Over the past years observations of young and populous star clusters
have shown that the stellar IMF appears to be an invariant featureless
Salpeter power-law with an exponent alpha=2.35 for stars more
massive than a few solar masses. A consensus has also emerged that most,
if not all, stars form in stellar groups and star clusters, and that
the mass function of young star clusters in the solar-neighborhood and
in interacting galaxies can be described, over the mass range of a few
10 Mo to 10^7 Mo, as a power-law with an exponent
ß ~2. These two results imply that galactic-field IMFs for
early-type stars cannot, under any circumstances, be a Salpeter
power-law, but that they must have a steeper exponent alpha(field) ~> 2.8.
This has important consequences for the
distribution of stellar remnants and for the chemo-dynamical and
photometric evolution of galaxies.