  The mass function of freshly formed star clusters is empirically often
described as a power law. However the cluster mass function of populations of
young clusters over the scale of a galaxy has been found to be described by a
Schechter-function. Here we address this apparent discrepancy. We assume that
in an annulus of an isolated self- regulated radially-exponential
axially-symmetric disk galaxy, the local mass function of very young (embedded)
clusters is a power law with an upper mass limit which depends on the local
star formation rate density. Radial integration of this mass function yields a
galaxy-wide embedded cluster mass function. This integrated embedded cluster
mass function has a Schechter-type form, which results from the addition of
many low mass clusters forming at all galactocentric distances and rarer
massive clusters only forming close to the center of the galaxy.
