Cuckoobud \Cuck"oo*bud"\ (k??k"??-b?d`), n. (Bot.)
   A species of {Ranunculus} ({Ranunculus bulbosus}); -- called
   also {butterflower}, {buttercup}, {kingcup}, {goldcup}.
   --Shak.
   
[1913 Webster]

Buttercup \But"ter*cup`\, n. (Bot.)
   A plant of the genus {Ranunculus}, or crowfoot, particularly
   {Ranunculus bulbosus}, with bright yellow flowers; -- called
   also {butterflower}, {golden cup}, and {kingcup}. It is the
   {cuckoobud} of Shakespeare.
   
[1913 Webster]