Cruciptera, A New Juglandaceous Winged Fruit from the Eocene and Oligocene of Western North America

Abstract

Propeller-like samaras from the Eocene and Oligocene of Oregon and from the Eocene of Washington and Wyoming have characters of internal nutlet morphology, sepal and bract con- figuration diagnostic of the Juglandaceae. These fruits, given the new generic name Cruciptera, consist of a globose unilocular nutlet with incomplete primary and secondary septa, four free epigynous sepals, and four elongate wings that radiate from the equatorial plane of the nutlet in the shape of a cross. The wings have subparallel, dichotomizing venation. The genus is also rec- ognized from the middle Eocene of southern England and western Germany. Although the associated foliage and pollen have not been recognized, available fruit characters support placement of Cru- ciptera in the tribe Juglandeae, near extant Cyclocarya and extinct Polyptera. The appearance of Cruciptera in the fossil record post-dates the earliest appearances of Cyclocarya and Polyptera and predates the first confirmed records of Pterocarya. The new combination, C. simpsonii, is also described. The Juglandaceae, with eight extant genera and about 60 species, are distributed in tem- perate to tropical areas, mostly in the Northern Hemisphere. Although the family is best known for the genera with large edible nuts such as Juglans and Carya, most genera possess winged