Marsh Straw Sedge

Carex hormathodes Fern.

Carex hormathodes line drawing
Britton, N.L., and A. Brown (1913); downloaded from USDA-Plants Database.

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
Apparently or Demonstrably Secure globally - Uncommon to common in the world, but not rare; usually widespread, but may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors. More information is needed to assign either G4 or G5.


Did you know?

Hormathodes means necklace-like (Fernald 1970) which is in reference to the spikes on the stems which appear somewhat like beads on a necklace. Some other species fit this description as well.

State Ranking Justification

There are fifteen known populations and over 20 historical sites. Many of the known sites are small or within degraded habitats. This plant is located along the upper borders of marsh habitats, a habitat that has been widely manipulated and subject to significant invasive species challenges. Phragmites and development have been the prime threats. As many as ten of the former historical locations are now extirpated. Additional populations are likley, but these may be small and also threatened by invasive species.

Short-term Trends

There are about 15 populations that have been seen in recent years. One population has over 100 plants. Three populations have under 50 plants. The extent and number of plants at the other populations is unknown. The limiting factor at many sites may be the extent of available habitat. Overall, short term trends are unclear.

Long-term Trends

In addition to the about 15 known extant populations there are at least 20 and probably up to about 30 populations that are only known from historical records. It is unknown if these populations are still extant. There are six populations which are known from Queens and Staten Island that are believed extirpated due to urban development. Long term trends clearly indicate a decline at least in the New York City region.

Conservation and Management


A few populations appear to be threatened by the invasive non-native species common reed (Phragmites australis ssp. australis). Trampling by people is another threat. Potential threats include habitat alteration due to road expansion and ditching.

Conservation Strategies and Management Practices

Phragmites should be monitored closely at sites where it appears to be negatively impacting C. hormathodes populations. If appropriate, the Phragmites should be controlled. At one population visitors needed to be prevented from trampling on the C. hormathodes. Ditching should be avoided at populations where C. hormathodes occurs.

Research Needs

Historical populations need to be surveyed to determine if they are still extant.



Carex hormathodes occurs most commonly in and adjacent to salt or brackish coastal, or rarely slightly inland, tidal marshes. In these settings it can occur in dune swales and on dry or wet sands. It also grows in fens, on margins of wetlands, and in wet forests adjacent to the coast (New York Natural Heritage Program 2006). Maritime rock ledges, brackish or freshwater marshes, moist coastal sands at sea level (Mastrogiuseppe et al. 2002). Brackish to fresh marshes, sands and rocks near the coast (Fernald 1970). Salt marshes and borders of salt marshes along the coast (Mackenzie 1931-1935).

Associated Ecological Communities

  • Brackish interdunal swales (guide)
    Temporarily tidally flooded temperate marshes in interdunal swales dominated by salt-tolerant graminoids. Individual swales occur as small patches positioned between fore-, primary and secondary dunes in a maritime dunes system, typically on barrier islands.
  • Brackish intertidal shore*
    A community of the intertidal gravelly or rocky shores of brackish tidal rivers and creeks where water salinity ranges from 0.5 to 18.0 ppt.
  • Brackish meadow (guide)
    A moist, moderately well-drained brackish (salinity 0.5-18 ppt) perennial grassland with occasional isolated shrubs that is typically situated in a belt at the upper edge of salt marshes bordering sandy uplands, but may occupy large portions of interdunal basins. The community usually develops in areas with a unique combination of soils and hydrology, on deep deposits of periodically windblown or overwashed gleyed sands that are usually flooded only during spring tides and during major coastal storms, approximately two to three times per year.
  • Brackish tidal marsh (guide)
    A marsh community that occurs where water salinity ranges from 0.5 to 18.0 ppt, and water is less than 2 m (6 ft) deep at high tide. The vegetation in a brackish tidal marsh is dense and dominated by tall grass-like plants.
  • 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.
  • Maritime beach* (guide)
    A community with extremely sparse vegetation that occurs on unstable sand, gravel, or cobble ocean shores above mean high tide, where the shore is modified by storm waves and wind erosion.
  • Maritime dunes* (guide)
    A community dominated by grasses and low shrubs that occurs on active and stabilized dunes along the Atlantic coast. The composition and structure of the vegetation is variable depending on stability of the dunes, amounts of sand deposition and erosion, and distance from the ocean.
  • Sea level fen (guide)
    A wetland that occurs at the upper edge of salt marshes but is fed primarily by acidic groundwater seeping out along the upland edge. This fresh water sometimes mixes with salt or brackish water during unusually high tides. There is a high abundance of sedges that decompose slowly and create a deep substrate of peat. This peat is underlain by deep sand or gravel. These fens usually have a high diversity of herbs but may also have scattered trees and shrubs.

* probable association but not confirmed.

Associated Species

  • Bolboschoenus maritimus ssp. paludosus (American salt marsh bulrush)
  • Cyperus polystachyos (many-spiked flat sedge)
  • Panicum virgatum (switch grass)
  • Phragmites australis ssp. australis
  • Pluchea odorata (salt marsh-fleabane)
  • Prunus maritima (beach plum)
  • Schoenoplectus pungens
  • Spartina patens (salt-meadow cord grass)


New York State Distribution

Carex hormathodes occurs adjacent to the ocean and brackish marshes mostly throughout Long Island and parts of New York City although many of the New York City populations are believed extirpated. There are also two populations reported from just north of New York City along the Hudson River. The most northern population occurs near the Bear Mountain Bridge in Orange Co. This population should be verified. There is a record from Yates County in central New York, collected by Sartwell. Sartwell wrote Penn Yan, Yates County on many of his specimen labels and it is clear that in many cases he was referring to where he lived and not where he collected the plant. Carex hormathodes does not grow away from the coast and clearly does not occur in Yates Co.

Global Distribution

Carex hormathodes occurs near the coast often within meters of the shoreline. It is known from Newfoundland and Quebec south along the coast to North Carolina (Mastrogiuseppe 2002).

Identification Comments

General Description

Marsh straw sedge is a tufted grass-like perennial. There are 3-5 leaves per stem. These are strap-like and 1-3 mm wide. Stems are 20-80 cm tall and are taller than the leaves. Towards the top of the stems are 3-9 stalkless flower/fruit clusters (spikes). The upper part of the stem, where the spikes occur, nods. The spikes are 6-15 mm long, widest in the middle, and are composed of female flowers above and male flowers below. The female flowers develop into fruits (perigynia) which are 3.8-5.6 mm long and taper at their apex to a beak.

Identifying Characteristics

Carex hormathodes is densely cespitose and short rhizomatous. Leaf sheaths are green-veined adaxially with at most a short hyaline area at the summits. Leaf blades are 1-3 mm wide. The reproductive culms are 20-80 cm long and are terminated by a nodding inflorescence 2.5-6.0 mm long. There are 3-9 gynecandrous spikes that are distant or the upper somewhat approximate, ellipsoid, and gradually taper to the apex and base. The staminate portion of the lateral spikes is equal to or less than 2 mm. Pistillate scales are lanceolate and are acuminate to awned at their apex. Perigynia spread, are lance-ovate to barely obovate, 1.9-2.8 mm wide, and 3.8-5.6 mm long. Perigynium beaks are less than half the length of the body (Mastrogiuseppe et al. 2002).

Best Life Stage for Proper Identification

The easiest time to identify C. hormathodes is when it possess just immature to mature perigynia which are not easily shedding.

Similar Species

Carex hormathodes is the only Ovales sedge in New York, besides Carex silicea, that will appear in saline to brackish waters and sands. With Carex silicea, the pistillate scales are as long as or longer than the perigynia they subtend and are acute at the apex. In comparison, C. hormathodes has pistillate scales that are shorter than the perigynia they subtend and are acuminate to awned at the apex.

Carex straminea is closely related and superficially similar. Carex straminea has spikes globose, the bases of the pistillate portions abruptly tapering at their bases, and the staminate portions of the spikes 2-6 mm long. In comparison, C. hormathodes has spikes ellipsoid, the pistillate portions gradually tapering at their bases, and the staminate portions of the spikes equal to or less than 2 mm long. In addition, C. straminea has longer beaks, perigynia bodes somewhat orbiculate, and grows in freshwater wetlands. Carex hormathodes has shorter beaks, perigynia bodies lance-ovate to barely obovate, and grows in maritime areas often getting some salt spray.

Best Time to See

Immature perigynia start in mid-June. These mature and persist till early August or sometimes later. Towards the end of this season the perigynia are shedding easily and the inflorescences tend to be more congested and less typical. Therefore, the best time to survey for C. hormathodes is from mid-June through July.

  • Fruiting

The time of year you would expect to find Marsh Straw Sedge fruiting in New York.

Marsh Straw Sedge Images

Images of Similar Species


Marsh Straw Sedge
Carex hormathodes Fern.

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

Additional Common Names

  • Sedge


  • Carex straminea var. invisa W. Boott

Comments on the Classification

Carex hormathodes is in section Ovales. It is sometimes treated as a variety of C. straminea, as in Gleason and Cronquist (1991), but C. hormathodes is distinct morphologically, ecologically, and geographically (Mastrogiuseppe et al. 2002).

Additional Resources

Best Identification Reference

Mastrogiuseppe, J., P.E. Rothrock, A.C. Dibble, and A.A. Reznicek. 2002. Carex Linnaeus sect. Ovales Kunth. Pages 332-378 in Flora of North America Editorial Committee (editors), Flora of North America, north of Mexico, Volume 23, Magnoliophyta: Commelinidae (in part): Cyperaceae. Oxford University Press, New York, New York, USA. 608pp + xxiv.

Other References

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.

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.

Mackenzie, K.K. 1931-1935. Cariceae. North American Flora 18: 1-478.

New York Natural Heritage Program. 2024. 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 University of South Florida]. New York Flora Association, Albany, New York


About This Guide

Information for this guide was last updated on: May 31, 2006

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Carex hormathodes. Available from: Accessed April 16, 2024.