217-13 Considering Evolutionary Adaptations and Finding Hidden Treasures Among Remains of the Latest Early Eocene Flora of Republic, Washington

Session: Paleontology, Paleoecology/Taphonomy

Presenting Author:

Authors:

Abstract:

The latest Early Eocene flora of Republic (Ferry County) Washington and related Okanogan Highlands localities in central British Columbia have been known since the late 1800s and well studied systematically since the 1980s by Jack Wolfe, Wes Wehr, Steve Manchester and others along with ourselves. Republic has been a significant flora in documenting the diversification of major families such as Rosaceae and Betulaceae, that today dominate the temperate deciduous biome of the Northern Hemisphere. Over 40 systematic studies have resulted from these collections, with more to come. Projects considering the flora in depositional, biodiversity and paleoecological contexts have been led by Kirk Johnson, David Greenwood and others. Many of these studies have been possible because of the managed public fossil collecting mediated by Stonerose Interpretive Center that provides a steady, ongoing source of new material.

Our approach to studying these upland lacustrine deposits has focused on considering the evolutionary adaptations that were necessary for plants to make in order to diversify into the temperate biome. In studies of the past dozen years we have documented evidence of 1) dormancy mechanisms, including long-shoot, short-shoot plant architecture; 2) hybridization in Rosaceae and Anacardiaceae; 3) combined sexual and asexual reproductive structures in onions;  and 4) evidence of herbivory deterrence in the production of stinging nettles (Urticaceae) during the time of modern mammal diversification.

More recently we have turned our attention to taphonomic questions of what plants and plant parts are typically recovered and why certain plants are either not well represented or not recognized. For example, although fossils are recovered, some groups such as filicalean ferns and aquatic monocots are rarely well documented in comparison to dicots and conifer remains. Moreover, some plants that may have been present in the flora may be difficult to identify without definitive reproductive structures. For instance, we have a slim chance of recovering the flowers and fruits of monocarpic plants. Remains of nondescript leaves and stems are overlooked and/or misidentified. Such is the case of temperate bamboos resembling modern Arundinaria currently under study.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-5279

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