A prickly subject

I found this plant among the dunes on Belhaven Beach. I not at all sure what it is whether it is a type of thistle or possibly even a cactus plant. It is the only one that I have ever found in the vast areas of Belhaven Dunes. I just love its stark outline and shape and the varying colours of the central flower (?) heads. I was going to process it monochrome but felt I wanted to retain the colours of the flowerheas.