Exner Marsh lies in a shallow glacial lake bed now entirely underlain by organic deposits and bordered by uplands consisting of both glacial till and outwash deposits. It is representative of the Morainal Section of the Northeastern Morainal Division. Emergent shallow water marsh is the dominant community punctuated throughout by shallow ponds. Cattails, bulrush and rice cut grass are the common plants of the marsh with white water lily, spatterdock and bladderwort the dominant plants of the shallow ponds. Calcareous floating mat community occupies a core of suspended peat and small scattered peat mats. This community is related to the early stages of bog development. Wire sedge, blue joint, and marsh shield fern are the common plants. Exner Marsh has rich wetland bird community including migratory species which use the marsh as a staging ground during their spring and fall migration. Bluewing teal, sora, Virginia rail, king rail, least bittern, pied-billed grebe, common moorhen and yellow-headed blackbird can be found in the marsh. Black-crowned night heron and great egret feed here. Prescribed burning and vegetation, fish and bird surveys are conducted to enhance and monitor the quality of the wetland. The site offers 1.5 miles of hiking trails. Along these trails, stop for a scenic view of the 116 acres of Illinois State Nature Preserve. After your hike, have a picnic lunch at the shelter on Lakewood.