Rough Chervil (Chaerophyllum temulentum)
The Cow Parsley that flowered in April and May is now over and yet there are still plants that you could easily take for Cow Parsley in full flower. Cow Parsley has been replabed by Rough Chervil.
Rough Chervil is as common as Cow Parsley and looks very similar at first glance. It is not at all easy to tell the difference. Indeed, even my flower 'bible' starts its description with 'resembles Cow Parsley and is its June successor''!
There are differences, of course, but apart from the time difference the other way is to run your fingers along the stem, if it is smooth it is Cow Parsley but if it is rough then, yes, it is Rough Chervil. On close examination, the leaves are different and Rough Chervil has almost black stems.
So, next time you are walking along by a hedgerow run your fingers over the stems of the Cow Parsley look-a-likes. If it feels rough then you have Rough Chervil!