Index of plants by genus
| Species | Common Name | Family |
| Cacalia atriplicifolia | Pale Indian Plantain | Asteraceae |
| Cakile edentula | Sea Rocket | Brassicaceae |
| Calamagrostis canadensis | Blue Joint Grass | Poaceae |
| Calamintha arkansana | Calamint | Lamiaceae |
| Calla palustris | Wild Calla | Araceae |
| Callitriche palustris | Vernal Water-starwort | Plantaginaceae |
| Calopogon tuberosus | Grass Pink Orchid | Orchidaceae |
| Caltha palustris | Marsh Marigold | Primulaceae |
| Calycanthus floridus | Carolina Allspice | Calycanthaceae |
| Calystegia sepium | Hedge Bindweed | Convolvulaceae |
| Calystegia spithamaea | Erect Bindweed | Convolvulaceae |
| Camassia scilloides | Wild Hyacinth | Liliaceae |
| Campanula americana | American Bellflower | Campanulaceae |
| Campanula aparinoides | Marsh Bellflower | Campanulaceae |
| Campanula rotundifolia | Harebell | Campanulaceae |
| Campsis radicans | Trumpetvine | Bignoniaceae |
| Capnoides sempervirens | Rock Harlequin | Papaveraceae |
| Cardamine bulbosa | Bulbous Springcress | Brassicaceae |
| Cardamine concatenata | Cut-leaved Toothwort | Brassicaceae |
| Cardamine dentata | White Cuckoo Bitter-cress | Brassicaceae |
| Cardamine diphylla | Broadleaf Toothwort | Brassicaceae |
| Cardamine douglassii | Purple Springcress | Brassicaceae |
| Cardamine maxima | Large Toothwort | Brassicaceae |
| Cardamine pensylvanica | Pennsylvania Bitter-cress | Brassicaceae |
| Cardamine pratensis | Pink Cuckoo Bitter-cress | Brassicaceae |
| Carex aestivalis | Summer Sedge | Cyperaceae |
| Carex alata | Broad-winged Sedge | Cyperaceae |
| Carex albicans | White-tinged Sedge | Cyperaceae |
| Carex albursina | White Bear Sedge | Cyperaceae |
| Carex alopecoidea | Foxtail Sedge | Cyperaceae |
| Carex amphibola | Eastern Narrow-leaved Sedge | Cyperaceae |
| Carex annectens | Yellow-fruited Sedge | Cyperaceae |
| Carex appalachica | Appalachian Sedge | Cyperaceae |
| Carex aquatilis | Water Sedge | Cyperaceae |
| Carex arctata | Bear Sedge | Cyperaceae |
| Carex argyrantha | Silvery-flowered Sedge | Cyperaceae |
| Carex atherodes | Wheat Sedge | Cyperaceae |
| Carex atlantica | Atlantic Star Sedge | Cyperaceae |
| Carex aurea | Golden Sedge | Cyperaceae |
| Carex backii | Back's Sedge | Cyperaceae |
| Carex baileyi | Bailey's Sedge | Cyperaceae |
| Carex bebbii | Bebb's Sedge | Cyperaceae |
| Carex blanda | Common Wood Sedge | Cyperaceae |
| Carex brevior | Short-beaked Sedge | Cyperaceae |
| Carex bromoides | Brome Hummock Sedge | Cyperaceae |
| Carex brunnescens | Green Bog Sedge | Cyperaceae |
| Carex bullata | Button Sedge | Cyperaceae |
| Carex bushii | Bush's Sedge | Cyperaceae |
| Carex buxbaumii | Buxbaum's Sedge | Cyperaceae |
| Carex canescens | Silvery Sedge | Cyperaceae |
| Carex careyana | Carey's Sedge | Cyperaceae |
| Carex castanea | Chestnut Sedge | Cyperaceae |
| Carex cephaloidea | Thin-leaved Sedge | Cyperaceae |
| Carex cephalophora | Oval-headed Sedge | Cyperaceae |
| Carex chordorrhiza | Creeping Sedge | Cyperaceae |
| Carex collinsii | Collins' Sedge | Cyperaceae |
| Carex communis | Fibrous-rooted Sedge | Cyperaceae |
| Carex conoidea | Open-field Sedge | Cyperaceae |
| Carex comosa | Bristly Sedge | Cyperaceae |
| Carex crawei | Crawe's Sedge | Cyperaceae |
| Carex crawfordii | Crawford's Oval Sedge | Cyperaceae |
| Carex crinita | Fringed Sedge | Cyperaceae |
| Carex cristatella | Crested Oval Sedge | Cyperaceae |
| Carex cryptolepis | Northeastern Sedge | Cyperaceae |
| Carex conjuncta | Green-headed Fox Sedge | Cyperaceae |
| Carex debilis | Weak Sedge | Cyperaceae |
| Carex deflexa | Northern Sedge | Cyperaceae |
| Carex deweyana | Dewey's Hummock Sedge | Cyperaceae |
| Carex diandra | Lesser Panicled Sedge | Cyperaceae |
| Carex digitalis | Slender Woodland Sedge | Cyperaceae |
| Carex disperma | Two-seeded Sedge | Cyperaceae |
| Carex eburnea | Ivory Sedge | Cyperaceae |
| Carex echinata | Star Sedge | Cyperaceae |
| Carex emoryi | Emory's Sedge | Cyperaceae |
| Carex exilis | Coastal Sedge | Cyperaceae |
| Carex flava | Yellow Sedge | Cyperaceae |
| Carex foenea | Bronze-headed Oval Sedge | Cyperaceae |
| Carex folliculata | Long Sedge | Cyperaceae |
| Carex formosa | Handsome Sedge | Cyperaceae |
| Carex frankii | Frank's Sedge | Cyperaceae |
| Carex gracilescens | Slender Loose-flowered Sedge | Cyperaceae |
| Carex gracillima | Graceful Sedge | Cyperaceae |
| Carex granularis | Limestone Meadow Sedge | Cyperaceae |
| Carex grayi | Common Bur Sedge | Cyperaceae |
| Carex grisea | Inflated Narrow-leaved Sedge | Cyperaceae |
| Carex gynandra | Nodding Sedge | Cyperaceae |
| Carex haydenii | Hayden's Sedge | Cyperaceae |
| Carex hirsutella | Fuzzy Wuzzy Sedge | Cyperaceae |
| Carex hirtifolia | Pubescent Sedge | Cyperaceae |
| Carex hitchcockiana | Hitchcock's Sedge | Cyperaceae |
| Carex hystericina | Porcupine Sedge | Cyperaceae |
| Carex interior | Inland Star Sedge | Cyperaceae |
| Carex intumescens | Shining Bur Sedge | Cyperaceae |
| Carex jamesii | James' Sedge | Cyperaceae |
| Carex lacustris | Common Lake Sedge | Cyperaceae |
| Carex laevivaginata | Smooth-sheathed Sedge | Cyperaceae |
| Carex lasiocarpa | Wooly-fruited Sedge | Cyperaceae |
| Carex laxiculmis | Weak-stemmed Wood Sedge | Cyperaceae |
| Carex laxiflora | Broad Loose-flowered Sedge | Cyperaceae |
| Carex lenticularis | Lakeshore Sedge | Cyperaceae |
| Carex leptalea | Bristle-stalked Sedge | Cyperaceae |
| Carex leptonervia | Few-nerved Wood Sedge | Cyperaceae |
| Carex limosa | Mud Sedge | Cyperaceae |
| Carex lucorum | Blue Ridge Sedge | Cyperaceae |
| Carex lupulina | Common Hop Sedge | Cyperaceae |
| Carex lurida | Sallow Sedge, Bottlebrush Sedge | Cyperaceae |
| Carex magellanica | Boreal Bog Sedge | Cyperaceae |
| Carex michauxiana | Michaux's Sedge | Cyperaceae |
| Carex muehlenbergii | Sand Sedge | Cyperaceae |
| Carex molesta | Troublesome Sedge | Cyperaceae |
| Carex nigromarginata | Black-edged Sedge | Cyperaceae |
| Carex normalis | Greater Straw Sedge | Cyperaceae |
| Carex novae-angliae | New England Sedge | Cyperaceae |
| Carex oligocarpa | Rich Woods Sedge | Cyperaceae |
| Carex oligosperma | Few-seeded Sedge | Cyperaceae |
| Carex pallescens | Pale Green Sedge | Cyperaceae |
| Carex pauciflora | Few-flowered Sedge | Cyperaceae |
| Carex peckii | Peck's Sedge | Cyperaceae |
| Carex pedunculata | Long-stalked Sedge | Cyperaceae |
| Carex pellita | Woolly Sedge | Cyperaceae |
| Carex pensylvanica | Common Oak Sedge | Cyperaceae |
| Carex plantaginea | Plantain-leaved Sedge | Cyperaceae |
| Carex platyphylla | Broad-leaved Sedge | Cyperaceae |
| Carex prairea | Prairie Sedge | Cyperaceae |
| Carex prasina | Drooping Sedge | Cyperaceae |
| Carex projecta | Necklace Sedge | Cyperaceae |
| Carex pseudocyperus | Cyperus-like Sedge | Cyperaceae |
| Carex radiata | Straight-styled Wood Sedge | Cyperaceae |
| Carex retrorsa | Retrorse Sedge | Cyperaceae |
| Carex rosea | Curly-styled Wood Sedge | Cyperaceae |
| Carex scabrata | Rough Sedge | Cyperaceae |
| Carex schweinitzii | Schweinitz's Sedge | Cyperaceae |
| Carex scirpoidea | Northern Single-spike Sedge | Cyperaceae |
| Carex scoparia | Lance-fruited Oval Sedge | Cyperaceae |
| Carex seorsa | Swamp Star Sedge | Cyperaceae |
| Carex shortiana | Short's Sedge | Cyperaceae |
| Carex sparganioides | Bur-reed Sedge | Cyperaceae |
| Carex sprengelii | Long-beaked Sedge | Cyperaceae |
| Carex squarrosa | Squarrose Sedge | Cyperaceae |
| Carex stipata | Common Fox Sedge | Cyperaceae |
| Carex stricta | Tussock Sedge | Cyperaceae |
| Carex striata | Walter's Sedge | Cyperaceae |
| Carex swanii | Downy Green Sedge | Cyperaceae |
| Carex tenera | Quill Sedge | Cyperaceae |
| Carex tetanica | Rigid Sedge | Cyperaceae |
| Carex texensis | Texas Sedge | Cyperaceae |
| Carex tonsa | Shaved Sedge | Cyperaceae |
| Carex torta | Twisted Sedge | Cyperaceae |
| Carex tribuloides | Blunt Broom Sedge | Cyperaceae |
| Carex trichocarpa | Hairy-fruited Sedge | Cyperaceae |
| Carex trisperma | Three-seeded Bog Sedge | Cyperaceae |
| Carex tuckermanii | Tuckerman's Sedge | Cyperaceae |
| Carex umbellata | Parasol Sedge | Cyperaceae |
| Carex utriculata | Swollen-beaked Sedge | Cyperaceae |
| Carex vesicaria | Blister Sedge | Cyperaceae |
| Carex vaginata | Sheathed Sedge | Cyperaceae |
| Carex virescens | Ribbed Sedge | Cyperaceae |
| Carex viridula | Little Green Sedge | Cyperaceae |
| Carex vulpinoidea | Brown Fox Sedge | Cyperaceae |
| Carex woodii | Pretty Sedge | Cyperaceae |
| Carpinus caroliniana | American Hornbeam | Betulaceae |
| Carya cordiformis | Yellowbud Hickory | Juglandaceae |
| Carya glabra | Pignut Hickory | Juglandaceae |
| Carya illinoinensis | Pecan | Juglandaceae |
| Carya laciniosa | Shellbark Hickory | Juglandaceae |
| Carya ovata | Shagbark Hickory | Juglandaceae |
| Carya tomentosa | Mockernut Hickory | Juglandaceae |
| Castanea dentata | American Chestnut | Fagaceae |
| Castilleja coccinea | Indian Paintbrush | Scrophulariaceae |
| Castilleja sessiflora | Downy Indian Paintbrush | Scrophulariaceae |
| Catalpa speciosa | Catalpa | Bignoniaceae |
| Caulophyllum giganteum | Early Blue Cohosh | Berberidaceae |
| Caulophyllum thalictroides | Blue Cohosh | Berberidaceae |
| Ceanothus americanus | New Jersey Tea | Rhamnaceae |
| Ceanothus herbaceus | Inland New Jersey Tea | Rhamnaceae |
| Celastrus scandens | American Bittersweet | Celastraceae |
| Celtis occidentalis | Hackberry | Ulmaceae |
| Cenchrus longispinus | Long-spined Sandbur | Poaceae |
| Cephalanthus occidentalis | Buttonbush | Rubiaceae |
| Cerastium strictum | American Field Chickweed | Caryophyllaceae |
| Ceratodon purpureus | Purple Ceratodon | Ditrichaceae |
| Cercis canadensis | Redbud | Caesalpiniaceae |
| Chamaecrista fasciculata | Partridge Pea | Fabaceae |
| Chamaecrista nictitans | Sensitive Partridge Pea | Fabaceae |
| Chamaecyparis thyoides | Atlantic White Cedar | Cupressaceae |
| Chamaedaphne calyculata | Leatherleaf | Ericaceae |
| Chamaenerion angustifolium | Fireweed | Onagraceae |
| Chara spp. | Muskgrass | Characeae |
| Chelone glabra | White Turtlehead | Scrophulariaceae |
| Chelone obliqua | Red Turtlehead | Scrophulariaceae |
| Chionanthus virginicus | White Fringetree | Oleaceae |
| Chimaphila maculata | Spotted Wintergreen | Pyrolaceae |
| Chimaphila umbellata | Pipsissewa | Pyrolaceae |
| Chrysopsis mariana | Maryland Golden-aster | Asteraceae |
| Chrysosplenium americanum | American Golden Saxifrage | Saxifragaceae |
| Cicuta bulbifera | Bulbet-bearing Water Hemlock | Apiaceae |
| Cicuta maculata | Spotted Water Hemlock | Apiaceae |
| Cimicifuga racemosa | Bugbane | Ranunculaceae |
| Cinna latifolia | Drooping Woodreed | Poaceae |
| Circaea alpina | Alpine Enchanter's Nightshade | Onagraceae |
| Circaea lutetiana | Broadleaf Enchanter's Nightshade | Onagraceae |
| Cirsium discolor | Field Thistle | Asteraceae |
| Cirsium muticum | Fen Thistle | Asteraceae |
| Cirsium pumilum | Pasture Thistle | Asteraceae |
| Cirsium pitcheri | Dune Thistle | Asteraceae |
| Cladium mariscoides | Smooth Sawgrass | Cyperaceae |
| Cladonia cristatella | British Soldier Lichen | |
| Cladrastis kentukea | Yellowwood | Fabaceae |
| Claytonia caroliniana | Carolina Spring Beauty | Portulacaceae |
| Claytonia virginica | Spring Beauty | Portulacaceae |
| Clematis occidentalis | Western Blue Virginsbower | Ranunculaceae |
| Clematis virginiana | Virginsbower | Ranunculaceae |
| Clethra alnifolia | Summersweet | Clethraceae |
| Climacium dendroides | Tree Moss | Climaciaceae |
| Clintonia borealis | Bluebead Lily | Liliaceae |
| Coeloglossum viride | Long-bracted Green Orchid | Orchidaceae |
| Collinsonia canadensis | Horsebalm | Lamiaceae |
| Comandra umbellata | Bastard Toadflax | Santalaceae |
| Comptonia peregrina | Sweet Fern | Myricaceae |
| Conioselinum chinense | Hemlock-parsley | Apiaceae |
| Conocephalum conicum | Scented Liverwort | Conocephalaceae |
| Conoclinium coelestinum | Blue Mistflower | Asteraceae |
| Conopholis americana | Squaw Root | Orobanchaceae |
| Coptis trifolia | Goldthread | Ranunculaceae |
| Corallorhiza maculata | Spotted Coralroot | Orchidaceae |
| Corallorhiza odontorhiza | Autumn Coralroot | Orchidaceae |
| Corallorhiza trifida | Early Coralroot | Orchidaceae |
| Coreopsis lanceolata | Lance-leaved Coreopsis | Asteraceae |
| Coreopsis grandiflora | Large-flowered Tickseed | Asteraceae |
| Coreopsis palmata | Prairie Coreopsis | Asteraceae |
| Coreopsis rosea | Pink Tickseed | Asteraceae |
| Coreopsis tripteris | Tall Coreopsis | Asteraceae |
| Cornus canadensis | Bunchberry | Cornaceae |
| Cornus alternifolia | Pagoda Dogwood | Cornaceae |
| Cornus florida | Flowering Dogwood | Cornaceae |
| Cornus obliqua | Silky Dogwood | Cornaceae |
| Cornus racemosa | Gray Dogwood | Cornaceae |
| Cornus rugosa | Roundleaf Dogwood | Cornaceae |
| Cornus sericea | Red Osier Dogwood | Cornaceae |
| Corydalis aurea | Golden Corydalis | Papaveraceae |
| Corydalis flavula | Yellow Corydalis | Papaveraceae |
| Corylus americana | American Filbert | Betulaceae |
| Corylus cornuta | Beaked Hazelnut | Betulaceae |
| Coryphantha vivipara | Spinystar | Cactaceae |
| Cotinus obovatus | American Smoketree | Anacardiaceae |
| Crataegus crus-galli | Cockspur Hawthorn | Rosaceae |
| Crataegus mollis | Downy Hawthorn | Rosaceae |
| Crataegus pruinosa | Frosted Hawthorn | Rosaceae |
| Crataegus punctata | Dotted Hawthorn | Rosaceae |
| Cryptotaenia canadensis | Canadian Honewort | Apiaceae |
| Cuscuta cephalanthi | Buttonbush Dodder | Convolvulaceae |
| Cuscuta gronovii | Common Dodder | Convolvulaceae |
| Cycloloma atriplicifolium | Winged Pigweed | Chenopodiaceae |
| Cyperus bipartitus | Brook Nut Sedge | Cyperaceae |
| Cyperus filiculmis | Slender Sand Sedge | Cyperaceae |
| Cyperus strigosus | Long-scaled Nut Sedge | Cyperaceae |
| Cypripedium acaule | Pink Lady's Slipper | Orchidaceae |
| Cypripedium arietinum | Ram's Head Lady's Slipper | Orchidaceae |
| Cypripedium candidum | White Lady's Slipper | Orchidaceae |
| Cypripedium parviflorum | Yellow Lady's Slipper | Orchidaceae |
| Cypripedium reginae | Showy Lady's Slipper | Orchidaceae |
| Cystopteris bulbifera | Bulblet Fern | Woodsiaceae |
| Cystopteris fragilis | Fragile Fern | Woodsiaceae |
| Cystopteris tenuis | Mackay's Fragile Fern | Woodsiaceae |
© 2004-2018 Michael Hough