These are the plants I’ve seen on Sumac Prairie, Sumac Field (the flat top of the point), and the surrounding Savanna remnants.

Agalinis aspera – Rough False Foxglove
Amorpha canescens – Leadplant
Amphicarpa bracteata – Hog Peanut
Andropogon gerardii – Big Bluestem
Anemone cylindrica – Thimbleweed
Antennaria neglecta – Field Pussytoes
Antennaria plantinifolia – Plantain-leaved Pussytoes
Arabis lyrata – Sandcress
Artemisia campestris – Wormwood
Asclepias exaltata – Poke Milkweed
Asclepias syriaca – Common Milkweed
Asclepias viridiflora – Green Milkweed
Asclepias verticillata – Whorled Milkweed
Aster ericoides – Heath Aster
Aster oblongifolius – Aromatic Aster
Aster oolentangiensis – Sky-blue Aster
Aster sagittifolius – Arrow-leaved Aster
Aster sericeus – Silky Aster
Aquilegia canadensis – Wild Columbine
Betula papyrifera – White Birch
Botrychium dissectum – Dissected Grape-fern
Bouteloua curtipendula – Side-oats Grama
Bouteloua hirsuta – Hairy Grama
Bromus kalmii – Prairie Brome
Campanula rotundifolia – Harebell
Carex pennsylvanica – Pennsylvania Sedge
Castilleja sessiliflora – Downy Yellow Painted Cup
Celastrus scandens – American Bittersweet
Cirsium discolor – Field Thistle
Comandra umbellata – Bastard Toadflax
Coreopsis palmata – Prairie Coreopsis
Cornus racemosa – Gray Dogwood
Dalea purpurea – Purple Prairie Clover
Draba reptans – Common Whitlow-grass
Elymus trachycaulus – Slender Wheat Grass
Eragrostis spectabilis – Purple Lovegrass
Erigeron pulchellus – Robin’s Plantain
Fragaria sp. – Wild Strawberry
Hedeoma hispida – Rough Pennyroyal
Helianthus occidentalis – Western Sunflower
Juniperus communis – Common Juniper
Juniperus virginiana – Eastern Red Cedar
Lespedeza capitata – Round-headed Bush Clover
Linum sulcatum – Grooved Yellow Flax
Lithospermum incisum – Fringed Puccoon
Lobelia spicata – Spiked Lobelia
Monarda fistulosa – Monarda
Muhlenbergia cuspidata – Prairie Satin Grass
Oenothera biennis – Evening Primrose
Panicum oligosanthes – Few-flowered Panicgrass
Pellaea glabella – Smooth Cliff Brake
Prunus americana – Wild Plum
Prunus pennsylvanica – Fire Cherry
Prunus serotina – Wild Black Cherry
Prunus virginiana – Chokecherry
Pteridium aquilinum – Bracken Fern
Quercus alba – White Oak
Quercus macrocarpa – Burr Oak
Quercus velutina – Black Oak
Rhus typhina – Staghorn Sumac
Rubus flagellaris – Northern Dewberry
Sanicula marilandica – Black Snakeroot
Schizachyrium scoparium – Little Bluestem
Scutellaria parvula var. missouriensis – Skullcap
Senecio paupercula – Balsam Ragwort
Sisyrinchium campestre – Blue-eyed Grass
Solidago nemoralis – Gray Goldenrod
Solidago ptarmicoides – Upland White Goldenrod
Sorghastrum nutans – Indian Grass
Spiranthes magnicamporum – Great Plains Ladies Tresses
Sporobolus heterolepis – Prairie Dropseed
Tradescantia ohiensis – Spiderwort
Viola x palmata – Early Blue Violet
Viola pedata – Bird’s-foot Violet
Viola pedatifida – Prairie Violet
Zanthoxylum americanum – Prickly Ash
Zigadenus elegans – White Camas
Zizia aurea – Golden  Alexander