Approximately 500 specimens of taxodiaceous seedlings and germinating seeds have been recovered from two Paleocene (Tiffanian) localities in central Alberta, Canada. Specimens occur in a flora that includes Palaeocarpinus joffrensis, Onoclea sensibilis, Joffrea speirsii, Equisetum sp., Wardiaphyllum, an Aphananthe-like leaf, a polypodiaceous fern, and a large number taxodiaceous conifers that resemble Metasequoia. Specimens occur at three horizons at Gao Mine and at two horizons at Munce’s Hill in a gray-green to buff-colored siltstone, interspersed with Joffrea seedlings. Layers containing seedlings are 5 cm thick and overly layers rich in taxodiaceous foliage and seeds. The taxodiaceous seedlings have two linear cotyledons 8 - 21 mm long and 1.2 - 3 mm wide, with a single midvein and epigeal germination. Cotyledons have parallel margins and rounded tips. Many seedlings display a root and an aerial shoot with opposite, decussate leaves. Basal foliar leaves are consistently smaller and thinner than cotyledons, and terminate in small, mucronate tips. Basal foliar leaves are linear, 3 - 14 mm long. Some specimens display axillary branches with 2 - 8 pairs of opposite leaves, 3 - 10 mm long. The largest leaves occur on the longest branches, and are interpreted to represent the oldest seedlings. Seeds are 5 - 6 mm long and 6 - 7 mm wide, and consist of a narrow body and two symmetrical wings. Some specimens show a chalazal notch that probably represents the point of attachment. The micropylar canal is typically inconspicuous, except in specimens from which a radicle protrudes. These conifers, like the angiosperm Joffrea, were probably colonizers of open flood plain habitats, and provide the first evidence for the mode of germination and seedling development in extinct taxodiaceous conifers.

Key words: Metasequoia, Paleocene, Seedling Development, Taxodiaceae