A fossil coryphoid palm from the Paleocene of western Canada

Palms (Arecaceae) are iconic plant fossils, providing evidence of warm climates in the geological past in geographical areas that today support temperate, boreal or even polar climates. Fossil palm leaves are well known from Paleocene sites in the U.S.A., including Montana, Washington, and Alaska. Palm megafossils are unknown, however, from the Canadian Paleocene. Here, palms from the Scollard Formation of Alberta are described and illustrated from the early Paleocene Genesee locality, central Alberta. These fossil palm leaves are fan palms (Subfamily Coryphoideae), but the limited diagnostic information of leaf fragments prevents assignment to a palm tribe. The Genesee megaflora represents a broad-leaf deciduous boreal forest growing under a temperate moist climate. The Genesee palm fossils demonstrate the northernmost Paleocene palms known from leaf fossils east of the Rocky Mountains, and are tiny at < 15 cm, likely reflecting plants growing at their cold northern limit.