Showing papers in "Taxon in 2005"

Phylogeny and classification of Pinus

Abstract: We used chloroplast DNA sequences from matK and rbcL to infer the phylogeny for 101 of the approximately 111 species of Pinus (Pinaceae). At the level of subsection and above, the cpDNA tree is congruent with phylogenies based on nuclear DNA with one notable exception: cpDNA sequences from subsect. Contortae are sister to all other North American hard pines rather than occupying a more derived position in the same clade. We used the cpDNA tree plus evidence from nuclear ribosomal DNA and morphology to propose a new classification for the genus. The molecular phylogenies are symmetrical at the deepest branches of the genus, allowing for the delineation of two subgenera, each with two sections that form sister groups. Within sections, clades were slightly asymmetric and sometimes ambiguously resolved. To accomodate ambiguity in some interrelationships, avoid the creation of new ranks, and retain traditional names, we recognised up to three monophyletic subsections per section. Subgenus Pinus (the diploxylon, or hard pines) is divided into the predominantly Eurasian and Mediterranean section Pinus, composed of subsections Pinus and Pinaster, and the strictly North American section Trifoliae, composed of subsections Australes, Ponderosae, and Contortae. Subgenus Strobus (the haploxylon, or soft pines) is divided into the strictly North American section Parrya, composed of subsections Cembroides, Nelsoniae, and Balfourianae, and the Eurasian and North American section Quinquefoliae, composed of subsections Gerardianae, Krempfianae, and Strobus. Mapping of ten morphological and distributional characters indicates that two were diagnostic for infrageneric taxa: the number of vascular bundles per leaf distinguishes subgenus Pinus from subgenus Strobus, and a terminal-positioned umbo on the ovulate cone scale is diagnostic of subsect. Strobus.

Vicariance and dispersal in the alpine perennial Bupleurum stellatum L. (Apiaceae)

Abstract: Using Amplified Fragment Length Polymorphism (AFLP), we explored the intraspecific phylogeography of the alpine vascular plant Bupleurum stellatum (Apiaceae), disjunctly distributed in the Alps and Corsica. Within the Alps, the species’ distribution area is also not contiguous, spatially isolated groups of populations occuring in the Dolomites (Italy) and the Montafon (Austria). A main goal of our study was to explore the degree of differentiation of the isolated populations in Corsica, the Dolomites and the Montafon from the populations in the main distributional area and to test for hypotheses of vicariance or dispersal. We also sought a better general knowledge of glacial refugia of low alpine silicicolous plants. Phenetic as well as cladistic analyses of the AFLP multilocus phenotypes reveal a substantial north-south split through the contiguous distribution area of B. stellatum in the Alps. The resulting phylogeographic groups can be related to glacial refugia in peripheral areas of the Alps that were recognised in previous studies. The disjunct populations in Corsica, the Dolomites and the Montafon, however, are less strongly differentiated. For example, the Corsican population clustered with high bootstrap support with populations from the Eastern Alps, suggesting immigration to Corsica from that region. Our study shows that deep phylogeographic splits resulting from old vicariance events can be concealed by presently contiguous distribution areas. In contrast, disjunctions, if they are due to dispersal events, need not be accompanied by genetic divergence.

Climate changes and tree phylogeography in the Mediterranean

Abstract: The Mediterranean Basin is expected to be more strongly affected by ongoing global climate change than most other regions of the earth. Given the magnitude of forecasted trends, there are great concerns for the particularly rich biodiversity found in the region. Studies of the consequences of past climate shifts on biodiversity represent one of the best sources of data to validate models of the ecological and evolutionary consequences of future changes. Here we review recent findings from palaeoecology, phylogeography and climate change research to (1) explore possible antecedents of the predicted climate warming in the younger geological history of the Mediterranean Basin, (2) assess how tree populations have reacted to them, and (3) evaluate the significance of the evolutionary heritage that is at stake. A major question of our retrospective approach is whether Quaternary tree extinctions took place primarily during glacial or during interglacial episodes. Available data are scanty and somewhat conflicting. In contrast, abundant phylogeographic evidence clearly indicates that the bulk of genetic diversity in European temperate tree species is almost invariably located in the southernmost part of their range. Long-term persistence of isolated populations have been common phenomena in the Mediterranean, to the point that the current genetic structure in this area probably often reflects population divergence that pre-dates the onset of the Mediterranean climate in the Pliocene. In particular, Tertiary migrations into the Mediterranean of tree taxa originating from Asia seem to have left their footprints in the current genetic structure in these slowly evolving organisms. Moreover, phylogeographic studies point to heterogeneous rates of molecular evolution across lineages that are inversely related with their stability. We conclude that relict tree populations in the Mediterranean Basin represent an evolutionary heritage of disproportionate significance for the conservation of European plant biodiversity.

Comparison of AFLPs with other markers for phylogenetic inference in wild tomatoes [Solanum L. section Lycopersicon (Mill.) Wettst.]

Abstract: ac.uk Wild tomatoes (Solanum section Lycopersicon) are native to western South America. The delimitation and relationships of tomato species have differed widely depending upon whether morphological or biological species concepts are considered more important. Molecular data from mitochondrial, nuclear, and chloroplast DNA restriction fragment length polymorphisms (RFLPs), nuclear microsatellites, isozymes, and gene sequences of internal transcribed spacers of nuclear ribosomal DNA (ITS; multiple-copy), the single-copy nuclear encoded Granule-bound Starch Synthase gene (GBSSI or waxy), and morphology, have been used to examine hypotheses of species relationships. This study is a companion to the previous GBSSI gene sequence study and to the morphological study of relationships of all ten wild tomato species (including the recently described S. galapagense), with a concentration on the most widespread and variable species S. peruvianum s.l. These new AFLP data are largely concordant with the GBSSI and morphological data and in general support the species outlined in the latest treatment by C.M. Rick, but demonstrate the distinct nature of northern and southern Peruvian populations of S. peruvianum, and suggest that their taxonomy needs revision. Solanum ochranthum is supported as sister to wild tomatoes, and S. habrochaites and S. pennellii reside in a basal polytomy in the tomato clade.

Further disintegration of Scrophulariaceae

Abstract: A phylogenetic study of plastid DNA sequences (ndhF, trnL/F, and rps16) in Lamiales is presented. In particular, the inclusiveness of Scrophulariaceae sensu APG II is elaborated. Scrophulariaceae in this sense are mainly a southern hemisphere group, which includes Hemimerideae (including Alonsoa, with a few South American species), Myoporeae, the Central American Leucophylleae (including Capraria), Androya, Aptosimeae, Buddlejeae, Teedieae (including Oftia, Dermatobotrys, and Freylinia), Manuleeae, and chiefly Northern temperate Scrophularieae (including Verbascum and Oreosolen). Camptoloma and Phygelius group with Buddlejeae and Teedieae, but without being well resolved to any of these two groups. Antherothamnus is strongly supported as sister taxon to Scrophularieae. African Stilbaceae are shown to include Bowkerieae and Charadrophila. There is moderate support for a clade of putative Asian origin and including Phrymaceae, Paulownia, Rehmannia, Mazus, Lancea, and chiefly parasitic Orobanchaceae, to which Brandisia is shown to belong. A novel, strongly supported, clade of taxa earlier assigned to Scrophulariaceae was found. The clade includes Stemodiopsis, Torenia, Micranthemum and probably Picria and has unclear relationships to the rest of Lamiales. This clade possibly represents the tribe Lindernieae, diagnosed by geniculate anterior filaments, usually with a basal swelling.

Is there really more biodiversity in Mediterranean forest ecosystems

Abstract: The Mediterranean Basin accounts for more than 10% of the world's vascular plant biodiversity in an area less than 1.5% the size of continental Earth. Forest tree taxa are also exceptionally diverse: more than 100 specieshave been recorded around the Mediterranean, but less than 30 species can be found in Temperate Europe. This amazing biodiversity was developed over millions of years due to the highly heterogeneous geology and climate of the Mediterranean. Did these factors also affect biodiversity within species, i.e., the genetic diversity of populations? Heterozygosity (the within-population gene diversity), and differentiation (the among-population spatial genetic structure), of neutral genes (isozymes) were used to measure within-species biodiversity in four conifer genera commonly found in the Mediterranean: Abies Mill., Cedrus Trew, Cupressus L., Pinus L. Their within-species biodiversity was significantly higher than that of other conifer species worldwide and did not correspond to expected values in terms of biogeography or levels of endemism. Gene diversity was significantly higher in the Eastern than in the Western Mediterranean Basin, and, surprisingly, was only mildly affected by human impact. A specific post-glacial recolonization model is proposed for the Mediterranean Basin, in which effective glacial refugia are more numerous, and genetic drift is less, than what is proposed for Europe. The within-species approach to biodiversity can help solve taxonomic questions, and when used as an indicator of evolutionary potentials, is an essential component of conservation strategies.

On resurrection of the families Pseudoleskeaceae Schimp. and Pylaisiaceae Schimp. (Musci, Hypnales)

Abstract: Results from our analysis of chloroplast trnL-trnF and nuclear ITS1 and ITS2 sequence data and 35 morphological characters for 134 taxa of pleurocarpous mosses provide an evidence for resurrecting two moss families, Pseudoleskeaceae and Pylaisiaceae. Both these families were described by Schimper in 1860, but soon afterwards included in Leskeaceae and Hypnaceae, respectively, and apparently never used in the 20 t h century. However, sequence-level data analysis (chloroplast encoded trnL intron and trnL-trnF spacer, nuclear encoded ITS1 & ITS2), and combined molecular and morphological analysis demonstrate the remote position of (1) the Lescuraea-group from the main part of Leskeaceae; and (2) a group of species belonging to Pylaisia, Homomallium and Hypnum (sections others than sect. Hypnum} from Hypnum sect. Hypnum (with H. cupressiforme as the type of the genus).

Phylogenetic relationships and biogeography of Ranunculus and allied genera (Ranunculaceae) in the Mediterranean region and in the European Alpine System

Abstract: Ranunculus s.l. shows a considerable species diversity and degree of endemism in the Mediterranean region and occurs with various life forms from the lowlands to the highest mountains. Based on a sampling from all continents, sequences of the ITS of nrDNA, the plastid matK, and the adjacent trnK regions were analysed using maximum parsimony and Bayesian inference. Both separate and combined analyses of the two datasets yielded a large core clade of Ranunculus excluding Ficaria, Coptidium, and the extraeuropean genera Beckwithia, Callianthemoides, Halerpestes, and Peltocalathos. The Ceratocephala-Myosurus-clade is sister to the core Ranunculus in the plastid and the combined datasets on very long branches, thus supporting a classification of Ceratocephala and Myosurus as separate genera. Within Ranunculus s.s., eight well supported and highly consistent clades correspond either to widespread ecological groups (wetlands, high altitudes/latitudes) or to regional (mainly European) geographical groups. Alpine Mediterranean buttercups belong to orophytic clades, most species of which also occur in the European alpine system; others show widespread northern hemisphere distributions. Only one Mediterranean clade is restricted to the Iberian Peninsula and adjacent regions. Present distribution patterns and molecular data support a hypothesis of an origin of alpine buttercups from lowland ancestors of the same geographical region. At lower altitudes, the predominant life forms, i.e., therophytes and geophytes, evolved multiple times suggesting parallel adaptations to the Mediterranean climate. Geophytes differentiated into an eastern and western Mediterranean group, and are most closely related to the subalpine, non-monophyletic "R. montanus" group, thus supporting a hypothesis of a common lowland ancestor. Tentative estimates for divergence times of the major clades in Ranunculus s.l. were made based on an age calibration for the Ranunculus-Xanthorhiza-split, using matK sequences and penalized likelihood analyses. The results from this study suggest that the split of allied genera from Ranunculus s.s. occurred during the Eocene and Oligocene, with the core clade of Ranunculus being c. 24.0 Myr old. Diversification of Ranunculus s.s. into main ecological/geographical clades took place in the late Miocene, and speciation within the Mediterranean groups during the Pliocene and Pleistocene. Diversification of life forms at lower altitudes occurred mainly during or after the establishment of the Mediterranean climate. Island endemics of Macaronesia and Crete are probably rather young descendents of neighbouring geographical groups. Diversification of alpine groups took place at different geological times, but is in general correlated with periods of colder climate. The high diversity of buttercups is likely a consequence of the broad spectrum of different habitats in the Mediterranean region.

XVII International Botanical Congress: preliminary mail vote and report of Congress action on nomenclature proposals

Abstract: A preliminary guiding mail vote on nomenclature proposals is required by Provision 4(a) of Division III (Provisions for the Governance of the Code) of the International Code of Botanical Nomenclature (McNeill & al. in Regnum Veg. 146. 2006). A “Synopsis of Proposals” was published in Taxon 60: 243–286. 2011. Ballot forms were distributed with the February 2011 issue of Taxon to all individual members of the International Association for Plant Taxonomy (IAPT) and mailed from Vienna in early March to other persons who were either members of a permanent nomenclature committee or authors of proposals. The deadline for return of ballots was 31 May 2011. All ballots received by that date were included in the vote count. Out of approximately 1400 ballots distributed, 140 valid ballots (10%) were returned. There were no ballots returned unsigned so none had to be disregarded. Submission was by mail (112), by fax (12), or as scanned attachments to e-mails (16). Although electronic submission was not confined to fax (as for the Vienna Congress) there was no change in the proportion using electronic means and the majority of ballots (80% of those returned) continued to be submitted in hard copy by regular mail. In all, 338 proposals to amend the Code at the Melbourne Congress were published in advance, summarized in the “Synopsis of Proposals” and included in the preliminary mail vote, by a small margin the largest number at any Congress since the Paris Congress in 1954 (see Table 1). Apart from a block of 26 proposals for editorial modification of the Glossary (App. VII), there were no special circumstances surrounding the proposals so it would seem that the general trend toward fewer proposals suggested in the report on the decisions in Vienna (McNeill & al. in Taxon 54: 1057–1064. 2005) has not been maintained. Of the 338 proposals, 190 were single-authored, 79 had two authors, 58 had three or more authors, and 11 came from The Special Committee on Electronic Publication. The tabulation below (Table 4 on p. 5 ff.) gives the result of the preliminary mail vote for each proposal, in the XVIII International Botanical Congress: Preliminary mail vote and report of Congress action on nomenclature proposals

Temporal and spatial diversification of Circum‐Mediterranean Compositae‐Anthemideae

Abstract: A combination of dispersal-vicariance analysis (DIVA) and molecular clock dating of a calibrated, ratesmoothed maximum-likelihood tree based on sequence information from the internal transcribed spacer region of the ribosomal repeat (nrDNA ITS) was used to reconstruct the biogeographical history of the Circum-Mediterranean clade of Compositae-Anthemideae. The reconstructions suggest that the ancestor of this clade diverged from the basal African lineages in the late Early Miocene (18 Myr), presumably in conjunction with the collision of the African and Eurasian platform through the Arabian plate. Recurrent dispersal/vicariance events during the Middle and Late Miocene (16–11 Myr) both between the eastern and western Mediterranean regions and (in the latter region) between the northern and southern Peri-Tethys platforms caused the further diversification of the clade and may have been triggered by episodes of marine regression/transgression events on the Eurasian platform and in the area of the Strait of Gibraltar, respectively. The analyses further show that both the western part of the North African platform and the Anatolian region played a paramount role in the radiation of different subclades of the Circum-Mediterranean Anthemideae, leading to the present day genus-richness of the western subclade and to the species-richness in the large genera (Achillea, Anthemis, Cota, Tanacetum, Tripleurospermum) of the eastern subclade. Whereas in the present analyses these radiations are reconstructed as sympatric speciation events, they may actually correspond to allopatric speciation events on a finer geographical scale within the two main centres of diversification (NW Africa, Anatolia). The Messinian salinity crisis (5.96–5.33 Myr) and the following re-inundation of the Mediterranean basin (Early Pliocene) triggered dispersal/vicariance events observable today on the level of species or species groups, as did the climatic changes during the Pleistocene.

Ecological differentiation of Mediterranean endemic plants

Abstract: A striking feature of the Mediterranean flora concerns the high rates of narrow endemism within many regions. The prevailing paradigm for the evolution of such endemism relies on an important role of geographic isolation and allopatric speciation. Until recently there has been little work on the precise ecological differences among endemic plants and their congeners in the Mediterranean region and the potential role of ecological specialisation in isolation and speciation. This paper has two objectives. First, we evaluate general ecological differences among endemic and widespread congeners in the flora of the western Mediterranean. The results and review of the literature attest to consistent patterns of ecological differentiation among endemic species and their snore widespread congeners. Second, we present results of a detailed study of morphological, molecular and ecological differentiation in a group of spring-flowering Mediterranean Cyclamen species. This study illustrates how differentiation in geographically peripheral and ecologically marginal populations may contribute to the diversification of endemic species whose contemporary distributions are disjunct from con-generic species.

IUCN Red List assessment and the Global Strategy for Plant Conservation: taxonomists must act now

Abstract: The Global Strategy for Plant Conservation (GSPC) sets a series of ambitious targets for 2010 to stem the loss of plant diversity. Target 2 calls for a preliminary assessment of the conservation status of all known plant species, at national, regional and international levels, but with less than 3% of global diversity assessed to date, the process must be greatly accelerated. This can best be done by mobilizing plant taxonomists to identify species that are threatened (or potentially threatened) using available distribution data from herbaria and other sources, and by including preliminary IUCN Red List assessments in all their taxonomic works. Emphasis should be placed on rare taxa with restricted ranges, which are the most likely to be at risk. Sufficient data are available for preliminary assessment of nearly all species, thereby limiting the number that must be relegated to "data deficient" status (DD). The taxonomic community can play a unique role in fulfilling the GSPC goals, but we must act quickly.

Terrestrial growth and marine dispersal? Comparative phylogeography of five coastal plant species at a European scale

Abstract: The phylogeography of five flowering plant species (Cakile maritima, Eryngium maritimum, Salsola kali, Halimione portulacoides, Crithmum maritimum) widespread along the European coasts was investigated across their entireEuropean range using AFLP evidence. Both similarities and dissimilarities were found. All species contain a distinct Black Sea/Aegean Sea cluster, and all except E. maritimum contain a distinct Adriatic Sea cluster or group of genetically very similar clusters. All species except Cr. maritimum contain a distinct Atlantic Ocean/North Sea/Baltic Sea cluster clearly separate from the Mediterranean material. In Ca. maritima a distinct Baltic Sea subcluster was found. In the western Mediterranean, two species groups can be recognized. Whereas in S. kali and E. maritimum material from this area falls into only one cluster or a group of genetically very similar clusters, it falls into two clusters or groups of clusters of either more Atlantic or more central Mediterranean similarity in Ca. maritima, H. portulacoides and Cr. maritimum. Similarities and dissimilarities in patterns found are discussed in terms of a combination of historical and extant abiotic and biotic factors. Thus, the distribution range of all species in the eastern Mediterranean area was not affected by Quaternary temperature changes, resulting in phylogeographic congruency here. The existence of distinct Black Sea/Aegean Sea and Adriatic Sea clusters or groups of clusters is the result of sea currents isolating these regions from each other. In the western Mediterranean basin the more cold-sensitive species (H. portulacoides, Cr. maritimum) but not the less cold-sensitive species (S. kali, E. maritimum) had to retreat from northern coasts. Re-colonization of these areas from two different directions is implied by their phylogeographic pattern. The existence of a distinct Gibraltar gap is explained in terms of extant sea currents. Comparison of phylogeographic patterns found with those observed in either marine or terrestrial organisms leads to the conclusion that marine dispersal is of overriding importance in these coastal plants.

Hanskerpia gen. nov. and phylogenetic relationships among the most ancient conifers (Voltziales)

Abstract: A new fossilized walchian (Voltziales) conifer plant from the Late Pennsylvanian Hamilton Quarry of Kansas, U.S.A. combines morphological characters of the morphogenus Walchia and the fossil plant genus Otovicia, with cuticular characters like those of the fossil plant genus Ernestiodendron, and seed cone morphology like that of the fossil plant genus Emporia. Internal anatomical characters are basically similar to the other walchian genera for which such features are known, but some are taxonomically informative. Numerical cladistic analysis reveals that this novel combination of characters defines a new fossil plant genus and species of walchian conifers Hanskerpia hamiltonensis. This analysis provides a test of hypotheses for relationships among walchian and other ancient conifers. Results of this analysis support some previously proposed relationships among the most primitive conifers and other Paleozoic coniferophytes. However, the analysis also calls to question the validity of all previously proposed familial circumscriptions for walchian conifers, and highlights the perplexing systematic challenges posed by the most ancient fossil conifers. The unexpected species richness of voltzialean conifers is interpreted as having resulted from the evolutionary ecology of unstable environments.

Polyphyly of the genus Micromeria (Lamiaceae)-evidence from cpDNA sequence data

Abstract: Micromeria Benth. (Lamiaceae, Nepetoideae) is a very common genus in the Mediterranean region. To test the monophyly of the genus and to elucidate its phylogenetic placement within subtribe Menthinae (Dumort) Endl. of tribe Mentheae Dumort we performed parsimony analysis of trnK intron sequence data of 51 accessions representing 15 genera of Nepetoideae and two genera of subfamily Ajugoideae. Tree topology reveals a well-supported "core group" indicating four distinct lineages. The first one comprises three species of Satureja L. s.str., the second one includes taxa of the genus Clinopodium L. from both the Old and the New World, paraphyletic with respect to Monarda L. and two species of Micromeria section Pseudomelissa Benth. A third group contains all samples of the remaining Micromeria species. Within this monophyly, a western lineage including taxa from NW Africa, the Balearic, and the Canary Islands, is sister to an eastern lineage with species distributed from SE Asia to the western Mediterranean. In a further clade the genera Thymbra L., Thymus L., and Origanum L. are grouped together. Combined analysis using a reduced dataset of trnK/trnL-F sequences increased support for the infrageneric resolution within Micromeria. Based on the phylogenetic reconstructions there is evidence that the genus as currently circumscribed is polyphyletic. Results are discussed in the context of morphology, karyology, and biogeography, outlining the necessity of removing section Pseudomelissa from Micromeria.

The importance of vouchers

Abstract: We object to the recently instituted policy of some editors that prohibits the publication of voucher informa tion in printed issues of the journal. Editors of scientific journals are under several pressures: to reduce the back log and the time from submission to publication and, at the same time, to keep publishing costs?and subscrip tion rates?as low as possible. In general, publishing journals is getting more expensive: printing and mailing costs are increasing and journals are publishing more pages, using larger formats and/or increasing the number of issues per year in response to increasing submissions of quality work. These factors have brought about policy changes in several journals with regard to publishing voucher information in printed issues. In 2003, American Journal of Botany {AJE) eliminated voucher information from their printed versions and relegated it to online access only. Recently, Systematic Botany changed its for mat from tables to paragraph form with smaller fonts. Three issues of Taxon from 2004 left out voucher infor mation following AJB's distressing example. Unless something is done to stem the tide, and even reverse the flow, it seems likely that other journals will adopt simi lar policies in the near future. We believe that eliminat ing voucher data from printed journals is ill advised and reflects a poor understanding of science. The Editor-in Chief of Taxon has just reversed Taxon's exclusion of hard-copy voucher information for future issues. But the failure to publish hard copy of voucher information is still the policy of AJB and it is under consideration by other journals. It is critical that the issue be clearly under stood and discussed before such decisions are made. The elimination of voucher lists is described as a cost-saving measure. The rationale for this policy is that voucher data are "supplemental", and their absence, unlike that of figures or tables, does not adversely affect authors' arguments, analyses, or conclusions. Further more, advocates argue, electronic access is available world-wide with few exceptions, and the websites host ed by sponsoring scientific societies are acceptable repositories of voucher information. We challenge each of these assertions. While we acknowledge that voucher tables often occupy considerable space and may be expensive to typeset and print, we think that such infor mation is integral to the publication and to the very process of scientific research. Separating voucher infor mation from the printed version of the publication effec tively eliminates vouchers from consideration. Electron ic publication, however laudable as a goal, is neither uni versally accessible nor guaranteed in the future. Natural history collections provide a critical service in the housing and maintenance of voucher specimens. A further consequence of this policy of down-grading the importance of vouchers is that natural history collections will find it even more difficult to illustrate the critical role that specimens play in scientific research. This ill conceived policy will therefore add another hurdle to garnering continued or increased support for collections, at a time when collections worldwide are struggling.

Global patterns of moss diversity: taxonomic and molecular inferences

Abstract: Taxonomic and molecular data were utilized to test the hypothesis that moss diversity is greatest near the equator. Species richness estimates from 86 taxonomic checklists representing global moss diversity do not support the hypothesis that, in general, mosses are more species-rich in the tropics than at higher latitudes. A significant latitudinal gradient was, however, detected for North, Central, and South American samples when analyzed alone. Taxonomic estimates of biodiversity patterns were compared to molecular estimates based on standing nucleotide diversity, and on phylogenetic diversity, the latter taking into account the historical information contained in a molecular phylogenetic tree for the mosses. Molecular estimates suggest that moss diversity is highest in the Southern Hemisphere and lowest in the Northern Hemisphere, with the tropics having an intermediate level. The differences, however, are slight, and analyses of molecular variance (AMOVA) indicate that there is virtually no generalized differentiation between major latitudinal zones. These results reflect the fact that virtually all moss lineages have representatives in all three latitudinal zones. At the nucleotide level, mosses best fit the pattern of “everything is everywhere”.

Spatio‐temporal relationships of the Macaronesian endemic flora: a relictual series or window of opportunity?

Abstract: Convolvulus is represented in Macaronesia by two endemic clades. The first (Clade I) has a predominantly western Mediterranean sister group whilst the second (Clade II) is nested within a predominantly eastern Mediterranean clade. The Relictual Series Hypothesis (RSH) predicts that degree of geographical disjunction between Macaronesian groups and their sister taxa is related to time available for continental extinction to occur and this would provide a possible explanation for the observed pattern in Convolvulus if Clade I is younger than Clade II. To test this hypothesis, mean relative divergence times for the two Macaronesian Convolvulus clades are estimated using a nrITS dataset. The results do not support the age-disjunction hypothesis and indicate that the mean divergence time for Clade I predates that of Clade II, although the difference between mean divergence times is small and the standard deviations are large. The inconsistency between this result and the RSH might be explained by the stochastic nature of evolution: with continental extinction events occurring during a similar time period, there may have been inadequate time for a clear spatio-temporal pattern to develop. An alternative explanation, termed the "Colonisation Window Hypothesis" (CWH), is also presented. This hypothesis emphasises island establishment rather than continental extinction as the prime determinant of spatio-temporal relationships of Macaronesian groups and predicts that opportunities for colonisation into Macaronesia has been temporally constrained to discrete waves of colonisation. Whilst the Convolvulus results are consistent with both RSH and CWH, a framework for establishing the ability of these two hypotheses to explain the spatial relationships of the Macaronesian endemic flora is presented.

Evolutionary trends in the simple thalloid liverworts (Marchantiophyta, Jungermanniopsida subclass Metzgeriidae)

Abstract: The phylogenetic history of and evolutionary trends within the simple thalloid liverworts (Jungermanniopsida, subclass Metzgeriidae) are reconstructed in a combined analysis of molecular and morphological data. The molecular dataset comprises loci from all three genomes, including trnL-F, rps4, rbcL, atpβ and pshA from the chloroplast, SSU rRNA and LSU rRNA from the nucleus, and nad5 from the mitochondrion, and 65 characters are scored in the morphological dataset. An initial analysis of a molecular dataset that included 16 out-group and 50 ingroup taxa resolved a Haplomitrium/Treubiaceae clade as the earliest diverging lineage of the ingroup. Subsequent analyses of ingroup only datasets, rooted on this clade, resolve Metzgeriidae as paraphyletic, with Blasiaceae sister to Marchantiopsida in all analyses. A combined analysis of morphological and molecular datasets resolves basically the same clades as analyses of the molecular dataset alone, except for the resolution of a weak sister group relationship between Metzgeriineae and the leafy liverworts. Reconstructions of morphological character evolution on the combined analysis topology confirm that there is substantial homoplasy in the morphology dataset, even in characters that have been traditionally considered diagnostic of hierarchial relationships, such as apical cell geometry, calyptral type and capsule wall thickness. Ancestral state reconstructions contradict many prevailing hypotheses of character evolution in hepatics, including the model of the ancestral liverwort prototype as an erect, radially symmetric plant. Instead, a more likely model is a prostrate, bilaterally symmetric plant with the diagnostic features of a simple thalloid liverwort.

Phylogenetic patterns and polyploid evolution within the Mediterranean genus Centaurium (Gentianaceae - Chironieae)

Abstract: The genus Centaurium (centauries) comprises ca. 27 annual species and subspecies primarily distributed in the Mediterranean basin. Phylogenetic relationships, inferred from sequences of both nrDNA (internal transcribed spacer, ITS) and cpDNA (trnL intron and trnL-F spacer) regions, confirm the monophyly of Centaurium and reveal the importance of polyploidy within the genus. In each ITS clade, diploid to hexaploid species of centauries occur. Furthermore, polyploidization is often associated with hybridization events, as suggested by the importance of additive polymorphic sites detected in the ITS region. Hence, reticulation appears to be the main cause of phylogenetic incongruence—and resulting systematic controversies—detected in the genus. Based on molecular and cytological evidence, the origin of several polyploid systems is discussed. Allopolyploidy, associated or not with introgression, appears to be the main evolutionary trend in Centaurium, and only a few autopolyploid taxa have been detected so far.

Molecular phylogeny of Trichostomoideae (Pottiaceae, Bryophyta) based on nrITS sequence data

Abstract: Bayesian analysis of an alignment of 83 nrITS sequences belonging to 66 taxa of Pottiaceae revealed representatives of subfamily Trichostomoideae in a well supported monophyletic lineage. Two robust clades within Trichostomoideae include species of Tortella and Weissia, respectively. Eucladium verticillatum is part of Trichostomoideae, and Anoectangium, Gymnostomum, Hymenostylium, and Tuerckheimia form a robust basal clade. Affinities of Hyophila and Leptoharhula to Trichostomoideae are unclear. Within Trichostomoideae, Pleurochaete squarrosa is resolved in Tortella while Trichostomum tenuirostris, Pseudosymhlepharis, and Chionoloma are placed as a separate genus or part of a broadly defined Tortella. The type species of Trichostomum, T. brachydontium, is nested in Weissia together with T. brittonianum, T. crispulum, and T. jamaicensis. Trichostomum unguiculatum and W. ayresii are resolved as closely related and separate from the rest of the Weissia clade. The genus Astomum, erected for cleistocarpous species of Weissia, is also nested within Weissia. Genetic divergence between selected accessions of Weissia controvesa and Astomum is sometimes smaller than between accessions of Weissia controversa.

Phylogeny of the tribe Cinchoneae (Rubiaceae), its position in Cinchonoideae, and description of a new genus, Ciliosemina

Abstract: Relationships of and within the Rubiaceae tribe Cinchoneae were estimated based on DNA sequence variation in five loci: the ITS region, the matK and rbcL genes, the rps16 intron, and the trnL-F region including the trnL intron and the trnL-F intergenic spacer. Within Cinchonoideae s.s., the tribe Naucleeae is the sister group of a clade that comprises all other taxa. Cinchoneae and Isertieae s.s., are strongly supported as sister groups. The tribe Cinchoneae is strongly supported as monophyletic in a restricted sense, including the genera Cinchona, Cinchonopsis, Joosia, Ladenbergia, Remijia and Stilpnophyllum. There is strong support that these genera are monophyletic as presently conceived, except that one species mostly referred to Remijia is of uncertain phylogenetic affinity. To accommodate this species and a morphologically closely similar one, a new genus, Ciliosemina A. Antonelli, is proposed and two new combinations are made.

Origin and subdivision of Plagiochila (Jungermanniidae: Plagiochilaceae) in tropical Africa based on evidence from nuclear and chloroplast DNA sequences and morphology

Abstract: Maximum likelihood analyses based on the internal transcribed spacer region of nuclear ribosomal DNA and the chloroplast protein coding gene rps4 were conducted to investigate phylogenetic relationships among species of Plagiochila and to reconstruct the ranges of natural species groups within the genus. Based on the results of the molecular analyses and on morphological evidence, the tropical African species of Plagiochila are assigned to the sections Arrectae, Cucullatae, Hylacoetes, Rutilantes, Vagae, and the new sect. Africanae (P. barteri, P. colorans). With the exception of Africanae, all sections possess intercontinental ranges; their centers of diversity are in the tropics. Clade and species diversity in Africa is lower than in other parts of the tropics and may reflect drought periods of the Pleistocene. Intercontinental ranges at specific level exist between tropical America and Africa whereas similarities between tropical Asia and Africa were only recovered at the sectional level. ITS sequence sets were used to test the monophyly of species with intercontinental ranges and to explore the-development of the Afro-American range of P. boryana. A well supported clade with accessions of P. boryana from Bolivia and Uganda is nested in the robust neotropical Hylacoetes. This topology and the low genetic distance of the different P. boryana accessions provide some evidence for long-range dispersal of P. horyana eastwards across the Atlantic, originating from the Neotropics. An African origin of the Vagae clade which includes neotropical and paleotropical taxa is suggested by the clustering of accessions from the East African Islands at the base of this clade. In addition, the presented data support the hypothesis of several switches from Africa to Asia and vice versa. A derived clade within Vagae includes accessions from the African mainland and the Neotropics. Our results seem to indicate that the extant tropical African Plagiochila flora is a mixture of old elements and rather recent immigrants.

Contrasting nuclear-plastidial phylogenetic patterns in the recently diverged Iberian Phlomis crinita and P. lychnitis lineages (Lamiaceae)

Abstract: This study was supported by the Spanish Ministry of Science and Technology (grant BOS2000-0450).

Karyotype analysis in several South American species of Solanum and Lycianthes rantonnei (Solanaceae)

Abstract: Somatic chromosomes of 17 species belonging to 4 subgenera and 7 sections of Solanum and Lycianthes rantonnei are studied. All taxa have 2n = 24. The chromosome numbers of S. tripartitum, S. tenuispinum, and S. vaillantiiare reported for the first time, and the karyotype analysis of L. rantonnei is the first one for the genus. Morphometric chromosome analyses bring estimates of karyotype composition and asymmetry. In general, karyotypes are symmetrical with the chromosomes smaller than 4 μm long, being metacentric (69%), sub-metacentric (24%), or more rarely subtelocentric (7%). Solanum tucumanense, S. palinacanthum, and Solanum sp. (Acanthophora) are unique by having mostly sm and st chromosomes. All species have nucleolar organizing regions and attached satellites of variable size on short arms of one chromosome pair, usually sm or st. All species can be cytologically distinguished. Karyotype data do not allow separation of L. rantonnei from species of Solanum. Results support the validity of S. tucumanense with respect to S. pseudocapsicum. Using chromosome data exclusively, cluster analysis in 10 species from Solanum subgen. Leptostemonum reinforce the systematic arrangement of taxa in subsections based on morphological features. Because of its increased karyotype asymmetry, section Acanthophora appears to be an advanced taxon within subgen. Leptostemonum.

Untangling Gloxinieae (Gesneriaceae). I. Phylogenetic patterns and generic boundaries inferred from nuclear, chloroplast, and morphological cladistic datasets

Abstract: Tribe Gloxinieae has been estimated to include 22 genera and approximately 290 species. This study presents maximum parsimony phylogenetic analyses of nuclear ribosomal DNA internal transcribed spacer regions sequences, the chloroplast DNA trnL intron and trnL-trnF intergenic spacer region sequences, a morphological cladistic dataset, and combined analyses of these datasets. These analyses suggest that the genera Gloxinia, Phinaea, and (possibly) Diastema are polyphyletic; Kohleria is paraphyletic in relation to Capanea; Bellonia and Pheidonocarpa should be considered members of tribe Gesnerieae; and Lembocarpus is a member of tribe Episcieae. Furthermore, the historically recognized genus Seemannia, now included in Gloxinia, appears to form a strongly supported monophyletic group; several Gloxinia species from southern Brazil appear to be most closely related to Goyazia; Capanea, Kohleria, Pearcea s.l., and Diastema vexans appear to form a strongly supported clade; and Diastema, Monopyle, Phinaea (in part), and a few Gloxinia species (Gloxinia dodsonii, G. lindeniana, and G racemosa) form a clade. Classification issues and generic boundaries of these lineages are discussed in detail.

Acacia : the case against moving the type to Australia

Abstract: Recent studies have shown that Acacia is polyphyletic and must be split into five genera. Proposal 1584 would retypify Acacia : the type of the Australian taxon A. penninervis would be conserved over the current lectotype ( A. scorpioides ) of an African taxon. We disagree with the recommendation of the Spermatophyte Committee to endorse this proposal. Contrary to Article 14.12 of the ICBN, no detailed case against conservation was presented in Proposal 1584. We maintain that there are strong arguments against conservation, such as the large number of countries that would be affected, the economic importance of the extra-Australian species, and the economic burden placed on developing countries. Acceptance of this proposal would also violate the guidelines for conservation which clearly state that the principle of priority should prevail when conservation for one part of the world would create disadvantageous change in another part of the world.