  We show that one can obtain a good fit to the measured main sequence mass
function (MF) of a large sample of Galactic clusters (young and old) with a
tapered Salpeter power law distribution function with an exponential
truncation. The average value of the power law index is very close to Salpeter
(~2.3), whereas the characteristic mass is in the range 0.1 - 0.5 Msolar and
does not seem to vary in a systematic way with the present cluster parameters
such as metal abundance and central concentration. However, a remarkable
correlation with age is seen, in that the peak mass of young clusters increases
with it. This trend does not extend to globular clusters, whose peak mass is
firmly at ~0.35 Msolar. This correlation is due to the onset of mass
segregation following early dynamical interactions in the loose cluster cores.
Differences between globular and younger clusters may depend on the initial
environment of star formation, which in turn affects their total mass.
