Degree Name

MS (Master of Science)



Date of Award


Committee Chair or Co-Chairs

Timothy D. McDowell

Committee Members

Christopher Liu, Foster Levy


The genus Tsuga is comprised of eight extant species found in North America and East Asia and four species represented by fossils from Europe and Japan. This study presents the first phylogenetic analysis based on structural, biochemical, and molecular sequence data. Characters obtained from published and unpublished literature were combined with new morphological characters from seeds, seedlings, and leaf cuticle material. Results from parsimony analyses of these characters differed from the published molecular based phylogeny. The non-molecular based phylogeny resolves two separate clades, a North American and an Asian, but did not group the western North American species, as in the molecular based analysis. Character states were traced on the trees to interpret character evolution. The combined analysis resulted in a phylogeny that differed from the previously published molecular tree by resolving a clade between T. caroliniana and T. diversifolia and placing T. dumosa outside of the Asian clade.

Document Type

Thesis - Open Access


Copyright by the authors.

Included in

Paleobiology Commons