Species At Risk

Horsetail Spike-rush

(Eleocharis equistoides)


Horsetail Spike-rush
Horsetail Spike-rush occurrences map


Horsetail Spike-rush is an aquatic, perennial plant in the sedge family. It reaches about 50 to 100 centimetres in height and grows in water four to 35 centimetres deep.

Horsetail Spike-rush flowers in the late spring and produces fruit from July to October. The fruits are found at the tip of the stem and are covered in light brown scales. The plant has pale green, hollow, straw-like leaves that grow in tufts from a rhizome or tuber.


In Canada, Horsetail Spike-rush has only been found at one location in Long Point National Wildlife Area in southwestern Ontario. Since its discovery there in 1953, the species has not been found anywhere else in Ontario, despite repeated searches by botanists. There were 151 stems counted in 1993 covering about six square metres.


Throughout its range, the Horsetail Spike-rush grows in shallow water along the edges of ponds.


Potential threats to Horsetail Spike-rush at Long Point include: competition from Common Reed, an invasive plant species; changing water levels; and browsing by deer. Small, isolated populations such as these are always prone to elimination by chance events such as a big storm.


The Horsetail Spike-rush is protected under Ontario’s Endangered Species Act and the federal Species at Risk Act.

What You Can Do to Help Horsetail Spike-rush

  • The Ministry of Natural Resources tracks species at risk such as Horsetail Spike-rush. You can use a handy online form to report your sightings to the Natural Heritage Information Centre. Photographs with specific locations or mapping coordinates are always helpful. nhic.mnr.gov.on.ca
  • Report any illegal activity related to plants and wildlife to 1-877-TIPS-MNR (847-7667).
  • Volunteer with your local nature club or provincial park to participate in surveys or stewardship work focused on species at risk.
  • Private land owners have a very important role to play in species recovery. You may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats.
  • Invasive species seriously threaten many of Ontario’s species at risk. To learn what you can do to help reduce the threat of invasive species, visit: ontario.ca/invasivespecies ; www.invadingspecies.com ; www.ontarioinvasiveplants.ca ; and, www.invasivespecies.gc.ca .

Did you know?

Horsetail Spike-rush is pollinated by the wind. It may also be dispersed by waterbirds, as the seeds are known to remain viable after passing through the guts of waterbirds.

Did you know?

Horsetail Spike-rush is at the northern extreme of its natural range in Ontario.

Did you know?

Horsetail Spike-rush was used by the Seminole Indians to make beads for jewelry.

The Endangered Species Act

Contact your local ministry office

Often the best source of local information on species at risk is your nearest ministry office. Call with your questions or concerns.