Globe Flat Sedge Cyperus echinatus (L.) Wood

Cyperus echinatus illustration USDA Plants website

Cyperus echinatus illustration
USDA Plants website

Class
Monocotyledoneae (Monocots)
Family
Cyperaceae (Sedge Family)
State Protection
Endangered
Listed as Endangered by New York State: in imminent danger of extirpation in New York. 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
S1
Critically Imperiled in New York - Especially vulnerable to disappearing from New York due to extreme rarity or other factors; typically 5 or fewer populations or locations in New York, very few individuals, very restricted range, very few remaining acres (or miles of stream), and/or very steep declines.
Global Conservation Status Rank
G5
Secure globally - Common in the world; widespread and abundant (but may be rare in some parts of its range).

Contents

  1. Summary
  2. Conservation and Management
  3. Habitat
  4. Range
  5. Identification Comments
  6. Taxonomy
  7. Additional Resources
  8. About This Guide

Summary

Did you know?

In New York this flatsedge has only ever been collected around the New York City area, mostly in the late 1800s and early 1900s. It was seen a few times after World War II up until 1950, but not collected again until the 1980s in the serpentine areas of Staten Island. These records represent the most northern extension of the species along the Atlantic coast.

State Ranking Justification

There are currently believed to be five existing populations, but two of them have not been seen since the 1980s and may have been shaded out by natural succession. They may still persist in the seed bank. Only one population has more than 100 plants. There are two old records from Staten Island which have not been resurveyed and there are nine more records which are now considered extirpated.

Short-term Trends

Short-term trends appear stable although a couple of populations are probably present only in the seed bank, waiting for a disturbance to facilitate germination.

Long-term Trends

This plant has declined severely over the last 100 years because of the development of New York City, especially on Staten Island where it was once considered relatively common. Remaining populations are small and long-term trends will probably continue downward.

Conservation and Management

Threats

Current populations are threatened by direct human disturbance from development and subsequent human use of nearby natural areas where plants are trampled. Lack of management has also allowed succession to eliminate the vegetative stems of two populations although they may still be in the seed bank.

Conservation Strategies and Management Practices

This species needs disturbance to reduce competition from woody plants or more aggressive herbaceous plants but too much direct disturbance to the plants will reduce or eliminate the population. Its habitat could be disturbed in the non-growing season to open it up for seed germination and colonization but direct disturbance should be prevented during the growing season.

Research Needs

Research is needed to understand habitat requirements and management practices to protect and augment populations.

Habitat

Habitat

The few New York records of this species are from open, disturbed areas, including serpentine grasslands, meadows kept open by fire and other disturbance, and the upland edge of a high salt marsh (New York Natural Heritage Program 2010). Disturbed, sunny sites, in mesic places, well-drained soils....predominantly an inland species of roadsides, pastures, and other disturbed ground (FNA 2002). Dry woods and fields (Gleason & Cronquist 1991). Sandy swamps, ditches, open woods and barrens (Fernald 1970).

Associated Ecological Communities

  • Coastal oak-hickory forest* (guide)
    A hardwood forest with oaks and hickories codominant that occurs in dry, well-drained, loamy sand of knolls, upper slopes, or south-facing slopes of glacial moraines of the Atlantic Coastal Plain. * probable association but not confirmed.
  • High salt marsh* (guide)
    A coastal marsh community that occurs in sheltered areas of the seacoast, in a zone extending from mean high tide up to the limit of spring tides. It is periodically flooded by spring tides and flood tides. High salt marshes typically consist of a mosaic of patches that are mostly dominated by a single graminoid species. * probable association but not confirmed.
  • Serpentine barrens (guide)
    A grass-savanna community that occurs on shallow soils over outcrops of serpentine bedrock. In New York this community is known only from Staten Island, where the remnants are relatively disturbed.

Associated Species

  • Agalinis
  • Asclepias syriaca (common milkweed)
  • Asclepias viridiflora (green milkweed)
  • Carex straminea (straw sedge)
  • Cenchrus
  • Eupatorium hyssopifolium (hyssop-leaved thoroughwort)
  • Euthamia graminifolia (common flat-topped-goldenrod)
  • Graphephorum melicoides (melic-oats)
  • Iva frutescens (salt marsh-elder)
  • Lespedeza capitata (round-headed bush-clover)
  • Myrica pensylvanica
  • Panicum virgatum (switch grass)
  • Phragmites
  • Quercus palustris (pin oak)
  • Rhus copallinum
  • Rhus typhina (stag-horn sumac)
  • Schizachyrium scoparium
  • Solidago altissima
  • Spartina patens (salt-meadow cord grass)
  • Spiranthes cernua (nodding ladies'-tresses)
  • Strophostyles

Range

New York State Distribution

This species is known from the New York City area where it is currently known from the Bronx and Staten Island but considered extirpated from Manhattan and Queens. There is also one historical record from the Yonkers area of Westchester County which is probably also extirpated.

Global Distribution

This flatsedge is most common from southeastern Pennsylvania south to northern Florida and west to Texas, Missouri, and Kansas. It reaches its northeastern range limit in southern New England and New York. There are a few disjunct populations from central Wisconsin, northern Illinois, Ontario, and in northern Ohio. It also occurs in the West Indies.

Identification Comments

General Description

Globose Flatsedge is a grass-like perennial herb, growing singly or in loose clumps, and up to 30 to 100 cm tall. Its stems are 3-sided and smooth. The leaves are flat or V-shaped, 3 to 9 mm wide, with rough edges. The infloresence is exceeded by the lowest bract, and consists of 1 or 2 sessile, terminal round or egg-shaped spikes, each with 3 to 12 ascending rays. Each spike in turn contains many spikes, radiating in all directions, each with 1 to 3 flowers subtended by persistent straw-colored to brownish scales 3 to 7.5 mm long. The fruit are brown, pitted, oblong achenes, about half as long as the flower scales (FNA 2002, Gleason and Cronquist 1991).

Best Life Stage for Proper Identification

Entire plants with mature fruit are needed for identification.

Similar Species

The New York flatsedge species Cyperus echinatus is most similar to C. retrorsus. C. retrorsus differs by having smaller spikelets, shorter flowering scales (1.8 to 2.5 mm long versus 3 to 4.5 mm for C. echinatus) and anthers, and shorter, relatively fatter achenes (1/3 to 1/2 as wide as long, versus no more than 1/3 as wide as long for C. echinatus) (FNA 2002, Gleason and Cronquist 1991).

Best Time to See

Globose Flatsedge's fruits mature in late July and may persist through September.

  • Fruiting

The time of year you would expect to find Globe Flat Sedge fruiting in New York.

Globe Flat Sedge Images

Taxonomy

Globe Flat Sedge
Cyperus echinatus (L.) Wood

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

Additional Common Names

  • Cyperus
  • Flat Sedge
  • Globose Flatsedge

Synonyms

  • Cyperus ovularis (Michx.) Torr.

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

Fernald, M. L. 1950. Gray's manual of botany. 8th edition. Corrected printing (1970). D. Van Nostrand Company, 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.

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.

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. 2023. New York Natural Heritage Program Databases. Albany, NY.

Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.

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

Links

About This Guide

This guide was authored by: Stephen M. Young

Information for this guide was last updated on: September 6, 2012

Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Cyperus echinatus. Available from: https://guides.nynhp.org/globose-flatsedge/. Accessed May 29, 2023.

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