VIRGINIANTHUS CALYCANTHOIDES GEN ET SP-NOV - A CALYCANTHACEOUS FLOWERFROM THE POTOMAC GROUP (EARLY CRETACEOUS) OF EASTERN NORTH-AMERICA

We describe a new well-preserved fossil flower, Virginianthus calycant hoides gen. et sp. nov., from the Early Cretaceous (Early or Middle Al bian) of Virginia. The flower is multipartite and has a distinct, deep floral cup. The perianth and androecium are borne on the rim of the f loral cup and arranged in several crowded series. Reconstruction of th e flower indicates that the perianth is composed of about 12 closely s paced tepals with apically directed hairs on the abaxial surface. The androecium consists of approximately 30-40 closely spaced, sessile sta mens. The anthers are dithecate and tetrasporangiate, with the pollen sacs borne toward the abaxial surface. Dehiscence is extrorse through laterally hinged valves. Pollen grains are monocolpate and reticulate and resemble the previously described pollen species Clavatipollenites minutus Brenner. Sterile structures in the transition zone between an droecium and gynoecium are interpreted as inner staminodes. The gynoec ium is composed of approximately 18-26 carpels borne in several series on the inner surface of the hypanthium. The flower is closely compara ble to extant member; of the family Calycanthaceae (including Idiosper mum) and constitutes the earliest documentation of calycanthoid featur es in the fossil record. Differences from extant Calycanthaceae are ma inly in details of the pollen sacs, anther dehiscence, and pollen morp hology.