Definitive identification of Larix (Pinaceae) wood based on anatomy from the middle Eocene, Axel Heiberg Island, Canadian High Arctic

This paper provides the first definitive identification of fossil Larix Miller wood using the characteristic features of ray-tracheid bordered pits. The wood was recovered from the middle Eocene (Lutetian/Uintan; 41.3-47.5 Ma) Buchanan Lake Formation on eastern Axel Heiberg Island in the Canadian High Arctic and extends the fossil record of Larix wood further back in geologic time. A new and rapid embedding method is described which provides a firm and non-destructive matrix for thin-sectioning and examining the well-preserved details of the wood. The wood is associated with Larix altoborealis LePage & Basinger, a short-bracted species, which was previously described from this locality as the earliest known species of Larix.