A NEW GENUS OF CORYLOIDEAE (BETULACEAE) FROM THE PALEOCENE OF NORTH-AMERICA

A new genus of Betulaceae, Cranea, is recognized from the Paleocene of central and northern Wyoming based on infructescences with associated leaves, staminate inflorescences, and in situ pollen. The elongate in fructescences bear numerous closely spaced sessile, persistent, obconi cal involucres that each envelope an elliptical nut with an epigynous perianth. Although some aspects of the infructescence morphology remai n unknown, the involucres and nuts are similar to those of extant Ostr yopsis of eastern Asia. The fossil infructescences are more elongate t han those of Ostryopsis, and the involucres at the apical and basal en ds of the infructescence are small and apparently infertile. Staminate catkins found in association with Cranea bear triporate pollen resemb ling that of Coryloideae. Associated leaves have compound teeth, close ly spaced parallel secondary veins, and closely spaced, percurrent ter tiary veins and are similar to the leaves of extant Carpinus and Ostry a. The reconstructed plant conforms to the subfamily Coryloideae but c annot be placed in a modern genus. Cranea and Palaeocarpinus are two e xamples of extinct coryleoid genera that appear in the fossil record p rior to the earliest confirmed fossil records of extant coryleoid gene ra.