Carlie J. Phipps
Project Topics / Abstracts:
"Pine pollen cones from the Middle Eocene of British Columbia, Canada"
Anatomically preserved pollen cones are described from the
Middle Eocene Princeton chert of British Columbia, Canada.
Cones are ellipsoidal, range from 2.8-6.9 mm in length,
1.6-3.5 mm in diameter, and are often subtended by scale
leaves. Cone axes contain longitudinally oriented, cortical
resin canals and 14-18 vascular bundles. Microsporophylls
are helically arranged, each bearing two abaxial pollen
sacs, many containing pollen grains. Grains are bisaccate
and monosulcate, ranging from 50-70 µm in length and 27-43
µm in width. Proximally, the corpus is rugulate with a
tectate-alveolate infrastructure. Sacci have a well-defined
endoreticulum and an external ornamentation that is psilate
to scabrate. Variations in cone size, cone anatomy, and
pollen morphology indicate that several developmental stages
are preserved. The large number of cones present in the
chert, especially those representing short-lived ontogenetic
stages, and the preservational quality of the cones support
depositional interpretations for a rapid burial and
preservation. These factors also indicate that the pollen
cone producing plants occupied a marginal position in close
proximity to the lacustrine environment. Four species of
Pinus, based on woody twigs, dwarf shoots, leaves, and
ovulate cones, are presently known from the Princeton chert.
The association of these pollen cones with P. similkameenensis leaves and
P. arnoldii ovulate cones
indicates possible taxonomic affinities among these species.
The Princeton chert specimens are the oldest Pinus pollen
cones to be described and are the first in the genus for
which fossil pollen ultrastructure has been described.
"Structurally preserved
spenophytes from the Triassic of Antarctica: Reproductive
remains of Spaciinodum"
Permineralized cones found organically attached to
Spaciinodum collinsonii stems are described from the early
Middle Triassic silicified flora from the Fremouw Formation
of Antarctica, and the species diagnosis is emended to
include the reproductive specimens. The apical cones are
organized into internodal and leaf-bearing nodal regions.
Nodal septations span the central pith and cortex, and thin
fimbrils subdivide the internodal areas into smaller
chambers. The vascular system consists of 31-33 continuous
bundles that do not alternate in position between successive
nodes and internodes. Simple sporangia are associated with
the coritcal chambers and occur in one whorl on the axis.
Spores are small, alck elaters, and have no discernible
ultrastructure preserved, and they are interpreted to be
immature. The Antarctic cones are different in structure
form typical cones of modern and fossil members of
Equisetales; however, they share similarities with some
morphologically aberrant cones of extant Equisetum and
several Late Paleozoic and Mesozoic compression-impression
fossils. Spaciinodum is now the most complete anatomically
described Mesozoic sphenophyte.
Publications:
1995 International Journal of Plant
Sciences 156: 117-124.
Abstract
1999 Review of Palaeobotany and Palynology
111: 225-235.
Abstract
Presentations:
1992 Truman Undergraduate Research
Symposium (Kirksville, MO)
1993 Missouri Academy of Science (Kansas
City, MO)
1993 Truman Undergraduate Research
Symposium (Kirksville, MO)
1994 National Conference on Undergraduate
Research (Kalamazoo, MI)
1994 Truman Undergraduate Research
Symposium (Kirksville, MO)
1994 Tri-Beta Biological Honor Society
Regional Meeting (Steelville, MO)
1994 Sigma Xi Student Research Symposium
(Kirksville, MO)
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