Shrubs and Woody Vines of Indiana and the Midwest: Identification, Wildlife Values, and Landscaping Use by Salley S. Weeks and Harmon P. Weeks, Jr. Purdue University Press. 2012.
Sedges of Indiana and the Adjacent States: The Non-Carex Species by Paul E. Rothrock. Indiana University Press. 2012.
Indiana Wildflowers by Kay Yatskievych. Indiana University Press. 2000.
Michigan
Field Manual of Michigan Flora by Edward G. Voss and Anton A. Reznicek. University of Michigan Press, Ann Arbor. 2012 and online database: MichiganFlora.net, with online dichotomous keys
Missouri
Erythronium americanum, yellow trout lily
The Flora of Missouri series by George Yatskievych. Missouri Botanical Garden Press. 1999–2014.
Trees of Missouri by Don Kurz. Missouri Department of Conservation. 2003.
Shrubs and Woody Vines of Missouri by Don Kurz. Missouri Department of Conservation. 1997.
A Key to Missouri Trees in Winter by Jerry Cliburn & Ginny Wallace. Missouri Department of Conservation. 1990.
Missouri Wildflowers by Edgar Denison, 6th. Missouri Department of Conservation. 2008 edition.
Wildflowers of Wisconsin and the Great Lakes Region: A Comprehensive Field Guide by Merel R. Black and Emmet J. Judziewicz. 2009. University of Wisconsin Press.
Field Guide to Wisconsin Sedges: An Introduction to the Genus Carex (Cyperaceae) by Andrew L. Hipp. 2008. University of Wisconsin Press.
Spring Flora of Wisconsin: A Manual of Plants Growing without Cultivation and Flowering Before June 15 by Norman Fassett. 1976. University of Wisconsin Press.