Equisetum giganteum is a species of horsetail

Horsetail

Equisetum is the only living genus in the Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.Equisetum is a "living fossil", as it is the only living genus of the entire class Equisetopsida, which for over one hundred million years was much more diverse and...

 native to South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 and Central America

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

, from central Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

 east to Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

 and north to southern Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

.

It is one of the largest horsetails, growing 2-5 m tall, exceeded only by the closely allied E. myriochaetum

Equisetum myriochaetum

Equisetum myriochaetum, also known as Mexican Giant Horsetail, is a species of horsetail that is native to Nicaragua, Costa Rica, Colombia, Venezuela, Ecuador, Peru and Mexico....

(which can achieve stem heights of 8 m, although such plants rely on surrounding herbage for support). The stems are the stoutest of any horsetail, 1-2 cm diameter (up to 3.5 cm diameter in some populations), and bear numerous whorls of very slender branches; these branches are not further branched, but some terminate in spore

Spore

In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

cones. Unlike some other horsetails, it does not have separate photosynthetic sterile and non-photosynthetic spore-bearing stems.

Populations from northern Chile with very stout stems up to 3.5 cm diameter have sometimes been treated as a separate species E. xylochaetum, but this is not widely regarded as distinct.