Abstract Detail

Pteridological Section/AFS

Silvius, John E. [1], Thomas, Daniel L. [2].

An Integrative Approach to the Characterization of Psilotum (Psilotophyta): Insights from the Past and Recommendations for the Future.

The intriguing whisk fern, Psilotum nudum (Psilotophyta), has resisted the efforts of biologists to pinpoint its taxonomic classification for the past century or more. Although the sporophyte of Psilotum develops from a unipolar embryo in a manner similar to other pteridophytes, its leafless, dichotomous stems bear only enations, and its rootless subterranean rhizomes bear only rhizoids which host arbuscular mycorrhizal fungi. The claims of  selected leading plant morphologists during the past century represent principal interpretations of the significance of these characteristics of Psilotum. Early in the 19th century, Eames represented the view that psilophytes are primitive and taxonomically isolated. Fifty years ago, Bierhorst associated Psilotum with the monilophytes because of its similarity to the fern Stromatopteris and opposed the primitive view with evidence for morphological reduction. More recently, Kaplan’s thorough analysis of shoot organization and development identified characteristics of Psilotum resembling those of seed plants. From our investigation into the history of Psilotum research, we suggest that a plant taxon can be better understood through a conceptual approach that is holistic and integrative. Using this integrative approach based upon Kaplan (2001), we performed a comparative analysis of Psilotum that emphasizes the importance of developmental biology, physiology, and ecology in understanding the morphology and systematics of Psilotum. Our holistic analysis lends a richness of perspective that expands upon reductionist approaches and offers potential for those who wish to pursue fruitful interdisciplinary collaboration.

Broader Impacts:

1 - Cedarville University, Science and Mathematics Department, 251 N Main Street, Cedarville,, Ohio, 45314, USA
2 - Cedarville University, Science and Mathematics Department, 251 N Main Street, Cedarville, OH, 45314, USA

Keywords:
Psilotum
fern systematics
whisk
morphology
physiology
development
ecology
genetics.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:30 PM
Number: PPD007
Abstract ID:757