I have only knowingly seen this occasionally, I say knowingly because it looks like quite a few other Umbellifers, particularly Cow Parsley, it is in the same genus as Cow Parsley. So unless you look carefully and spend some time checking it out then with just a casual glance it is just another white flowering umbel. It is commonest in East Anglia, and so having spent 30 years in Norfolk I would have no doubt seen it many times, however in those days I usually had 30 to 40 students in tow and was busy giving out the info on the sand dune ecology or telling them how to carry out their transect and record the plants, so no time to inspect the local flora.
On close inspection there are several characteristics which when combined together serve to identify it. The stems often appear red and are sometimes blotchy, but not always. The leaves are dissected like Cow Parsley but to me they appear less robust, sometimes almost slightly shrivelled up, also a lighter green. The flowers are small white umbels, more delicate and not so prominent as in some other members of the carrot family. It flowers at the same time as several other members of the group, between May and June. When the seeds form they are covered with short bristles and so it is like a little bur. The other common name is Beaked Parsley because the short projections from the seed are like little beaks.
This species often found close to the sea, I have seen it both at Chesil Bank and at Slimbridge, which is almost coastal, on the top end of the Bristol Channel, but it will grow inland usually on sandy or gravelly soil.
Coastal Wild flowers 