The Collaborative International Dictionary of English v.0.48:

campanular \cam*pan"u*lar\ (k[a^]m*p[a^]n"[-u]*l[~e]r), adj.
   shaped like a bell or campana; campaniform.

   Syn: campanulate, campanulated, campaniform, campaniliform.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

campanular
    adj 1: shaped like a bell or campana; "campanulate flowers of
           the genus Campanula" [syn: campanulate, campanular,
           campanulated]