This sedge was quite recently discovered, and described as a species new to science, during fieldwork in New York's Hudson Highlands. It was first discovered by New York botanist David Werier in 2006. It is named for Dr. Anton Reznicek of the University of Michigan, a Carex expert and enthuiast, in recognition of his ongoing teaching and research on sedges.
There are only four known extant and one historical population of Carex reznicekii from southeastern New York, including Long Island and the Lower Hudson Valley. This species is at the northerneastern edge of its range in New York with a few populations known from southern Connecticut and Rhode Island. It occurs in dry-mesic oak-hickory forests, which is a relatively common habitat. It also is difficult to identify after May, is a somewhat inconspicuous plant, and was only first described as a separate species in 2006. For these reasons, this species may be more common than current records indicate.
As it is a recently described species, we have no data on population trends for Carex reznicekii.
As it is a recently described species, we have no data on population trends for Carex reznicekii.
The ecology of this newly discovered species is not yet well-studied. As it occurs in forested habitats, canopy removal is a potential threat.
Sites with Carex reznicekii should be managed to protect the forest canopy and prevent the dominance of exotics in the understory or herb layer.
Additional inventory work is needed to determine the distribution and extent of this newly-discovered, early-fruiting, and easily-overlooked sedge.
In New York Carex reznicekii grows in mesic to dry-mesic forests with rocky, shallow soils. It may prefer more calcareous, shaded, and lower-slope sites than Carex nigromarginata, though the two species' habitats overlap (New York Natural Heritage Program 2009, Werier 2006). Oaks are the dominant canopy trees at each of the four known New York sites (New York Natural Heritage Program 2009).
* probable association but not confirmed.
Carex reznicekii is currently known from Long Island and from Orange and Ulster Counties in the Hudson River Valley. There is also a single historical record from Manhattan. With abundant good habitat in the state, additional survey work is needed to determine this species' range in New York, particularly elsewhere in the Hudson Valley
Carex reznicekii occurs from southern New England and New York south as far as Georgia, and west as far as southern Missouri and northern Arkansas (Werier 2006).
Carex reznicekii is a densely tufted, evergreen, grass-like perennial. Its widest leaves are 1.2 to 2.2 (up to 2.4) mm wide. Its fruiting stalks (culms) are short, and often hidden by overlaying leaves near the base of the plant. The terminal spike is staminate, and the flowers and fruits occur in tight clusters (spikes) at the top of these culms. Although often hidden near the base of the plant, upon close inspection the spikes are not truly basal but rather arise singly from the nodes of the culms. The perigynia (fruit) are 2.5 to 3.9 mm long and 3-sided, with two prominent nerves extending their full length, the distal (away from the stem) end narrowed into a distinct beak.
Mature fruits are preferred for positive identification of this species.
The two species most likely to be confused with Carex reznicekii are C. nigromarginata and C. umbellata. C. reznicekii differs from C. nigromarginata by having narrower leaf blades (generally 1.2 to 2.2 millimeters wide, as compared to 2.3 to 4.5mm wide for C. nigromarginata) and less reddish to purplish black color on the pistillate scales (which usually extends from the margin nearly to the mid-vein on C. nigromarginata.) It differs from C. umbellata by its lack of basal spikes, staminate spikes which have 2 to 4 pistillate spikes (versus 0 to 2 for C. umbellata), and staminate spikes extending no more than 3.7 millimeters past the pistillate spikes (versus staminate spikes extending up to 9.0 millimeters past the pistillate ones (if present) for C. umbellata).
Carex albicans and C. novae-angliae each have narrow leaves like those of C. reznicekii. C. albicans is rhizomatous rather than clump-forming, and has longer fruiting stalks. C. novae-angliae tends to fruit later (in June and July) than C. reznicekii, and has shorter (2.2 to 2.6 millimeters), nerveless perigynia.
The fruits are visible from late April through May.
The time of year you would expect to find Reznicek's Sedge fruiting in New York.
Reznicek's Sedge
Carex reznicekii Werier
Werier, David A. 2006. Carex reznicekii, a new widespread species of Carex Section Acrocystis (Cyperaceae) from eastern North America. SIDA 22(2): 1049-1070.
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.
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
Weldy, Troy W. and David Werier. 2009. New York Flora Atlas. [S.M. Landry and K.N. Campbell (original application development), Florida Center for Community Design and Research. University of South Florida]. New York Flora Association, Albany, NY. Available on the web at (http://www.newyork.plantatlas.usf.edu/).
Information for this guide was last updated on: March 7, 2019
Please cite this page as:
New York Natural Heritage Program. 2023.
Online Conservation Guide for
Carex reznicekii.
Available from: https://guides.nynhp.org/rezniceks-sedge/.
Accessed September 24, 2023.