HERNANDEZ-CASTILLO, GENARO* and RUTH A. STOCKEY. Department of Biological Sciences, University of Alberta. Edmonton, Alberta. T6G 2E9. Canada. - Taxodiaceous pollen cones from the Eocene of British, Columbia, Canada.
The North American record of fossil conifers from the Upper Cretaceous
and Early Tertiary is extensive. Most of these conifers have been
assigned to the Cupressaceae/Taxodiaceae. However, the internal
anatomy of cones is only known for a few of these taxa. Two fossil
pollen cones have been collected at the Late Eocene Appian Way
Locality, just south of Shelter Point on the east coast of Vancouver
Island, British Columbia. Fossils are permineralized, and studied
using the cellulose acetate peel technique and scanning electron
microscopy. Cones are attached to stems that bear oppositely arranged
leaves with a single vascular bundle and an adaxial resin canal. The
cone axis bears decussate scale-like leaves that subtend and enclose
the microsporophylls. Microsporophylls are peltate with upturned
distal tips and a central resin canal. Three abaxial pollen sacs are
born on each sporophyll, and contain abundant non-saccate, papillate
pollen grains that are 13 - 20 µm in diameter. The walls of
pollen sacs are composed of thick-walled rectangular cells. These
cones show closest similarities to those in the
Cupressaceae/Taxodiaceae. Curved papillae on pollen grains, the
opposite arrangement of scale leaves, and the number of pollen sacs
per microsporophyll suggest affinities with the genus
Metasequoia. These cones are associated with numerous
taxodiaceous leaf and twig remains at the locality that show similar
anatomical characters to those of pollen cones, and will be the
subject of further study in the attempt to reconstruct this conifer as
a whole plant.
Key words: conifer, permineralization, pollen cone, Taxodiaceous