  We present a theory of electronic transport in graphene in the presence of
randomly placed adsorbates. Our analysis predicts a marked asymmetry of the
conductivity about the Dirac point, as well as a negative weak-localization
magnetoresistivity. In the region of strong scattering, renormalization group
corrections drive the system further towards insulating behavior. These results
explain key features of recent experiments, and are validated by numerical
transport computations.
