It is one of the largest horsetails, growing 2–5 m tall, exceeded only by the closely allied E. myriochaetum (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 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.
It is a popular ornamental plant in hot regions with a humid climate.
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