Masters Theses

Date of Award

5-2000

Degree Type

Thesis

Degree Name

Master of Science

Major

Botany

Major Professor

Edward E. Schilling

Committee Members

B. E. Wofford, J. L. Gittleman

Abstract

The purpose of this study was to make a comprehensive analysis of the systematic relationships within Trilliaceae, a family of flowering herbaceous plants found in north temperate mixed forests As currently circumscribed it includes Trillium L, Paris L., Kinugasa Tatew. and Sutô, and Daiswa Raf. Results of previous rbcL studies showed that the members of Trilliaceae segregate out into a distinct, cohesive unit separate from other liliaceous genera, and reinforced the concept that Trilliaceae are not a part of the Liliaceae and should in fact be an independent family. The present study focused on the relationships within Pans s I ;(i.e., Pans, Daiswa, and Kinugasa); between Pans, s I. and Trillium, and within Trillium itself. A total of 86 taxa, including all of those currently recognized, was selected for morphological, cladistic analysis and scored for 110 morphological characters It was also possible to obtain matK and ITS molecular characters for a subset of taxa used in the morphological analysis. Several genera outside the family were considered for outgroup selection, but none of those taxa proved satisfactory. Based on preliminary analyses, Trillium rivale was shown to be distinctive and was used as the outgroup The data sets were analyzed with the PAUP* program using maximum parsimony as well as maximum likelihood. Character congruence analysis gave contradictory results with the Mickevich and Farris measures showing less than 5% variation between data set, and the Paup* Homogeneity of Partitions test indicating incongruence between the morphological and molecular data sets. Taxonomic congruence gave results showing that most clades were supported across all analyses, and rival trees were less than 5% longer than the constraint tree for a given data set. Analysis of the combined ITS and matK sequence data produced 6 shortest trees, the morphological data for the same set of taxa for which molecular data were available produced 13 shortest trees, the combined morphological and molecular data sets produced 3 trees, and the full data set of 86 taxa produced 1,296 shortest trees with an average Cl (consistency index) of 0.74 Trillium rivale is distinct from both Pans and Trillium and should be placed in its own genus. Trillium and Paris are clearly distinct based on molecular as well as morphological evidence. Trillidium govamanum is more similar to Pans than it is to Trillium, but should be recognized as a distinct monotypic genus Trillium undulatum is clearly a Trillium based on morphology and biogeography. The cladistic analysis provided support for the separation of Pans s I into Daiswa, Kinugasa, and Pans. The monophyly of Trillium was supported in all analyses.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS