Plants characteristic of dry, mesic, and wet prairies occur at Midewin.
Many species are indicative of degraded or disturbed sites.
Native plants persist as indicators of the communities that existed prior to European settlement and provide guidance for the restoration of the site Outwash sand at Midewin NTP Plants typical of sand prairie and dry prairie occur near the Kankakee River, where the substrate consists of outwash sand and stratified pebbles. Because most soils at Midewin contain a high percentage of dolomite, plants characteristic of dolomite prairie occur throughout the upland prairies at the site. However, as opposed to the shallow soils of the dolomite prairie, the upland prairie soils are fine-textured, loamy, and deep. The leaves of compass plant also orient to the sunlight. Cup plant has opposite leaves fused at the stem, forming a cup.