Characterizing morphological traits in Phragmites australis subsp. berlandieri

Rapid expansion of invasive plant species may cause adverse genetic, ecological, economic, and even medical effects. One species of concern in the United States is the invasive grass Phragmites australis subsp.  australis from Europe.  Although the invasive genotype, native genotype P.  australis subsp. americanus, and Gulf Coast genotype P. australis subsp. berlandieri  have been found in parts of the United States, few studies have described the genotype present on the Gulf of Mexico. In conjunction with a companion genetic study identifying the subspecies found in the Coastal Bend of Texas, we characterized morphological features from a total of 100 plant samples from four populations across the Coastal Bend of Texas. These characteristics include stem texture, stem flexibility, stem density, rhizome diameter, rhizome shape, stem color, leaf color, and base stem color. To asses color differences quantitatively, we developed a new method using the GNU Image Manipulation Program (GIMP). The project is partially completed, and we expect final results at the beginning of August 2011. Not only were we able to describe features of Phragmites in the Coastal Bend of Texas, but we also developed a color assessment technique that may aid identification of any Phragmites and adapted for use in other species in which color is an important distinguishing feature. Results from this project will also help aid local land managers make scientifically informed decisions about their Phragmites populations.