  At half filling, the electronic structure of graphene can be modelled by a
pair of free two-dimensional Dirac fermions. We explicitly demonstrate that in
the presence of a geometrically induced gauge field, an everywhere-real Kekule
modulation of the hopping matrix elements can correspond to a non-real Higgs
field with non-trivial vorticity. This provides a natural setting for
fractionally charged vortices with localized zero modes. For fullerene-like
molecules we employ the index theorem to demonstrate the existence of six
low-lying states that do not depend strongly on the Kekule-induced mass gap.
