caeruleus
dark blue
caespitosus
tufted
campanula
small blue
campestris
growing in fields
canadensis
of Canada
candidus
white
capitatus
forming heads
cardinalis
bright red (like the bird)
carneus
flesh-coloured
caudatus
tailed
chinensis
of China (also sinensis)
chrysanthus
gold-flowered
coccineus
scarlet
communis
common
concolor
uniform in colour
conglomeratus
crowded together
contortus
twisted
convolvulus
twisted
cordatus
heart-shaped
corniculatus
having horns
corymbosus
having corymbs
crispus
curled
cristatus
crested
cruciformis
cross-shaped (crucifix)