Mean stellar abundance ratios of the galaxy sample at z ≈ 0. Oxygen was chosen to represent α enrichment. Akin to Figure 7, different regions of the diagram are predominantly occupied by specific classes. A clear gradient emerges from the top left to the bottom right of the distribution as QE-QL-RQ-Ct-RM-MS. Main-sequence-type galaxies tend to the right-most corner of the distribution.