Equisetum giganteum, with the common name southern giant horsetail, is a species of horsetail native to South America and Central America, from central Chile east to Brazil and north to southern Mexico.
It is one of the largest horsetails, growing 2–5 metres (6.6–16.4 ft) tall, exceeded only by the closely allied Equisetum myriochaetum (up to 8 metres (26 ft) relying on surrounding plants' support). The stems are the stoutest of any horsetail, 1–2 cm diameter (up to 3.5 cm diameter in some populations), ...