  The electronic structure of few-layer graphene (FLG) samples with crystalline
order was investigated experimentally by infrared absorption spectroscopy for
photon energies ranging from 0.2 - 1 eV. Distinct optical conductivity spectra
were observed for different samples having precisely the same number of layers.
The different spectra arise from the existence of two stable polytypes of FLG,
namely, Bernal (AB) stacking and rhombohedral (ABC) stacking. The observed
absorption features, reflecting the underlying symmetry of the two polytypes
and the nature of the associated van Hone singularities, were reproduced by
explicit calculations within a tight-binding model. The findings demonstrate
the pronounced effect of stacking order on the electronic structure of FLG.
