,Musci) endemic to the Bonin Islands,Japan

Leucobryum boninense is endemic to the Bonin Islands, Japan, and its related species are widely distributed in Asia and the Pacific. We aimed to clarify the phylogenetic relationships among Leucobryum species and infer the origin of L. boninense. We also describe the utility of the chloroplast trnK intron including matK for resolving the phylogenetic relationships among Leucobryum species, as phylogenetic analyses using trnK intron and/or matK have not been performed well in bryophytes to date. Fifty samples containing 15 species of Leucobryum from Asia and the Pacific were examined for six chloroplast DNA regions including rbcL, rps4, partial 5′ trnK intron, matK, partial 3′ trnK intron, and trnL‐F intergenic spacer plus one nuclear DNA region including ITS. A molecular phylogenetic tree showed that L. boninense made a clade with L. scabrum from Japan, Taiwan and, Hong Kong; L. javense which is widely distributed in East and Southeast Asia, and L. pachyphyllum and L. seemannii restricted to the Hawaii Islands, as well as with L. scaberulum from the Ryukyus, Japan, Taiwan, and southeastern China. Leucobryum boninense from various islands of the Bonin Islands made a monophylic group that was closely related to L. scabrum and L. javense from Japan. Therefore, L. boninense may have evolved from L. scabrum from Japan, Taiwan, or Hong Kong, or L. javense from Japan. We also described the utility of trnK intron including matK. A percentage of the parsimony‐informative characters in trnK intron sequence data (5.8%) was significantly higher than that from other chloroplast regions, rbcL (2.4%) and rps4 (3.2%) sequence data. Nucleotide sequence data of the trnK intron including matK are more informative than other chloroplast DNA regions for identifying the phylogenetic relationships among Leucobryum species.     

First record of the bacterial endosymbiont Wolbachia for phytophagous hoverflies from genus Merodon (Diptera: Syrphidae)

Wolbachia is a widespread bacterial endosymbiont among arthropod species. It influences the reproduction of the host species and also mitochondrial DNA diversity. Until now there were only a few studies that detected Wolbachia infections in hoverflies (Diptera: Syrphidae), and this is the first broader study with the aim of examining the incidence of Wolbachia in the hoverfly genus Merodon. The obtained results indicate an infection rate of 96% and the presence of both Wolbachia supergroup A and B, which are characteristic for most of the infected arthropod species. Additionally, the presence of multiple Wolbachia strains in the Merodon aureus group species was detected and the mitochondrial DNA COI‐based relationships of the group are discussed in the light of infection. Finally, we discuss plant‐mediated horizontal transmission of Wolbachia strains among the studied hoverfly species.     

Ontogenetic Changes in Carbohydrate Storage and Sprouting Ability in Pioneer Tree Species in Peninsular Malaysia

Sprouting ability is highly variable among different tree species. In many cases, there are trade‐offs in carbon allocations between growth and storage in seedlings. However, this trade‐off is likely to change with growth stages from seedling to mature plant because carbon investments in reproductive activities and/or risk of disturbance also change by species and growth stage. To examine how sprouting ability and carbohydrate storage change with growth stage, we compared two tropical secondary‐forest trees, Macaranga bancana and M. gigantea, which have different ecological traits. Maximum tree size and growth rate are higher in M. gigantea. We monitored sprout growth and stored resources, including total non‐structural carbohydrate (TNC) and nitrogen in the root, among different tree sizes for 12 months following stem‐cutting treatment. Sprouting ability (total sprout mass) and TNC concentrations were significantly higher in small individuals than in larger specimens in both species. TNC concentration decreased in all size classes after stem cutting. Macaranga bancana had greater sprout survivorship than M. gigantea, which had higher sprouting ability in larger tree‐size classes. Thus, sprouting ability likely depends on root TNC concentration and tree‐size class in both Macaranga species. Higher TNC concentration and sprout survival rates in M. bancana may be related to greater carbon allocation in survival than in growth. This hypothesis is consistent with the ecological traits of M. bancana, such as its growth rate, which was lower than that of M. gigantea.     

Effects of an Epiphytic Orchid on Arboreal Ant Community Structure in Panama

Epiphytes are conspicuous structural elements of tropical forest canopies. Individual tree crowns in lowland forests may support more than 30 ant species, yet we know little about the effects of epiphytes on ant diversity. We examined the composition of arboreal ant communities on Annona glabra trees and their interactions with the epiphytic orchid Caularthron bilamellatum in Panama. We surveyed the ants on 73 trees (45 with C. bilamellatum and 28 lacking epiphytes) and recorded their nest sites and behavioral dominance at baits. We found a total of 49 ant species (in 20 genera), ranging 1–9 species per tree. Trees with C. bilamellatum had higher average (±SD) ant species richness (4.2±2.28) than trees without epiphytes (2.7±1.21). Hollow pseudobulbs (PBs) of C. bilamellatum were used as nest sites by 32 ant species, but only 43 percent of suitable PBs were occupied. Ant species richness increased with PB abundance in trees, but nest sites did not appear to be a limiting resource on A. glabra. We detected no close association between ants and the orchid. We conclude that higher ant species richness in the presence of the orchid is due to bottom‐up effects, especially the year‐round supply of extrafloral nectar. The structure of ant communities on A. glabra partly reflects interference competition among behaviorally dominant species and stochastic factors, as observed in other forests.     

Polygyny does not explain the superior competitive ability of dominant ant associates in the African ant‐plant,Acacia (Vachellia) drepanolobium

The Acacia drepanolobium (also known as Vachellia drepanolobium) ant‐plant symbiosis is considered a classic case of species coexistence, in which four species of tree‐defending ants compete for nesting space in a single host tree species. Coexistence in this system has been explained by trade‐offs in the ability of the ant associates to compete with each other for occupied trees versus the ability to colonize unoccupied trees. We seek to understand the proximal reasons for how and why the ant species vary in competitive or colonizing abilities, which are largely unknown. In this study, we use RADseq‐derived SNPs to identify relatedness of workers in colonies to test the hypothesis that competitively dominant ants reach large colony sizes due to polygyny, that is, the presence of multiple egg‐laying queens in a single colony. We find that variation in polygyny is not associated with competitive ability; in fact, the most dominant species, unexpectedly, showed little evidence of polygyny. We also use these markers to investigate variation in mating behavior among the ant species and find that different species vary in the number of males fathering the offspring of each colony. Finally, we show that the nature of polygyny varies between the two commonly polygynous species, Crematogaster mimosae and Tetraponera penzigi: in C. mimosae, queens in the same colony are often related, while this is not the case for T. penzigi. These results shed light on factors influencing the evolution of species coexistence in an ant‐plant mutualism, as well as demonstrating the effectiveness of RADseq‐derived SNPs for parentage analysis.     

Foraging Behavior and Coexistence of Two Sunbird Species in a Kenyan Woodland

We investigated the mechanism of coexistence of the rare Amani Sunbird (Hedydipna pallidigastra) and the widespread Collared Sunbird (H. collaris), within Brachystegia woodland in the Arabuko‐Sokoke Forest, Kenya. We compared how prey abundance and search strategies affect resource exploitation by the two species. We used foraging theory to direct our measures of feeding activities as influenced by sunbird species, tree species and foraging height. We evaluated invertebrate abundance among tree species at different heights within trees. The Collared Sunbird primarily used the understory, and the Amani Sunbird primarily used the upper‐canopy. Overall, the rate of prey attacks per flight of the Amani Sunbird was 2.8 times greater than that of the Collared Sunbird. The Amani Sunbird, however, used increased search and attack rates in the understory compared with the mid‐ and upper‐canopies, but the Collared Sunbird foraged similarly throughout all strata. We hypothesize that the increased foraging rate of the Amani in the understory reflects increased foraging costs due to interference from the Collared Sunbird in that stratum. Furthermore, the Collared Sunbird exploits rich patches by moving frequently from place to place. The Amani Sunbird forages slowly, with reduced travel rates, and with a greater number of prey captures within a patch. Arthropod density did not differ among the vegetative strata, but was higher in Brachystegia spiciformis and Hymenaea verrucosa than in six other tree species. We hypothesize that the Amani Sunbird appears dependent upon continued tall B. spiciformis trees within the canopy of the Arabuko‐Sokoke Forest.     

Utility of mitochondrial‐encoded cytochrome c oxidase I gene for phylogenetic analysis and species identification of the planktonic diatom genus Skeletonema

Small subunit (SSU) and large subunit (LSU) rDNA sequences have been commonly used to delineate the taxonomy and biogeography of the planktonic diatom genus Skeletonema, but the genes occur as multiple copies and are therefore not suitable for barcoding purposes. Here, we analyzed phylogenetic relationships of Skeletonema using the mitochondrial‐encoded cytochrome c oxidase I gene (cox1), as well as partial LSU rDNA (D1–D3) and SSU rDNA, to identify the factors that define species and to evaluate the utility of these three markers for this taxon. Twelve Skeletonema species were divided into six clades, I–VI, each of which comprised the same species by the three markers: clades I (S. japonicum, S. grethae, S. pseudocostatum, and S. tropicum), II (S. menzelii), III (S. dohrnii and S. marinoi), IV (S. costatum, S. potamos, and S. subsalsum), V (S. grevillei), and VI (S. ardens). However, the branching order among these clades was incongruent among the markers. In clade III, six S. marinoi strains had identical cox1 sequences. These S. marinoi strains branched along with S. dohrnii, except for strains from the Gulf of Naples, with high support in cox1. Species delimitation between S. dohrnii and S. marinoi was therefore not supported. In clade IV, S. costatum and S. subsalsum were robustly clustered, with S. potamos as a sister clade in the cox1 tree, not in the LSU and SSU trees. In clade II, cox1 also confirmed that S. menzelii includes three subclades potentially distinguishable from each other by morphological features. Cox1 proved to be the most useful marker for the identification of Skeletonema species because it gave a tree with highly supported clades, has sufficient variation within and among species, encodes a protein in a single copy, and requires relatively few primers.     

Share the wealth: Trees with greater ectomycorrhizal species overlap share more carbon

The mutualistic symbiosis between forest trees and ectomycorrhizal fungi (EMF) is among the most ubiquitous and successful interactions in terrestrial ecosystems. Specific species of EMF are known to colonize specific tree species, benefitting from their carbon source, and in turn, improving their access to soil water and nutrients. EMF also form extensive mycelial networks that can link multiple root‐tips of different trees. Yet the number of tree species connected by such mycelial networks, and the traffic of material across them, are just now under study. Recently we reported substantial belowground carbon transfer between Picea, Pinus, Larix and Fagus trees in a mature forest. Here, we analyze the EMF community of these same individual trees and identify the most likely taxa responsible for the observed carbon transfer. Among the nearly 1,200 EMF root‐tips examined, 50%–70% belong to operational taxonomic units (OTUs) that were associated with three or four tree host species, and 90% of all OTUs were associated with at least two tree species. Sporocarp ¹³C signals indicated that carbon originating from labelled Picea trees was transferred among trees through EMF networks. Interestingly, phylogenetically more closely related tree species exhibited more similar EMF communities and exchanged more carbon. Our results show that belowground carbon transfer is well orchestrated by the evolution of EMFs and tree symbiosis.     

Comparative phylogeographic study of Hosta sieboldiana and Hosta albomarginata (Asparagaceae) in Japan

We analyzed variations in chloroplast DNA (cpDNA) in the widespread herbaceous species Hosta sieboldiana and Hosta albomarginata across large portions of their geographic ranges in the Japanese archipelago. Our objective was to compare the phylogeographic histories and phylogeographic structures of the two congeneric species in the Japanese archipelago. The location of the study is Japanese archipelago. We sequenced 1380 bp of noncoding cpDNA from 45 populations of H. sieboldiana (n = 362) and 55 populations of H. albomarginata (n = 436) to assess genetic variations within and among populations across almost the entire distributions of the species in Japan. Extant patterns of geographic structure were analyzed using statistical parsimony networks and spatial analysis of molecular variance (SAMOVA). We also used Monmonier's algorithm to detect genetic barriers between regions. Relationships between the populations were examined using a neighbor‐joining (NJ) method. Four haplotypes were found for H. sieboldiana, whereas eight haplotypes were identified for H. albomarginata. Total genetic haplotype diversity (hT) and within‐population haplotype diversity (hS) for H. sieboldiana were 0.352 and 0.040, respectively, while the values for H. albomarginata were 0.529 and 0.085, respectively. The population differentiations (GST) for H. sieboldiana and H. albomarginata were 0.839 and 0.886, respectively. The SAMOVA analysis revealed two clusters in H. sieboldiana and four clusters in H. albomarginata. Differentiations between and among the clusters were supported by the BARRIER analysis and the NJ tree. We detected differences in the population genetic structure between the two species. We found that H. sieboldiana had lower haplotype diversity than H. albomarginata. These results may be partially explained by the difference in ecological habitats and geographic distributions between the species. Hosta albomarginata is more widely distributed than H. sieboldiana in East Asia including Russia, and this large distribution range would enable more chances to intraspecific gene flow.     

Recent phylogeographic structure in a widespread ‘weedy’ Neotropical tree species,Cordia alliodora (Boraginaceae)

Aim Although hundreds of tree species have broad geographic ranges in the Neotropics, little is known about how such widespread species attained disjunct distributions around mountain, ocean and xeric barriers. Here, we examine the phylogeographic structure of a widespread and economically important tree, Cordia alliodora, to: (1) test the roles of vicariance and dispersal in establishing major range disjunctions, (2) determine which geographic regions and/or habitats contain the highest levels of genetic diversity, and (3) infer the geographic origin of the species. Location Twenty‐five countries in Central and South America, and the West Indies. Methods Chloroplast simple sequence repeats (cpSSR; eight loci) were assayed in 67 populations (240 individuals) sampled from the full geographic range of C. alliodora. Chloroplast (trnH–psbA) and nuclear (internal transcribed spacer, ITS) DNA sequences were sampled from a geographically representative subset. Genetic structure was determined with samova , structure and haplotype networks. Analysis of molecular variance (AMOVA) and rarefaction analyses were used to compare regional haplotype diversity and differentiation. Results Although the ITS region was polymorphic it revealed limited phylogeographic structure, and trnH–psbA was monomorphic. However, structure analysis of cpSSR variation recovered three broad demes spanning Central America (Deme 1), the Greater Antilles and the Chocó (Deme 2), and the Lesser Antilles and cis‐Andean South America (Deme 3). samova showed two predominant demes (Deme 1 + 2 and Deme 3). The greatest haplotype diversity was detected east of the Andes, while significantly more genetic variation was partitioned among trans‐Andean populations. Populations experiencing high precipitation seasonality (dry ecotype) had greater levels of genetic variation. Main conclusions Cordia alliodora displayed weak cis‐ and trans‐Andean phylogeographic structure based on DNA sequence data, indicative of historical dispersal around this barrier and genetic exchange across its broad range. The cpSSR data revealed phylogeographic structure corresponding to three biogeographic zones. Patterns of genetic diversity are indicative of an origin in the seasonally dry habitats of South America. Therefore, C. alliodora fits the disperser hypothesis for widespread Neotropical species. Dispersal is evident in the West Indies and the northern Andean cordilleras. The dry ecotype harbours genetic variation that is likely to represent the source for the establishment of populations under future warmer and drier climatic scenarios.     

Chemical Composition and Content of Lipophilic Seed Extractives of Some Abies and Picea Species

The chemical content and composition of the lipophilic extracts from seeds of some fir species: Abies alba, A. cephalonica, A. concolor, and A. koreana, as well as of a few spruce species: Picea abies, P. orientalis, and P. pungens, were examined. The amount of lipophilic extractives is diverse among the tree species and it varies from 9.8% to 41% of seeds. The chemical characterization showed significant differences, not only in the content, but also in the composition of extractives. However, most of the identified compounds like resin alcohols, ‐aldehydes, and ‐acids, as well as fatty acids, were detected in the seed extracts of all the examined tree species. The dominating identified compound group was esterified fatty acids (2.5 – 55.4% w/w of dry extract), occurring mainly as tri‐ and diglycerides, as well as free acids. The main representatives of this group were linoleic and oleic acids. The resin acids, among which the main were abietic, neoabietic, dehydroabietic, and palustric acids, were also detected at high levels, from 1.8% to 16.9% of the dry seed extracts. Phytosterols, tocopherols, resin hydrocarbons, and resin esters, as well as fatty alcohols were also identified. The coniferous tree seeds, as a renewable natural material, could represent a prospective raw material for producing valuable chemicals.