Horsetails

While walking around the reservoir yesterday, we found a few clumps of this, surprisingly odd-looking plant...

...Known as a Great Horse-tail (Equisetum telmateia). The plant has many uses throughout the world. It contains several chemicals which can be used medicinally. It is rich in the minerals silicon (10%), potassium, and calcium, which gives it diuretic properties. It is prescribed to care for conjunctive tissues (cartilage, tendons, and bones) and also polyps, epistasis, and bleeding. The buds are eaten as a vegetable in Japan in spring time.

It was also once used to polish pewter and wood (gaining the name pewterwort) and to strengthen fingernails. Also as an abrasive: it was used by Hurdy-Gurdy players to dress the wheels of their instruments by removing resin build up. In herbalism it is used to treat kidney and bladder problems, gastro-enteritis, and prostate and urinary infections. Externally it is used for chilblains and wounds. Quite a useful plant! In fact, Equisetum is the only surviving genus of the entire class Equisetopsida, which for over one hundred million years was very diverse and dominated the understory of late Paleozoic forests. Some Equisetopsida were large trees reaching to 30 meters tall; the genus Calamites of family Calamitaceae for example is abundant in coal deposits from the Carboniferous period.
As any gardener will tell you, Horsetails are very difficult to get rid of. This is mainly due to their extraordinarily deep root systems which have been recorded in mines, hundreds of feet down.