Ovate Spike Rush

Eleocharis ovata (Roth) Roemer & J.A. Schultes

Eleocharis ovata spikelets
Richard Ring

Monocotyledoneae (Monocots)
Cyperaceae (Sedge Family)
State Protection
Listed as Threatened by New York State: likely to become Endangered in the foreseeable future. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
Imperiled or Vulnerable in New York - Very vulnerable, or vulnerable, to disappearing from New York, due to rarity or other factors; typically 6 to 80 populations or locations in New York, few individuals, restricted range, few remaining acres (or miles of stream), and/or recent and widespread declines. More information is needed to assign either S2 or S3.
Global Conservation Status Rank
Secure globally - Common in the world; widespread and abundant (but may be rare in some parts of its range).


Did you know?

The genus name to Eleocharis comes from the Greek "elos" for marsh and "charis" for grace. With more herbarium work and field study we might find that this little Eleocharis graces many more of the marshes in our state. This and many other Eleocharis species are important wildlife food for wetland birds and other animals. You can often see damselflies and dragonflies perching on the tops of the stems.

State Ranking Justification

There are 11 existing populations but two them contain over 100 plants. There are about 10 historical records from upstate New York and the Adirondacks which have not been checked.

Short-term Trends

The short-term trend may be declining as most existing populations were small and in dynamic habitats. Two of largest populations have not been relocated recently. Current survey work is needed to see if this species still exists in New York.

Long-term Trends

It is unclear if the long-term trend is declining because many historical sites in upstate New York have not been resurveyed specifically for this species.

Conservation and Management


Specific threats to all of these populations have not been determined but one population was found to be chewed by ducks and others could be threatened by shoreline succession or erosion.

Conservation Strategies and Management Practices

Existing habitat needs to be protected from succession or direct human destruction. Shorelines should be allowed to remain dynamic and open.

Research Needs

Studies are needed to determine habitat preference and how populations respond to the dynamic habitat where they grow. Population augmentation studies could be done to see if existing populations can be enlarged.



More habitat information is needed for this species in New York. It has been collected from artificial ponds, shallow natural ponds in larger swamps, and from marshy area on river islands (New York Natural Heritage Program 2007). Wet, open places, local (Fernald 1970). Marshes and other wet places, sometimes intertidal (Gleason 1952).

Associated Ecological Communities

  • Farm pond/artificial pond
    The aquatic community of a small pond constructed on agricultural or residential property. These ponds are often eutrophic, and may be stocked with panfish such as bluegill and yellow perch.
  • Freshwater tidal marsh (guide)
    A marsh community that occurs in shallow bays, shoals, and at the mouth of tributaries of large tidal river systems, where the water is usually fresh (salinity less than 0.5 ppt), and less than 2 m (6 ft) deep at high tide. Typically there are two zones in a freshwater tidal marsh: a low-elevation area dominated by short, broadleaf emergents bordering mudflats or open water, and a slightly higher-elevation area dominated by tall grass-like plants.

Associated Species

  • Alisma
  • Carex comosa (bristly sedge)
  • Cephalanthus occidentalis (buttonbush)
  • Eleocharis palustris (common spike-rush)
  • Galium
  • Leersia oryzoides (rice cut grass)
  • Ludwigia palustris (water-purslane)
  • Onoclea sensibilis (sensitive fern)
  • Penthorum
  • Schoenoplectus tabernaemontani (soft-stemmed bulrush)
  • Scirpus cyperinus (common wool-grass)
  • Sium suave (hemlock water-parsnip)
  • Sparganium eurycarpum (giant bur-reed)


New York State Distribution

Most Eleocharis ovata collections in New York have been from Suffolk County on Long Island, though there have been widely scattered collections from across the state.

Global Distribution

Eleocharis ovata is found in most of the midwestern and northeastern US states, in eastern Canada from Newfoundland to Ontario, and is disjunct to Western Canada, Washington, Oregon, and Arizona. It also occurs in Eurasia.

Identification Comments

General Description

Spikerushes consist of a simple stem (the leaves bladeless and inconspicuous), with the infloresence consisting of a solitary, many-scaled spikelet at the top of the stem. The perianth (sepals and petals), if present, is reduced to (usually 3 or 6) bristles. The base of the style is expanded into a tubercle, and is usually persistent on the fruit (achenes). Eleocharis ovata is an annual species, from 2 to 35 cm high, with ovoid spikelets 2-8 mm high by 2-4 mm wide. The achenes are lenticular, light to dark brown, shining, and 1 mm long. The tubercles are short, higher than wide, flattened, broad-based, and about half as broad as the achenes. The bristles clearly overtop the achenes.

Similar Species

E. engelmannii has tubercles as broad as the achenes. E. obtusa has mostly 3-parted styles and 3 stamens, and wider (.5 to .8 mm) tubercles.

Best Time to See

Eleocharis ovata fruits from July to mid-October.

  • Fruiting

The time of year you would expect to find Ovate Spike Rush fruiting in New York.

Ovate Spike Rush Images


Ovate Spike Rush
Eleocharis ovata (Roth) Roemer & J.A. Schultes

  • Kingdom Plantae
    • Phylum Anthophyta
      • Class Monocotyledoneae (Monocots)
        • Order Cyperales
          • Family Cyperaceae (Sedge Family)


  • Eleocharis annua (Thuill.) House
  • Eleocharis ovata (Roth) Roemer & J.A. Schultes

Additional Resources

Best Identification Reference

Flora of North America Editorial Committee. 2002. Flora of North America, North of Mexico. Volume 23. Magnoliophyta: Commelinidae (in part): Cyperaceae. Oxford University Press, New York. 608 pp.

Other References

Crow, Garrett E. and C. Barre Hellquist. 2000. Aquatic and wetland plants of northeastern North America: A revised and enlarged edition or Norman C. Fassett's a manual of aquatic plants. Volume two angiosperms: Monocotyledons. The University of Wisconsin Press. Madison, Wisconsin. 456 pp.

Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.

Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.

Haines, Arthur and Thomas F. Vining. 1998. Flora of Maine. A Manual for Identification of Native and Naturalized Vascular Plants of Maine.

Haines, Arthur. 2003. Eleocharis aestuum (Cyperaceae) in New York. NY Flora Association Newsletter. Vol 14(1): 4-6. March 2003.

Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.

Larson, B.M.H. and P.M. Catling. 1996. The separation of Eleocharis obtusa and Eleocharis ovata (Cyperaceae) in eastern Canada. Canad. J. Bot. 74: 238-242.

New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.

New York Natural Heritage Program. 2024. New York Natural Heritage Program Databases. Albany, NY.

Voss, E.G. 1972. Michigan Flora, Part I. Gymnosperms and Monocots. Cranbrook Institute of Science Bulletin 55 and the University of Michigan Herbarium. Ann Arbor. 488 pp.

Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York

Weldy, Troy W. and David Werier. 2005. New York Flora Atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research. University of South Florida]. New York Flora Association, Albany, NY. Available on the web at (http://newyork.plantatlas.usf.edu/).


About This Guide

Information for this guide was last updated on: January 18, 2008

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Eleocharis ovata. Available from: https://guides.nynhp.org/ovate-spike-rush/. Accessed May 26, 2024.