Bet if I would ask you “what is the flower of December?” you would answer “the poinsettia!” But you would only be kinda-sorta-half right.
According to The Ultimate Authoritative Answer To Everything, Wikipedia: The narcissus is the December birth flower and symbolizes good wishes, faithfulness and respect. The narcissus can often be confused with the daffodil, the birth flower for March, which is a type of narcissus.
Now you know. If you wuz wondering.