Speciation inVirgilia (Fabaceae): Allopatric divergence followed by introgression?

Levels of variation revealed by starch gel-electrophoresis were compared with morphological and chemical variation within and among the species and subspecies ofVirgilia:V. oroboides subsp.oroboides, V. oroboides subsp.ferruginea andV. divaricata. The data sets exhibited concordance in that all point to a very close relationship between the taxa. Differences are mostly quantitative and an overlapping east-west gradient of character variation is indicated. Analysis of morphological and chemical characters showed thatV. oroboides subsp.ferruginea andV. divaricata are relatively distinct, whereas allozyme analysis indicated a high degree of genetic similarity among populations of these two taxa. The observed pattern of variation suggests relatively recent speciation with subsequent introgressive hybridisation resulting in a geographical and ecological gradient.     

Flavonoids and Isoflavonoids of Millettia dura and Millettia ferruginea: Phytochemical review and chemotaxonomic values

The phytochemical information on Millettia dura Dunn, M. ferruginea (Hochst.) Baker and M. ferruginea subsp. darassana (Cufod.) J.B. Gillett was reviewed. All the three taxa elaborate mainly isoflavones (33 reported), occurring in the flowers, seeds/seed pods, stem bark and root bark. Out of the 33 isoflavones reported, some 19 (ca. 58%) contain prenyl at C-8 or its modification as 2,2-dimethylchromene ring at C-7/C-8, occurring in all the three taxa. Except for three isoflavones isolated from M. ferruginea subsp. darassana, all the isoflavones of these taxa are 5-deoxygenated. In these taxa, oxygenation at C-6 is a common feature, while isoflavones with C-8 oxygenation are rare, only three reported, and all of these from M. dura. There are 7 rotenoids reported from these taxa, and occur almost entirely in the seeds/seedpods of these plants. The major rotenoid with methylenedioxy group at C-2/C-3, millettone and its 12a-hydroxy derivative, millettosine, occur only in M. dura, this appears to distinguish M. dura from M. ferruginea.     

Nodules from Fynbos legume Virgilia divaricata have high functional plasticity under variable P supply levels

Legumes have the unique ability to fix atmospheric nitrogen (N₂) via symbiotic bacteria in their nodules but depend heavily on phosphorus (P), which affects nodulation, and the carbon costs and energy costs of N₂ fixation. Consequently, legumes growing in nutrient-poor ecosystems (e.g., sandstone-derived soils) have to enhance P recycling and/or acquisition in order to maintain N₂ fixation. In this study, we investigated the flexibility of P recycling and distribution within the nodules and their effect on N nutrition in Virgilia divaricata Adamson, Fabaceae, an indigenous legume in the Cape Floristic Region of South Africa. Specifically, we assessed tissue elemental localization using micro-particle-induced X-ray emission (PIXE), measured N fixation using nutrient concentrations derived from inductively coupled mass-spectrometry (ICP-MS), calculated nutrient costs, and determined P recycling from enzyme activity assays. Morphological and physiological features characteristic of adaptation to P deprivation were observed for V. divaricata. Decreased plant growth and nodule production with parallel increased root:shoot ratios are some of the plastic features exhibited in response to P deficiency. Plants resupplied with P resembled those supplied with optimal P levels in terms of growth and nutrient acquisition. Under low P conditions, plants maintained an increase in N₂-fixing efficiency despite lower levels of orthophosphate (Pi) in the nodules. This can be attributed to two factors: (i) an increase in Fe concentration under low P, and (ii) greater APase activity in both the roots and nodules under low P. These findings suggest that V. divaricata is well adapted to acquire N under P deficiency, owing to the plasticity of its nodule physiology     

Bark and ambrosia beetles (Curculionidae: Scolytinae), their phoretic mites (Acari) and associated Geosmithia species (Ascomycota: Hypocreales) from Virgilia trees in South Africa

Bark and ambrosia beetles are ecologically and economically important phloeophagous insects that often have complex symbiotic relationships with fungi and mites. These systems are greatly understudied in Africa. In the present study we identified bark and ambrosia beetles, their phoretic mites and their main fungal associates from native Virgilia trees in the Cape Floristic Region (CFR) of South Africa. In addition, we tested the ability of mites to feed on the associated fungi. Four species of scolytine beetles were collected from various Virgilia hosts and from across the CFR. All were consistently associated with various Geosmithia species, fungi known from phloeophagous beetles in many parts of the world, but not yet reported as Scolytinae associates in South Africa. Four beetle species, a single mite species and five Geosmithia species were recovered. The beetles, Hapalogenius fuscipennis, Cryphalini sp. 1, and Scolytoplatypus fasciatus were associated with a single species of Elattoma phoretic mite that commonly carried spores of Geosmithia species. Liparthrum sp. 1 did not carry phoretic mites. Similar to European studies, Geosmithia associates of beetles from Virgilia were constant over extended geographic ranges, and species that share the same host plant individual had similar Geosmithia communities. Phoretic mites were unable to feed on their Geosmithia associates, but were observed to feed on bark beetle larvae within tunnels. This study forms the first African-centred base for ongoing global studies on the associations between arthropods and Geosmithia species. It strengthens hypotheses that the association between Scolytinae beetles and dry-spored Geosmithia species may be more ubiquitous than commonly recognised.     

A detailed study ofCrocus speciosus and its allyC. pulchellus (Iridaceae)

Crocus speciosus is a widely distributed autumn-flowering species showing considerable variation in its morphological characters. Three subspecies are recognised, two of which are endemic to small areas of Turkey. The third, subsp.speciosus, occurs in a much wider area and contains a number of different cytotypes.C. pulchellus is a distinct but closely related species. The morphological relationships between the species and subspecies are discussed and a key to the taxa is provided. Cytological data are given and a distribution map of the cytotypes is provided. A detailed study of the leaf anatomy is presented.     

The Complex Biogeography of the Plant Pathogen Xylella fastidiosa: Genetic Evidence of Introductions and Subspecific Introgression in Central America

The bacterium Xylella fastidiosa is a plant pathogen with a history of economically damaging introductions of subspecies to regions where its other subspecies are native. Genetic evidence is presented demonstrating the introduction of two new taxa into Central America and their introgression into the native subspecies, X. fastidiosa subsp. fastidiosa. The data are from 10 genetic outliers detected by multilocus sequence typing (MLST) of isolates from Costa Rica. Six (five from oleander, one from coffee) defined a new sequence type (ST53) that carried alleles at six of the eight loci sequenced (five of the seven MLST loci) diagnostic of the South American subspecies Xylella fastidiosa subsp. pauca which causes two economically damaging plant diseases, citrus variegated chlorosis and coffee leaf scorch. The two remaining loci of ST53 carried alleles from what appears to be a new South American form of X. fastidiosa. Four isolates, classified as X. fastidiosa subsp. fastidiosa, showed a low level of introgression of non-native DNA. One grapevine isolate showed introgression of an allele from X. fastidiosa subsp. pauca while the other three (from citrus and coffee) showed introgression of an allele with similar ancestry to the alleles of unknown origin in ST53. The presence of X. fastidiosa subsp. pauca in Central America is troubling given its disease potential, and establishes another route for the introduction of this economically damaging subspecies into the US or elsewhere, a threat potentially compounded by the presence of a previously unknown form of X. fastidiosa.     

Phylogenetic analysis and differentiation of Veronica subgenus Stenocarpon in the Balkan Peninsula

The Balkan Peninsula is considered the most important refugium for species during the Pleistocene glaciations and today harbours c. 2000 endemic species, but we know surprisingly little about the evolution of taxa in this region. Veronica saturejoides, V. thessalica and V. erinoides are a group of closely related alpine taxa endemic to the Balkan Peninsula. Here, we analyse four DNA regions [the nuclear chalcone synthase intron (CHSi) and ribosomal internal transcribed spacer (ITS) region and the plastid rpoB‐trnC spacer and trnL‐trnL‐trnF region] and amplified fragment length polymorphism (AFLP) fingerprints to provide a phylogenetic hypothesis for the relationships among these taxa. Additionally, we analyse leaf morphological characters used to distinguish the three subspecies of V. saturejoides. The analyses support the distinction of the three subspecies based on previously intuitively suggested characters. Nuclear chalcone synthase intron data indicate that the southern taxa are genetically much more diverse than the more northern V. saturejoides subsp. saturejoides. Phylogenetic relationships inferred from this region and AFLP fingerprints support the monophyly of V. saturejoides. In contrast, plastid DNA regions suggest a closer relationship of V. saturejoides subsp. saturejoides to V. thessalica. The most likely scenario involves introgression into V. saturejoides subsp. saturejoides from V. thessalica. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 616–636.     

Karyosystematics ofVeronica sect.Beccabunga (Scrophulariaceae) with special reference to the taxa in Turkey

The chromosome numbers ofVeronica beccabunga subsp.abscondita (2n=18),V. anagallis-aquatica subsp.lysimachioides (2n=18),V. anagallis-aquatica subsp.michauxii (2n=36), and of a presumable hybridV. poljensis × V. anagalloides (2n=36) are new for the relevant taxa. — A new number was found forV. anagalloides subsp.heureka (2n=18). The other counts, ofV. scardica (2n=18),V. anagalloides subsp.anagalloides (2n=18), andV. anagallis-aquatica subsp.oxycarpa (2n=36) agree with earlier findings.—Data from the literature have been critically evaluated, in some cases the relevant vouchers have been checked and, where needed, the original determinations have been revised. For several taxa, comments concerning their systematics and remarks on their distribution in Turkey are given.     

Taxonomic status of the subspecies of Teucrium lamiifolium in Turkey: reevaluation based on macro‐ and micro‐morphology,anatomy and chemistry

Teucrium stachyophyllum P. H. Davis was first described as a separate species in the ‘Syrian, Lebanon and Palestine Flora’, but was reduced to a subspecies of T. lamiifolium d’Urv. in the ‘Turkish Flora’. Studies on the macro‐ and micro‐morphology as well as the anatomy of populations of T. lamiifolium subsp. stachyophyllum (P. H. Davis) Hedge & Ekim and T. lamiifolium subsp. lamiifolium in Turkey have been carried out based on herbarium specimens and field observations. The results from the anatomical studies on stems and leaves show that although the two taxa are similar in stem anatomy, they differ in terms of mesophyll thickness and occurrence of crystals in the upper epidermal cells of the leaf. Light and scanning electron microscope analyzes revealed striking differences in colour, size, sculpture and gland density between nutlets of the two taxa. Morphological studies also showed that there were important differences between the two taxa in terms of inflorescence, indumentum, and stem length and thickness. In addition, the essential oils from aerial parts of T. lamiifolium subsp. stachyophyllum and T. lamiifolium subsp. lamiifolium were isolated by steam distillation and analysed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The major components were characterized as β‐caryophyllene (23.5–44.8%), trans‐β‐bergamotene (22.4–26.4%), germacrene D (22.2%) and (Z)‐β‐farnesene (14.0%) for subp. lamiifolium and trans‐β‐bergamotene (38.1–41.1%) and β‐caryophyllene (8.7–8.9%) for subsp. stachyophyllum, respectively. As a result of the studies, it is proposed that the taxon treated as T. lamiifolium subsp. stachyophyllum in the Turkish flora should be raised to specific rank as T. stachyophyllum.     

A taxonomic revision of the Antennaria media (Asteraceae: Inuleae) polyploid species complex in western North America

TheAntennaria media polyploid species complex has been evaluated, at least in part, on numerous occasions without consensus on either the taxa that should be included within the complex or the rank at which these taxa should be recognized. The primary purpose of this quantitative, multivariate, phenetic study is to propose a taxonomy for the polyploid species complex that not only is independent of a knowledge of either chromosome number or reproductive biology but that concurrently minimally reflects morphological variation associated with each. The use of canonical discriminant analysis facilitates this purpose. In an attempt to maintain consistency with other recent revisions of polyploid complexes within the genus, the rank of subspecies (A. media subsp.media, A. media subsp.ciliata, A. media subsp.compacta, A. media subsp.fusca, andA. media subsp.pulchella) is selected as the infraspecific rank that satisfies the purpose of the phenetic study and is supported by the analyses. These subspecies differ to varying degrees with respect to reproductive characters (corolla length, pappus length), vegetative-reproductive characters (involucre length, peduncle length, cauline leaf length, cauline leaf width), and vegetative characters (basal leaf length and basal leaf width).Antennaria media subsp.pulchella is a sexually reproducing, diploid subspecies, whereas the remaining four subspecies are essentially agamospermous polyploids.     

Effect of anatomical structure on the buoyancy of achenes of two subspecies ofBolboschoenus maritimus

Differences between two subspecies ofBolboschoenus maritimus (L.)Palla (=Scirpus maritimus L.) in different habitats (littoral and terrestrial) are partly due to variations in the buoyancy of their achenes, caused by different anatomical structure of the fruits. This hypothesis was tested by comparing fruit buoyancy and anatomy of both subspecies at several localities. Plants were sampled fromBolboschoenus maritimus subsp.maritimus (plants with branched inflorescences and triangular fruits, 4 localities) andB. maritimus subsp.compactus (Hoffm.)Hejný (plants with compact inflorescences and prevailing concave fruits, 4 localities) in the Czech and Slovak Republics, andB. maritimus subsp.compactus (plants with compact inflorescences and convex fruits, 1 locality) from the coast of South Sweden. From each locality a plant with several tubers connected by rhizomes was taken and transferred into the experimental garden; from these cultivated plants (clones) mixed samples of fruits collected from each clone were used for buoyancy tests and a study of their anatomy. Fruit buoyancy was found to depend on the anatomical structure of the pericarp—the presence of aeriferous tissue in the exocarp serves as the main floating organ. This differentiated all plants studied into two groups: short-floating subsp.maritimus, with a thin or none acriferous tissue in the exocarp, and long-floating subsp.compactus with well developed aeriferous tissue. Differences in fruit buoyancy corresponds to differences in the prevailing habitat types of both subspecies studied in the inland sites: the frequent occurrence of subsp.compactus in temporarily flooded terrestrial habitats contrasts with the prevalence of subsp.maritimus in the littoral of water bodies. This is an example of intra-specific ecological differentiation leading to differentiation in wetland communities.     

Electrophoretic study of isozyme patterns in some wild populations of Aubrieta columnae Guss. (Cruciferae)

Aubrieta columnae Guss. is currently divided into three subspecies: A. columnae subsp. columnae, A. columnae subsp. italica, both found as isolated and fragmented populations in rocky habitats of Central and Southern Apennines (Italy), and A. columnae subsp. croatica found in the Balkan region. In order to gain information about the degree of genetic variability and to clarify taxonomic relationships among these taxa, we studied the isozyme patterns at 8 marker loci of 376 individuals from 8 populations by means of starch gel electrophoresis. Data analysis by using Wright's F-statistics and UPGMA clustering method was performed. The results show: 1) a general deviation from Hardy–Weinberg equilibrium within each subspecies; 2) a lesser genetic variation in populations occurring in habitats characterized by milder climatic conditions and relatively small seasonal variations; 3) a relatively high degree of differentiation between the three subspecies; 4) the possible common transadriatic origin of A. columnae subsp. italica and A. columnae subsp. croatica; 5) the possible origin of A. columnae subsp. columnae from A. columnae subsp. italica; and 6) that the current taxonomic status of A. columnae may be substantially confirmed, even if the findings are from a limited number of loci explored.     

A taxonomic revision of the Antennaria rosea (Asteraceae: Inuleae: Gnaphaliinae) polyploid complex

TheAntennaria rosea species complex is circumscribed to contain four subspecific taxa. A complete synonymy and key to the subspecies ofA. rosea is presented. The following new combinations are proposed:Antennaria rosea subsp.arida (E. Nels.) R. Bayer,A. rosea subsp. confinis (Greene) R. Bayer, andA. rosea subsp. pulvinata (Greene) R. Bayer. The affinities ofA. rosea to other species ofAntennaria are discussed and a key to separateA. rosea from related polyploid complexes is provided.     

Reproductive isolation of two sympatric subspecies ofJuniperus phoenicea (Cupressaceae) in southern Spain

The phenology, reproductive cycle and cone crop of two sympatric subspecies ofJuniperus phoenicea (Cupressaceae) were studied during three consecutive years in southern Spain. The flowering pattern of each subspecies was constant during this period: inJ. phoenicea subsp.turbinata flowering was always in October–November, whileJ. phoenicea subsp.phoenicea flowered in February–March. There was no overlap between the flowering periods of the two taxa. The reproductive cycle of the two subspecies was similar, though there were some important differences because of their flowering times. Male cone development in both subspecies occurred in autumn, but the male cones ofJ. phoenicea subsp.phoenicea did not shed pollen until the end of February. InJ. phoenicea subsp.turbinata, the gap between pollination and fertilisation was seven months while inJ. phoenicea subsp.phoenicea it was only three months, fertilisation taking place at the same time in the two taxa. Post-fertilisation events were similar in the two subspecies, leading to a cycle of two years inJ. phoenicea subsp.turbinata and a shorter one of about 20 months inJ. phoenicea subsp.phoenicea. Alternating good and slight seed cone crops were found in both taxa during the three years studied, the good crops of one subspecies coinciding with the slight crops of the other one. Although the proximity of the two subspecies and method of pollination could make hybridisation between the taxa possible, the different flowering seasons prevent hybridisation isolating them reproductively.     

Variability of perigynium morphology of Central European members of Carex sect. Phaestoglochin (Cyperaceae) from variable plant communities

The number and range of taxa belonging to the Central European section Phaestoglochin (Carex L.) differ significantly among systematic classifications. Our study revealed that all of the quantitative morphological features of perigynia of Carex spicata Huds., Carex muricata subsp. muricata L., Carex muricata subsp. lamprocarpa ?elak., Carex divulsa subsp. divulsa Stokes, and Carex divulsa subsp. leersii Koch., had statistically significant differences among taxa. However, this differentiation did not reflect the known taxonomic divisions of the group and therefore, it did not represent a determining criterion for distinguishing the particular taxa. It also did not confirm the close and significant connections between subspecies within the species studied. Based on morphological features of perigynia, we showed that C. divulsa is a well-distinguished taxon, while the other taxa form a complex group. Analysis of the differentiation of perigynium features among the taxa studied against the background of the plant communities where the plants were grown indicated a distinct effect of the habitat conditions on the morphological features of perigynia.     

Comparison of Salmonella enterica Serovar Typhimurium LT2 and Non-LT2 Salmonella Genomic Sequences, and Genotyping of Salmonellae by Using PCR

Genes of Salmonella enterica serovar Typhimurium LT2 expected to be specifically present in Salmonella were selected using the Basic Local Alignment Search Tool (BLAST) program. The 152 selected genes were compared with 11 genomic sequences of Salmonella serovars, including Salmonella enterica subsp. I and IIIb and Salmonella bongori (V), and were clustered into 17 groups by their comparison patterns. A total of 38 primer pairs were constructed to represent each of the 17 groups, and PCR was performed with various Salmonella subspecies including Salmonella enterica subsp. I, II, IIIa, IIIb, IV, VI, and V to evaluate a comprehensive DNA-based scheme for identification of Salmonella subspecies and the major disease-causing Salmonella serovars. Analysis of PCR results showed that Salmonella enterica subsp. I was critically divided from other subspecies, and Salmonella strains belonging to S. enterica subsp. I were clustered based on their serovars. In addition, genotypic relationships within S. enterica subsp. I by PCR results were investigated. Also, Salmonella signature genes, Salmonella enterica serovar Typhimurium signature genes, and Salmonella enterica subsp. I signature genes were demonstrated based on their PCR results. The described PCR method suggests a rapid and convenient method for identification of Salmonella serovars that can be used by nonspecialized laboratories. Genome sequence comparison can be a useful tool in epidemiologic and taxonomic studies of Salmonella.     

New Middle Devonian conodont data from the Dong Van area,NE Vietnam (South China Terrane)

Middle Devonian conodonts from the Si Phai section in NE Vietnam are described. The section ranges from the Middle Devonian ensensis to timorensis conodont zones to the Late Devonian rhomboidea conodont Zone. A rich overall assemblage is described, including 27 taxa of species or subspecies rank and 11 taxa described in an open nomenclature. Among the dominant Polygnathus forms, four new taxa are described: Polygnathus linguiformis saharicus subsp. nov., Polygnathus linguiformis vietnamicus subsp. nov., Polygnathus rhenanus siphai subsp. nov., and Polygnathus xylus bacbo subsp. nov. Conodont assemblages are attributed to polygnathid, polygnathid-klapperinid, and klapperinid conodont biofacies representing hemipelagic to pelagic environments. The klapperinid biofacies, unreported in the previous literature, are here attributed to offshore areas of the external shelf. The taxonomic compositions of the studied conodont assemblages, as well as their CAI characteristics (CAI 4–5), suggest a palaeogeographic affinity of the studied strata to the Chinese Devonian Guangxi Basin, and the South China Terrane in general. Furthermore, the conodont biofacies and the palaeogeographic distribution of the fauna are discussed.     

Assessment of Daucus carota L. (Apiaceae) subspecies by chemotaxonomic and DNA content analyses

For a clearer distinction between the four subspecies of Daucus carota native from Portugal (subsp. carota, subsp. maximus, subsp. gummifer and subsp. halophilus), morphological features of the fruits, DNA content analyses by flow cytometry, and chemical characterization of the essential oils were undertaken.We found chemotaxonomic evidences to consider D. carota subsp. maximus as a separate species rather than a subspecies of D. carota. This separation is based on the morphometric analysis of the fruits and in the high levels of asarone present only in the essential oil of the subsp. maximus. The remaining subspecies are difficult to distinguish from each other based on the morphology of the fruits and in DNA content. However, based on the essential oils, it was possible to distinguish the subspecies halophilus from the other two (subsp. gummifer and subsp. carota) because of its high content of elemicin, with the other two having high levels of geranyl acetate.Based on these results, the subspecies maximus is proposed as a different species (Daucus maximus Desf.) and the taxonomic status of other three subspecies (subsp. carota, subsp. gummifer and subsp. halophilus) is maintained. Still, the latter three taxa need to be further studied for a more precise taxonomic characterization.