Daisy is a derivative of the name Margaret. The French flower marguerite is known in English speaking countries as the Daisy. Margaret of Anjou (1429 - 1482) wife of England's King Henry VI, used the Daisy as her personal emblem.
Daisy is Old English and means the eye of the day or Vision. People who have this name tend to be able to see prophetically. In the Bible it says: "My people persih without vision."
The name has been used as a nickname of Candace, though as the pronunciation "can-DAY-see" has become old-fashioned, the association with it is much weakened.