MAPES, GENE* and GAR ROTHWELL. Department of Environmental and Plant Biology, Ohio University, Athens OH 45701 USA. - A distinctive long needled walchian conifer from the uppermost Pennsylvanian Hamilton Quarry, Kansas.
The diverse uppermost Pennsylvanian flora from the Hamilton Quarry,
Kansas includes approximately five conifers and conifer like
coniferophytes. These are the short needled Emporia lockardii,
two other short needled species, the long needled coniferophyte
Barthelia furcata, and a long needled conifer species with a
distinctive pattern of branching, cuticular features, and internal
anatomy. This plant is represented by approximately 40 specimens of
vegetative shoots and one ovulate cone. The long needled conifer
shoots consist of two orders of plagiotropic branches with helically
arranged leaves. Leaves are amphistomatic, with parallel rows of
stomata like the European genus Ernestiodendron rather than two
adaxial bands like most other species of walchian conifers. Ultimate
leaves are simple, while penultimate leaves are forked. Internal
anatomy is similar to Emporia lockardii, but the solid pith has
sclerotic nests that are not known to occur in E. lockardii.
The ovulate cone is compound, with ovuliferous dwarf shoots in the
axils of helically arranged, forked bracts. Ovuliferous dwarf shoots
have numerous sterile scales and 2-3 interspersed sporophylls, each
bearing an inverted terminal ovule. This new conifer displays a
distinctive combination of characters that include regularly branched
plagiotropic shoots, position-dependent heterophylly, long needles on
ultimate branches, amphistomatic leaves with stomata in parallel rows,
Emporia-like ovuliferous dwarf shoots, and sclerotic nests in
the otherwise parenchymatous pith. Numerous conifer pollen cones of
generally similar morphology also occur at the locality, but have not
yet been found attached to other organs of this plant. All are simple
cones with adaxially attached clusters of pollen sacs that bear
Potonieisporites-type eusaccate prepollen. Assuming that at
least some of these cones were produced by this long needled conifer,
then the microsporangiate structures of the plant are similar to those
of Emporia. This combination of characters is not present in
any previously described species of walchian conifers.
Key words: conifer, Late Paleozoic, walchian