Benedict, John C. , DeVore, Melanie L. , Pigg, Kathleen B. .
Rosaceous flowers resembling Prunus from the Eocene Republic flora of eastern Washington State, USA.
The Eocene Republic Flora of eastern Washington State is well known for its diverse leaf compression flora and insect fauna, as well as beautifully preserved flowers, fruits and seeds. This flora is significant in documenting the radiation of several families of importance in temperate regions of the world today, among them Rosaceae, Betulaceae, and the maples (Acer, Sapindaceae). Here we describe rosaceous flowers and young fruits preserved as coalified compressions, some of which contain anthers with in situ pollen. Four of these flowers closely resemble those of extant Prunus, including one with 10 attached stamens. Flowers are found compressed longitudinally and are solitary on pedicels up to 1.4 cm long, and are perigynous with a clearly superior ovary. In some specimens the ovary is asymmetric, as would be expected in a drupaceous fruit with a single developing ovule. Perianth parts and stamens are attached to the hypanthium and stamens are recurved inward toward the gynecium. The style is up to 4 mm long and terminates in a broad, flattened stigma that is quite similar to those seen in extant Prunus flowers. Mature Prunus endocarps have described from the Princeton chert and Clarno Nut Beds, however, these Repubic specimens document the first information on Eocene floral and young fruit remains. The rapid radiation of Rosaceae is “caught in the act” in the assemblages of sites collectively known as the Okanogan Highlands floras and is of significant biogeographic importance.
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1 - Arizona State University, School of Life Sciences, P.O. Box 874501, Tempe, Arizona, 85287-4501, USA
2 - Georgia College & State University, Biological & Environmental Sciences, 135 Herty Hall, Campus Box 81, Milledgeville, Georgia, 31061, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 1:30 PM