Characteristic abundances increase with galactic luminosity, and this trend embraces irregulars as well as spirals (Skillman et al. 1989; Garnett 1999; ZKH). This trend may involve the escape of nucleosynthesis products in winds from galaxies with low escape velocities (Matteucci & Chiosi 1983). Garnett (2001a) plots the dependence of effective yield on luminosity; effective yields for low surface brightness galaxies (LSBs) as a class fall below those for normal galaxies. Stellar abundances in elliptical galaxies also increase with galactic luminosity (HW, and references therein).