Fagaceous Flowers, Fruits, and Cupules from the Campanian (Late Cretaceous) of Central Georgia, USA

A new genus of fossil angiosperms (Protofagacea allonensis gen. et sp. nov.) is established for staminate flowers with associated fruits and cupules from the Campanian (Late Cretaceous) Buffalo Creek Member of the Gaillard Formation in central Georgia, U.S.A. Staminate flowers are typically borne in sevenflowered dichasia (more rarely three- or five-flowered) subtended by three series of bracts. Flowers have six small imbricate tepals in two cycles of three, 12 stamens in two cycles of six, and a vestigial gynoecium with three styles surrounded by a mass of simple trichomes. Pollen is very small, prolate, tricolporate, and reticulate to microfoveolate. Associated fruits are triangular or lenticular in cross section and the triangular fruits bear six short tepals at the apex. Fossil pollen identical to that produced by the staminate flowers is attached to the apex of the fruits. Associated cupules are pedunculate and four-lobed and bear three or more fruits. The cupule lobes bear three series of bracts similar to those subtending the staminate dichasia. Scars on the internal surface indicate that each cupule contained a central fruit that was elliptical in cross section and two lateral fruits that were triangular in cross section. Comparisons of P. allonensis with extant taxa clearly indicate a relationship to extant Fagaceae sensu lato, based particularly on the presence of the cupule, the form of the fruits, and the morphology of staminate inflorescences and flowers. However, pollen morphology (probably plesiomorphic) differs from that of extant taxa, and detailed resolution of the affinities of Protofagacea will require a clearer understanding of relationships among extant Fagaceae sensu stricto and Nothofagaceae.