Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.

A Cretaceous fern flora haas been recently discovered near Westwater, Grand County, Utah. Among specimens collected from Westwater are many forms related to extant members of the fern family Matoniaceae. This family was widely distributed geographically throughout most of the Mesozoic Era, and matoniaceous ferns have been collected from several fossil localities in the United States. The Matoniaceae was especially important in the United States during Lower Cretaceous times. Five species, Matonidium brownii Rushforth, Matonidium lanceopennis Rushforth, Matonidium galleyi (Miner) Rushforth, Matonidium americanum Berry em. Rushforth, and Matonidium sp., and one variety, Matonidium brownii var. extenda Rushforth, are considered in the present paper.