Davidia, a genus that is now endemic to China, played a prominent role in Paleocene vegetation of mid-latitude North America that previously was overlooked. Davidia antiqua (Newberry) comb. nov. is now known from co-occurring leaves and fruits at eight localities in the Fort Union Group of North Dakota, Montana, and Wyoming. The leaves, for more than a century called Viburnum antiquum (Newberry) Hollick, conform to extant Davidia in the long petiole, cordate base, pinnate venation, basal secondary veins with regular branches to the margin, typically blunt, large marginal dentations with medial vein insertion, and closely spaced percurrent tertiaries. Fruits are borne singly on otherwise staminate inflorescence heads. The peduncle bears two prominent scars, well below the head, interpreted as the attachment points of large bracts. The fruit stones are ellipsoidal, composed of fibers, with six to eight single-seeded locules, each with an elongate dorsal germination valve. Vascular bundles are not axial, but are scattered through the septae. Although only two-thirds the size of the fruits of extant Davidia involucrata Baillon, and less prominently sculptured, the fossil fruits correspond closely to the extant ones in morphology and anatomy. Similar leaf and fruit impressions occur together in Paleocene deposits of eastern Russia, but additional work is required to determine if they represent the same species as the North American material. This work establishes that extant Davidia had evolved by the Paleocene, prior to the first known occurrences of Nyssa in the Eocene, and was a contemporary of the extinct nyssoid genus Amersinia. The available stratigraphic record thus implies rapid evolution of Nyssoids within the early Tertiary, or may be taken to indicate that this group of Asterids began its diversification in the Cretaceous.

Communicating Editor: Matt Lavin