I have no idea what this is but it was growing in Priory Park along with the cow parsley. It's not the shot I was looking for but I rather like how the flower stands out on it's own. Thanks for your indulgence with my month of May flowers - I'll be glad to move on to something else!
@rosiekind It was in St. Neots. I went looking for the fallen blossom as I thought it would make a fitting end for my month of flowers bu didn't find the shot I was looking for.