Canadian horseweed 
Canary Bellflower 
Canterbury-Bells 
Cape marigold 
Cape Sable whiteweed 
Cape-Ivy 
Cardinal Flower 
Cardo Personata 
Cardoon 
Carlina frigida 
Carlina lanata 
Carlina libanotica 
Carlina racemosa 
Carline Thistle 
Carline Thistle 
Carolina elephantsfoot 
Carolina False Dandelion 
Carpesium cernuum 
Carthamus lanatus 
Carthamus persicus 
Cassinia subtropica 
centaura jacea 
Centaurea aegyptiaca 
Centaurea ammocyanus