Single-generation Galactic stellar mass for various choices of the dispersion in the three parameters of the stellar clusters IMFs: Γ, γ, and M_ch. The three stacked images in the top left panel show cases with cluster-to-cluster variations only in Γ, the top right panel displays cases with variations only in γ, and the lower left panel displays cases that include variations only in M_ch. The ensemble of black curves in each of the stacked images are similar. The models in each of the stacked images are compared to the Kroupa (2001), Chabrier (2005), and Parravano et al. (2011) Galactic field stellar mass function (red line) with their associated uncertainties (hatched regions in red).