Greater knapweed (Centaurea scabiosa) can survive in dry places. Its purple flowers contrast with the yellow grass.
Like with other members of the Daisy family (the Compositaea), what looks like a flower is in fact a flower head which contains several individual florets. Those are surrounded by a number of bracts which form an involucre. Here below those are visible as brown-edged scales under the flower head.
In Greater Knapweed all florets are tubular, those on the outside are somewhat larger. The ants enjoy!