HANSEN, AMANDA, L.* and KATHLEEN, B. PIGG. Department of Plant Biology, Arizona State University, Box 1601, Tempe, AZ, 85287-1601 USA. - Taxodiaceous conifers from the middle Miocene Yakima Canyon flora, Washington State, USA.
Anatomically preserved taxodiaceous conifer remains are described from
the middle Miocene Yakima Canyon flora of central Washington State,
USA. These remains include ovulate cones and seeds, isolated cone
scales, wood, foliage and twigs of possible taxodiaceous affinity.
Some seeds contain mature embryos. While many specimens are contained
within the chert matrix, others have been weathered out and are
preserved in the round, showing external morphological features.
Isolated cone scales range from 9-11 mm high x 11-12 mm wide x 4 mm
thick and bear two seed depressions on their inner surface. The
apophysis has an umbo that protrudes 3 mm from the outer surface of
the scale and a dentate margin on the apical half. Isolated seeds are
winged, elongate, 11.5-13 mm long x 6 mm wide x 3-4 mm high, and are
triangular in cross section. Foliage shows prominent stomatal furrows.
The taxodiaceous remains at Yakima Canyon occur commonly with the
ferns Osmunda wehrii Miller, Woodwardia
virginica (L.) J. E. Smith, and a third small filicalean form
and are considerably more abundant than the previously described pine
from this same site, Pinus foisyi Miller.
Key words: fossil conifer, Miocene, permineralization, Taxodiaceae, Yakima Canyon