MAPES, GENE* AND GAR W. ROTHWELL. Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701. - A new conifer-like coniferophyte in the Upper Pennsylvanian of Kansas.
Among the thousands of plant specimens collected from Upper
Pennsylvanian sediments near Hamilton KS are coniferous stems with
forked leaves. Some of these represent penultimate axes of conifers
like Emporia lockardii, which has forked leaves on penultimate
shoots and simple leaves on ultimate branches. However, other
specimens represent a new plant that branches sparsely and has robust
ultimate shoots bearing both simple and forked leaves. The angle of
leaf bifurcation varies considerably, ranging from 75 to 180 degrees
on a single shoot. Leaves at attached branch bases are simple.
Several isolated branches show forked leaves proximally and simple
leaves at the apex. Attached forked leaves are 1.2 - 3.4 cm long,
whereas simple leaves on the same stems are smaller, ranging up to 1.4
cm long. Internal anatomy of the stems consists of pycnoxylic wood
that surrounds a parenchymatous pith with sclerotic plates. Primary
bundles are endarch, and the bark region is relatively thin. Below
the fork, leaves have a single vein within a broad midrib. Epidermal
cells are brick-shaped, or isodiametric with a prominent papilla.
Uniseriate, multicellular trichomes occur on stem surfaces, at leaf
margins and on leaf surfaces. Stomata occur in longitudinal rows
within stomatal bands, and consist of a ring of subsidiary cells that
surround inconspicuous guard cells. Each subsidiary cell has a single
papilla that overarches the stoma. Associated ovulate structures are
up to 16 cm long and 2 cm wide, comprising a compound shoot with
helically arranged bracts that subtend axillary ovulate shoots. None
of the ovulate structures show an apex, but some have a vegetative
zone distal to the fertile area, and in this regard resemble the
ovulate structures of Voltzia hexagona and Trichopitys
heteromorpha.
Key words: conifer, coniferophyte, Kansas, Upper Pennsylvanian