Caesar's mushroom (see Yellow Caesar)
Campion, Evening (see Lychnis, Evening/ Evening Campion)
Campion, Rose (see Pink, Mullein/ Rose Campion)
Campion, Starry Silene stellata Pink
Canada mayflower (see Lily of the valley, wild)
Candle flame lichen Candelaria concolor Lichen
Carbon balls (see Coal fungus)
Cardinal Flower Lobelia cardinalis Lobelia
Carpetweed/ Indian Chickweed/ Devil's Grip Mollugo verticellata Carpetweed
Carrion Flower Smilax herbacea Lily
Carrot, Wild (see Queen Anne's Lace/ Wild Carrot)
Cat's-ear Hypochoeris radicata Dandelion-Like
Catalpa, Hardy (see Catalpa, Northern)
Catalpa, Northern Catalpa speciosa Bignonia
Catchfly, Night Flowering Silene noctiflora Pink
Catfoot/Sweet Everlasting Gnaphalium obtusifolia No Obvious Symmetry
Catnip Nepeta cataria Mint
Cattail, Common Typha latifolia Cattail
Cattail, Narrow-leaved Typha angustifolia Cattail
Cedar, Northern White Thuja occidentalis Cypress
Celandine Chelidonium majus Poppy
Celandine Poppy, Wood Poppy Stylophorum diphyllum Poppy
Cellar fungus Crusts And Slimes
Ceramic parchment Xylobolus frustulatus Crusts And Slimes
Chamomile, stinking (see Mayweed)
Chanterelle, false (see Jack o'lantern)
Chanterelle, smooth Cantharellus lateritius Miscellaneous Fungi
Charlock Brassica kaber Mustard
Checkerberry (see Wintergreen/ TeaBerry/ Checkerberry)
Cheeses (see Mallow, Common/ Cheeses)
Cherry, Bird (see Cherry, Sweet)
Cherry, Black Prunus serotina Rose
Cherry, Mazzard (see Cherry, Sweet)
Cherry, Sweet Prunus avium Rose
Cherry, Wild (see Cherry, Black)
Chestnut, American Castanea dentata Beech
Chestnut, Chinese Castanea mollissima Beech
Chicken mushroom (see Chicken of the woods)
Chicken of the woods Laetiporus sulphureus Mushrooms With Pores (Polypores)
Chicken of the woods, white pored Laetoporus cincinnatus
Chickweed, Common Mouse-ear Cerastium vulgatum Pink
Chickweed, Common/ Starwort Stelleria media Pink
Chickweed, Giant Stellaria aquatica Pink
Chickweed, great (see Chickweed, star)
Chickweed, Indian (see Carpetweed/ Indian Chickweed/ Devil's Grip)
Chickweed, Long-leaved/ Long Leaved Stitchwort Stellaria longifolia Pink
Chickweed, Marsh (see Starwort, Bog/ Marsh Chickweed)
Chickweed, Mouse-ear Cerastium viscosum Pink
Chickweed, star Stellaria pubera Pink
Chicory Cichorium intybus E Miscellaneous
Choke Cherry Prunus virginiana Rose
Cicely, Sweet Osmorhiza claytoni Parsley
Cigar tree (see Catalpa, Northern)
Cinquefoil, Common Potentilla simplex Rose
Cinquefoil, Dwarf/ Fivefingers Potentilla canadensis Rose
Cinquefoil, Rough Potentilla norvegica Rose
Cinquefoil, Rough Fruited Potentilla recta Rose
Cinquefoil, Shrubby Potentilla fruticosa Rose
Clearweed Pilea purnila Nettle
Cleavers/ Goosegrass Galium apartine Bedstraw (Madder)
Clintonia, White Clintonia umbellulata Lily
Clitocybe, abundant Clitocybula abundans Gilled Mushrooms
Clitocybe, fat-footed (see Funnelcap, clubfoot)
Clitocybe, funnel (see Funnelcap, forest)
Clotbur Xanthium italicum Composite
Clotbur, Common Xanthium chinense Composite
Clover, Hop Trifolium agrarium Pea
Clover, Least Hop/ Little Hop Clover Trifolium dubium Pea
Clover, Little Hop (see Clover, Least Hop/ Little Hop Clover)
Clover, Rabbit-foot Trifolium arvense Pea
Clover, Red Trifolium, pratense Pea
Clover, Smaller Hop/ Low Hop Clover Trifolium procumbens Pea
Clover, White Trifolium repens Pea
Clover, White Sweet Melilotus alba Pea
Clover, Yellow Sweet Melilotus officinalis Pea
Clubfoot Amanita rhopalopus Gilled Mushrooms
Clubmoss, Fan Diphasiastrum digitatum Clubmoss
Clubmoss, Round-branched (see Pine, Ground)
Clubmoss, Running (see Clubmoss, Staghorn)
Clubmoss, Shining Huperzia lucidula Clubmoss
Clubmoss, Staghorn Lycopodium clavatum Clubmoss
Clubmoss, Trailing Evergreen (see Clubmoss, Shining)
Clubmoss, Tree (see Pine, Ground)
Clustered bonnet Mycena inclinata Gilled Mushrooms
Coal fungus Daldinia concentrica Miscellaneous Fungi
Cocklebur (see Clotbur, Common)
Cohosh, Black/ Bugbane/ Black Snakeroot Cimicifuga racemosa Buttercup
Cohosh, Blue Caulophyllum thalictroides Barberry
Collybia, buttery Rhodocollybia butyracea Gilled Mushrooms
Collybia, oak-loving Gymnopus dryophilus Gilled Mushrooms
Collybia, rooted (see Agaric, rooted)
Coltsfoot, Coughwort Tussilago farfara Dandelion-Like
Columbine, Eastern (see Columbine, Wild/ Eastern Columbine)
Columbine, Garden Aquilega vulgaris Buttercup
Columbine, Wild/ Eastern Columbine Aquilegia canadensis Buttercup
Comfrey Symphytum officinale Forget-Me-Not/Borage
Compass Plant (see Lettuce, Prickly/ Compass Plant)
Coneflower, Green-Headed/ Wild Goldenglow Rudbeckia laciniata Sunflower-Like
Coneflower, purple Echinacea purpurea Composite
Coneflower, thin-leaved (see Brown-eyed Susan)
Conifer tuft Hypholoma capnoides Gilled Mushrooms
Coral slime Ceratomyxa fruliticulosa Crusts And Slimes
Coreopsis, Lance-leaved Coreopsis lanceolata Composite
Corn Salad Valerianella olitoria Valerian
Corydalis, Yellow Corydalis flavula Poppy
Cottonwood, common (see Cottonwood, eastern)
Cottonwood, eastern Populus deltoides Willow
Coughwort (see Coltsfoot, Coughwort)
Cow-wheat Melampyrum lineare Snapdragon (Figwort)
Cowbane, Spotted (see Water-Hemlock/ Spotted Cowbane)
Cowslip, Virginia (see Bluebells, Virginia/ Virginia Cowslip/ Mertensia)
Crabapple, Wild Malus coronaria Rose
Cramp balls (see Coal fungus)
Cranberry, Highbush (see Viburnum, Cranberry)
Cranesbill, Carolina Geranium carolinianum Geranium
Cranesbill, Dove's Foot Geranium molle Geranium
Cranesbill, Small-Flowered Geranium pusillum Geranium
Crater lichen Diploschistus scruposus Lichen
Creeper, Thicket Parthenocissus inserta Grape
Creeper, Virginia Parthenocissus quinquefolia Grape
Crep, flat Crepidotus applanatus Gilled Mushrooms
Cress, Bitter (see Cress, Spring/ Bitter Cress)
Cress, Bitter Winter (see Cress, Winter/ Bitter Winter Cress)
Cress, Cow/ Field Pepper-Grass Lepidium campestre Mustard
Cress, Creeping Yellow Rorippa sylvestris Mustard
Cress, Mouse Ear/ Thale-Cress Sisymbrium thalianum Mustard
Cress, Purple Cardamine douglassii Mustard
Cress, Spring/ Bitter Cress Cardamine bulbosa Mustard
Cress, Winter/ Bitter Winter Cress Barbarea vulgaris Mustard
Cress, Yellow Rorippa islandica Mustard
Crinkleroot (see Toothwort, Two Leaved/ Pepperwort/ Crinkleroot)
Crowfoot, Celery-leaved (see Crowfoot, Cursed)
Crowfoot, Cursed (see Crowfoot, Cursed)
Crowfoot, early (see Buttercup, early)
Crown coral fungus Clavicorona pyxidata Miscellaneous Fungi
Crumblecap, fringed Psathyrella candolleana Gilled Mushrooms
Crust, brown toothed Hydnochaete olivaceum Crusts And Slimes
Crust, reddish brown Tabacena hymenochaete Crusts And Slimes
Cucumber Tree Magnolia acuminata Magnolia
Cucumber, Bur/ Star Cucumber Sicyos angulatus Cucumber
Cucumber, Star (see Cucumber, Bur/ Star Cucumber)
Cucumber, Wild/ Balsam Apple Echinocystis lobata Cucumber
Cup fungus Peziza repanda Miscellaneous Fungi
Cup lichen Cladonia didyma
Currycomb bracket Daedaleopsis confragosa Mushrooms With Pores (Polypores)
Cylindrobasidium evolvens Cylindrobasidium evolvens Crusts And Slimes
Cyperus, shining Cyperus rivularis Sedge
Cleome spinosa
Mollugo verticellata
Rhus radicans
Rhus glabra
Rhus typhina
Typha latifolia
Typha angustifolia
Diphasiastrum digitatum
Huperzia lucidula
Lycopodium clavatum
Aster dumosus
Aster macrophyllus
Aster acuminatus
Rudbeckia triloba
Xanthium italicum
Xanthium chinense
Xanthium chinense
Echinacea purpurea
Coreopsis lanceolata
Leucanthemum superbum
Inula helenium
Chrysanthemum parthenium
Solidago rigida
Hieracium paniculatum
Eupatorium maculatum
Lactuca sativa
Anthema cotula
Parthenium integrifolium
Eupatorium album
Asimina triloba
Thuja occidentalis