Cache Valley Buckwheat
Cactus Apple
Caespitose Four-nerve Daisy
Cainville Thistle
Calibrachoa
Calico
Calicoflower
California Alkaligrass
California Amaranth
California Ash
California Barrel Cactus
California Bearpoppy
California Brickellbush
California Caltrop
California Cottonrose
California Croton
California Evening Primrose
California Fagonbush
California False Hellebore
California Hesperochiron
California Loosestrife
California Mustard
California Nettle
California Oatgrass
California Plumeseed
California Poppy
California Redbud
California Satintail
California Waterwort
Callaway Milkvetch
Caltrop
Camas
Camelthorn
Camphorweed
Campsis
Canada Bluegrass
Canada Cocklebur
Canada Germander
Canada Goldenrod
Canada Lettuce
Canada Thistle
Canada Wildrye
Canadian Gooseberry
Canadian Horseweed