journal article
LitStream Collection
Home
Lehtonen, Samuli; Wahlberg, Niklas; Christenhusz, Maarten J. M.
doi: 10.1111/j.1095-8339.2012.01312.xpmid: N/A
AbstractWe analysed one nuclear gene (18S) and seven plastid markers [five protein coding (atpA, atpB, rbcL, rpoC1, rps4) and two non-coding (trnH-psbA, trnL-trnF] for 31 members of Polypodiales and four outgroup taxa. We focused our sampling on the lindsaeoids and associated ferns in order to obtain a better understanding of the diversification of the early polypods. However, the exact phylogenetic position of Saccoloma and Cystodium remained uncertain. Based on relaxed molecular clock analyses, it appears that the crown group lindsaeoids diversified in the Caenozoic, more or less simultaneously with the main radiation of other Polypodiales, even though the original divergence between the lindsaeoid and non-lindsaeoid polypods occurred before the end of the Jurassic. The current pantropical distribution of lindsaeoids can be explained by either long-distance dispersal across the oceans or vicariance caused by the retreat of previously widely distributed tropical forests from higher to lower latitudes.
Clennett, John C. B.; Chase, Mark W.; Forest, Félix; Maurin, Olivier; Wilkin, Paul
doi: 10.1111/j.1095-8339.2012.01302.xpmid: N/A
AbstractFor a nearly complete set of species of Erythronium (Liliaceae), we examined two plastid loci (the rps16 intron and the 5′ trnK intron, excluding the matK exon), one nuclear locus (nrITS) and morphology to evaluate species relationships and that of Erythronium to Amana, the putatively most closely allied genus. A matrix of morphological characters was developed through observation of around 900 living and herbarium specimens; evolution of these was examined using character optimization on the combined (total-evidence) tree. Parsimony methods were used to examine the morphological and molecular data sets produced, both separately and in combination, with Bayesian methods also used on the molecular data sets. These established that the genus is probably sister to Amana (although most analyses placed Amana inside Erythronium) and that Tulipa is sister to the pair of Erythronium and Amana. Within Erythronium, there are three strongly supported geographically distinct clades: (1) Eurasian and (2) eastern and (3) western North American. Separation of species in these three clades is less clear, particularly among the western North American taxa.
Bozek, Monika; Leitch, Andrew R.; Leitch, Ilia J.; Záveská Drábková, Lenka; Kuta, Elżbieta
doi: 10.1111/j.1095-8339.2012.01314.xpmid: N/A
AbstractThe present study examines chromosome and genome size evolution in Luzula (woodrush; Juncaceae), a monocot genus with holocentric chromosomes. Detailed karyotypes and genome size estimates were obtained for seven Luzula spp., and these were combined with additional data from the literature to enable a comprehensive cytological analysis of the genus. So that the direction of karyotype and genome size changes could be determined, the cytological data were superimposed onto a phylogenetic tree based on the trnL-F and internal transcribed spacer (ITS) DNA regions. Overall, Luzula shows considerable cytological variation both in terms of chromosome number (2n = 6–66) and genome size (15-fold variation; 2C = 0.56–8.51 pg; 547.7–8322.8 Mb). In addition, there is considerable diversity in the genomic mechanisms responsible, with the range of karyotypes arising via agmatoploidy (chromosome fission), symploidy (chromosome fusion) and/or polyploidy accompanied, in some cases, by the amplification or elimination of DNA. Viewed in an evolutionary framework, no broad trend in karyotype or genome evolution was apparent across the genus; instead, different mechanisms of karyotype evolution appear to be operating in different clades. It is clear that Luzula exhibits considerable genomic flexibility and tolerance to large, genome-scale changes.
Adebowale, Adekunle; Nicholas, Ashley; Lamb, Jennifer; Naidoo, Yougasphree
doi: 10.1111/j.1095-8339.2012.01308.xpmid: N/A
AbstractLeaves can be a useful source of taxonomic information in plants particularly when flowers and fruits are absent during certain periods of the year. In this study, we applied an elliptic Fourier analysis (EFA)-based morphometric technique to assess leaf morphological divergence among four species of southern African Strychnos section Densiflorae. Using leaf specimen images from field and herbarium collections, we extracted six shape variables [i.e. principal components (PCs)] from the Fourier coefficients and used these variables to describe leaf outline among the species. Our results indicate that the symmetric component of a leaf is the main source of shape differences accounting for 90.25% of total leaf shape variation and captures the more obvious range of observed shapes. PC1 of the symmetric variables describes a wide range of visually observable leaf shape among the species. MANOVA revealed significant interspecific differences except between S. innocua and S. madagascariensis, which could not be separated by outline analysis. A cross-validated group classification suggests that S. gerrardii, with a classification rate of 88.4%, is distinct from S. madagascariensis, contrary to some taxonomic treatments. We discuss the value of geometric morphometrics at detecting subtle morphological variations and the evolutionary implications of such variations, which may be undetectable to the human eye.
Silva, Maria Francilene Souza; De Andrade, Ivanilza Moreira; Mayo, Simon Joseph
doi: 10.1111/j.1095-8339.2012.01309.xpmid: N/A
AbstractLeaf characters of populations of the aquatic macrophyte Montrichardia linifera were studied using geometric morphometrics to compare variation with traditional circumscriptions of the two recognized species. Two hundred and ten individuals were sampled from seven populations in the delta region of the Rio Parnaíba, north-east Brazil. Six landmarks of the leaf blade were digitized from images and analysed with MorphoJ software. Procrustes-aligned configurations were studied using principal component analysis and canonical variates analysis in the pooled data and individual populations. Sinus shape variation was studied using landmark configurations of the posterior lobe basiscopic lamina. Covariation of leaf blade shape, basiscopic lamina shape, secondary vein number and petiole ligule length was investigated with partial least squares analysis. Allometry of these variables with leaf blade centroid size was investigated using multivariate regression, linear modelling and analysis of covariance. Measured variables varied continuously over the ranges previously reported for the two species. The characters of the two species morphotypes covaried and were only partly influenced by allometric effects. Symmetric shape variables predominated, but a distinctive left- and right-handed asymmetry occurred in all populations. Genetic and ecological studies are needed to investigate the significant inter-population differences further. The study offers a methodology for a broader combined morphometric/molecular investigation.
Salmaki, Yasaman; Zarre, Shahin; Govaerts, Rafaël; Bräuchler, Christian
doi: 10.1111/j.1095-8339.2012.01317.xpmid: N/A
AbstractStachys is a large and taxonomically complex genus of Lamiaceae (Lamioideae: Stachydeae). On the basis of morphological examination and field investigation, we revised the genus Stachys in Iran. We examined about 3500 specimens from various herbaria and produced a key for identification of all taxa found in Iran. The following are provided for each taxon: a description along with the complete synonymy, notes on nomenclature and relationships within the genus, geographical distribution, habitat, IUCN conservation status assessment and selected materials examined. The following taxa are reported here as new for Iran: S. atherocalyx, S. kotschyi, S. melampyroides and S. recta subsp. subcrenata. Several taxa are placed in synonymy for the first time here: S. persica is a synonym of S. alpina, S. koelzii is a synonym of S. aucheri, S. ballotiformis is a synonym of S. kurdica subsp. kurdica, and S. setifera subsp. daenensis and S. setifera subsp. iranica are synonyms of S. setifera. Two taxa are reduced to the rank of subspecies: S. kurdica subsp. asterocalyx and S. pilifera subsp. ixodes. According to the present revision, the genus contains 32 species, nine subspecies and two hybrids in Iran with 17 endemic taxa.
Foggi, Bruno; Parolo, Gilberto; Šmarda, Petr; Coppi, Andrea; Lastrucci, Lorenzo; Lakušić, Dmitar; Eastwood, Ruth; Rossi, Graziano
doi: 10.1111/j.1095-8339.2012.01313.xpmid: N/A
AbstractThe Festuca alpina group includes several small fescues growing in rocky habitats across the European mountain chains. A taxonomic study of F. alpina and F. alfrediana, the two most common species of this group, is presented here. Morphological data collected from 298 specimens across 37 populations from all the major European mountain ranges, genetic inter simple sequence repeat (ISSR) data, chromosome counts and DNA ploidy information were analysed. We found that the two species are differentiated by a combination of morphological and genetic characters, which are in line with the geographical distributions. Festuca alpina is distributed from the Pyrenees and Alps to the western Carpathians, whereas F. alfrediana is found in Sardinia, the Apennines and the Dinarids. Here, F. alfrediana is split into three subspecies on the basis of quantitative morphological characters and complete geographical segregation: F. alfrediana subsp. alfrediana in the Corso-Sardinian area; F. alfredianasubsp.ferrariniana in the Apennines; and F. alfredianasubsp.durmitorea in the Balkan Peninsula. The last two taxa are newly described here. Detailed description and information on identification, distribution, ecology, illustrations, synonyms and type material are provided.
Showing 1 to 10 of 12 Articles