Systematics and phytogeography of selected Eocene Okanagan Highlands plants

Authors

Melanie L. DeVore, Georgia College & State University
Kathleen B. Pigg, Arizona State University
Wesley C. Wehr, University of Washington

Document Type

Article

Publication Date

2005

Publication Title

Canadian Journal of Earth Sciences

Abstract

The diverse Early to Middle Eocene Okanagan Highlands floras of south central British Columbia and northeastern Washington reflect a time of rapid evolution and the early radiation of many dicot families that are currently significant elements of temperate floras. Recent studies of the Republic, Washington flora (Klondike Mountain Formation) and related Okanagan floras in British Columbia have documented both the earliest, and sometimes the only, known fossil occurrences of genera. Today many once more widespread taxa are restricted, particularly to Asian and (or) eastern North American refugia. Examples include members of the families Betulaceae (birch, hazelnut), Rosaceae (rose), Hamamelidaceae (witch hazel), and the endemic Asian family Trochodendraceae. Earliest occurrences are noted for Neviusia (Rosaceae), Trochodendron (Trochodendraceae), Corylus and Carpinus (both Betulaceae). The first unequivocal leaf records of Corylopsis and Fothergilla (both Hamamelidaceae), and two new Eocene species of the extinct fruit Palaeocarpinus (Betulaceae) are also recognized. Today, Trochodendron and Corylopsis are restricted to Asia, whereas Neviusia and Fothergilla, genera with close Asian relatives, occur only in North America. Corylus johnsonii from Republic is most similar to the extant Asian species C. heterophylla, C. wangii, and C. ferox. Neviusia leaves from One Mile Creek near Princeton, British Columbia are more similar to N. cliftonii, an endemic from Mount Shasta, California, than to N. alabamensis of southeastern North America. A better documentation of the Okanagan Highlands floras is essential to our understanding of the evolution of North American temperate floras and the nature of Asian - North American disjunct taxa.

Department

Biological and Environmental Sciences

Volume Number

42

Issue Number

2

First Page

205

Last Page

214

Comments

© 2005 NRC Canada.

DOI

10.1139/e04-072

Recommended Citation

DeVore, M.L., Pigg, K.B., & Wehr, W.C. (2005). Systematics and phytogeography of selected Eocene Okanagan Highlands plants. Canadian Journal of Earth Sciences, 42(2), 205-214.