A new genus is recognized on the basis of wind-dispersed fruits from the Eocene of western North America and Miocene of eastern Asia. The fruits consist of an accrescent hypogynous calyx of five obovate sepals and one or more globose fruit bodies. Although the fossils were formerly placed in the extant genera Porana (Convolvulaceae) and Astronium (Anacardiaceae), our investigation of numerous specimens from several floras in the western United States (e.g., Florissant, Green River, Clarno) and Canada (Whipsaw Creek, British Columbia) and the Yilan and Shanwang floras of China reveals unique characters that indicate that the fossils are a distinct genus, which we name Chaneya. Unlike Porana and Astronium, the fossil calyces have stomata that are longitudinally aligned, and early stages of fruit development show a gynoecium of five apocarpous carpels, of which only one or two usually enlarge at maturity. Precise systematic placement of the fossil genus is uncertain, but similarities to the extant Picrasma of the Simaroubaceae are suggestive of possible affinities. Two species are recognized: Chaneya tenuis (Lesq.) comb. nov., from the Eocene of western North America and northeastern China, and Chaneya kokangensis (Endo) comb. nov., from the Miocene of eastern Asia.