Back's sedge was first discovered in Connecticut in 1988 (Mehrhoff 1995), Massachusetts in 1997 (Bertin et. al 2002), and the southern Finger Lakes area of New York in 2004 (Werier 2004). Some think it has been overlooked due to its inconspicuous nature. The species is named in honor of Sir George Back (1796-1878).
There are currently 16 known populations of Carex backii and approximately ten historical populations. This plant tends to prefer wooded sites with a shallow limestone bedrock. Since this is a somewhat specific requirement, habitat options are limited. Invasive species may pose a threat, but for now this threat has had minimal impacts. There are real concerns that swallowwort (Cynanchum spp.) will reduce or eliminate a few populations.
About ten new locales for Carex backii have been found in the past 20 years. With a limited season to easily identify this plant and as an inconspicuous plant, these new locales probably represent populations that have been overlooked in the past. Approximately ten additional populations have not been seen in over 20 years but searches to most of these sites have not been conducted and original site location information is obscure. Of populations that have been documented more than once there does not appear to be any clear trends. As a speculative trend, the trend of this plant appears stable. Some may argue there is an increase in range, but this could just reflect overlooked populations.
A few populations have been known for over 50 years but clear data on trends for these populations is lacking.
Overall most populations are not threatened. Exotics are currently and could potentially threaten a few sites. Trampling and human disturbances such as dumping, logging, and residential development are also potential threats at a couple of sites. Most of these threats are speculative and might not have a negative impact on populations.
At a few sites, if feasible, exotics including swallowwort (Cynanchum sp.) should be controlled. Trampling by ATV's and foot traffic should be monitored and restricted if necessary.
This sedge grows primarily in dry, rocky deciduous, mixed, or evergreen open forests or woodlands, often over limestone. It occurs on or adjacent to rocky ledges, rock outcrops, ridges, calcareous pavement barrens and woodlands, thickets, and sand plain thickets. Open canopied forests are preferred but it also grows in more forested as well as more open habitats. (New York Natural Heritage Program 2005). Dry, rocky, open, or shaded slopes, ridges, and barrens, in hardwood, mixed, or coniferous forests, including pine plantations, on acidic and calcareous substrates (Crins et al. 2002). In quite varied habitats, the species frequently occurs in mesic deciduous forests near streams and rivers. Soils often have a high organic content with an abundance of leaf litter. Signs of localized, natural disturbance are usually evident. It also grows in open, prairie habitats with scattered Quercus macrocarpa, on open granite outcrops, and along disturbed roadsides (Saarela and Ford 2001). Dry rocky or sandy woods and bluffs (Fernald 1970).
This sedge occurs in eastern New York from Dutchess County north. It also occurs in northern New York and there are two records from central New York (Onondaga and Tompkins Counties).
A north temperate and boreal species Carex backii is most frequent in the Great Lakes region as well as the prairie provinces. It is quite infrequent in the extreme western and eastern part of its range. Overall, this sedge ranges from the Gaspé peninsula in eastern Quebec and southeastern New Brunswick west through Ontario, Manitoba, Saskatchewan, Alberta, and British Columbia south to New England, New Jersey (one historical population), Pennsylvania (one historical population), Michigan, Minnesota, North Dakota, and northwestern Montana with disjunct populations in western South Dakota, Wyoming, and Colorado (Rhoads and Klein 1993, Saarela and Ford 2001, Snyder 2001).
A densely tufted grass-like plant, this sedge has leaves 1.3-5.4 mm wide. The leaves are up to 37 cm long and the whole plant often appears somewhat flattened. The flowers and fruits, which occur in clusters 0.7-1.6 cm long, are borne on the tips of stalks which are shorter than the leaves. The flowers and fruits are inconspicuous because they are completely concealed by leaf like structures (scales) which surround each individual flower/fruit in a cluster. The best way to look for this plant is to search for these leafy scales.
This cespitose (growing in tufts or clumps) Carex with relatively short rhizomes (<3.0 mm long) has dull-green to yellow-green, plicate to flat leaves which are 1.3-5.4 mm wide. The reproductive shoots produce one terminal spike on apically dilated culms which are 1.4-24.9 cm long. At the base of the culms, arise 0-3 basal spikes, which are terminal on elongate peduncles. The spikes are androgynous with 2-3 staminate and 2-7 pistillate flowers. The spikes are not subtended by bracts. The pistillate flowers/perigynia are subtended by leaf-like scales which completely surround them. The lowest scale of the terminal spike is 1.9-7.2 cm long and 2.0-6.5 mm wide. The more distal scales become gradually reduced in size. Perigynia are 4.8-6.6 mm long and gradually taper to an elongated beak 1.9-2.9 mm long.
This species can be identified in flower although fruiting characteristics are best. A complete reproductive shoot with mature perigynia should be collected to verify the identification.
In New York there are two (Carex jamesii and C. willdenowii) and perhaps a third (C. juniperorum) species that are somewhat closely related and similar morphologically. Carex backii can be distinguished from all three by its wider pistillate scales (2-6.5 mm wide compared to 1.6-2.22 mm for C. willdenowii, 1.4-3.0 mm for C. jamesii, and 1.2-3.0 mm for C. juniperorum) which completely conceal the perigynia in C. backii as compared to not concealing the perigynia in these other species. These scales and particularly the upper scales have narrow hyaline or green margins in C. backii as well as C. juniperorum but have broad hyaline margins in C. willdenowii and C. jamesii. Carex backii also has 2-3 staminate flowers per terminal spike as compared to 3-29 for C. willdenowii, 3-13 for C. jamesii, and 5-21 for C. juniperorum. In addition, C. backii has clavate, minutely papillose stigmas as compared to filiform, strongly papillose stigmas of C. willdenowii, C. jamesii, and C. juniperorum.
The species is in fruit from late May to mid July although fruits are shedding by the end of this season making identification more complicated at this time. Surveys for this species should be done from late May through June.
The time of year you would expect to find Back's Sedge fruiting in New York.
Carex backii Boott
The closely related species Carex saximontana (from the Great Plains) has sometimes been considered a synonym of C. backii (e.g. Gleason and Cronquist 1991). Recent work has shown that the two are distinct and that a third recently described species, C. cordillerana (from west of the Rockies), may have led to previous confusion regarding the distinctiveness of C. saximontana (Saarela and Ford 2001).
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Bertin, R.I., K.B. Searcy, and P. Somers. 2002. A new native plant for Massachusetts, Carex backii (Cyperaceae). Rhodora 104(918): 201-204.
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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.
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New York Natural Heritage Program. 2019. New York Natural Heritage Program Databases. Albany, NY.
Rhoads, Ann F. and Timothy A. Block. 2000. The Plants of Pennsylvania, an Illustrated Manual. University of Pennsylvania Press, Philadelphia, PA.
Saarela, J. M. and B. A. Ford. 2001. Taxonomy of the Carex backii Complex (Section Phyllostachyae, Cyperaceae). Systematic Botany 26(4): 704-721.
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
Werier, D.W. 2004. Carex backii (Back's sedge) a new native species for the southern Finger Lakes Region of New York. Solidago: The Newsletter of the Finger Lakes Native Plant Society 5(3): 4-5.
Information for this guide was last updated on: January 13, 2009
Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Carex backii. Available from: https://guides.nynhp.org/backs-sedge/. Accessed May 22, 2019.