TAXODIUM-WALLISII SP. NOV - FIRST OCCURRENCE OF TAXODIUM FROM THE UPPER CRETACEOUS

Exceptionally well-preserved silicified remains of a new species of Ta xodium have been recovered from the Late Cretaceous (ca. 70 million ye ars old) sediments of the Horseshoe Canyon Formation near Drumheller, Alberta, Canada. Specimens include three-dimensionally preserved branc hes bearing dimorphic leaves, pollen cones, pollen, seed cones, and se eds. The abundance and quality of preservation of these remains have a llowed for detailed examination of morphological and anatomical featur es for comparison with extant representatives of the Taxodiaceae. The vegetative axes bear taxodioid leaves and rare cupressoid leaves; stam inate and pistilate axes are subtended entirely by cupressoid leaves. The seed cones are erect, short-stalked, and globose, arranged alterna tely on branches, and bear up to fifteen helically arranged, deciduous bract-scale complexes. Each cone scale bears two more or less triangu lar seeds. Vasculature and arrangement of the resin canals of the cone scales are much more complex than that of any of the extant species e xamined. The pollen cones are typical of extant Taxodium; the pollen g rains are structurally comparable, but small when compared with extant representatives of the genus. Comparison of these fossils with extant representatives of the Taxodiaceae indicate that they are most simila r to Taxodium, but are comparable to Glyptostrobus and Cryptomeria in some features. The Horseshoe Canyon Taxodium is the first unequivocal report of Cretaceous Taxodium from North America and provides insight into the early evolution of the genus and phylogenetic relationships a mong other representatives of the family.