PIGG, K. B.1*, M. L. DEVORE2, D. L. DILCHER3, and D. FREILE4. 1Department of Plant Biology, Arizona State University, Box 871601, Tempe, AZ 85287-1601; 2Department of Biological and Environmental Sciences, Georgia College & State University, Milledgeville, GA 31062-0001; 3Florida Museum of Natural History, University of Florida, Gainesville, FL 32611-7800; 4Geology, Berry College, Mt. Berry, GA 30149. - Fagaceous infructescences from the Oligocene Catahoula Formation of Texas.
Spiny, husk-like infrutescences ("frilly fruits") are
described from the Oligocene Catahoula Formation from near Huntsville,
Texas, and the middle Eocene Claiborne Formation of Tennessee, USA.
The fruits are 5.5- 8 mm long and 8 mm wide and have a peduncle up to
10 mm long. They have a central body surrounded by a fibrous flange
that becomes thin and paper-like and covered with "fringe"
and trichomes toward its periphery. The peduncle also has trichomes of
two sizes. Specimens lack seeds and are fractured to show internal
carpel walls, which sometimes have vertical stripes similar to those
seen in extant Fagus. The general organization of these fruits
suggests possible affinities with Fagaceae, particularly Fagus
or perhaps Castanea. Associated with these fruits are leaves of
the Castenophyllum and Berryophyllum types, some of
which may represent the same fagaceous plant. The occurrence of these
infructescences in both the western Tennessee Claiborne Formation and
the eastern Texas Catahoula Formation floras is significant because it
suggests that elements of the middle Eocene Claiborne flora may have
migrated westward along the Gulf coastal plain. These infructescences
have not been reported from Eocene floras of Texas. The Catahoula
Formation represents a very different depositional environment than
the fine clays deposited in the oxbow lakes of the Claiborne. The
Catahoula, which contains large amounts of volcanic ash, was most
likely deposited in a tidal flat-paralic marginal marine environment.
Key words: Catahoula, Claiborne, Eocene Floras, Fagaceae, Oligocene Floras