for additional reading and study

		Charles C. Deam, 1910. Flora of Indiana second reprint 1984, J. Cramer. David B. Lellinger, 1985. Ferns and Fern-Allies of the United States and Canada, Smithsonian Institution Press. Ron Panzer, Don Stillwaugh, Rich Gnaedinger, George Derkovitz, 1995. "Prevalence of Remnant Dependence among the Prairie-and Savanna-inhabiting Insects of the Chicago Region", Natural Areas Journal, vol 15, #2, April 1995. Floyd Swink and Gerould Wilhelm, 1979. Plants of the Chicago Region, 3rd ed. The Morton Arboretum. J.E. Weaver, 1968. Prairie Plants and Their Environment, A Fifty-Year Study in the Midwest, University of Nebraska Press.