Ophelia gives the queen a daisy to signify “that her light and fickle love ought not to expect constancy in her husband.” So the daisy is explained by Greene to mean a Quip for an upstart courtier. (Anglo-Saxon dages eage, day's eye.)
The word is Day's eye, and the flower is so called because it closes its pinky lashes and goes to sleep when the sun sets, but in the morning it expands its petals to the light. (See Violet.)
That well by reason men calle it maie. The daisie, or else the eie of the daie.
Daisy (Solomon). Parish clerk of Chigwell. He had little, round, black, shiny eyes like beads; wore rusty black breeches, a rusty black coat, and a long-flapped waistcoat with queer little buttons. Solomon Daisy, with Phil Parkes, the ranger of Epping Forest, Tom Cobb, the chandler and post-office keeper, and John Willet, mine host, formed a quadrilateral or village club, which used to meet night after night at the Maypole, on the borders of the forest. Daisy's famous tale was the murder of Mr. Reuben Haredale, and the conviction that the murderer would be found out on the 19th of March, the anniversary of the murder. (Dickens: Barnaby Rudge, chap. i., etc.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894