A different sedge species (Carex gravida) was reported from New York for many years but specimens formerly identified as such were determined to be misidentifications of C. aggregata and/or C. sparganioides. This led to the removal of C. gravida from the checklist of New York State plants.
There is only one known population within New York, however a subsequent survey to this site was not able to relocate this population. The original report indicates this was a very small population. This population needs further survey work. Fewer than five populations have ever been reported from New York which is at the northeastern edge of this sedge's range. Tony Reznicek, University of Michigan and Flora of North America Carex author, has seen and verified the identity of the only known New York population.
There is only one known population that has been seen within the past 20 years. An attempt at relocating this population was unsuccessful but there was more habitat to search. Overall short term trends are unknown.
All but one population have not been seen in over 20 years. Searches to these historical populations have not been conducted and it is unknown if these populations are still extant. Therefore, long term trends are unknown.
One population is known from a cemetery. The impacts of cemetery management are not known, but it may be useful to monitor the impacts or benefits of mowing and other management activities.
Information about the one population known from a cemetery as well as conservation concerns need to be communicated to the owners of the property.
Surveys to historical occurrences are needed. In addition, one population that was seen in 1988 needs to be relocated and surveyed.
Sandy soils in a cemetery and rich woods (New York Natural Heritage Program 2006). Meadows, thickets, open forests, usually on calcareous soils (Ball 2002). Moist woods, meadows, and ditches (Rhoads and Block 2000). Dry clearings of an open hackberry forest over shallow limestone soils (Oldham and Crins 1988). Rich woods, thickets, and meadows (Fernald 1970).
There have only been a few populations ever reported from New York. These are scattered from the southern tier of western New York, through central New York, and into southeastern New York including Long Island.
Carex aggregata occurs from New York west to southern Ontario, Michigan (probably adventive), Minnesota, and South Dakota south to North Carolina, Tennessee, Alabama, Missouri, and Oklahoma (Voss 1972, Oldham and Crins 1988, Ball 2002).
Carex aggregata is a tufted, perennial, grass-like plant. It has long strap-like leaves that are up to 3.5 to 5.0 mm wide. From the tufts of leaves at the base of the plant, a stem 20-100 cm tall arises. Leaves come off of this stem and at the top of the stem is a dense cluster of flowers/fruits. The flower/fruit cluster is 1.5-5 cm long, 8-13 mm wide, and contains many numerous, small, and inconspicuous flowers. Small (3.4-4.6 mm long) green fruits (perigynia) form from the flowers (Ball 2002).
Carex aggregata is a cespitose perennial. The rhizomes are inconspicuous. Culms are (20-) 30-100 cm long. Leaf sheaths are usually loose with the fronts hyaline and the summit of the fronts yellow or brown and thickened. The backs of the proximal leaf sheaths are green and white striped and mottled with conspicuous cross veins. Leaf blades are up to 3.5-5 mm wide. The ligules are shorter than to as long as wide. There are 5-10 androgynous short spikes densely clustered on the top (1.5-) 2-5 cm of the culms. Pistillate scales are 2.2-3.5 mm long, acuminate to short-awned, and the bodies of the scales are 0.67 times to almost as long as the perigynia. The anthers are 1.5-2.5 mm long (Ball 2002).
Carex aggregata is easiest to identify when it is in mature fruit but the fruits are not yet easily shedding.
There are three other members of Carex section Phaestoglochin (C. sparganioides, C. cephaloidea, and C. gravida) that are similar.
Carex sparganioides is perhaps the most different from C. aggregata of these three. It has a more elongated inflorescences (3-15 cm long) with a larger proximal internode. In addition the widest leaf blades are 5-10 mm wide (Ball 2002).
Carex cephaloidea is the most similar to C. aggregata of the species that occur in New York. Carex cephaloidea has the widest leaf blades (4-)5-8 mm wide and the ligules are just longer than wide. In addition, the pistillate scales are 1.5-2 mm long, subobtuse to acute, and the bodies are no more than 0.5 times the length of the perigynia (Ball 2002). Mackenzie (1906) in his description of C. aggregata (as C. agglomerata) used culm scabrousity to separate C. cephaloidea and C. aggregata. The angles of the culms of Carex cephaloidea being strongly serrulate while those of C. aggregata are only roughened just below the inflorescence. These character states may be incorrect or subtle.
Carex gravida does not occur in NY but was attributed to the state incorrectly in the past (Mitchell and Tucker 1997, Mitchell 1998). It is not expected in the state. Carex gravida mainly differs in having the summit of the leaf sheath fronts white, hyaline, not thickened, and fragile (Ball 2002).
Carex aggregate is in just immature to mature fruit that are not easily shedding from June through early July. Therefore surveys are most successful if conducted during this time period.
The time of year you would expect to find Glomerate Sedge fruiting in New York.
Carex aggregata Mackenzie
Carex aggregata is in section Phaestoglochin. This section had previously been lumped under section Bracteosae which is now considered a distinct section from Central and South America (Ball 2002). Specimens previously identified as C. gravida from NY were misidentifications of C. aggregata or C. sparganioides (Mitchell 1998).
Ball, P.W. 2002. Carex Linnaeus sect. Phaestoglochin Dumortier. Pages 285-297 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.
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. 1906. Notes on Carex I. Bulletin of the Torrey Botanical Club 33: 439-443.
Mitchell, R. S. 1998. Amendments to the State Checklist I. New York Flora Association Newsletter 9(3): 1-2.
Mitchell, Richard S. and Gordon C. Tucker. 1997. Revised Checklist of New York State Plants. Contributions to a Flora of New York State. Checklist IV. Bulletin No. 490. New York State Museum. Albany, NY. 400 pp.
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. 2019. New York Natural Heritage Program Databases. Albany, NY.
Oldham, M. J., and W. J. Crins. 1988. New and significant records of Ontario sedges (Cyperaceae). Canadian Field-Naturalist 102(3):500-507.
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.
Rhoads, Ann F. and Timothy A. Block. 2000. The Plants of Pennsylvania, an Illustrated Manual. University of Pennsylvania Press, Philadelphia, PA.
Voss, E.G. 1972. Michigan Flora, Part I. Gymnosperms and Monocots. Cranbrook Institute of Science Bulletin 55 and the University of Michigan Herbarium. Ann Arbor. 488 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 http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://www.nyflora.org/, Albany, New York
Information for this guide was last updated on: May 21, 2006
Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Carex aggregata. Available from: https://guides.nynhp.org/glomerate-sedge/. Accessed January 17, 2019.