  We present estimates for the iron content of the stellar and diffused
components of elliptical galaxies, as derived respectively from integrated
optical spectra and from ASCA X-ray observations. A macroscopic discrepancy
emerges between the expected iron abundances in the hot interstellar medium
(ISM) and what is indicated by the X-ray observations, especially when
allowance is made for the current iron enrichment by Type Ia supernovae. This
strong discrepancy, that in some extreme instances may be as large as a factor
of $\sim 20$, calls into question our current understanding of supernova
enrichment and chemical evolution of galaxies. We discuss several astrophysical
implications of the inferred low iron abundances in the ISM, including the
chemical evolution of galaxies and cluster of galaxies, the evolution of gas
flows in ellipticals, and the heating of the intracluster medium. Some of the
consequences appear hard to accept, and in the attempt to avoid some of these
difficulties we explore ways of hiding or diluting iron in the ISM of
ellipticals. None of these possibilities appears astrophysically plausible, and
we alternatively rise the question of the reliability of iron-L line
diagonostic tools. Various thin plasma emission models are shown to give iron
abundances that may differ significantly, especially at low temperatures ($kT
\lsim 1$ keV). From a collection of ASCA and other X-ray observatory data, it
is shown that current thin plasma codes tend to give very low iron abundances
when the temperature of the objects is below $\sim 1$ keV. We conclude that --
besides rethinking the chemical evolution of galaxies -- one should also
consider the possibility that existing thin plasma models may incorporate
inaccurate atomic physics for the ions responsible for the iron-L complex.
