Well, I doubt I should have done this searching for you if you’re doing a report on it, but i’d thought i’d give you some help. This is from WikiTravel, so i’d find additional sources, but it seems to have some information for you:
http://wikitravel.org/en/Indiana_Dunes_National_Lakeshore
“Many ecosystem types can be readily recognized by amateurs. Ecosystem types, and characteristic grasses and flowering plants, that exist within the Indiana Dunes include the following:
* Sand dunes – marram grass, prickly pear, puccoon
* Wetlands (bogs, marshlands, and swamps) – marsh marigold, skunk cabbage
* Ponds – bladderwort, gentian
* Prairies – black-eyed susan, butterfly weed, goldenrod, lupine, prairie grass
* Savannas – asters, prairie grass
* Dry woods – columbines, hepatica, Solomon’s seal
* Wet woods – Dutchmen’s breeches, hepatica, trillium, violet”