The milkweed plant is an important source of food and protection for a wide variety of arthropods; milkweeds are the only plant on which monarch butterflies can lay their eggs and on which monarch caterpillars can survive. Monarch butterflies play an important role as pollinators of the prairie ecosystems which cover Illinois. Milkweeds are therefore a species that warrants investigation for the sake of preserving the monarch communities and the general Illinois natural landscape. I am studying how the phenotypic characteristics of milkweeds reared from urban versus rural populations differ in an effort to understand the affects of urbanization on milkweeds.