Daisy 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."
Chaucer