  The inflessence model has recently been proposed in an attempt to explain
both early inflation and present day accelerated expansion within a single
mechanism. The model has been successfully tested against the Hubble diagram of
Type Ia Supernovae, the shift parameter, and the acoustic peak parameter. As a
further mandatory test, we investigate here structure formation in the
inflessence model determining the evolution of matter density contrast $\delta
\equiv \delta \rho_M/\rho_M$ in the linear regime. We compare the growth factor
$D(a) \equiv \delta/a$ and the growth index $f(z) \equiv d\ln{\delta}/d\ln{a}$
to these same quantities for the successful concordance $\Lambda$CDM model with
a particular emphasis on the role of the inflessence parameters $(\gamma,
z_Q)$. We also evaluate the anisotropy spectrum of the cosmic microwave
background radiation (CMBR) to check whether the inflessence model may be in
agreement with the observations. We find that, for large values of $(\gamma,
z_Q)$, structure formation proceeds in a similar way to that in the
$\Lambda$CDM scenario, and it is also possible to nicely fit the CMBR spectrum.

Astrophysics