] There are so many flowers and herbs mentioned, especially in Ophelia's mad speech. She says rosemary is for remembrance, pansies for thoughts, both of which make a kind of sense with what she's gone through, but what do the others mean? Is there any significance to fennel and columbines, etc?

] Fennel and columbines respectively symbols for flattery and ingratitude, rue for sorrow and repentence Daisy and violets symbolize dissembling and faithfulness. In terrms of the "with a difference" to represent a different cause of sorrow, difference is a term from heraldry, meaning a variation in a coat of arms made to distinguish different members of a family.
The RS is a college text that all the English teachers at our high school used in college. We keep a copy of it the the library.