Field horsetail (Equisetum arvense), Oxbow Nature Study Area. May 27, 2016.

Smooth horsetail (Equisetum laevigatum) in Oxbow Nature Study Area, May 2016. Photo: K. Fitzgerald.

Smooth horsetail
Equisetum laevigatum
  • Stems are green and jointed, with one dark bands between each segment.
  • Cone-shaped strobilus at tip of stem holds spores. Cone is yellow and black, rounded at tip.
  • Stem lightly ridged (10-26 ridges per stem).
  • Grows near water, often in large clumps, connected by underground roots (rhizomes).
Record Observations
Species Description

The Equisetum are the only surviving genus of the class Equisetopsida (sometimes called Sphenopsida), which first appeared in the fossil record during the Devonian period, more than 350 million years ago – long before the time of the dinosaurs (Taylor et al. 2009). A class is a fairly large division of the taxonomic scale (like “mammalia,” the mammals,  or “reptilia,” the reptiles, for example), so to outlive all other members of their class, the Equisetum have evidently been doing something right.

Ancient relatives of today’s Equisetum thrived during the Carboniferous period, approximately 359 to 299 million years ago. In swamp forest ecosystems, they grew to tree-sized proportions of up to about 60 feet tall (Taylor et al. 2009). Today, about 15 species of Equisetum remain (Taylor et al. 2009), and have evolved into something more closely resembling small, jointed drinking straws.

Along the Truckee River, the smooth horsetail (Equisetum laevigatum, also sometimes called the “smooth scouring rush”) is common around Reno. Other species of Equisetum may exist along different portions of the river, including field horsetail (E. arvense), scouringrush horsetail (E. hyemale), and hybrids.

All species of Equisetum contain silica in the stem, and can be handy for scrubbing dishes or sanding wood (Vizgirdas & Rey-Vizgirdas 2006). Members of the Washoe Tribe called this plant “mep” and used it for sanding bows and arrows (Murphey, 1959).


References & Links

Murphey, E. V. 1959. Indian Uses of Native Plants. Fort Bragg, CA: Mendocino County Historical Society.

Preston, R.E. & R.L. Hauke. 2016. Equisetum laevigatum, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=24427, accessed on June 09, 2016.

Taylor, T.N., Taylor, E.L. and M. Krings. 2009. Sphenophytes, in Paleobotany: The Biology and Evolution of Fossil Plants. Academic Press. Available: http://www.sciencedirect.com.unr.idm.oclc.org/science/article/pii/B9780123739728000103. Accessed June 9, 2016.

Vizgirdas, Ray and Edna Rey-Vizgirdas. 2006. Wild Plants of the Sierra Nevada. Reno, NV: University of Nevada Press.

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