Stellar mass distribution as a function of [Mg/Fe] predicted by the PM04 chemical evolution model for a typical elliptical galaxy (solid line). The luminosity distribution as a function of [Mg/Fe] is given by the dotted line. The dashed line gives the luminosity distribution when the SSPs formed at  [Fe/H]  <  −1 are not taken into account (see text). The curves have been arbitrarily rescaled to the same value and offset to make differences in the tails more visible.