Common names - Horsetail, Scouring Rush, Jointweed, Bullpipes, Shavebrush, Pewterwort, and a number of others. This is a varied group, from the tall (up to about 3 feet) one in the photo above, that seems to prefer damp places and will grow in light shade, to the one below, a miniature form, probably about 6 inches tall at most, that likes damp places also, but that will grow in full sun. Both are sometimes a little tricky to get started, but once settled in, are quite long lived. The tall one seems to make wide-spread colonies, a stem here and another there, while the miniature one makes a mat, which very nicely chokes out most weeds. Neither bloom with anything resembling a flower and are grown for their interesting stems only. These are quite ancient plants, from the very beginnings of when the flowering plants first appeared.
Horsetail seems to be poisonous to animals which is good because nothing seems to eat it, but which would also seem to urge caution in using it in any medicinal way. The dried, powdered stems have sometimes been used to stop bleeding, though I'm not sure if this is through any action of the chemicals in the plant, or just the action of putting a powder on a wound.
Their main use has always been related to their common name of scouring rush and pewterwort. The plant contains high amounts of silica which is what makes the stems so good for scrubbing. I first learned about this when I used to spend a lot of time camping in the woods and didn't want to carry too much with me.
It is an interesting accent to other leafy things and we have small colonies in several places. Although it spreads, I would never consider it invasive, but always have enough, especially of the miniature one, to share.
Jane - where the sun is shining and it will be warm and sunny enough to hang the wash outside today - YEAH!