Compassplant _Silphium laciniatum_ 53 Coneflower _Dracopis_; _Rudbeckia_ 41, 51 Conyza _Conyza_ 40 Copperleaf _Acalypha_ 35 Cordgrass _Spartina_ 25 Coreopsis _Coreopsis_ 40 Corkwing, mountain _Cymopterus montanus_ 40 Corn _Zea_ 26 Corncockle _Agrostemma_ 35 Cornflower _Centaurea cyanus_ 38 Cornsalad _Valerianella_ 54 Corydalis _Corydalis_ 40 Cotton _Gossypium_ 44 Cottontop _Trichachne_ 26 Cottonwood _Populus_ 57 Cowlily _Nuphar_ 48 Cowpea _Vigna_ 35 Crabapple _Pyrus_ 57 Crabgrass _Digitaria_ 20 Crazyweed _Oxytropis_ 33 Creeper _Parthenocissus_ 57 Cress, hoary _Cardaria draba_ 38 Cristatella _Cristatella_ 40 Crotalaria _Crotalaria_ 31 Croton _Croton_ 40 Crotonopsis _Crotonopsis_ 40 Crowfoot _Ranunculus_ 51 Crownbeard _Verbesina_ 55 Crownvetch _Coronilla_ 31 Cryptantha _Cryptantha_ 40 Cudweed _Gnaphalium_ 43 Culversphysic _Veronicastrum virginicum_ 55 Cupgrass _Eriochloa_ 21 Cuphea _Cuphea_ 40 Curlymesquite _Hilaria belangeri_ 22 Currant _Ribes_ 58 Cutgrass _Leersia_ 22 Cyclanthera _Cyclanthera_ 40 Cymopterus _Cymopterus_ 40 Dalea _Dalea_ 31 Dallisgrass _Paspalum dilatatum_ 24 Dandelion _Taraxacum_ 54