Browsing by Subject "GENUS"
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Item Open Access Are there too many fern genera?(Taxon, 2018-06-01) Schuettpelz, E; Rouhan, G; Pryer, KM; Rothfels, CJ; Prado, J; Sundue, MA; Windham, MD; Moran, RC; Smith, ARItem Open Access Berge–Gabai knots and L–space satellite operations(Algebraic & Geometric Topology, 2015-01-15) Hom, J; Lidman, T; Vafaee, F© 2014 Mathematical Sciences Publishers. All rights reserved. Let P(K) be a satellite knot where the pattern P is a Berge–Gabai knot (ie a knot in the solid torus with a nontrivial solid torus Dehn surgery) and the companion K is a nontrivial knot in S3. We prove that P(K) is an L–space knot if and only if K is an L–space knot and P is sufficiently positively twisted relative to the genus of K. This generalizes the result for cables due to Hedden [13] and Hom [17].Item Open Access DNA barcoding exposes a case of mistaken identity in the fern horticultural trade.(Molecular ecology resources, 2010-11) Pryer, Kathleen M; Schuettpelz, Eric; Huiet, Layne; Grusz, Amanda L; Rothfels, Carl J; Avent, Tony; Schwartz, David; Windham, Michael DUsing cheilanthoid ferns, we provide an example of how DNA barcoding approaches can be useful to the horticultural community for keeping plants in the trade accurately identified. We use plastid rbcL, atpA, and trnG-R sequence data to demonstrate that a fern marketed as Cheilanthes wrightii (endemic to the southwestern USA and northern Mexico) in the horticultural trade is, in fact, Cheilanthes distans (endemic to Australia and adjacent islands). Public and private (accessible with permission) databases contain a wealth of DNA sequence data that are linked to vouchered plant material. These data have uses beyond those for which they were originally generated, and they provide an important resource for fostering collaborations between the academic and horticultural communities. We strongly advocate the barcoding approach as a valuable new technology available to the horticulture industry to help correct plant identification errors in the international trade.Item Open Access Fern phylogeny inferred from 400 leptosporangiate species and three plastid genes(Taxon, 2007-01-01) Schuettpelz, E; Pryer, KMIn an effort to obtain a solid and balanced approximation of global fern phylogeny to serve as a tool for addressing large-scale evolutionary questions, we assembled and analyzed the most inclusive molecular dataset for leptosporangiate ferns to date. Three plastid genes (rbcL, atpB, atpA), totaling more than 4,000 bp, were sequenced for each of 400 leptosporangiate fern species (selected using a proportional sampling approach) and five outgroups. Maximum likelihood analysis of these data yielded an especially robust phylogeny: 80% of the nodes were supported by a maximum likelihood bootstrap percentage ≥ 70. The scope of our analysis provides unprecedented insight into overall fern relationships, not only delivering additional support for the deepest leptosporangiate divergences, but also uncovering the composition of more recently emerging clades and their relationships to one another.Item Open Access Phylogeny, divergence time estimates, and phylogeography of the diploid species of the polypodium vulgare complex (Polypodiaceae)(Systematic Botany, 2014-01-01) Sigel, EM; Windham, MD; Haufler, CH; Pryer, KM© 2014 by the American Society of Plant Taxonomists. The Polypodium vulgare complex (Polypodiaceae) comprises a well-studied group of fern taxa whose members are cryptically differentiated morphologically and have generated a confusing and highly reticulate species cluster. Once considered a single species spanning much of northern Eurasia and North America, P. vulgare has been segregated into 17 diploid and polyploid taxa as a result of cytotaxonomic work, hybridization experiments, and isozyme studies conducted during the 20th century. Despite considerable effort, however, the evolutionary relationships among the diploid members of the P. vulgare complex remain poorly resolved. Here we infer a diploids-only phylogeny of the P. vulgare complex and related species to test previous hypotheses concerning relationships within Polypodium sensu stricto. Using sequence data from four plastid loci (atpA, rbcL, matK, and trnG-trnR), we recovered a monophyletic P. vulgare complex comprising four well-supported clades. The P. vulgare complex is resolved as sister to the Neotropical P. plesiosorum group and these, in turn, are sister to the Asian endemic Pleurosoriopsis makinoi. Using divergence time analyses incorporating previously derived age constraints and fossil data, we estimate an early Miocene origin for the P. vulgare complex and a late Miocene-Pliocene origin for the four major diploid lineages of the complex, with the majority of extant diploid species diversifying from the late Miocene through the Pleistocene. Finally, we use our node age estimates to reassess previous hypotheses, and to propose new hypotheses, about the historical events that shaped the diversity and current geographic distribution of the diploid species of the P. vulgare complex.Item Open Access Toward a monophyletic Notholaena (Pteridaceae): Resolving patterns of evolutionary convergence in xeric-adapted ferns(Taxon, 2008-01-01) Rothfels, CJ; Windham, MD; Grusz, AL; Gastony, GJ; Pryer, KMCheilanthoid ferns (Pteridaceae) are a diverse and ecologically important clade, unusual among ferns for their ability to colonize and diversify within xeric habitats. These extreme habitats are thought to drive the extensive evolutionary convergence, and thus morphological homoplasy, that has long thwarted a natural classification of cheilanthoid ferns. Here we present the first multigene phylogeny to focus on taxa traditionally assigned to the large genus Notholaena. New World taxa (Notholaena sensu Tryon) are only distantly related to species occurring in the Old World (Notholaena sensu Pichi Sermolli). The circumscription of Notholaena adopted in recent American floras is shown to be paraphyletic, with species usually assigned to Cheilanthes and Cheiloplecton nested within it. The position of Cheiloplecton is particularly surprising - given its well-developed false indusium and non-farinose blade, it is morphologically anomalous within the "notholaenoids". In addition to clarifying natural relationships, the phylogenetic hypothesis presented here helps to resolve outstanding nomenclatural issues and provides a basis for examining character evolution within this diverse, desert-adapted clade.