  A factorial analogue of the supersymmetric Schur functions is introduced. It
is shown that factorial versions of the Jacobi--Trudi and Sergeev--Pragacz
formulae hold. The results are applied to construct a linear basis in the
center of the universal enveloping algebra for the Lie superalgebra gl(m|n) and
to obtain super-analogues of the higher Capelli identities.
