Plants and Animals:
Prairie Plant Communities

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. (The sorting of different-textured materials from sand to gravel is characteristic of materials that have been deposited by water.) Typical plants include green milkweed (Asclepias viridiflora) and sand milkweed (Asclepias amplexicaulis) both of which are adapted to soils that are low in nutrients and organic matter.

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. Poorly drained soils support wet prairie species such as water horehound (Lycopus americanus), common mountian mint (Pycnanthemum virginianum), prairie cordgrass (Spartina pectinata), prairie milkweed (Asclepias sullivantii), swamp milkweed (Asclepias incarnata), and Cardinal flower (Lobelia cardinalis) which also occurs along streams. Switch grass (Panicum virgatum) occurs in less wet areas, and blazing star (Liatris pychnostachya) occurs on mesic to moist sites.

Prairie dock (Silphium terebinthinaceum) is one of the most striking plants of mesic prairie. It has large rhubarb-sized basal (lower) leaves that orient to the sunlight for optimal rates of photosynthesis. Compass plant (Silphium laciniatum), rosin weed (Silphium integrifolia), and cup plant (Silphium perfoliatum) are in the same genus as prairie dock and occur on mesic to moist sites. The leaves of compass plant also orient to the sunlight. Cup plant has opposite leaves fused at the stem, forming a cup.

Big bluestem (Andropogon gerardii) is the most prominent species on the mesic prairie. Little bluestem (Schizachryrium scoparium) and Indian grass (Sorghastrum nutans) are also present, along with gray-headed or globular coneflower (Ratibida pinnata), Culver’s root (Veronicastrum virginianum), purple coneflower (Echinacea purpurea), purple prairie clover (Dalea purpurea), and rattlesnake master (Eryngium yuccifolium). Lead plant (Amorpha canescens) is a typical plant of mesic to dry mesic prairie and was often used in folk medicines.

Whorled milkweed (Asclepias verticillata), a tiny milkweed with delicate, narrow leaves, occurs on the dolomite praire. Other plants characteristic of dry and dry mesic prairie include biennial gaura (Gaura biennis), wild quinine (Parthenium integrifolium), black-eyed susan (Rudbeckia hirta), and in disturbed areas, wild bergamot (Monarda fistulosa).