Well, I could make a stretch and say "Chrissy" or something like that as a derivation of Chrysanthemum, but it would seem much more likely to be a diminutive of Christine or the like.
I can't think of a name to take from Orchid, Statice, or Carnation. Those are the most common flowers for the floats (all the above-mentioned, not just these three).
Oh, wait, Mary or Marie? (Marigolds)