Doctoral Dissertations

Date of Award

5-2002

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Botany

Major Professor

Karen W. Hughes

Committee Members

Ronald H. Petersen, Edward E. Schilling, Paul A. Delcourt

Abstract

This study comprises a complete reevaluation of genera Artomyces J filich and Clavicorona Doty, based primarily on analysis of nuclear ribosomal ITS 1 — 5.88 — ITS 2 DNA (ITS) sequences and complemented with morphological characterizations. Clavicorona, as represented by the type species C. taxophila was completely divergent from Artomyces and probably is more closely related to the Omphalina — Gerronema - Chrysomphalina group. A total of 16 species are recognized in Artomyces, including eight species described as new and one species name transferred from Clavicorona. Although a phylogenetic estimation based on the ITS sequences revealed little resolution in the basal nodes, five major and two monospecific clades were identified. Broad biogeographical patterns among the species of Artomyces could not be identified, but intraspecific biogeographical patterns were observed within the widespread species A. pyxidatus. Previous studies established that populations of A. pyxidatus from the eastern United States, Sweden, and China were conspecific based on mating compatibility and enzyme profiles. In this study, mating compatibility was extended to include collections from Russia, Costa Rica, Mexico, and Utah. The molecular diversity within A. pyxidatus was examined by DNA sequence and restriction site analyses of the ITS region. A phylogenetic analysis of twelve collections based on ITS sequences revealed a broad geographical pattern in which Eurasian collections comprised a sister clade to North American collections. North American collections were further subdivided into northeastern and southwestern clades. A survey of 255 A. pyxidatus collections using restriction enzymes revealed variable RFLP patterns that followed similar geographical patterns.

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