Spatial Segregation among Phacelia bipinnatifida Morphotypes in Shakerag Hollow

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Michel, J.T.
Evans, Dr. Jon
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Scholarship Sewanee 2023 , University of the South , morphotype , spatial segregation , polymorphisms , genetic isolation
Phacelia bipinnatifida, also known as scorpionweed, is a biennial wildflower that lives in old-growth cove forest sites such as Shakerag Hollow. Polymorphisms exist in certain flower populations, with varying characteristics being present in different groups of one species. Polymorphisms, observed as morphotypes, exist in P. bipinnatifida through a variation in flower color (blue and purple), scent, spotted leaves, and stamen length. Populations of each morphotype are spatially segregated as large patches in the Shakerag Hollow landscape. The objectives of this research are to 1) determine why these Phacelia bipinnatifida patches stay true to morphotype with each successive two-year (biennial) cohort, and 2) identify the ecological processes responsible for maintaining the homogeneity of a morphotype patch despite the opportunity for gene flow between patches. To accomplish these objectives, complementary ecological and genetic research will be conducted. The ecological analyses focus on pollinator fidelity to one morphotype and soil composition as agents of spatial morphotype segregation. Genetic research will evaluate single nucleotide polymorphisms (SNPs) through microsatellite data that will determine the degree of gene flow between the two morphotypes. After considering the ecological and genetic data, we will be able to determine the cause of this novel sympatric morphotype segregation.