Thicket Sedge

Carex abscondita Mackenzie

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

Monocotyledoneae (Monocots)
Cyperaceae (Sedge Family)
State Protection
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
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
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?

The specific epithet abscondita means concealed (Fernald 1970) which could refer to both: the staminate spike which is sessile and often concealed by the distal bract and/or pistillate spikes; as well as the culms which are shorter than and concealed by the leaves of the vegetative shoots.

State Ranking Justification

There are currently six known populations and 15-20 historical populations, although some mis-identifications may exists. This plant may be overlooked, but New York is near its northern range limit. Still, we should anticipate finding a few more populations once more people have a better search image. All currently known populations are relatively small. No trend information is known and the threats are likely minimal.

Short-term Trends

All six extant sites have only been surveyed once and therefore, short term trends are unknown.

Long-term Trends

There are numerous historical populations (15-20) that have not been seen for over 20 years. These sites have not been revisited so it is unknown if the populations at these sites are still extant. All six extant sites were first seen in the 1980's and 90's. Some of these may be misidentifications while others were probably overlooked in the past. Therefore, long term trends are unknown.

Conservation and Management

Research Needs

It is clear that some voucher specimens are misidentifications of Carex digitalis. All specimens should be verified. Historical populations should be revisited to see if these populations are still extant.



Carex abscondita occurs in successional shrublands, mesic young and mature forests, forested banks of streams, and in or near swamps (New York Natural Heritage Program 2006). Rich, moist, wet slopes or bottomlands, deciduous or mixed deciduous-evergreen forests, on or just above flood plain of streams and rivers (Bryson and Naczi 2002).

Associated Ecological Communities

  • Floodplain forest* (guide)
    A hardwood forest that occurs on mineral soils on low terraces of river floodplains and river deltas. These sites are characterized by their flood regime; low areas are annually flooded in spring, and high areas are flooded irregularly.
  • Red maple-sweetgum swamp* (guide)
    A hardwood swamp that occurs on somewhat poorly drained seasonally wet flats, usually on somewhat acidic soils. Red maple-sweetgum swamps often occur as a mosaic with upland forest communities. Sweetgum is often the dominant tree or may be codominant with red maple. Other codominant trees include pin oak and blackgum.
  • Successional old field
    A meadow dominated by forbs and grasses that occurs on sites that have been cleared and plowed (for farming or development), and then abandoned or only occasionally mowed.
  • Successional shrubland
    A shrubland that occurs on sites that have been cleared (for farming, logging, development, etc.) or otherwise disturbed. This community has at least 50% cover of shrubs.
  • Successional southern hardwoods*
    A hardwood or mixed forest that occurs on sites that have been cleared or otherwise disturbed. Canopy trees are usually relatively young in age (25-50 years old) and signs of earlier forest disturbance are often evident. Characteristic trees and shrubs include any of the following: American elm, slippery elm, white ash, red maple, box elder, silver maple, sassafras, gray birch, hawthorn, eastern red cedar, and choke-cherry.

* probable association but not confirmed.

Associated Species

  • Acer rubrum var. rubrum (common red maple)
  • Acer saccharum (sugar maple)
  • Betula alleghaniensis (yellow birch)
  • Carex digitalis
  • Carex swanii (Swan's sedge)
  • Nyssa sylvatica (black-gum, sour-gum)
  • Quercus rubra (northern red oak)


New York State Distribution

Carex abscondita occurs almost exclusively in southeastern New York including Long Island, but a single extant record is reported from Steuben County. This record should be verified as it is quite disjunct from the rest of the range of the species and may represent C. digitalis or C. cumberlandensis. The range of this species in New York may be slightly obscured because some of the records of this species may be misidentified.

Global Distribution

Carex abscondita occurs from eastern Massachusetts, Rhode Island, and southern Connecticut south mostly near the coast and on the coastal plain to the western panhandle of Florida west to southwestern Kentucky, southeastern Missouri, southeastern Oklahoma, and eastern Texas (Naczi et al. 2001).

Identification Comments

General Description

Carex abscondita is a perennial, tufted grass-like plant. Its leaves are long and strap like and 3-9 mm wide. Stems arise out of the leaves at the base of the plants and are 7-30 cm tall. The stems are relatively short and mostly are hidden among the leaves. Flower/fruit clusters occur at the end of secondary branches which come off of the main stems. The fruit clusters are 6-12 mm long. Fruits (perigynia) are 2.8-4.2 mm long (Bryson and Naczi 2002).

Identifying Characteristics

Carex abscondita is a cespitose perennial. Leaf sheaths of the lower leaves are white to brown. Leaf blades are 3-9 mm wide. Culms are 7-30 cm tall and the tallest vegetative shoots (measured from the base of the vegetative shoots to the longest fully outstretched leaves) are (1.4-)1.7-3.7(-4.9) times taller than the tallest culms. Therefore, the culms appear hidden in the leaves. There are (3-)4 spikes per culm. The lateral are pistillate and widely separated with the lowest being basal. The terminal is staminate, sessile to subsessile, and (3.5-)4.5-10.2(-11.5) mm long. It is often hidden by the approximate pistillate spikes and/or distal bracts. Staminate scales are obtuse. Perigynia are sharply trigonous in cross section at maturity, spirally arranged, and 2.8-4.2 mm long (Bryson and Naczi 2002).

Best Life Stage for Proper Identification

As with many other Carex species, C. absondita is most easily identified when the perigynia are almost mature to mature but are not yet shedding heavily.

Similar Species

Carex digitalis is closely related and somewhat similar to C. abscondita. The former has longer culms relative to the vegetative shoots (the tallest vegetative shoots are 0.5-1.3 (-1.8) times as long as the tallest culms). In addition, C. digitalis has wider staminate spikes ((1-)1.2-2.7 mm wide vs 0.6-1.4(-1.6) mm wide for C. abscondita), acute staminate scales, and often narrower leaves (0.8-5 mm wide) (Bryson and Naczi 2002).

Best Time to See

Carex abscondita is in immature to mature fruit from early June through early August. During the early part of this season the fruits are quite immature and identification is a little difficult. Likewise, toward the end of this season the fruits are shedding and identification is also more difficult. Therefore, surveys are most successful if conducted between mid-June and mid-July.

  • Fruiting

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

Thicket Sedge Images


Thicket Sedge
Carex abscondita Mackenzie

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

Additional Common Names

  • Sedge


  • Carex ptychocarpa Steudel

Comments on the Classification

Carex abscondita is in section Careyanae. It had previously been placed in section Laxiflorae by many authors. A recently described species, C. cumberlandensis, which occurs south of NY, was segregated out of C. abscondita (Naczi et al. 2001). So, only recent descriptions of C. abscondita should be used.

Additional Resources

Best Identification Reference

Bryson, C.T. and R.F.C. Naczi. 2002. Carex Linnaeus sect. Careyanae Tuckerman ex Kakenthal. Pages 443-448 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.

Naczi, R. F., R. Kral, and C. T. Bryson. 2001. Carex cumberlandensis, a new species of Section Careyanae (Cyperaceae) from the Eastern United States of America. Sida 19(4): 993-1014.

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.

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: February 13, 2006

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Carex abscondita. Available from: Accessed April 17, 2024.