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- Schuettpelz, Eric, et al.
(författare)
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A community-derived classification for extant lycophytes and ferns
- 2016
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Ingår i: Journal of Systematics and Evolution. - : Wiley. - 1674-4918 .- 1759-6831. ; 54:6, s. 563-603
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Tidskriftsartikel (refereegranskat)abstract
- Phylogeny has long informed pteridophyte classification. As our ability to infer evolutionary trees has improved, classifications aimed at recognizing natural groups have become increasingly predictive and stable. Here, we provide a modern, comprehensive classification for lycophytes and ferns, down to the genus level, utilizing a community-based approach. We use monophyly as the primary criterion for the recognition of taxa, but also aim to preserve existing taxa and circumscriptions that are both widely accepted and consistent with our understanding of pteridophyte phylogeny. In total, this classification treats an estimated 11 916 species in 337 genera, 51 families, 14 orders, and two classes. This classification is not intended as the final word on lycophyte and fern taxonomy, but rather a summary statement of current hypotheses, derived from the best available data and shaped by those most familiar with the plants in question. We hope that it will serve as a resource for those wanting references to the recent literature on pteridophyte phylogeny and classification, a framework for guiding future investigations, and a stimulus to further discourse.
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- Aagaard, Sunniva Margrethe Due
(författare)
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Reticulate Evolution in Diphasiastrum (Lycopodiaceae)
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis relationships and the occurrence of reticulate evolutionary events in the club moss genus Diphasiastrum are investigated. Diphasiastrum is initially established as a monophyletic group within Lycopodiaceae using non recombinant chloroplast sequence data. Support is obtained for eight distinct parental lineages in Diphasiastrum, and relationships among the putative parent taxa in the hypothesized hybrid complexes; D. alpinum, D. complanatum, D. digitatum, D. multispicatum, D. sitchense, D. tristachyum and D. veitchii are presented. Feulgen DNA image densitometry data and sequence data obtained from three nuclear regions, RPB2, LEAFY and LAMB4, were used to infer the origins of three different taxa confirmed to be allopolyploid; D. zanclophyllum from South Africa, D. wightianum from Malaysia and an undescribed taxon from China. The two Asian polyploids have originated from two different hybrid combinations, D. multispicatum x D. veitchii and D. tristachyum x D. veitchii. Diphasiastrum zanclophyllum originates from a cross between D. digitatum and an unidentified diploid taxon. The occurrence of three homoploid hybrid combinations commonly recognized in Europe, D. alpinum x D. complanatum, D. alpinum x D. tristachyum and D. complanatum x D. tristachyum, are verified using the same three nuclear regions. Two of the three hybrid combinations are also shown to have originated from reciprocal crosses. Admixture analyses performed on an extended, dataset similarly identified predominately F1 hybrids and backcrosses. The observations and common recognition of hybrid species in the included populations are hence most likely due to frequent observations of neohybrids in hybrid zones. Reticulate patterns are, however, prominent in the presented dataset. Hence future studies addressing evolutionary and ecological questions in Diphasiastrum should emphasize the impact of gene flow between parent lineages rather than speciation as the result of hybridization.
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- Geiger, Jennifer M.O., et al.
(författare)
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Molecular phylogenetic relationships of Cibotium and origin of the Hawaiian endemics
- 2013
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Ingår i: American Fern Journal. - : American Fern Society. - 0002-8444 .- 1938-422X. ; 103:3, s. 141-152
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Tidskriftsartikel (refereegranskat)abstract
- The tree fern genus Cibotium comprises nine species distributed in tropical regions of Asia, Mesoamerica, and the Hawaiian Islands. The four Hawaiian species are endemic to the Hawaiian Islands. The goals of this paper were to determine the relationships among the Cibotium species, determine whether the Hawaiian species are monophyletic, and infer the dispersal pathway likely responsible for delivering an ancestral Cibotium species to the Hawaiian Islands. Molecular phylogenetic analyses based on four coding and five non-coding plastid DNA sequences supported Hawaiian Cibotium as monophyletic, suggesting a single colonization of the Hawaiian Islands. Hawaiian Cibotium are most closely related to species in Mesoamerica. If the ancestor of Hawaiian Cibotium dispersed to the Hawaiian Islands via wind dispersed spores, our analyses suggest the trade winds or storms delivered spores from Mesoamerica or the Hawaiian Islands were colonized first by a species from Asia, followed by subsequent dispersal to Mesoamerica from Hawai'i. Our analyses do not allow us to favor one hypothesis over the other.
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