Where Does Equisetum Horsetail Live?

The genus Equisetum includes a suite of plants commonly called "horsetails" or "scouring rushes." These widely-distributed organisms are the only surviving representatives of the once-mighty class Sphenopsida, which first appeared more than 350 million years ago.

Equisetum typically grows in moist or wet environments.

Identification

Equisetum species are distinctive: They have thick, green, gritty stalks and, on a number of types, distinctive whorls of stiff bristles. The plants range in height from about 13 centimeters to more than 8 meters.

Geography

There are at least 15 species of extant Equisetum broadly distributed globally, although no representatives are naturally found in Australia, New Zealand and certain oceanic island systems.

Diversity

Equisetum diversity reaches its zenith in the temperate latitudes of the Northern Hemisphere.

Habitat

Horsetails and scouring rushes favor moist to wet environments; they're common sights on the margins of wetlands, in bottomland woods and any low, poorly drained areas. They can tap subterranean water through extensive rhizome (underground stem) systems, one of their salient characteristics, and so sometimes appear to be growing in areas drier than their usual preference.

Colonizers

Those rhizomes allow Equisetum species to aggressively and opportunistically colonize disturbed landscapes. Roadside ditches constitute a great new habitat for many species. Horsetails were some of the first plants to reclaim the lava- and ash-flooded slopes of Mount St. Helens in the Washington Cascades after the volcano's 1980 eruption.

References

• Fossil Record of the Spenophyta
• An Introduction to the Genus Equisetum and the Class Spenopsida as a whole
• Cascade-Olympic Natural History; Daniel Mathews; 1999

Resources

• Equisetum (Flora of North America)