Common name: tworank sedge
Synonyms and Other Names: Carex distique, two-rank sedge, two rank sedge
available through www.itis.gov
Identification: Culms trigonous, scabrous-angled distally, 30–120 cm; vegetative culms somewhat taller. Leaves: basal sheaths brown; sheaths with inner band green, veined, apex hyaline, prolonged 0.7–3 mm; glabrous; ligules 1.8–16 mm; blades 1.8–5.2 mm wide. Inflorescences contracted near middle, 2–7 cm; spikes ascending, ovate, 4–16 × 1.2–9 mm, basal spikes larger than those near middle. Pistillate scales reddish brown at maturity, hyaline margins very narrow or absent, ovate, acute to acuminate, glabrous. Staminate scales reddish brown, narrowly ovate, apex acute to acuminate, glabrous. Perigynia (3.8–)4–5.5(–6.1) × 1.7–2.3 mm; beak (0.8–)1–1.9(–2.3) mm. Achenes brown.
Size: 30-120 cm
Native Range: Eurasia
Hydrologic Unit Codes (HUCs) Explained
Puerto Rico &
Interactive maps: Point Distribution Maps
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Carex disticha are found here.
Table last updated 9/30/2019
† Populations may not be currently present.
Ecology: Carex disticha is a monocotyledonous perennial that produces extensive rhizomatous systems via sympodial growth. Individual ramets and the connections between them appear long-lived, potentially surviving 4 years or longer. Carex disticha is also capable of transporting and sharing resources between ramets across long distances though its ramet system (D’Hertefeldt and Falkengren-Grerup 2002).
Tworank sedge fruits from June–July. It is found in productive habitats, including wet meadows, stream banks, lakeshores, pastures, and disturbed areas (D’Hertefeldt and Falkengren-Grerup 2002).
Means of Introduction: Solid ballast (USEPA 2008). Carex disticha may have been introduced through the shipment of hay, animal forage or bedding, or packing materials (Mills et al. 1993).
Impact of Introduction: thus far still a sporadic introduction
References: (click for full references)
Canadensys. 2012. Carex disticha
. Université de Montréal Biodiversity Centre. Available http://data.canadensys.net/vascan/name/Carex%20disticha
. Accessed 17 April 2012.
Catling, P.M., A.A. Reznicek, and B.S. Brookes. 1988. The separation of Carex disticha and Carex sartwellii and the status of Carex disticha in North America. Canadian Journal of Botany 66:2323—2330.
Cayouette, J., and P.M. Catling. 1992. Hybridization in the Genus Carex with special reference to North America. Botanical Review 58(4): 351—438.
D’Hertefeldt, T. and U. Falkengren-Grerup. 2002. Extensive physiological integration in Carex arenaria and Carex disticha in relation to potassium and water availability. New Phytologist 156:469—477.
Flora of North America. 2008. www.eFloras.org
Grootjans, A.P., H.W.T. Geelen, A.J.M. Jansen, and E.J. Lammerts. 2002. Restoration of coastal dune slacks in the Netherlands. Hydrobiologia 478: 181—203.
Mills, E.L., J.H. Leach, J.T. Carlton, C.L. Secor. 1993. Exotic species in the Great Lakes: a history of biotic crises and anthropogenic introductions. Journal of Great Lakes research 19(1):1-54.
Riutta, T., J. Laine, and E-S. Tuittila. 2007. Sensitivity of CO2 exchange of fen ecosystem components to water level variation. Ecosystems 10: 718—733.
U.S. Army Corps of Engineers (USACE). 2011. Aquatic herbicides. 8 pp.
United States Environmental Protection Agency (US EPA). 2008. Predicting future introductions of nonindigenous species to the Great Lakes. National Center for Environmental Assessment, Washington, DC. 138 pp.
United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS). 2012. Plants Database. Available http://plants.usda.gov/java/. Accessed 17 April 2012.
Larson, J. L. Berent, and A. Fusaro
Revision Date: 11/19/2018
Larson, J. L. Berent, and A. Fusaro, 2020, Carex disticha Huds.: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2676, Revision Date: 11/19/2018, Access Date: 9/19/2020
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.