Abstract
Fossil fruits document the former presence of Sloanea L. (Elaeocarpaceae) in Greenland and midlatitude North America during the early Tertiary. First described as Castanea ungeri by Heer in 1869 from the Paleocene of Greenland, the distinctive spiny fruits have since been discovered at several Paleocene to lower Eocene sites in Colorado, Wyoming and Montana.
The fruits are 3-5-valved capsules 2.5-3.5 cm in diameter, borne on long pedicels. Immature, unopened capsules show a single persistent style.
The capsules open from the apex with valves separating to the lower 10% of the fruit. Each valve has a smooth inner surface with a pronounced median septum and is ornamented dorsally with closely spaced, erect spines, 4-8mm long.
The North American and Greenlandic fossils are classified together as Sloanea ungeri (Heer) comb. n., a species that extended from the Lower Paleocene (Puercan) to the Lower Eocene (Lost Cabinian) in the Rocky Mountain region.