Over the past 3 months my wife and I have regularly walked a path at Highwoods Country Park, Colchester. At one point on the walk (TM009268) we have noted a spear thistle beside the path, just out of mower reach. When first seen we thought it was hosting a large caterpillar. Closer inspection revealed it to be a deformed flower head curled round in a crescent. This grew over time until it eventually caused the crown of the plant to collapse, and became a crescent of flower heads. We have never seen anything like this before and it would be interesting to known the cause of the phenomena. Is it something genetic in the plant or is there an outside cause.