Species · GBIF taxon 7924597
field horsetail
Equisetum arvenseAlso known as Common Horsetail, Shavegrass, Pewterwort, Bottle Brush
Field horsetails are living fossils belonging to an ancient lineage of vascular plants that dominated the landscape over three hundred million years ago. In early spring, pale, unbranched fertile stems emerge to release spores from cone-like tips before dying back. Soon after, the sterile green stems arise, displaying whorls of needle-like branches that resemble miniature pine trees or horse tails.
Ancient LineageSpore-bearingSilica-rich
1 / 7—observations
—countries
—peak records
Least ConcernConservation statusIUCN Red List categoriesLCNTVUENCREWEXLeast ConcernRed List categories, explained →
Diet & prey
- Photosynthetic (Autotrophic)
Predators
- Sawfly larvae
- Canada geese
- Snails
ThreatsHabitat destruction and heavy herbicide application
HabitatsWet meadows, fields, roadsides, riverbanks, and disturbed soils
Life spanPerennial (rhizomes can survive for decades)
Size / weightNot available
Classification
- FamilyEquisetaceae
- SpeciesEquisetum arvense
Range data is not available yet.
Interaction riskHigh
- Low
- Moderate
- High
- Very high
- Why interaction risk is high
- Contains thiaminase which is toxic to livestock and pets; do not ingest.
- Why it is dangerous
- Contains thiaminase, an enzyme that depletes vitamin B1, making it highly toxic to horses and other livestock when contaminated in hay.
- How to recognize a risky encounter
- Recognized by its jointed, hollow green stems with whorls of pine-like branches, or pale brown fertile spring shoots with cone-like tips.
- What to do
- Do not harvest for consumption, and ensure pastures are cleared of dense patches to protect grazing animals.
Responsible observation
- Observe the stems: Feel the rough, abrasive texture caused by microscopic silica crystals embedded in the plant tissue.
- Track the seasons: Look for the pale, cone-tipped fertile shoots in early spring before the green, brush-like sterile stems emerge.
- Examine the joints: Pull gently on a stem segment to see how it easily pops apart at the dark-toothed sheath nodes.
Look-alike 
Close Relative (c) Tatiana Strus, some rights reserved (CC BY), uploaded by Tatiana Strus · cc-by
Close Relative (c) Timothy McNitt, some rights reserved (CC BY) · cc-by
Close Relative Ryan Hodnett / CC BY-SA 4.0 · cc-by-sa
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