GeoGraph - photograph every grid square

At the end of the summer insects take advantage of the remaining blossoms of which the purple tufts of knapweed or hardhead are one of the most prolific.
Geoffrey Grigson records dozens of popular names for this flower, mostly relating to the knobbly heads with the brush-like topknots.
The generic name, Centaurea, derives from the mythical centaur, Chiron, said have used the plant to heal wounds, which was its former medicinal function.