[Wikipedia] Range, Subspecies Information: Equisetum telmateia, the great horsetail or northern giant horsetail, is a species of Equisetum (puzzlegrass) with an unusual distribution, with one subspecies native to Europe, western Asia and northwest Africa, and a second subspecies native to western North America. The North American subspecies is often simply but ambiguously called "giant horsetail", but that name may just as well refer to the Latin American Equisetum giganteum and Equisetum myriochaetum. Equisetum telmateia subsp. braunii[7] (Milde) Hauke (syn. Equisetum braunii Milde). Northern giant horsetail. Western North America, from southeastern Alaska and western British Columbia south to California. Main stem between branch whorls green. (contributed by Mary Ann Machi)