| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| COTE10 | Coriflora texensis (Buckl.) W.A. Weber | Clematis texensis | Ranunculaceae
|
| COVE9 | Coriflora versicolor (Small ex Rydb.) W.A. Weber | Clematis versicolor | Ranunculaceae
|
| COVI10 | Coriflora viorna (L.) W.A. Weber | Clematis viorna | Ranunculaceae
|
| COVI11 | Coriflora viticaulis (Steele) W.A. Weber | Clematis viticaulis | Ranunculaceae
|
| COVI16 | Coriscium viride (Ach.) Vainio | Omphalina hudsoniana | Tricholomataceae
|
| COAMA2 | Corispermum americanum (Nutt.) Nutt. var. americanum | American bugseed | Chenopodiaceae
|
| COAMR | Corispermum americanum (Nutt.) Nutt. var. rydbergii Mosyakin | American bugseed | Chenopodiaceae
|
| COAM8 | Corispermum americanum (Nutt.) Nutt. | American bugseed | Chenopodiaceae
|
| COEM2 | Corispermum emarginatum Rydb. | Corispermum villosum | Chenopodiaceae
|
| COHYE | Corispermum hyssopifolium L. var. emarginatum (Rydb.) Boivin | Corispermum villosum | Chenopodiaceae
|
| COHYR | Corispermum hyssopifolium L. var. rubricaule Hook. | Corispermum ochotense var. alaskanum | Chenopodiaceae
|
| COHY | Corispermum hyssopifolium L. p.p. | Corispermum americanum var. rydbergii | Chenopodiaceae
|
| COHY | Corispermum hyssopifolium L. p.p. | Corispermum pacificum | Chenopodiaceae
|
| COLE9 | Corispermum leptopterum (Aschers.) Iljin | Corispermum pallasii | Chenopodiaceae
|
| COMA23 | Corispermum marginale Rydb. p.p. | Corispermum americanum var. americanum | Chenopodiaceae
|
| CONA4 | Corispermum navicula Mosyakin | crescent bugseed | Chenopodiaceae
|
| CONI15 | Corispermum nitidum Kit. ex J.A. Schultes | shiny bugseed | Chenopodiaceae
|
| CONI3 | Corispermum nitidum auct. non Kit. ex J.A. Schultes | Corispermum americanum var. rydbergii | Chenopodiaceae
|
| COOCA | Corispermum ochotense Ignatov var. alaskanum Mosyakin | Alaskan bugseed | Chenopodiaceae
|
| COOC9 | Corispermum ochotense Ignatov | | Chenopodiaceae
|
| COORE | Corispermum orientale Lam. var. emarginatum (Rydb.) J.F. Macbr. | Corispermum villosum | Chenopodiaceae
|
| COOR3 | Corispermum orientale auct. non Lam. | Corispermum americanum var. americanum | Chenopodiaceae
|
| COPA37 | Corispermum pacificum Mosyakin | common bugseed | Chenopodiaceae
|
| COPA38 | Corispermum pallasii Steven | Siberian bugseed | Chenopodiaceae
|
| COPA39 | Corispermum pallidum Mosyakin | pale bugseed | Chenopodiaceae
|
| COSI8 | Corispermum sibiricum Iljin p.p. | Corispermum pallasii | Chenopodiaceae
|
| COSI6 | Corispermum simplicissimum Lunell | Corispermum americanum var. americanum | Chenopodiaceae
|
| COVI5 | Corispermum villosum Rydb. | hairy bugseed | Chenopodiaceae
|
| COWE | Corispermum welshii Mosyakin | Welsh's bugseed | Chenopodiaceae
|
| CORIS | Corispermum L. | bugseed | Chenopodiaceae
|
| COCA27 | Cornella canadensis (L.) Rydb. | Cornus canadensis | Cornaceae
|
| COSU10 | Cornella suecica (L.) Rydb. | Cornus suecica | Cornaceae
|
| COAC3 | Cornicularia aculeata (Schreber) Ach. | Cetraria aculeata | Parmeliaceae
|
| COCA37 | Cornicularia californica (Tuck.) Du Rietz | Kaernefeltia californica | Parmeliaceae
|
| CODI15 | Cornicularia divergens Ach. | Bryocaulon divergens | Parmeliaceae
|
| COFI4 | Cornicularia fibrillosa (Ach.) Halsey | Bryoria furcellata | Parmeliaceae
|
| COMU6 | Cornicularia muricata (Ach.) Ach. | Cetraria muricata | Parmeliaceae
|
| CONO2 | Cornicularia normoerica (Gunn.) Du Rietz | brittle lichen | Parmeliaceae
|
| COOD4 | Cornicularia odontella (Ach.) Westend. | Cetraria odontella | Parmeliaceae
|
| COPS | Cornicularia pseudosatoana Asah. | Bryocaulon pseudosatoanum | Parmeliaceae
|
| CORNI | Cornicularia (Schreber) Hoffm. | brittle lichen | Parmeliaceae
|
| COHY2 | Cornucopiae hyemalis Walt. | Agrostis hyemalis | Poaceae
|
| COPE7 | Cornucopiae perennans Walt. | Agrostis perennans | Poaceae
|
| COALS | Cornus alba L. ssp. stolonifera (Michx.) Wangerin | Cornus sericea ssp. sericea | Cornaceae
|
| COALB | Cornus alba L. var. baileyi (Coult. & Evans) Boivin | Cornus sericea ssp. sericea | Cornaceae
|
| COALC | Cornus alba L. var. californica (C.A. Mey.) Boivin | Cornus sericea ssp. occidentalis | Cornaceae
|
| COALI | Cornus alba L. var. interior (Rydb.) Boivin | Cornus sericea ssp. sericea | Cornaceae
|
| COALO | Cornus alba L. var. occidentalis (Torr. & Gray) Boivin | Cornus sericea ssp. occidentalis | Cornaceae
|
| COAL80 | Cornus alba L. p.p. | Cornus sericea ssp. sericea | Cornaceae
|
| COAL2 | Cornus alternifolia L. f. | alternateleaf dogwood | Cornaceae
|
| COAMO | Cornus amomum P. Mill. ssp. obliqua (Raf.) J.S. Wilson | Cornus obliqua | Cornaceae
|
| COAMS | Cornus amomum P. Mill. var. schuetzeana (C.A. Mey.) Rickett | Cornus obliqua | Cornaceae
|
| COAM2 | Cornus amomum P. Mill. | silky dogwood | Cornaceae
|
| COAR7 | Cornus �arnoldiana Rehd. | | Cornaceae
|
| COAS2 | Cornus asperifolia Michx. | toughleaf dogwood | Cornaceae
|
| COBA6 | Cornus baileyi Coult. & Evans | Cornus sericea ssp. sericea | Cornaceae
|
| COCA26 | Cornus �californica C.A. Mey. | Cornus sericea ssp. occidentalis | Cornaceae
|
| COCAD | Cornus canadensis L. var. dutillyi (Lepage) Boivin | Cornus canadensis | Cornaceae
|
| COCA13 | Cornus canadensis L. | bunchberry dogwood | Cornaceae
|
| COCA45 | Cornus capitata Wall. ex Roxb. | Bentham's cornel | Cornaceae
|
| CODR | Cornus drummondii C.A. Mey. | roughleaf dogwood | Cornaceae
|
| COFL2 | Cornus florida L. | flowering dogwood | Cornaceae
|
| COFOM | Cornus foemina P. Mill. ssp. microcarpa (Nash) J.S. Wilson | Cornus asperifolia | Cornaceae
|
| COFOR | Cornus foemina P. Mill. ssp. racemosa (Lam.) J.S. Wilson | Cornus racemosa | Cornaceae
|
| COFO | Cornus foemina P. Mill. | stiff dogwood | Cornaceae
|
| COFR9 | Cornus �friedlanderi W.H. Wagner | | Cornaceae
|
| COGL3 | Cornus glabrata Benth. | brown dogwood | Cornaceae
|
| COIN5 | Cornus instolonea A. Nels. | Cornus sericea ssp. sericea | Cornaceae
|
| COIN6 | Cornus interior (Rydb.) N. Petersen | Cornus sericea ssp. sericea | Cornaceae
|
| COKO2 | Cornus kousa Hance | Kousa dogwood | Cornaceae
|
| COMA21 | Cornus mas L. | Cornelian cherry | Cornaceae
|
| CONU4 | Cornus nuttallii Audubon ex Torr. & Gray | Pacific dogwood | Cornaceae
|
| COOB9 | Cornus obliqua Raf. | silky dogwood | Cornaceae
|
| COOC6 | Cornus occidentalis (Torr. & Gray) Coville | Cornus sericea ssp. occidentalis | Cornaceae
|
| COPA23 | Cornus paniculata L'H�r. | Cornus racemosa | Cornaceae
|
| COPR4 | Cornus priceae Small | Cornus drummondii | Cornaceae
|
| COPU10 | Cornus purpusii Koehne | Cornus obliqua | Cornaceae
|
| CORA6 | Cornus racemosa Lam. | gray dogwood | Cornaceae
|
| CORU | Cornus rugosa Lam. | roundleaf dogwood | Cornaceae
|
| COSA81 | Cornus sanguinea L. | bloodtwig dogwood | Cornaceae
|
| COSEO | Cornus sericea L. ssp. occidentalis (Torr. & Gray) Fosberg | western dogwood | Cornaceae
|
| COSES | Cornus sericea L. ssp. sericea | redosier dogwood | Cornaceae
|
| COSES2 | Cornus sericea L. ssp. stolonifera (Michx.) Fosberg | Cornus sericea ssp. sericea | Cornaceae
|
| COSEI | Cornus sericea L. var. interior (Rydb.) St. John | Cornus sericea ssp. sericea | Cornaceae
|
| COSE16 | Cornus sericea L. | redosier dogwood | Cornaceae
|
| COSE3 | Cornus sessilis Torr. ex Dur. | blackfruit dogwood | Cornaceae
|
| COSL | Cornus �slavinii Rehd. | | Cornaceae
|
| COSTB | Cornus stolonifera Michx. var. baileyi (Coult. & Evans) Drescher | Cornus sericea ssp. sericea | Cornaceae
|
| COSTC4 | Cornus stolonifera Michx. var. californica (C.A. Mey.) McMinn | Cornus sericea ssp. occidentalis | Cornaceae
|
| COSTI | Cornus stolonifera Michx. var. interior (Rydb.) St. John | Cornus sericea ssp. sericea | Cornaceae
|
| COSTO2 | Cornus stolonifera Michx. var. occidentalis (Torr. & Gray) C.L. Hitchc. | Cornus sericea ssp. occidentalis | Cornaceae
|
| COST4 | Cornus stolonifera Michx. | Cornus sericea ssp. sericea | Cornaceae
|
| COST13 | Cornus stricta Lam. | Cornus foemina | Cornaceae
|
| COSU4 | Cornus suecica L. | Lapland cornel | Cornaceae
|
| COUN | Cornus unalaschkensis Ledeb. | western cordilleran bunchberry | Cornaceae
|
| CORNU | Cornus L. | dogwood | Cornaceae
|
| COOB4 | Cornutia obovata Urban | nigua | Verbenaceae
|
| COPY2 | Cornutia pyramidata L. | azulejo | Verbenaceae
|
| CORNU2 | Cornutia L. | cornutia | Verbenaceae
|
| COIN17 | Cornutispora intermedia Punith & D. Hawksw. | | Uncertain Lichen Family
|
| COLI16 | Cornutispora lichenicola D. Hawksw. & B. Sutton | | Uncertain Lichen Family
|