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Molecular Systematics and Morphology of the Adiantum peruvianum Group (Pteridaceae)

McCarthy, Mirabai R.

Abstract Details

2012, Doctor of Philosophy, Miami University, Botany.
The nearly cosmopolitan Adiantum (Pteridaceae) comprises approximately 200 species, most of which are tropical in distribution. Adiantum ferns are predominantly terrestrial forest taxa, but some have adapted to living along stream banks or moist, rocky habitats. Historically, Adiantum has been divided into morphological species groups, as a means to help taxonomists categorize species and interpret inter-specific relationships within the genus. However, group concepts and circumscriptions have changed extensively over time, due in part to different interpretations about the relative importance of various morphological characters, and subsequently, alternate group names have been used in the literature. Currently there is no clear consensus on how species should be grouped. The present study utilizes molecular phylogenetics to delineate species groups within Adiantum, and traditional morphology to revise and circumscribe one species group, the A. peruvianum Group. Our phylogenetic analyses revealed four primary clades (A, B, C, and D) within Adiantum. Clades A & B contain temperate species, clade C contains primarily paleotropical species, and clade D contains neotropical species. Neotropical clade D contains two sub-clades D1 and D2. Clade D1 contains species with visible venuloid idioblasts present between veins, whereas clade D2 contains species lacking visible venuloid idioblasts between veins. The Adiantum peruvianum Group is a sub-clade (clade D2.III) within clade D2, and contains at least eight species: A. anceps, ‘A. ecuadorianum’, ‘A. exuberans’, A. mathewsianum, A. pectinatum, A. peruvianum, A. polyphyllum, and A. trapeziforme. Members of this group can be identified by having clathrate rhizome scales with minutely denticulate margins; segment stalks that stop abruptly at segment bases; discreet sori that are depressed-ovate, reniform, or occasionally lunate; ultimate segments that are dimidiate, trapeziforme, deltate, or occasionally ovate-falcate; free, dichotomous veins that end in marginal teeth; and laminar tissue that lacks visible idioblasts between veins. A taxonomic account, including descriptions and distributions of the species within this group is presented. Two members of this group, ‘Adiantum ecuadorianum’ and ‘A. exuberans’, are described as new, as is A. mariposatum, a member of clade D2.I.
R. James Hickey, PhD (Advisor)
Michael Vincent, PhD (Committee Member)
Richard Moore, PhD (Committee Member)
Martin Henry Stevens, PhD (Committee Member)
Ellen Currano, PhD (Committee Member)
105 p.

Recommended Citations

Citations

  • McCarthy, M. R. (2012). Molecular Systematics and Morphology of the Adiantum peruvianum Group (Pteridaceae) [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1350236402

    APA Style (7th edition)

  • McCarthy, Mirabai. Molecular Systematics and Morphology of the Adiantum peruvianum Group (Pteridaceae). 2012. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1350236402.

    MLA Style (8th edition)

  • McCarthy, Mirabai. "Molecular Systematics and Morphology of the Adiantum peruvianum Group (Pteridaceae)." Doctoral dissertation, Miami University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=miami1350236402

    Chicago Manual of Style (17th edition)