Browsing by Subject "AFFINITIES"

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    Baja: A New Monospecific Genus Segregated from Cheilanthes s. l. (Pteridaceae)
    (Systematic Botany, 2019-09-06) George, LO; Pryer, KM; Kao, T; Huiet, L; Windham, MD
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    Phylogeny and relationships of the neotropical Adiantum raddianum group (Pteridaceae)
    (Taxon, 2016-12-01) Hirai, RY; Schuettpelz, E; Huiet, L; Pryer, KM; Smith, AR; Prado, J
    © International Association for Plant Taxonomy (IAPT) 2016. With more than 200 species, the maidenhair fern genus Adiantum is among the top ten most diverse fern genera. Adiantum is pantropical in distribution and, due to the presence of a unique synapomorphy (sporangia borne on indusia rather than laminae), perhaps the most easily recognized fern genus. Many of its members, including numerous cultivars derived from A. raddianum, are grown as ornamentals. Because of its size, a comprehensive taxonomic study of Adiantum is difficult and the genus is perhaps better approached through a series of narrower studies. Here, we focus specifically on A. raddianum and putative allies. We find a newly defined A. raddianum group to be strongly supported as monophyletic and segregated from other maidenhair ferns on the basis of genetic as well as morphological characteristics. Bayesian inference and maximum likelihood analyses of plastid atpA, chlL, chlN, rbcL, and rpoA sequences support the A raddianum clade as sister to A poiretii and its allies. We identify round-reniform indusia to be a characteristic of the A.raddianum group (vs. lunate in the A.poiretii group). Additionally, we find species in the Apoiretii group to differ in having a unique 66 nucleotide deletion in our chlN gene alignment. The neotropical Araddianum group comprises at least 17 species (14 studied here), some widely distributed; one was recently described (A. alan-smithii).
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    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, KM
    Cheilanthoid 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.