A Unified Approach to Taxonomic Delimitation in the Fern Genus &lt;I&gt;Pentagramma&lt;/I&gt; (Pteridaceae)

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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“…(≡ Gymnogramma triangularis Kaulf.). Circumscription sensu Schuettpelz et al (). Monophyletic (Schuettpelz et al, ).…”

Section: Classificationunclassified

A community‐derived classification for extant lycophytes and ferns

2016

J of Sytematics Evolution

1,125

273

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“…PCR products from the plastid marker trnG ‐ trnR were cleaned using an ExoSAP‐IT PCR cleanup kit (United States Biochemical, Cleveland, Ohio, USA) following Schuettpelz et al. (), and were sequenced using the PlateSeq Service provided by Eurofins Genomics (Louisville, Kentucky, USA) on a 3730XL DNA Analyzer (Applied Biosystems, Waltham, Massachusetts, USA) using Big Dye Terminator version 3.1 Cycle Sequencing reagents. The reads were assembled using SeqMan Pro (DNASTAR, ).…”

Section: Methodsmentioning

confidence: 99%

“…The ploidy of individuals included in the phylogenetic analyses was inferred by measuring spores and comparing these to spore samples from plants whose ploidy level was established by direct counting of chromosomes. This approach is based on the well‐established correlation between spore size and ploidy level within cheilanthoid ferns (Grusz et al., ; Beck et al., ; Schuettpelz et al., ; Kao et al., ). Four of the plants providing DNA samples had chromosome counts: T.‐T.Kao 17‐004 ( n = 30), T.‐T.Kao 17‐010 ( n = 60), T.‐T.Kao 17‐016 ( n = 30), and M.D.Windham 525 ( n = 30).…”

Section: Methodsmentioning

confidence: 99%

Infraspecific diversification of the star cloak fern (Notholaena standleyi) in the deserts of the United States and Mexico

Kao

Rothfels

Melgoza‐Castillo

et al. 2020

American J of Botany

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2020. Infraspecific diversification of the star cloak fern (Notholaena standleyi) in the deserts of the United States and Mexico.PREMISE: Not all ferns grow in moist and shaded habitats. One well-known example is Notholaena standleyi, a species that thrives in deserts of the southwestern United States and Mexico. This species exhibits several "chemotypes" that differ in farina (flavonoid exudates) color and chemistry. By integrating data from molecular phylogenetics, cytology, biochemistry, and biogeography, we circumscribed the major evolutionary lineages within N. standleyi and reconstructed their diversification histories. METHODS:Forty-eight samples were selected from across the geographic distribution of N. standleyi. Phylogenetic relationships were inferred using four plastid and five nuclear markers. Ploidy levels were inferred using spore sizes calibrated by chromosome counts, and farina chemistry was compared using thin-layer chromatography. RESULTS:Four clades are recognized, three of which roughly correspond to previously recognized chemotypes. The diploid clades G and Y are found in the Sonoran and Chihuahuan deserts, respectively; they are estimated to have diverged in the Pleistocene, congruent with the postulated timing of climatological events separating these two deserts. Clade P/YG is tetraploid and partially overlaps the distribution of clade Y in the eastern Chihuahuan Desert. It is apparently confined to limestone, a geologic substrate rarely occupied by members of the other clades. The cryptic (C) clade, a diploid group known only from southern Mexico and highly disjunct from the other three clades, is newly recognized here. CONCLUSIONS:Our results reveal a complex intraspecific diversification history of N. standleyi, traceable to a variety of evolutionary drivers including classic allopatry, parapatry with or without changes in geologic substrate, and sympatric divergence through polyploidization.

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“…Each alignment (one per sample) was then analyzed using a heuristic maximum parsimony search in the program PAUP* version 4.0 beta 10 (Swofford, 2002), with the default settings. The most parsimonious tree (or a consensus of equally most parsimonious trees) from each analysis was then examined to identify least‐inclusive clades (i.e., groups of sequences united by at least one apomorphy but not themselves containing other, similarly defined, groups of sequences) following an established approach (Grusz et al, 2009; Li et al, 2012; Schuettpelz et al, 2015). A consensus sequence for each group of clones was computed; these were deposited as alleles into the Fern Lab Database (http://fernlab.biology.duke.edu) and GenBank () and then subjected to additional analyses (see below).…”

Section: Methodsmentioning

confidence: 99%