Charlock 
Chinese Violet Cress 
Chorisphora tenella 
Chorispora purpurascens 
Chorispora tenella 
Clasping Pepperweed 
Cleome arabica 
Cleome austroarabica 
Cleome brachycarpa 
Cleome chelidonii 
Cleome chrysantha 
Cleome droserifolia 
Cleome ornithopodioides 
Cleome rupicola 
Cleome violacea 
Clypeola aspera 
Clypeola jonthlaspi 
Clypeola lappacea 
Columbia bladderpod 
Columbia Gorge rockcress 
Coralroot Bittercress 
Crambe hispanica 
Crateva greveana 
Cuckooflower