genus of rushlike conspicuously jointed perennial herbs. Also known as horsetails. Grow in moist, rich soils in all parts of the world except Australasia. Some species produce two kinds of shoots: those with conelike clusters (strobili) of spore capsules and those lacking such structures. Some are evergreen; others send up new shoots annually from underground rootstalks. Their hollow, jointed, ridged stems contain silicate and other minerals. The leaves are reduced to sheaths that clasp and encircle the shoots.

Britannica Editors. "horsetail". Encyclopedia Britannica, 5 Jun. 2014, https://www.britannica.com/plant/horsetail. Accessed 19 October 2026.