Horsetail's are pretty unmistakeable but deciding which specific species can be a bit tricky. Fortunately, the various species tend to have their own habitat preference and if you find a horsetail in damp meadows then it will almost certainly be marsh horsetail (Equisetum palustre). There are other differences between this and its cousins but you need a good field guide to help you with that although, in general, you will also find the 'fronds' are shorter and pointing upward in this species!
Where it grows it will usually be quite common, even abundant, but as many meadows have been drained for 'agricultural improvement' it is considered a declining species. It can be found in some profusion on Wareham Common in summer. It is poisonous to both horses and cattle and yet cattle frequently graze on the common and presumably do not touch this stuff! Cows do seem to know what is good for them and what is not.
Sadly, horsetails seem to be rather boring plants and no one ever takes any notice of them.