Source: Checklist of Endangered and Threatened Animals and Plants of Illinois
Illinois Endangered Species Protection Board, February 22, 2011
* = Federally Threatened ** = Federally Endangered
| Adoxa moschatellina | Moschatel |
| Asclepias lanuginosa | Wooly Milkweed |
| Asclepias meadii* | Mead’s Milkweed |
| Asclepias ovalifolia | Oval Milkweed |
| Asclepias stenophylla | Narrow-leaved Green Milkweed |
| Asplenium bradleyi | Bradley’s Spleenwort |
| Asplenium resiliens | Black Spleenwort |
| Astragalus distortus | Bent Milk Vetch |
| Astragalus tennesseensis | Tennessee Milk Vetch |
| Baptisia tinctoria | Yellow Wild Indigo |
| Botrychium campestre | Prairie Moonwort |
| Botrychium matricariifolium | Daisyleaf Grape Fern |
| Botrychium multifidum | Northern Grape Fern |
| Botrychium simplex | Dwarf Grape Fern |
| Calla palustris |
Water Arum |
| Calopogon oklahomensis | Oklahoma Grass Pink Orchid |
| Calopogon tuberosus | Grass Pink Orchid |
| Camassia angusta | Wild Hyacinth |
| Cardamine pratensis var. palustris | Cuckoo Flower |
| Castilleja sessiliflora | Downy Yellow Painted Cup |
| Chamaelirium luteum | Fairy Wand |
| Chimaphila maculata | Spotted Wintergreen |
| Chimaphila umbellata | Pipsissewa |
| Cimicifuga americana | American Bugbane |
| Cimicifuga racemosa | False Bugbane |
| Circaea alpina | Small Enchanter’s Nightshade |
| Clematis crispa | Blue Jasmine |
| Clematis occidentalis | Mountain Clematis |
| Clematis viorna | Leatherflower |
| Collinsia violacea | Violet Collinsia |
| Comptonia peregrina | Sweetfern |
| Cornus canadensis | Bunchberry |
| Corydalis aurea | Golden Corydalis |
| Corydalis halei |
Hale’s Corydalis |
| Corydalis sempervirens | Pink Corydalis |
| Cynosciadium digitatum | Cynosciadium |
| Cypripedium acaule | Moccasin Flower |
| Cypripedium parviflorum var. makasin | Small Yellow Lady’s Slipper |
| Cypripedium reginae | Showy Lady’s Slipper |
| Cystopteris laurentiana | Laurentian Fragile Fern |
| Dalea foliosa** | Leafy Prairie Clover |
| Dennstaedtia punctilobula | Hay-scented Fern |
| Drosera rotundifolia | Round-leaved Sundew |
| Dryopteris celsa | Log Fern |
| Echinodorus tenellus | Small Burhead |
| Eryngium prostratum | Eryngo |
| Euonymus americanus | American Strawberry Bush |
| Eupatorium hyssopifolium | Hyssop-leaved Thoroughwort |
| Euphorbia spathulata | Spurge |
| Filipendula rubra | Queen-of-the-Prairie |
| Fimbristylis vahlii | Vahl’s Fimbristylis |
| Galium lanceolatum | Wild Licorice |
| Geranium bicknellii | Northern Cranesbill |
| Gratiola quartermaniae | Hedge Hyssop |
| Gymnocarpium dryopteris | Oak Fern |
| Gymnocarpium robertianum | Scented Oak Fern |
| Helianthus giganteus | Tall Sunflower |
| Heliotropium tenellum | Slender Heliotrope |
| Heteranthera reniformis | Mud Plantain |
| Hexalectris spicata | Crested Coralroot Orchid |
| Hudsonia tomentosa | False Heather |
| Hydrolea uniflora | One-flowered Hydrolea |
| Hypericum adpressum | Shore St. John’s Wort |
| Hypericum kalmianum | Kalm’s St. John’s Wort |
| Iliamna remota | Kankakee Mallow |
| Iresine rhizomatosa | Bloodleaf |
| Isoetes butleri | Butler’s Quillwort |
| Isotria verticillata | Whorled Pogonia |
| Justicia ovata | Water Willow |
| Lespedeza leptostachya* | Prairie Bush Clover |
| Lesquerella ludoviciana | Silvery Bladderpod |
| Lonicera dioica var. glaucescens | Red Honeysuckle |
| Lonicera flava | Yellow Honeysuckle |
| Luzula acuminata | Hairy Woodrush |
| Lysimachia radicans | Creeping Loosestrife |
| Malvastrum hispidum | False Mallow |
| Matelea decipiens | Climbing Milkweed |
| Medeola virginiana | Indian Cucumber Root |
| Megalodonta beckii | Water Marigold |
| Melanthera nivea | White Melanthera |
| Melica mutica | Two-Flowered Melic Grass |
| Mimulus glabratus | Yellow Monkey Flower |
| Mirabilis hirsute | Hairy Umbrella-wort |
| Nemophila triloba | Baby Blue-eyes |
| Nothocalais cuspidata | Prairie Dandelion |
| Opuntia fragilis | Fragile Prickly Pear |
| Orobanche fasciculata | Clustered Broomrape |
| Oxalis illinoensis | Illinois Wood Sorrel |
| Penstemon brevisepalus | Short-sepaled Beard Tongue |
| Penstemon grandiflorus | Large-flowered Beard Tongue |
| Penstemon tubaeflorus | Tube Beard Tongue |
| Phacelia gilioides | Ozark Phacelia |
| Phegopteris connectilis | Long Beech Fern |
| Phlox pilosa subsp. sangamonensis | Sangamon Phlox |
| Platanthera ciliaris | Orange Fringed Orchid |
| Platanthera clavellata | Wood Orchid |
| Platanthera flava var. flava | Tubercled Orchid |
| Platanthera leucophaea* | Eastern Prairie Fringed Orchid |
| Platanthera psycodes | Purple Fringed Orchid |
| Pogonia ophioglossoides | Snake-mouth |
| Polanisia jamesii | James’ Clammyweed |
| Polygala incarnata | Pink Milkwort |
| Polygonatum pubescens | Downy Solomon’s Seal |
| Polygonum arifolium | Halberd-leaved Tearthumb |
| Polygonum careyi | Carey’s Heartsease |
| Primula mistassinica | Bird’s-eye Primrose |
| Ptilimnium nuttallii | Mock Bishop’s Weed |
| Rhexia mariana | Dull Meadow Beauty |
| Rosa acicularis | Bristly Rose |
| Sabatia campestris | Prairie Rose Gentian |
| Sagittaria australis | Arrowhead |
| Sanguisorba canadensis | American Burnet |
| Sanicula smallii | Southern Sanicula |
| Sarracenia purpurea | Pitcher Plant |
| Saxifraga virginiensis | Early Saxifrage |
| Silene ovata | Ovate Catchfly |
| Silene regia | Royal Catchfly |
| Sisyrinchium montanum | Mountain Blue-eyed Grass |
| Spiranthes lucida | Yellow-lipped Ladies’ Tresses |
| Spiranthes vernalis | Spring Ladies’ Tresses |
| Stellaria pubera | Great Chickweed |
| Stenanthium gramineum | Grass-leaved Lily |
| Stylisma pickeringii | Patterson’s Bindweed |
| Synandra hispidula | Hairy Synandra |
| Talinum calycinum | Fameflower |
| Tetraneuris herbacea* | Lakeside Daisy |
| Thelypteris noveboracensis | New York Fern |
| Trichomanes boschianum | Filmy fern |
| Trientalis borealis | Star-flower |
| Trillium cernuum | Nodding Trillium |
| Trillium erectum | Ill-scented Trillium |
| Trillium viride | Green Trillium |
| Utricularia cornuta | Horned Bladderwort |
| Utricularia minor | Small Bladderwort |
| Valeriana uliginosa | Marsh Valerian |
| Valerianella chenopodifolia | Corn Salad |
| Valerianella umbilicata | Corn Salad |
| Veronica americana | American Brooklime |
| Viola blanda | Hairy White Violet |
| Viola canadensis | Canada Violet |
| Viola primulifolia | Primrose Violet |
| Woodsia ilvensis | Rusty Woodsia |
| Zigadenus elegans | White Camass |