  Perez-Marco proved the existence of non-trivial totally invariant connected
compacts called hedgehogs near the fixed point of a nonlinearizable germ of
holomorphic diffeomorphism. We show that if two nonlinearisable holomorphic
germs with a common indifferent fixed point have a common hedgehog then they
must commute. This allows us to establish a correspondence between hedgehogs
and nonlinearizable maximal abelian subgroups of Diff$(\bf C,0)$. We also show
that two nonlinearizable germs are conjugate if and only if their rotation
numbers are equal and a hedgehog of one can be mapped conformally onto a
hedgehog of the other. Thus the conjugacy class of a nonlinearizable germ is
completely determined by its rotation number and the conformal class of its
hedgehogs.
