Carex disticha
Huds.
Common Name:
Tworank sedge
Synonyms and Other Names:
Carex distique, two-rank sedge, two rank sedge
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
Great Lakes Nonindigenous Occurrences:
First Great Lakes sighting was on Lake Ontario in 1866, near Belleville, Ontario, although the original specimen could not be located and verified (Catling et al. 1988). It was also reported at two sites in Canada, both associated with ports on the Great Lakes-St. Lawrence system.
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).
Status:
Established
Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...
There is little or no evidence to support that Carex disticha has significant environmental impacts in the Great Lakes.
Realized:
Thus far, tworank sedge introduction in the Great Lakes has been sporadic. However, it was reportedly a dominant established plant in Simcoe County, Ontario (Catling et al. 1988).
Potential:
Carex disticha is capable of dominating eutrophic, coastal dune slacks in its native range (Grootjans et al. 2002). As of 1992, a total of 253 Carex hybrids have been reported in North America. This indicates that this genus is highly capable of hybridization, and invading species, such as C. disticha, may be a genetic threat to native species of sedges (Cayouette and Catling 1992). Carex spp. can transport oxygen from above ground portions to their deep root systems, which enables these species to compete in water-logged ecosystems (Riutta et al. 2007).
There is little or no evidence to support that Carex disticha has significant socio-economic impacts in the Great Lakes.
There is little or no evidence to support that Carex disticha has significant beneficial effects in the Great Lakes.
Potential:
Historically, C. disticha has been an important hay and forage species in its native range in the USSR (Catling et al. 1988).
Management:
Regulations (pertaining to the Great Lakes region)
Tworank sedge has not been found in the United States, but it is classified as an “introduced species” in Ontario, Canada (Canadensys 2012, USDA NRCA n.d.). Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
Biological
There are no known biological control methods for this species.
Physical
Carex spp. are able to withstand water-logged conditions, suggesting that water level increase may not be an effective form of control (Riutta et al. 2007).
Chemical
There are no known chemical control methods for C. disticha; however, imazapyr has been effective in controlling other sedge species (USACE 2011).
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for herbicide use. Follow all label directions.
References
(click for full reference list)
Author:
Larson, J. L. Berent, and A. Fusaro
Contributing Agencies:
Revision Date:
11/19/2018
Citation for this information:
Larson, J. L. Berent, and A. Fusaro, 2024, Carex disticha Huds.: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI, https://nas.er.usgs.gov/queries/greatlakes/FactSheet.aspx?Species_ID=2676&Potential=N&Type=0&HUCNumber=DHuron, Revision Date: 11/19/2018, Access Date: 5/1/2024
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.