Cabbageworm (various)
Cabbageworm, Cross-striped (Evergestis rimosalis)
Cabbageworm, Imported (Pieris rapae)
Cabbageworm, Southern (Pontia protodice)
Cactus (Cactaceae)
Cactus, Cholla (Optunia imbricata)
Cadelle (Tenebroides mauritanicus)
Calamondin (Citrofortunella microcarpa)
Callalily, Brazil (Richardia brasiliensis)
Caltrop (Tribulus terrestris)
Camelthorn (Acacia erioloba)
Camelthorn (Alhagi maurorum)
Camelthorn (Alhagi pseudalhagi (A. camelorum))
Camphor Tree (Cinnamomum camphora)
Camphorweed (Heterotheca subaxillaris)
Campion (Silene spp.)
Campion, Bladder (Silene vulgaris)
Campion, White (Silene alba (Melandrium album))
Canarygrass (Phalaris canariensis)