The Collaborative International Dictionary of English v.0.48:

Supervolute \Su`per*vo*lute"\, a. [L. supervolutus, p. p. of
   supervolvere to roll over; super over + volvere to roll.]
   (Bot.)
   Having a plaited and convolute arrangement in the bud, as in
   the morning-glory.
   [1913 Webster]