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Office: N-607 Research Interest: Plant Taxonomy, Plant Systematics, Ecology Re-evaluating the Schrankia (Fabaceae) complex within the genus Mimosa
:
The genus Schrankia has been incorporated, taxonomically, within the
Mimosa genus of the legume family. We are looking at two genes, the rRNA
gene and the rbc L chloroplast gene to determine if this taxonomic change
is valid. We are sequencing these genes from the 15 species of Mimosa
that are found in Texas and plan to analyze the data using some or all
of the following programs to create phylogenetic trees showing relationships
between these taxa in an attempt to answer this question: PHYLP, neighbor
joining, and maxim mum likelihood
An analysis of the Mimosa quadravalvis complex:
The 5 species of Schrankia that were incorporated into the Mimosa
genus were initially classified under the species name quadravalvis with each
being represented as a variety within that species. If indeed the Schrankia
members do belong within the Mimosa genus, the question of their status
needs to be clarified. At first they were put within the quadravalvis
complex and later elevated to the level of individual species. The question
remains - which taxonomic designation is the most correct for these members
of Mimosa. Using molecular analysis of
sequences of the rRNA and rbc L genes we hope to answer these questions.
Re-evaluation of Mimosa strigillosa:
Mimosa strigillosa is always described in taxonomic keys as being
herbaceous and unarmed (no prickles) while the rest of the Mimosa group
are armed with prickles. M. strigillosa is found in many counties along
the Texas Gulf Coast and we do see variations between the members in the
upper Gulf Coast region and members in the Rio Grande valley. Specimens
collected in the valley frequently have some prickles (a few) and tend
to have woody stem bases, unlike their herbaceous members. Using molecular
analysis of the rRNA gene and the
rbc L chloroplast gene we hope to answer this question.
Celtis laevigata, sugar hackberry, has three varietal forms that are
difficult to distinguish morphologically and there is some disagreement
of the naming of these varieties. Some feel that one of them should have
a species designation. We will investigate this taxonomic problem using
the molecular techniques mentioned above.
Ecological restoration at Sheldon Lake State Park
I have been involved with the Sheldon Lake State Park Grassland Restoration
and Succession Study for several years. This is a collaborative study
involving several members of the Department of Natural Sciences at UHD.
A large area of the park has been under cultivation for over 50 years
but TPWD is now trying to return it to its natural state of a Gulf Coastal
Prairie. I have evaluated the plant life within a woodland adjacent to
the to-be-restored prairie. The prairie area is characterized by low areas
that hold water during wet periods and raised areas called mima mounds that
act as areas of microhabitat. As the Parks Department sows native Texas
grass seeds, we will
study the distribution of the native grasses throughout the prairie
looking for areas of preferential growth and compare that with changes
in soil microbes and fungal populations as the area undergoes ecological
change. Research is underway on characterizing soil microbes and fungi
but I am waiting on the Parks Department to sow the grass seeds. We hope
to determine if restoration of a native grass prairie is possible by comparing
the changes occurring at Sheldon Lake State Park with a remnant of native
Gulf Coastal Prairie located near
League City and owned by the University of Houston. My work should
resume in the spring of 2005.
Environmental Assessment of the Presence of Xylella fastidiosa in native
Gulf Coastal plants. Working with Dr. Lisa Morano I have been involved
in identifying plants in the area that we are testing for the presence
of Xylella fastidiosa, a bacterium that causes Pierce's Disease of grapes.
Member - American Botanical Society
Member - Texas Academy of Sciences
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