FRUITS OF THE JUGLANDACEAE FROM THE EOCENE OF MESSEL, GERMANY, AND IMPLICATIONS FOR EARLY TERTIARY PHYTOGEOGRAPHIC EXCHANGE BETWEEN EUROPE AND WESTERN NORTH-AMERICA

The extinct genus Cruciptera, formerly documented only from the Tertia ry of western North America, is recognized on the basis of well-preser ved four-winged samaras, and a new species is described: Cruciptera sc haarschmidtii. Analysis of the cuticle reveals peltate scales that com plement morphological data in confirming the position of this genus in the Juglandaceae. The Messel fruits, together with two specimens from the middle Eocene pipe clays of southern England, indicate that Cruci ptera was distributed in Europe as well as North America during the Eo cene. A survey of juglandaceous fruits from the Eocene of Messel, Germ any, reveals two additional genera: Palaeocarya and Hooleya. The triba l affinities of the Messel fruit genera are compared with those of jug landaceous foliage and pollen previously described from the same sedim ents. Palaeocarya and Hooleya share a similar paleogeographic distribu tion to that of Cruciptera, suggesting exchange via the Eocene North A tlantic land bridge.