Citrus reticulata [Mandarin Orange Tree]
Citrus sinensis x Poncirus trifoliata [Carrizo Citrange]
Clammy Cuphea [Cuphea viscosissima]
Clarkia rubicunda [Ruby Chalice Fairyfan]
Climbing Nightshade [Solanum dulcamara]
Clover, Silky Prairie [Petalostemum villosum]
Clover, Crimson [Trifolium incarnatum]
Clover, Japanese [Kummerowia striata]
Clover, Purple [Trifolium pratense]
Clover, White [Trifolium repens]
Coastal Scrub Wattle [Acacia minuta]
Codlins and Cream [Epilobium hirsutum]
Coffea arabusta [Coffee]
Coffee [Coffea arabusta]
Coffeeweed [Cassia obtusifolia]
Conium maculatum [Poison Hemlock]
Copaifera aromatica
Coral Honeysuckle [Lonicera sempervirens]
Cordgrass, Common [Spartina anglica]
Corkscrew Vallisneria [Vallisneria tortifolia]
Cordgrass, Saltmeadow [Spartina patens]
Cordgrass, Smooth [Spartina alterniflora]
Corn [Zea mays]
Corncockle [Agrostemma githago]
Cornus florida [Eastern Flowering Dogwood]
Correa schlechtendalii
Cotton [Gossypium hirsutum]
Cottongrass, Tussock [Eriophorum vaginatum]
Cottonwood, Black [Populus trichocarpa]
Cottonwood, Eastern [Populus deltoides]
Crabgrass, Hairy [Digitaria sanguinalis]
Crabgrass, Natal [Digitaria natalensis]
Creosote Bush [Larrea tridentata]
Crested Dogstailgrass [Cynosurus cristatus]
Crotalaria juncea [Sunn Hemp]
Cucumber, Garden [Cucumis sativus]
Cucumis melo [Cantaloupe]
Cucumis sativus [Garden Cucumber]
Cucurbita pepo [Summer Squash]
Cudweed [Gnaphalium affine]
Cuphea viscosissima [Clammy Cuphea]
Cynosurus cristatus [Crested Dogstailgrass]
Cyperus esculentus [Yellow Nutsedge]
Cyperus rotundus [Purple Nutsedge]