Tcherepova, Maria , Pigg, Kathleen B. .
Vitaceae: fossil seeds and wood from the Middle Miocene of Yakima Canyon, Washington, USA.
Permineralized seed and wood remains with vitaceous affinities are described from the middle Miocene Yakima Canyon flora of south-central Washington. Four complete seeds are found weathered out from the matrix, and several partially preserved and two complete seeds are found embedded in the matrix. Two additional seed casts from the nearby Umtanum locality are also studied. The Yakima seeds measure 3.5-4.0 mm in height and 2.5-3.0 mm in width. In face view they have a cordiform shape, and are bilaterally symmetrical with a pointed base. Seeds have ventral infolds that are slightly divergent, and a dorsally positioned elliptical to circular chalazal depression. From the overall morphology they have similarities to seed casts assigned to Ampelopsis rooseae from the middle Eocene Clarno Formation of Oregon, and to some species of Vitis. Seeds from Umtaneum are 2.5-3.0 mm high x 1.0 mm wide with a rounder outline and a pointed base. The ventral folds are positioned close to the edges of the seed, are either vertically positioned and parallel to one another or angled slightly outward. Eight small grape vines are also known from Yakima, with diameters from 5-10 mm and showing characteristic vitaceous anatomy. Today Vitaceae comprises around 15 genera and 700 species worldwide with a major center of diversity at the generic level in the Old World Tropics. Fossilized seed, wood, and leaf remains are common in the Tertiary floras, with records dating back to the early Eocene. The Yakima Canyon fossils demonstrate the presence of vitaceous plants within a Taxodium-dominated swamp, such as associated with similar environments today.
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Kathleen Pigg's laboratory website
1 - Arizona State University, School of Life Sciences, Asu, Main Campus, Po Box 874501, Tempe, Arizona, 85287-4501, USA
Presentation Type: Oral Paper
Location: Salon G - Austin Grand Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 3:00 PM