Pityopsis ruthii (Small) Small, currently listed as an endangered species by the State of Tennessee and the U.S. Fish and Wildlife Service, is a perennial plant belonging to the family Asteraceae. The distribution of P. ruthii is limited to soil that has accumulated in cracks and crevices of phyllite or graywacke boulders along the Ocoee and Hiwassee Rivers. Analysis of both the soil and the boulders indicate neither the absence nor the presence of any unusual nutrient. P. ruthii is most likely restricted to this habitat mainly because of its inability to compete with other more vigorously growing associates. The construction of dams along both rivers, resulting in lower frequency of flooding and reduced water flow, may have complicated the situation by creating a more favorable habitat for competitors, specifically Liatris microcephala L. and Andropogon ternarius Michx. In order to study the competition between P. ruthii and its two main competitors, L. microcephala and A. ternarius, the natural environment has been simulated in the greenhouse, using concrete blocks to create 1/4" cracks filled with sand. Six treatments were devised with different combinations of P. ruthii, L. microcephala, and A. ternarius, planted at a density of one plant per inch.
Lee, Helen, "The Competition of Pityopsis ruthii with Liatris microcephala and Andropogon temarius" (1996). Senior Research Projects. 116.