Simple elements of partial order theory turned out be useful tools when rankings are needed. Here we show, how a subset of objects, mutually incomparable (called an antichain) can be further analyzed. There is a surprising relation to extremal graph theory, namely an application of the famous thorem of Turan. As example, we analyze the partially ordered sets of regions in the South - West of Germany, where the characterizing attributes are discretized concentrations of Lead, Cadmium, Zinc and Sulfar in the herb layer.