Observed abundances (log number relative to solar; one panel per species) versus iron abundance (same units) for EHe stars (blue squares), majority RCB stars (red diamonds), minority RCB stars (red triangles; from Jeffery et al. 2011, and references therein) and KPD 0005+5106 (green filled circle). The upper limit for Mg is indicated by an arrow. The dashed lines indicate the solar composition scaled to iron.