Species Profile

Horsetail Spike-rush

Scientific Name: Eleocharis equisetoides
Taxonomy Group: Vascular Plants
COSEWIC Range: Ontario
COSEWIC Assessment Date and Status Change: November 2000
COSEWIC Status: Endangered
COSEWIC Status Criteria: B1+3d; D1
COSEWIC Reason for Designation: A perennial herb found at one site where it likely represents a single clonal individual occupying less than 10 square metres of pond shoreline.
COSEWIC History of Status Designation: Designated Endangered in November 2000.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2003-06-05

Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.

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Quick Links: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | National Recovery Program | Documents

Image of Horsetail Spike-rush

Horsetail Spike-rush Photo 1



Horsetail Spike-rush is a perennial plant that belongs to the sedge family. It has tufts of slender aerial stems that grow from a coarse, stout rhizome (an underground stem that is usually horizontal). The aerial stems, or culms, are light green, rounded in cross-section and can be up to one meter in height and 3 to 5 millimeters in diameter. Regular cross-lines, or septa, occur every 3 to 5 cm along the stem. The leaves are sheaths at the base of the stem; they do not have blades. When in flower, the top of the stem has a blunt or slightly pointed spikelet containing the fruit. The spikelet is 15 to 40 millimeters long and is covered with straw-coloured scales, which are dotted with purple spots on the inside. The Horsetail Spike-rush fruit is a shiny golden-brown colour. It is slightly flattened, oval-shaped, and has a triangular projection, called a tubercle, at one end.


Distribution and Population

The Horsetail Spike-rush occurs locally from southern Ontario and the lower southern peninsula of Michigan south, primarily along the Atlantic Coastal Plain from Massachusetts (formerly) to central-northern Florida, and then west along the Gulf Coastal Plain to extreme eastern Texas. It formerly also occurred at a number of isolated localities in inland North America in Wisconsin, Illinois, northwestern New York, Missouri, and Arkansas. In Canada, the Horsetail Spike-rush occurs at a single site on Long Point, Lake Erie, in southwestern Ontario. Population data for the Horsetail Spike-rush in Canada are few. It has been documented only at the Canadian site where it was originally found. The species is clonal (reproduces asexually to produce clusters of stems) by nature and the actual number of plants at the Canadian site is unknown. In fact, it is possible that only one plant is involved in this population. There are too few data to detect a long term trend. Survey data indicate an increase in size and area covered by the plant(s) from 12 stems (1m²) in 1988 to 151 stems (6m²) in 1993. It is important to note that fluctuations in these measurements may only represent annual variations.



At its one location in Canada, Horsetail Spike-rush occurs along the shore of a pond, which is situated between two forested dune ridges. The pond is fringed with buttonbush (Cephalanthus occidentalis) and red-osier dogwood (Cornus stolonifera). The Horsetail Spike-rush occurs along the edge of the pond as a shallow water emergent (a plant rooted in shallow water but having most of its stem and leaves above water) and further from the shore in water up to 35 centimeters deep. It grows with a variety of other plants, including northern wildrice (Zizania palustris), Small’s spike-rush (Eleocharis smallii) and swaying rush (Scirpus subterminalis).



The Horsetail Spike-rush occurs in shallow water or along the shorelines of ponds. The species flowers every year and its fruit mature from July to September. Very little is known about its reproductive biology, but it is assumed that the Horsetail Spike-rush is wind-pollinated like other members of its genus.



Beavers currently occupy the pond in which the Horsetail Spike-rush is found in Canada. It is not known whether beavers have always maintained the water level in this pond or whether beavers have arrived recently. Neither is it known to what extent the plant can withstand extended periods of flooded conditions. Consequently, the degree to which the maintenance of water levels in the pond poses a threat to the survival of the species at Long Point is unknown.



Federal Protection

The Horsetail Spike-rush is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

The Horsetail Spike-rush occurs in the Long Point National Wildlife Area, which is federal land protected under SARA. It is also protected by the Ontario Endangered Species Act in specific locations. Under this Act, it is prohibited to kill, harm, harass, or collect this species, or to destroy its habitat.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.


Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for the Horsetail Spike-rush (Eleocharis equisetoides) in Canada
Status Final posting on SAR registry


Recovery Progress and Activities

Summary of Progress to Date A recovery strategy has been developed which focuses on reducing or eliminating the threats to Horsetail Spike-rush. An action plan will be created by 2008. Summary of Research/Monitoring Researchers are monitoring culms (stems of Horsetail Spike-rush), spread of Phragmites australis (invasive European reed grass), water level fluctuations, and deer herbivory. Turkey Point is being surveyed to confirm presence of colonies previously found during surveys in 1999. Summary of Recovery Activities Critical habitat for Horsetail Spike-rush has been identified and protected. Researchers are investigating the potential of collecting, archiving, and propagating Horsetail Spike-rush seeds. URLs Ontario’s Biodiversity: Species at Riskhttp://www.rom.on.ca/ontario/risk.php?doc_type=fact&lang=&id=157


PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

3 record(s) found.

Recovery Strategies

  • Recovery Strategy for the Horsetail Spike-rush (Eleocharis equisetoides) in Canada (2006-10-25)

    The horsetail spike-rush (Eleocharis equisetoides) is under the management jurisdiction of Environment Canada (Canadian Wildlife Service – Ontario Region). The Species at Risk Act (SARA, Section 37) requires the competent minister to prepare recovery strategies for listed extirpated, endangered, or threatened species.The horsetail spike-rush was assessed as Endangered by COSEWIC in November 2000 and listed under SARA in 2003. The Canadian Wildlife Service – Ontario Region, Environment Canada, led the development of this recovery strategy. The strategy meets SARA requirements in terms of content and process (Sections 39–41). The Ontario Ministry of Natural Resources reviewed this document. Although the species is currently under the sole jurisdiction of Environment Canada, the Ontario Ministry of Natural Resources will be engaged in the recovery process and all recovery decisions if the species is discovered off federal lands.

Action Plans

  • Action Plan for the Horsetail Spike-rush (Eleocharis equisetoides) in Canada (2011-05-30)

    Horsetail Spike-rush was listed as Endangered on Schedule 1 of the Species at Risk Act in June 2003. The Minister of the Environment is the competent minister for the recovery of the Horsetail Spike-rush and has prepared this action plan to implement the recovery strategy, as per section 49 of SARA. It has been prepared in cooperation with the Ontario Ministry of Natural Resources. This action plan follows from the Recovery Strategy for the Horsetail Spike-rush (Eleocharis equisetoides) in Canada.

Critical Habitat Descriptions in the Canada Gazette

  • Description of critical habitat of the Horsetail spike-rush in Long Point National Wildlife Area (2007-01-22)

    In Canada, Horsetail spike-rush is only known to occur at a single location—within Long Point National Wildlife Area in southwestern Ontario. Critical habitat in the Long Point National Wildlife Area is identified in the Recovery Strategy for the Horsetail spike-rush as "the inland pond where it grows in sandy organic muck along the south-facing shoreline. The pond lies between two stabilized dune ridges near the tip of Long Point National Wildlife Area."
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