The Permian Horsetail Plant

The horsetail plant has existed for milleniums.

The Permian horsetail plant is the last surviving genus of the Equisetopsida class that existed over a hundred million years ago. The horsetail plant survived the most massive extinction known to man at the end of the Permian period, when continents shifted and merged, creating one supercontinent. This geological event caused 95 percent of all animal species and many plant species to become extinct. Does this Spark an idea?

The Permian Period

The only survivor of its class

The Permian period was 300 to 250 millions years ago, preceding the Carboniferous period. The early Permian period was the end of an ice age. As continents began to shift, the climate became hotter and drier by the mid-Permian period. This caused swampy areas to dry out, and plants from the carboniferous period were replaced by more heat- and wind-resistant plants like seed ferns and conifers. The Permian horsetail plant survived these changes, but the large horsetail trees that formerly survived in swamps did not.



The horsetail plant is scientifically classified as from the kingdom of Plantae, from the division of Equisetophyta, class Equisetopsida, order Equisetopsida and family Equisetaceae.

A Relic From the Past

The large group of primitive vascular plants called Equisetophyta, the division containing the horsetail, is considered relictual. Horsetail, the only remaining genus, called Equisetum, means “horse bristle” in Latin.

Survivors of the Permian Period

Many plants that needed a moister climate died off by the end of the Permian period. Herbal club mosses, horsetails and seed ferns lived on but did not fare as well as their predecessors, resulting in diminished physical size. Fossils indicate that ancient horsetail plants were much bigger, even “tree-like,” though not to be confused with the ancient Permian horsetail trees, which became extinct by the end of the period.

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Fossils from the Permian period can be found mostly in Germany and France. The Permian period was named by the Scottish geologist Roderick Murchison in 1841, after the kingdom of Permia in modern day Russia.

Physical Appearance

Horsetails are named for the way they look, resembling a horse’s tail with a long stem and hair-like fronds radiating outward. They have whorls and small scale-like leaves with a hollow, jointed stem that carries on photosynthesis within it. Some horsetails have special non-green shoots with a cone shape that bears spores. The horsetail reproduces by alternation of generations. The tropical American species of horsetail (E. gigantum) reaches more than 30 feet (9.1 m) in height. Most other species of horsetail grow to under three feet (91 cm).

Current Regions

The most common types of horsetail grow in North America and Eurasia. E. arvense thrives in dryer climates, while E. hyemale lives in moist, wooded areas. The latter species is used today in cleaning products, and other species are used as herbal remedies. Horsetails are currently found in most temperate and tropical regions, except for New Zealand and Australia.