Talking about cow parsley still, we walked past a ton of it on Sunday, near the river (Thames), and I also noticed a clump of plants quite similar, but with yellow flowers. I think it's alexanders, which used to be used in cooking. Presumably it's one of the umbelliferae, which is a massive family, including things like chervil, cicely, angelica, and of course, who could forget, pig-nut.