Carex nigromarginata - Schwein.
Black-edge Sedge
Other Common Names: black edge sedge
Synonym(s): Carex nigromarginata var. nigromarginata
Taxonomic Status: Accepted
Related ITIS Name(s): Carex nigromarginata Schwein. (TSN 39719)
Unique Identifier: ELEMENT_GLOBAL.2.155682
Element Code: PMCYP039B0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Sedge Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Cyperales Cyperaceae Carex
Check this box to expand all report sections:
Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Carex nigromarginata
Taxonomic Comments: This record is for the treatment of Carex nigromarginata in the strict sense, excluding var. floridana, which is treated as a distinct species in Kartesz (1999).
Conservation Status

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 21Jul2016
Global Status Last Changed: 13May1994
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Reasons: Carex nigromarginata is relatively common with hundreds of reported occurrences (in floras and in the literature) across a fairly large geographic range. The species tolerates and even requires moderate disturbance.
Nation: United States
National Status: N5
Nation: Canada
National Status: N1 (04Oct2017)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alabama (SNR), Arkansas (S5), Connecticut (SH), Delaware (S5), District of Columbia (SNR), Florida (SNR), Georgia (SNR), Illinois (S1), Kentucky (S4?), Louisiana (SNR), Maryland (SNR), Mississippi (S5), Missouri (S4), New Jersey (S5), New York (S2), North Carolina (S3?), Ohio (SNR), Pennsylvania (S4), South Carolina (SNR), Tennessee (SNR), Texas (SNR), Virginia (S5), West Virginia (S3), Wisconsin (SNR)
Canada Ontario (S1)

Other Statuses

Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Candidate (High) (10Jul2017)

NatureServe Global Conservation Status Factors

Range Extent Comments: A plant typical of the dry woods from Quebec and Ontario south along the Atlantic Coast and west to the Mississippi Valley; possibly disjunct to Saskatchewan.

Number of Occurrences: 81 to >300
Number of Occurrences Comments: Carex nigromarginata is fairly common in southern states and along the Atlantic Coast, becoming less frequent inland. In Texas alon there are more than 100 sites. There are documented, extant populations on the edge of its range in Ontario (one), Illinois (one), Missouri (one), and West Virginia (four). In 16-17 Georgia counties, mostly in the northern part of the state (Allison 1994). Reznicek (1994) suspects that it might exist in the hill country of Louisiana. It is not considered rare and is not tracked in Ohio where it is widespread and common (sometimes in huge patches) and occurring in at least 10 counties (Cusick 1994).

There is only one location known in Canada, and it is very likely that it is the only one in existence there. No other site has been found in southern Ontario despite the many general botanical surveys made by knowledgeable botanists for land use planning (Catling 1994).

The species is known only from historic records in Connecticut (Bean et al. 1962, Fernald 1902) and New York, where there are records of six element occurrences (last of which was seen in the 1980's near Rochester). There are a few historical sites that have yet to be checked again (NY NHP 1994).

There are no known extant occurrences in Indiana (Homoya 1992). Any reports for the state are regarded as false, based on misidentification of specimens (Hellmich 1994).

Population Size Comments: This species is considerably common. On the west end of its range, in Texas alone, there are more than 10,000 individuals (Jones 1994). Because Carex nigromarginata is a clone-forming plant that also reproduces sexually, it is difficult to estimate how many individuals exist in any population. The plants do not form long rhizomes. If clumps occur several meters apart, they are likely separate individuals; however, if they abut, they are likely clones. The "ring effect," in which the plant clones outward with the center decaying away, does not occur strongly with this sedge, but might appear to some extent (Jones 1994).

Overall Threat Impact Comments: Although this species does well in areas where there is minor disturbance in the canopy, such as treefalls, it will not tolerate clear-cutting (Gaddy 1994). Excessive light and exposure is not so much a problem to the individual plants, but the following succession of shurbs and herbaceous species that usually follows a clear-cut will crowd out Carex nigromarginata. In addition, it is uncertain whether the species' seedbanks will last long enough for the forest to mature and natural openings to be created to provide habitat once again. If clear-cutting is used and then is followed by prescribed burns, there may be some potential to maintain the Carex nigromarginata population (Reznicek 1994). Succession can be a threat for this species in overgrown forests that do not allow for edges and light openings. This is a potential threat in some protected nature reserves. A similar situation occurs in forests managed to well-stocked stands of commercial timber, a practice which basically eliminates biodiversity of the understory and the ability for Carex nigromarginata to survive. Small localized soil disturbances are beneficial; however, too much (e.g., that caused by bulldozing) is a threat (Gaddy 1994). On occasion, logging skidders seem to produce advantageous soil disturbance (Reznicek 1994). Threats to the species include anything that might impact the rhizosphere (e.g., excessive grazing) (Ladd 1994). All species in the section Montanae root poorly and can be easily pulled out. Grazing by sheep has the potential to be most harmful, followed by horses and cows. Native browsers such as deer are generally not as harmful (Reznicek 1994). The deer population in the Ontario site is high; however, C. nigromarginata is probably not as threatened as other understory species. Campers trample some of the dune areas but generally not in the older dune area where C. nigromarginata exists (Catling 1994). In Georgia, invasion of Japanese honeysuckle may be the greatest threat to the species (Allsion 1994).

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: The global population of C. nigromarginata is stable and relatively not threatened. It occurs in stable, resistant, and sometimes nearly weedy populations (Rettig 1994). The species is limited to an extent by its habaitat availability. It is possible that in the future, shortage of this habitat due to development and succession may cause a decline in populations of Carex nigromarginata.

Intrinsic Vulnerability Comments: Carex nigromarginata thrives on disturbances that produce openings in forest canopies and some soil scarification. It can withstand some trampling and will withstand most grazing provided the rhizosphere is left intact. Succession, on the other hand my be destructive to populations of C. nigromarginata if not enough light is available for the plants to remain productive. In this case, populations could disappear. The potential for regeneration in these areas from natural seedbanks is not well-enough understood to assume that populations will return when the habitat is improved.

Other NatureServe Conservation Status Information

Global Range: A plant typical of the dry woods from Quebec and Ontario south along the Atlantic Coast and west to the Mississippi Valley; possibly disjunct to Saskatchewan.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States AL, AR, CT, DC, DE, FL, GA, IL, KY, LA, MD, MO, MS, NC, NJ, NY, OH, PA, SC, TN, TX, VA, WI, WV
Canada ON

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
CT New London (09011)*
IL Alexander (17003)*, Hardin (17069), Monroe (17133), Pope (17151), Union (17181)
MO Butler (29023), Carter (29035), Douglas (29067), Dunklin (29069)*, Iron (29093), Laclede (29105), Oregon (29149), Phelps (29161), Reynolds (29179), Ripley (29181)*, Shannon (29203), Ste. Genevieve (29186), Stoddard (29207), Wayne (29223)*
NY Orange (36071), Putnam (36079), Suffolk (36103), Ulster (36111)
WV Boone (54005)*, Braxton (54007), Cabell (54011), Fayette (54019), Gilmer (54021), Greenbrier (54025), Hampshire (54027), Jefferson (54037), Kanawha (54039)*, Mason (54053), McDowell (54047), Pendleton (54071), Pleasants (54073)*, Ritchie (54085)*, Wayne (54099), Wirt (54105)*
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Pawcatuck-Wood (01090005)+*, Thames (01100003)+*
02 Middle Hudson (02020006)+, Rondout (02020007)+, Hudson-Wappinger (02020008)+, Hackensack-Passaic (02030103)+, Northern Long Island (02030201)+, Southern Long Island (02030202)+, South Branch Potomac (02070001)+, Cacapon-Town (02070003)+, Shenandoah (02070007)+
05 Little Muskingum-Middle Island (05030201)+*, Little Kanawha (05030203)+, Greenbrier (05050003)+, Lower New (05050004)+, Upper Kanawha (05050006)+*, Lower Kanawha (05050008)+, Coal (05050009)+*, Lower Guyandotte (05070102)+, Tug (05070201)+, Twelvepole (05090102)+, Lower Ohio-Bay (05140203)+
07 Cahokia-Joachim (07140101)+, Big (07140104)+, Upper Mississippi-Cape Girardeau (07140105)+, Cache (07140108)+*
08 Upper St. Francis (08020202)+, Lower St. Francis (08020203)+*, Little River Ditches (08020204)+
10 Upper Gasconade (10290201)+, Lower Gasconade (10290203)+
11 North Fork White (11010006)+, Upper Black (11010007)+, Current (11010008)+, Eleven Point (11010011)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Basic Description: Tufted perennial from short rhizomes; inflorescences sessile; pistillate spikes (2-3) with large perigynia (3-4mm wide), slightly flattened, oblong and abruptly contracted into a slender beak (1mm), scales dark purple and largely concealing the perigynia.
General Description: Cusick (1992) describes Carex nigromarginata as "a beautiful sedge with brightly-colored scales of rich chestnut or purple with a green midrib".

The plants are perennial herbs, 4-12 in. tall, growing in dense tufts, often producing short branches which root. Each stem produces a single inflorescence. Principal leaf blades are very narrow. The flowers are unisexual. Staminate flowers occur on the end of the elongated flower structure, the pistillate below. Staminate flowers contain three small, slender, erect stamens which project beyond the petals when pollen is produced. There are 1-4 pistillate flowers (usually 2 or 3) up to .25 in. long, stemless, often crowded, and the lowest sometimes slightly separated but overlapping the next above. The small dry fruit does not open at maturity, is three-angled or nearly round, and contains 3 stigmas. (derived from Gleason 1952).

Technical Description: Carex nigromarginata is in the section Montanae. Gleason (1952) describes Carex nigromarginata as follows:

FLOWERS unisexual, each in the axil of a scale, the staminate and pistillate in different parts of the same spike. Terminal spike staminate throughout. STAMENS 3, exsert at anthesis. PISTIL 1. Pistillate scales ovate. SPIKES all approximate and often crowded, the lowest sometimes slightly separated but overlapping; staminate spike slender, erect, usually 5-10 mm long; pistillate spikes 1-4, usually 2 or 3, 4-8 mm long, sessile; lowest bract foliaceous, from shorter than to slightly exceeding the inflorescence. OVARY lenticular or trigonous with 2 or 3 styles, surrounded by a sac, the PERIGYNIUM, with a terminal orifice through which the styles protrude at anthesis. Perigynium-body (beak and contracted base excluded) broadest above the middle, usually rounded above; narrowly obovoid above a stipe-like base, slightly flattened, 2-keeled, minutely pubescent, 3-4.5 mm long; abruptly prolonged into a short bidentulate beak that is about half as long as the body; distinctly longer than wide, usually wider than thick, at maturity distinctly but obtusely 3-angled. FRUIT; Achenes trigonous or nearly round, stigmas 3; SPIKES usually subtended by a bract, which may be sheathless or sheathing at base, leaf-like or reduced to sheath only. PLANTS are 1-3 dm tall, cespitose, often short-stoloniferous; culms shorter or longer than the leaves, each culm producing a single peduncle. Perennial herbs, with long and usually narrow 3-ranked leaves. Principal leaf blades 2-4 mm wide.

Diagnostic Characteristics: Carex nigromarginata is a distinct taxon. The plant remains mostly uniform in character and habitat throughout its range (Cusick 1994); however, the relative length of culm and blades, the shape and coloration of pistillate scales, the shape of staminate scales, and the size of the perigynia are variable. This has lead to the fabrication of varieties, subspecies, and species according to some authors (Gleason 1952).

Carex nigromarginata is a member of the section Montanae (Kunth) [Acrocystis Dumort.] and can be separated from similar species of this section in North America by the following characteristics: "The culms are shorter than the stiff blades and of varying lengths but concentrations of peduncled pistillate spikes at the very base of the plant are lacking; the leaf sheaths are strongly fibrillose with age and the plants are cespitose, without elongate stolons; the perigynia are quite large, mostly 3-4 mm in length with the body definitely longer than wide and are more or less concealed by dark purplish-margined scales approximately equal to the perigynia in length" (Reznicek and Catling 1982). In addition, the plant is a clump-former with no elongate rhizomes. It is a very earlier bloomer (Reznicek 1994).

Carex nigromarginata is also very similar to C. umbellata and C. abdita because of its partially hidden spikelets and its persistent and often tattered leaves. C. nigromarginata is distinguished by its much narrower perigynia (Mohlenbrock et al. 1962).

Ecology Comments: Carex nigromarginata does not compete well with other herbaceous species (Gaddy 1994). It is a seed banking species that does well in bare soil and areas where the soil is disturbed, such as on soil tip mounds, ant hills, logging roads, road banks, and burned areas (Reznicek 1994).

Pre-existing and seeded plants tend to be almost weedy in areas with new openings in the canopy (e.g., under new windfalls), then will persist as succession shades them into less productive populations (Gaddy 1994). Phenology: The black-edged sedge is one of the few Carices to produce evergreen or overwintering leaves. Evergreen leaves allow growth to continue in late autumn after tree leaf fall has occurred and prior to leaf flourishing in the spring. Early growth in the spring allows these plants to out-compete neighboring plants by producing large clumps before other vegetation has the chance to begin growth for the year. Flowering and fruiting occur very early for this species. In South Carolina, it flowers in late March and early April and fruits soon after (Gaddy 1986, Gaddy 1994, Radford et al. 1968). In New York, this species flowers through May and fruits in early June (New York Natural Heritage Program 1994).

Dispersal: Carex nigromarginata was demonstrated to be regularly, but perhaps not solely, dispersed by ants in the southern Appalachians of South Carolina (Gaddy 1986). Fresh Carex nigromarginata diaspores were presented to two ant species, Crematogaster lineolata and Prenolepis impairis. In 100% of all encounters with the diaspores, both species of ants transported the diaspores more than ten centimeters. This high rate may be explained by the relatively large white elaiosomes, swellings near the base of the perigynia present on the diaspores. The ants typically move these seeds into disturbed areas such as soil piles caused by treefalls or onto areas where soil sloughs off of tree bases.

Reproduction: A plant can clone outward and sustain a population theoretically "forever" under optimum conditions, eliminated only by a change of habitat. What sometimes appears to be a large population of 20-30 clumps may in reality be a single clone, the central vegetative material simply decayed away over time. The species can produce a seedbank that lasts at least decades and questionably for centuries (Reznicek 1994). It is also evident that sexual reproduction occurs in a population; the tussocks are generally of varying sizes (Cusick 1994). Chromosome number: 2n = 34, n=17 (Smith 1988).

Habitat Comments: Carex nigromarginata is thought to be a species of fire systems. It tends to occur in stable, resistant populations although the habitat and soil conditions are somewhat limited globally (Reznicek 1994). It is found on dry to mesic, acidic, sandy, or rocky substrates in deciduous (commonly oak/oak-hickory) woods edges, openings, oak savannas, road banks, etc., in the eastern United States. Less commonly, it is found associated with open coniferous habitats. Other dry woodland sedges, also of the section Montanae, are typically found with C. nigromarginata (Reznicek 1994). It is locally abundant in light gaps such as those created by windfalls and is easily established on patches of bare soil. Along the southern end of its range in the Appalachians, the habitat amplitude increases to include more mesophytic sites in deciduous forests, commonly on steep slopes where the soil is naturally disturbed by erosion and light is better able to reach the forest floor. In these situations, C. nigromarginata is the predominant understory species. Along the western end of its range, it is more likely to be found in forest openings with a fair amount of graminoids. (Cusick 1994, Reznicek 1994).

Habitat types are listed per state below. The information is accurate; however, it may not be comprehensive:

In Alabama, Carex nigromarginata is confined to the unglaciated Appalachian Plateau. It is locally common in oak-pine woods and on the tops of sandstone exposures (Cusick 1992). One collection was on a north-south ravine of sandy loam with Quercus alba, Liquidambar spp., Pinus spp., and Cornus florida (University of Michigan Herbarium).

In Arkansas, J. H. Rettig made collections in 1986 from habitats including: dry, sandy soil and partial shade in sandhill vegetation of Quercus incana, Q. stellata and Pinus spp.; rocky slopes and shade above a river and road with Carpinus caroliniana, Pinus spp. and Cornus florida; and in a sandstone area with Pinus echinata, Quercus alba and Carya spp. A collection was also made in mesic slope habitat below a cliff in shale and sandstone soils with Quercus alba, Acer saccharinum, and Hamamelis sp. (University of Michigan Herbarium).

In Connecticut, a 1901 historic collection was made on Lantern Hill, New London County "among rocks." This occurrence has not been relocated (Connecticut Natural Diversity Database 1994).

In Georgia, C. nigromarginata is generally found in dry rocky woods in partial shade (Allison 1994). Notes from collections that have been made include: a rocky woods near the summit of Graves Mountain, altitude 850 ft. (University of Minnesota Herbarium); on top of a sandstone formation; and in sandy loam soil at the edge of an opening in low woods of Carya, Pinus and Quercus nigra (University of Michigan Herbarium).

In Illinois, Carex nigromarginata occurs on a wooded bluff with a steep slope in the Ozark Hill Prairie Research Natural Area (Illinois Natural Heritage Division 1994). A collection was made on a low, open, west-facing slope underlain with sandstone. This site "was almost certainly a savanna in the past" (University of Michigan Herbarium).

In Kentucky, a collection was made from a rocky slope of a south-facing creek valley in young oak woods (University of Michigan Herbarium).

In Massachusetts, a collection was made on an east-facing mountain slope in a woodland clearing (University of Minnesota Herbarium).

A Mississippi collection was made on the south side of Highway 82 on sandy loam soil with thick leaf litter under mixed hardwoods and pines (University of Michigan Herbarium).

In Missouri, this species has been collected from the Ozarks and from acid soils on wooded sandstone slopes, in crevices on sandstone or chert outcrops, and on gravely wooded soils of Crowley Ridge (Steyermark 1963). It is also known from a site on a steep open hillside in nearly pure sand (Missouri Natural Heritage Database 1994). It is a species of savanna remnants and dry oak forests in openings. New populations are found with some regularity (Ladd 1994, Yatskievych 1994).

In Ohio, the species grows in very dry, well-drained upland white oak/Virginia pine woodlands in acidic (never basic) soil on sandstone ledges and cliffs (Cusick 1994).

A population on Long Point on the north shore of Lake Erie in Norfolk County, Ontario, is the only population confirmed from Canada (Catling 1994, Oldham 1994, Ontario Conservation Data Centre 1994, Reznicek and Catling 1982, Reznicek and Catling 1989). The old dune area is unique to this part of Canada and is strongly influenced by the moderating local climate of the lake. Catling (1994) believes that the most important environmental influence on this population is this climate. The plants are found in two sites. In the first site, they are frequent and locally dominant in the driest areas of sandy knolls in an open Quercus rubra and Acer rubrum woodland (Reznicek and Catling 1982, University of Michigan Herbarium). These areas receive a significant amount of light due to the presence of an open marsh and pools surrounding the small knolls and the absence of shrubs and saplings due to deer browsing. The rooting medium has a pH of 4.6 and includes an upper 2 cm of coarse sand mixed with much organic material. The substrate is almost pure sand at 5 cm depth and has a pH of 5.0. Dominant associates included the mosses Leucobryum albidum, Polytrichum ohioense, and Dicranum scoparium; a sparse cover of vascular plants including Carex artitecta, Danthonia spicata (Poverty Grass), Panicum linearifolium (Panic Grass), and Poa compressa (Canada bluegrass). Also included are Panicum latifolium, P. oligosanthes, Carex muhlenbergii, and C. pensylvanica. The second site is on low dunes in a sandy opening of a Betula papifera forest with lichens and Polytrichum sp. (Reznicek and Catling 1982, University of Michigan Herbarium).

In Pennsylvania, a collection was made on an open logging road in a mixed hardwood forest (University of Michigan Herbarium). It was also collected in dry fields and wooded slopes (University of Minnesota Herbarium).

In South Carolina, a collection was made from a dry, steep hardwood forest above a small stream (University of Michigan Herbarium) and on a bluff in a mixed hardwood forest (University of Minnesota Herbarium).

In Tennessee, collections were made from dry cherty ridgetop forests dominated by Quercus prinus. Two mesic woods locations are also worth noting. (University of Michigan Herbarium).

In Virginia, a collection was made on a north-northwest facing roadbank with Fagus grandifolius, Liriodendron, Quercus falcata, and Liquidambar (University of Michigan Herbarium) and in a dry pine and oak woods.

In West Virginia, a collection was made on a dry, rocky road bank (University of Michigan Herbarium). Other locations include a sandstone cliff; an oak-hemlock slope; a dry rocky road bank; an open, dry woodland area; and a dry ridge top between a meander of Sugar Creek (West Virginia Natural Heritage Program 1992).

In the Great Smoky Mountains National Park, this species is scarce (P1). Although it has been known to occur in rich woods at low elevations, a specimen was collected recently from a post-fire dry woods (Rock 1994). Radford (1968) also describes this as a dry woods species.

Economic Attributes Not yet assessed
Management Summary
Stewardship Overview: Carex nigromarginata is neither rare or ubiquitous, weedy or fragile. It tends to occur in stable, resistant populations, although the habitat and soil conditions are somewhat limited globally (Reznicek 1994). It is thought to be a species of fire systems and is found on dry to mesic, acidic, sandy, or rocky substrates in deciduous woods edges, openings, road banks, etc., in the eastern United States.

Although the species is not rare, a community-wide management approach may be considered in some parts of its range. Unlike other members of its genus, the species is not determined to be fire-dependent; however, evidence shows that it does well in areas that are frequented by fire. Forests should be managed with consideration for natural light gaps from treefalls or openings managed with prescribed burns. Small areas of soil disturbance should be allowed and even encouraged; however, over-trampling and large-scale soil disturbance would be damaging to populations of Carex nigromarginata. Clear-cutting is potentially fatal for a population not because of excess light, but because of the following competition from the newly succeeding community. Selective cutting, however, could be beneficial as it would provide necessary light gaps and small-scale soil disturbance.

Restoration Potential: Because of the pioneering nature of the species, it is assumed that restoration potential is very good. Natural populations establish well in disturbed soil. When in appropriate habitat, populations tend to remain stable and resilient. Carex nigromarginata also has long-lived seedbanks. New plants may naturally emerge from these seedbanks when conditions are favorable (e.g., under a new opening in the canopy or in disturbed soil). In the long-term, populations may be dependent on the long life of these seedbanks (Reznicek 1994).
Preserve Selection & Design Considerations: Carex nigromarginata is not rare enough globally to receive much conservation focus. Where preserved, it is best that it is preserved as a part of a natural system. Protection of habitats with high diversity (e.g., oak openings) should take precedence over highly manipulated habitats such as road ditches. Hydrology is not a major factor for the preservation of this upland species and its habitat. Attention may need to be focused on maintaining a proper canopy structure with edge and openings and preventing secondary succession from closing the forb and shrub layer. In such cases, it may be desirable to manage an area with fire; accordingly, one must consider the availability of proper fire breaks in the preserve design.
Management Requirements: A forest managed with concern for edge habitat and wildlife will generally provide appropriate habitat for this species. It is preferable to manage the habitat holistically. Carex nigromarginata requires open deciduous woodlands and woods edges. Too much succession leading to excessive shade may cause populations to thin and become less productive. If the habitat is not maintained naturally with windfalls and fire, selective cutting to create openings in areas that are succeeding would help the population restore vigor (Cusick 1994, Gaddy 1994, Rettig 1994). The species has a seed bank that may last at least decades and questionably for centuries (Reznicek 1994). These seed banks may regenerate a population in unexpected areas when the canopy is opened or the soil is scarified.

Although other members of the genus have been proven to be fire related, this taxon has not (Cusick 1994). Regardless, fire is recognized as a good management tool since it removes competing vegetation and returns nutrients to the soil (Reznicek 1994). Members of the section Acrocystis are often robust with stimulated fruiting following a fire (Catling 1994, Cusick 1992). It is obvious that the species can survive some fire, as there are many herbarium specimens that show fire scars (Rettig 1994). In addition, post-fire plants in sites such as Long Point, Ontario are known to do well following a fire (Catling 1994). Prior to the days of fire suppression, C. nigromarginata was more commonly collected. This may suggest that forest openings and edges were more common then (Reznicek 1994).

If logging is inevitable, selective cutting of woodlands is preferable over clear-cutting as too much soil disturbance and the resulting succession can be destructive to the species habitat. If clear-cutting is inevitable, it might be possible to maintain the population if fire management follows the cut, keeping competing vegetation to a minimum (Allison 1994, Reznicek 1994).

C. nigromarginata can withstand a good deal of disturbance, although excessive trampling and livestock grazing could be damaging to its rhizosphere (Cusick 1994). Scarification of the soil, on the other hand, opens up habitat for this pioneering species in areas such as road cuts and tip mounds.

Two species of ants are known dispersal agents (Gaddy 1994). How significant these ant species are to the viability of the plant and whether other species are also capable dispersal agents is not known. It may be necessary for the ant populations to remain intact in order to allow for the long-term protection of this Carex.

Monitoring Requirements: Of primary importance is accurate identification. This species flowers and fruits very early, and therefore is easily overlooked on field surveys. Someone who knows the species very well might recognize it after it fruits (Reznicek 1994); however, individual plants do not always exhibit all the necessary traits for identification. It is best to collect mature fruiting specimens with underground parts and to consider a range of individuals within a population for accurate identification of the species (Cusick 1992).

In addition, because Carex nigromarginata is a clone-forming plant that also reproduces sexually, it is difficult to estimate how many individuals exist in any population. The plants do not form long rhizomes. If clumps occur several meters apart, they are likely separate genetic individuals; however, if they abut, they are likely clones. The "ring effect," in which the plant clones outward with the center decaying away, does not occur strongly with this sedge but might appear to some extent (Jones 1994). Rings may up to .5 m across, but are typically less. A clump composed of a single individual may be up to 2 dm in diameter. (Rettig 1994).

C. nigromarginata is a long-lived perennial species. Permanent transects for demographic mapping and monitoring are recommended in areas where preservation of this species is a priority (Ladd 1994). In addition to monitoring the plant, it could be important to monitor seed-dispersing ant populations in areas where this plant is rare. Protection of these ant species could be important in the long-term protection of this Carex (Gaddy 1994).

Management Programs: In Missouri, fire is used on some sites in which C. nigromarginata occurs, but not specifically for this species. In those sites, the populations seem healthy and secure (Ladd 1994). The Ontario site is also not managed for C. nigromarginata. There, the site has been very heavily grazed by deer. The deer may positively effect Carex nigromarginata by eliminating understory competition for light. In 1993, however, the deer herd was reduced, and any impacts of this are yet to be seen (Oldham 1994). Fire has never been used as a management tool at the site.
Monitoring Programs: There are no known monitoring programs for this species.
Management Research Programs: There are no known management research programs for C. nigromarginata at this time.
Management Research Needs: The occurrence of Carex nigromarginata in dry and open areas and in post-fire dry woods may suggest that fire is an effective management tool; however, there is currently no solid basis on which to judge this.
Additional topics: Carex nigromarginata and one of its seed-dispersal agents, the ant Prenolepis impairis, are both early spring species. There is some speculation that a significant evolutionary relationship exists between these two species. Gaddy is working to define this relationship more clearly (Gaddy 1994).
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 10Jun1994
NatureServe Conservation Status Factors Author: Hengelfelt, J. (1994); S.L. Neid (1998).
Management Information Edition Date: 10Jun1994
Management Information Acknowledgments: We are indebted to all the botanists, ecologists, information managers, and others who took the time to provide the information necessary for the preparation of this and many other Element Stewardship Abstracts.
Element Ecology & Life History Edition Date: 10Jun1994
Element Ecology & Life History Author(s): HENGELFELT, J.S.L., D.W. SCHUEN, AND M.R. PENSKAR

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

  • Argus, G.W., K.M. Pryer, D.J. White and C.J. Keddy (eds.). 1982-1987. Atlas of the Rare Vascular Plants of Ontario.. Botany Division, National Museum of National Sciences, Ottawa.

  • Argus, G.W., K.M. Pryer, D.J. White, and C.J. Keddy. 1982-1987. Atlas of the Rare Vascular Plants of Ontario. Parts 1-4. Botany Divison, National Museum of Natural Sciences, Ottawa, Ontario.

  • Argus, G.W., and K.M. Pryer. 1990. Rare vascular plants in Canada. Our natural heritage. Canadian Museum Nature, Ottawa. 191 pp. + maps.

  • Ashby, W.C., and J.E. Ozment. 1967. Plant species of Beall's Woods, Wabash County, Illinois. Trans. Ill. State Acad. Sci. 60:174-183.

  • Bean, R.C., A.F. Hill, and R.J. Eaton. 1962. Fifteenth report of the Committee on Plant Distribution. Rhodora 64:168-179.

  • Bowles, M.L., et al. 1991. Rarely seen endangered plants, rediscoveries, and species new to Illinois. Erigenia 11:27-51.

  • Bryson, Charles T. 2002. Preliminary abundance and range estimates for Cyperaceae species of Mississippi. Handwritten notes provided to Mississippi Natural Heritage Program, Jackson, MS. 100 pp.

  • Correll, D.S. and M.C. Johnston. 1970. Manual of the Vascular Plants of Texas. Texas Research Foundation, Renner, TX.

  • Crins, W.J. and J.H. Rettig. 2002. Carex Linnaeus sect. Acrocystis Dumortier. Pages 532-545 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.

  • Cusick, A. 1992. Carex Section Acrocystis (Cyperaceae) in Ohio. Michigan Botanist 31: 99-108.

  • Fernald, M.L. 1902. Preliminary lists of New England plants - X. CAREX. Rhodora 4:218-230.

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

  • Flora of North America Editorial Committee. 2002b. Flora of North America north of Mexico. Vol. 23. Magnoliophyta: Commelinidae (in part): Cyperaceae. Oxford Univ. Press, New York. xxiv + 608 pp.

  • Gaddy, L.L. 1986. Twelve new ant-dispersed species from the southern Appalachians. Bull. Torrey Bot. Club. 113: 247-251.

  • Gleason, H.A. 1952. Change of Name for Certain plants on the 'Manual Range.' Phytologia 4(1): 20-25.

  • Gleason, H.A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. New York Botanical Garden, Bronx, New York. 910 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.

  • Jones, S. B., Jr., and N. C. Coile. 1988. The distribution of the vascular flora of Georgia. Department of Botany, University of Georgia, Athens.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.

  • Mohlenbrock, R. H., et al. 1962. A floristics study of the Devils Kitchen area, Williamson and Union counties, Illinois. Castanea 27:101-131.

  • Mohlenbrock, R., Ozment, and Folkerts. 1962. Additions to the Flora of Illinois. Rhodora 64:356-357.

  • Mohlenbrock, R.H. 1986. Guide to the vascular flora of Illinois. Southern Illinois University Press, Carbondale, IL.

  • Mohlenbrock, R.H. and K. Wilson. 1985. A floristic study of Fountain Bluff, Jackson County, Illinois. Erigenia 6:29-55.

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

  • Radford, A. E., H. E. Ahles, and C. R. Bell. 1964. Manual of the Vascular Flora of the Carolinas. University of North Carolina Press, Chapel Hill, North Carolina.

  • Radford, A.E., H.E. Ahles, and C.R. Bell. 1968. Manual of the vascular flora of the Carolinas. Univ. North Carolina Press, Chapel Hill, NC. 1183 pp.

  • 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.

  • Rettig, J.H. 1988. A biosystematic study of the Carex pensylvanica group (section Acrocystis) in North America. Ph.D. dissertation. University of Georgia, Athens.

  • Rettig, J.H. 1990. Achene micromorphology of the Carex nigromarinata complex (section Acrocystis, Cyperaceae). Rhodora 92: 70-79.

  • Rettig, J.H. and D.E. Giannasi. 1990. Foliar flavonoids of the Carex nigromarginata complex (section Acrocystis, Cyperaceae). Biochemical Syst. and Ecol. 18: 393-397.

  • Rettig, J.H., and D.E. Giannasi. 1990. Foliar flavonoids of the Carex nigromarginata complex (Sect. Acrocystis, Cyperaceae). Biochemical Systematics and Ecology 18(6):393-397.

  • Reznicek, A.A. 1990 Four new species of Carex (Cyperaceae) from Mexico, with note on the Mexican Carex flora. Contr. Univ. Mich. Herb. 17: 279-293.

  • Reznicek, A.A. and P.M. Catling. 1982. Cyperaceae new to Canad from Long Point, Morfolk County. Can. Field Nat. 96: 184-188.

  • Reznicek, A.A. and P.M. Catling. 1989. Flora of Long Point, Regional Municipality of Haldimand-Norfolk, Ontario. Michigan Botanist 28(3): 99-175.

  • Reznicek, A.A. and P.M. Catling. 1989. Flora of Long Point, regional municipality of Halimand-Norfolk, Ontario. Mich. Bot. 28(3): 99-175.

  • Rhoads, A.F., and W. Klein. 1993. Atlas of the Flora of Pennsylvania: An Annotated Checklist. American Philosophical Society, Philadelphia, PA.

  • Rhoads, Ann F. and Timothy A. Block. 2000. The Plants of Pennsylvania, an Illustrated Manual. University of Pennsylvania Press, Philadelphia, PA.

  • Roalson, E.H. and E.A. Friar. 2004. Phylogenetic relationships and biogeographic patterns in North American members of Carex section Acrocystis (Cyperaceae) using nrDNA its and ETs sequence data. Plant Systematics and Evolution 243: 175-187

  • Smith, E. B. 1988b. An atlas and annotated list of the vascular plants of Arkansas, 2nd edition. University of Arkansas, Fayetteville.

  • Smith, E.B. 1988b. An atlas and annotated list of the vascular plants of Arkansas. Second edition. Univ. Arkansas, Fayetteville. 489 pp.

  • Steyermark, J.A. 1963. Flora of Missouri. Iowa State Univ. Press, Ames. 1728 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 University of South Florida]. New York Flora Association, Albany, New York

  • Wieland, Ronald. 1999. Summary of Dr. Charles Bryson and Bruce Sorrie's understanding of the general status of Eleocharis equisetoides, E. geniculata, Carex alata, and Carex nigromarginata. Mississippi Natural Heritage program. 1 pp.

Use Guidelines & Citation

Use Guidelines and Citation

The Small Print: Trademark, Copyright, Citation Guidelines, Restrictions on Use, and Information Disclaimer.

Note: All species and ecological community data presented in NatureServe Explorer at were updated to be current with NatureServe's central databases as of March 2019.
Note: This report was printed on

Trademark Notice: "NatureServe", NatureServe Explorer, The NatureServe logo, and all other names of NatureServe programs referenced herein are trademarks of NatureServe. Any other product or company names mentioned herein are the trademarks of their respective owners.

Copyright Notice: Copyright © 2019 NatureServe, 2511 Richmond (Jefferson Davis) Highway, Suite 930, Arlington, VA 22202, U.S.A. All Rights Reserved. Each document delivered from this server or web site may contain other proprietary notices and copyright information relating to that document. The following citation should be used in any published materials which reference the web site.

Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2019. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:

Full metadata for the Mammal Range Maps of North America is available at:

Restrictions on Use: Permission to use, copy and distribute documents delivered from this server is hereby granted under the following conditions:
  1. The above copyright notice must appear in all copies;
  2. Any use of the documents available from this server must be for informational purposes only and in no instance for commercial purposes;
  3. Some data may be downloaded to files and altered in format for analytical purposes, however the data should still be referenced using the citation above;
  4. No graphics available from this server can be used, copied or distributed separate from the accompanying text. Any rights not expressly granted herein are reserved by NatureServe. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any trademark of NatureServe. No trademark owned by NatureServe may be used in advertising or promotion pertaining to the distribution of documents delivered from this server without specific advance permission from NatureServe. Except as expressly provided above, nothing contained herein shall be construed as conferring any license or right under any NatureServe copyright.
Information Warranty Disclaimer: All documents and related graphics provided by this server and any other documents which are referenced by or linked to this server are provided "as is" without warranty as to the currentness, completeness, or accuracy of any specific data. NatureServe hereby disclaims all warranties and conditions with regard to any documents provided by this server or any other documents which are referenced by or linked to this server, including but not limited to all implied warranties and conditions of merchantibility, fitness for a particular purpose, and non-infringement. NatureServe makes no representations about the suitability of the information delivered from this server or any other documents that are referenced to or linked to this server. In no event shall NatureServe be liable for any special, indirect, incidental, consequential damages, or for damages of any kind arising out of or in connection with the use or performance of information contained in any documents provided by this server or in any other documents which are referenced by or linked to this server, under any theory of liability used. NatureServe may update or make changes to the documents provided by this server at any time without notice; however, NatureServe makes no commitment to update the information contained herein. Since the data in the central databases are continually being updated, it is advisable to refresh data retrieved at least once a year after its receipt. The data provided is for planning, assessment, and informational purposes. Site specific projects or activities should be reviewed for potential environmental impacts with appropriate regulatory agencies. If ground-disturbing activities are proposed on a site, the appropriate state natural heritage program(s) or conservation data center can be contacted for a site-specific review of the project area (see Visit Local Programs).

Feedback Request: NatureServe encourages users to let us know of any errors or significant omissions that you find in the data through (see Contact Us). Your comments will be very valuable in improving the overall quality of our databases for the benefit of all users.