The Collaborative International Dictionary of English v.0.48:

fiddle-shaped \fiddle-shaped\ adj.
   shaped like a fiddle; -- of a leaf shape.

   Syn: pandurate, panduriform.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Fiddle-shaped \Fid"dle-shaped`\, a. (Bot.)
   Inversely ovate, with a deep hollow on each side. --Gray.
   [1913 Webster]

WordNet (r) 3.0 (2006):

fiddle-shaped
    adj 1: (of a leaf shape) having rounded ends and a contracted
           center [syn: pandurate, panduriform, fiddle-shaped]