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- Korall, Petra, 1968-, et al.
(author)
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A molecular phylogeny of scaly tree ferns (Cyatheaceae)
- 2007
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In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 94:5, s. 873-886
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Journal article (peer-reviewed)abstract
- Tree ferns recently were identified as the closest sister group to the hyperdiverse clade of ferns, the polypods. Although most of the 600 species of tree ferns are arborescent, the group encompasses a wide range of morphological variability, from diminutive members to the giant scaly tree ferns, Cyatheaceae. This well-known family comprises most of the tree fern diversity (similar to 500 species) and is widespread in tropical, subtropical, and south temperate regions of the world. Here we investigate the phylogenetic relationships of scaly tree ferns based on DNA sequence data from five plastid regions (rbcL, rbcL-accD IGS, rbcL-atpB IGS, trnG-trnR, and trnL-trnF). A basal dichotomy resolves Sphaeropteris as sister to all other taxa and scale features support these two clades: Sphaeropteris has conform scales, whereas all other taxa have marginate scales. The marginate-scaled clade consists of a basal trichotomy, with the three groups here termed (1) Cyathea (including Cnemidaria, Hymenophyllopsis, Trichipteris), (2) Alsophila sensu stricto, and (3) Gymnosphaera (previously recognized as a section within Alsophila) + A. capensis. Scaly tree ferns display a wide range of indusial structures, and although indusium shape is homoplastic it does contain useful phylogenetic information that supports some of the larger clades recognised.
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| 4. |
- Korall, Petra, 1968-, et al.
(author)
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Tree ferns : Monophyletic groups and their relationships as revealed by four protein-coding plastid loci
- 2006
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In: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 39:3, s. 830-845
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Journal article (peer-reviewed)abstract
- Tree ferns are a well-established clade within leptosporangiate ferns. Most of the 600 species (in seven families and 13 genera) are arborescent, but considerable morphological variability exists, spanning the giant scaly tree ferns (Cyatheaceae), the low, erect plants (Plagiogyriaceae), and the diminutive endemics of the Guayana Highlands (Hymenophyllopsidaceae). In this study, we investigate phylogenetic relationships within tree ferns based on analyses of four protein-coding, plastid loci (atpA, atpB, rbeL, and rps4). Our results reveal four well-supported clades, with genera of Dicksoniaceae (sensu Kubitzki, 1990) interspersed among them: (A) (Loxomataceae, (Culcita, Plagiogyriaceae)), (B) (Calochlaena, (Dicksonia, Lophosoriaceae)), (C) Cibotium, and (D) Cyatheaceae, with Hymenophyllopsidaceae nested within. How these four groups are related to one other, to Thyrsopteris, or to Metaxyaceae is weakly supported. Our results show that Dicksoniaceae and Cyatheaceae, as currently recognised, are not monophyletic and new circumscriptions for these families are needed. (c) 2006 Elsevier Inc. All rights reserved.
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| 5. |
- Rydin, Catarina, et al.
(author)
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Evolutionary relationships in Ephedra (Gnetales), with implications for seed plant phylogeny
- 2009
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In: International journal of plant sciences. - : University of Chicago Press. - 1058-5893 .- 1537-5315. ; 170:8, s. 1031-1043
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Journal article (peer-reviewed)abstract
- Evolutionary relationships in Ephedra are difficult to resolve, mainly because there are few informative characters in investigated loci and long distances to outgroups. We address these problems by using a large data set that includes information from seven plastid and nuclear loci and 204 vascular plants. The deepest divergences in Ephedra are weakly supported and differ by analytical method, but they indicate a basal grade of species distributed in the Mediterranean area. New World species are monophyletic, with a South American clade possibly nested within a North American clade. A mainly Asian clade comprises several well-supported subgroups, of which some are endemic to restricted geographic regions in East or Central Asia; others have a broad distribution that may extend into Europe (E. distachya, E. major) and/or Africa (E. pachyclada-E. somalensis). Ephedra laristanica and E. somalensis are nested within other species, whereas the recognition of E. milleri as a separate species is supported. Our results provide another example of how exceptionally difficult it is to disentangle the early divergences of seed plants. Bayesian analysis strongly supports the "gnetifer'' hypothesis, a result rarely found in the literature, but it conflicts with our results from only chloroplast data ("gne-cup'') and with results of most maximum parsimony analyses ("Gnetales sister'').
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| 6. |
- Schuettpelz, Eric, et al.
(author)
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Plastid atpA data provide improved support for deep relationships among ferns
- 2006
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In: Taxon. - 0040-0262 .- 1996-8175. ; 55:4, s. 897-906
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Journal article (peer-reviewed)abstract
- DNA sequence data and phylogenetic approaches have contributed greatly to our understanding of fern relationships. Nonetheless, the datasets analyzed to date have not been sufficient to definitively resolve all parts of the global fern phylogeny; additional data and more extensive sampling are necessary. Here, we explore the phylogenetic utility of the plastid atpA gene. Using newly designed primers, we obtained atpA sequences for 52 fern and 6 outgroup taxa, and then evaluated the capabilities of atpA relative to four other molecular markers, as well as the contributions of atpA in combined analyses. The five single-gene datasets differed markedly in the number of variable characters they possessed; and although the relationships resolved in analyses of these datasets were largely congruent, the robustness of the hypotheses varied considerably. The atpA dataset had more variable characters and resulted in a more robustly supported phylogeny than any of the other single gene datasets examined, suggesting that atpA will be exceptionally useful in more extensive studies of fern phylogeny and perhaps also in studies of other plant lineages. When the atpA data were analyzed in combination with the other four markers, an especially robust hypothesis of fern relationships emerged. With the addition of the atpA data, support increased substantially at several nodes; three nodes, which were not well-supported previously, received both good posterior probability and good bootstrap support in the combined 5-gene (> 6 kb) analyses.
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| 7. |
- Smith, Alan R., et al.
(author)
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A classification for extant ferns
- 2006
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In: Taxon. - 0040-0262 .- 1996-8175. ; 55:3, s. 705-731
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Research review (peer-reviewed)abstract
- We present a revised classification for extant ferns, with emphasis on ordinal and familial ranks, and a synopsis of included genera. Our classification reflects recently published phylogenetic hypotheses based on both morphological and molecular data. Within our new classification, we recognize four monophyletic classes, 11 monophyletic orders, and 37 families, 32 of which are strongly supported as monophyletic. One new family, Cibotiaceae Korall, is described. The phylogenetic affinities of a few genera in the order Polypodiales are unclear and their familial placements are therefore tentative. Alphabetical lists of accepted genera (including common synonyms), families, orders, and taxa of higher rank are provided.
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