Browsing by Subject "species complex"

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    A plastid phylogeny of the cosmopolitan fern family cystopteridaceae (Polypodiopsida)
    (Systematic Botany, 2013-06-01) Rothfels, CJ; Windham, MD; Pryer, KM
    Among the novel results of recent molecular phylogenetic analyses are the unexpectedly close evolutionary relationships of the genera Acystopteris, Cystopteris, and Gymnocarpium, and the phylogenetic isolation of these genera from Woodsia. As a consequence, these three genera have been removed from Woodsiaceae and placed into their own family, the Cystopteridaceae. Despite the ubiquity of this family in rocky habitats across the northern hemisphere, and its cosmopolitan distribution (occurring on every continent except Antarctica), sampling of the Cystopteridaceae in phylogenetic studies to date has been sparse. Here we assemble a three-locus plastid dataset (matK, rbcL, trnG-R) that includes most recognized species in the family and multiple accessions of widespread taxa from across their geographic ranges. All three sampled genera are robustly supported as monophyletic, Cystopteris is strongly supported as sister to Acystopteris, and those two genera together are sister to Gymnocarpium. The Gymnocarpium phylogeny is deeply divided into three major clades, which we label the disjunctum clade, the robertianum clade, and core Gymnocarpium. The Cystopteris phylogeny, similarly, features four deeply diverged clades: C. montana, the sudetica clade, the bulbifera clade, and the fragilis complex. Acystopteris includes only three species, each of which is supported as monophyletic, with A. taiwaniana sister to the japonica/tenuisecta clade. Our results yield the first species-level phylogeny of the Cystopteridaceae and the first molecular phylogenetic evidence for species boundaries. These data provide an essential foundation for further investigations of complex patterns of geographic diversification, speciation, and reticulation in this family. © Copyright 2013 by the American Society of Plant Taxonomists.
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    A step-by-step protocol for meiotic chromosome counts in flowering plants: A powerful and economical technique revisited.
    (Applications in plant sciences, 2020-04-23) Windham, MD; Pryer, KM; Poindexter, DB; Li, F; Rothfels, CJ; Beck, JB
    Premise:Counting chromosomes is a fundamental botanical technique, yet it is often intimidating and increasingly sidestepped. Once mastered, the basic protocol can be applied to a broad range of taxa and research questions. It also reveals an aspect of the plant genome that is accessible with only the most basic of resources-access to a microscope with 1000× magnification is the most limiting factor. Methods and Results:Here we provide a detailed protocol for choosing, staining, and squashing angiosperm pollen mother cells. The protocol is supplemented by figures and two demonstration videos. Conclusions:The protocol we provide will hopefully demystify and reinvigorate a powerful and once commonplace botanical technique that is available to researchers regardless of their location and resources.
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    Low-copy nuclear data confirm rampant allopolyploidy in the cystopteridaceae (Polypodiales)
    (Taxon, 2014-10-01) Rothfels, CJ; Johnson, AK; Windham, MD; Pryer, KM
    © International Association for Plant Taxonomy (IAPT) 2014. Here we present the first nuclear phylogeny for Cystopteridaceae (Polypodiales), using the single-copy locus gapCp “short”. This phylogeny corroborates broad results from plastid data in demonstrating strong support for the monophyly of the family’s three genera—Cystopteris, Acystopteris, and Gymnocarpium—and of the major groups within Cystopteris (C. montana, the sudetica and bulbifera clades, and the C. fragilis complex). In addition, it confirms the rampant hybridization (allopolyploidy) that has long been suspected within both Cystopteris and Gymnocarpium. In some cases, these data provide the first DNA-sequence-based evidence for previous hypotheses of polyploid species origins (such as the cosmopolitan G. dryopteris being an allotetraploid derivative of the diploids G. appalachianum and G. disjunctum). Most of the allopolyploids, however, have no formal taxonomic names. This pattern is particularly strong within the C. fragilis complex, where our results imply that the eight included accessions of “C. fragilis” represent at least six distinct allopolyploid taxa.