Sparganium glomeratum
(Laestad.) L. Neum.
Common Name:
Northern bur-reed
Synonyms and Other Names:
Sparganium erectum Linnaeus var. glomeratum, clustered bur-reed, European bur-reed
Identification:
Plants slender to robust, to 0.4 (--0.6) m; at least some leaves and inflorescences emergent, erect. Leaves stiff, weakly keeled, to 50 cm, 6 mm. Inflorescences: rachis unbranched, condensed, erect; bracts ascending, somewhat inflated near base; pistillate heads 2--6, mostly supra-axillary, sometimes opposite bract above, upper crowded, sessile, proximal head not contiguous with upperdistal, peduncled, 1.2--1.6(--2) cm diam. and contiguous in fruit; staminate heads 1(--2), contiguous or not with distalmost pistillate head. Flowers: tepals without subapical dark spot, entire to erose; stigma 1, lanceolate. Fruits greenish brown, lustrous, stipitate, fusiform, body not faceted, slightly constricted near equator, 3--6 ï‚´ 2--3 mm, tapering to beak; beak straight, 1.5--2 mm; tepals attached at base, reaching 1/3 to 1/2 length of fruit. Seeds 1. 2n = 30.
Size:
to 0.6m
Native Range:
Eurasia and North America.
Great Lakes Nonindigenous Occurrences:
Until recently, Sparganium glomeratum was thought to be fully nonindigenous to the Great Lakes basin, as this region was thought to be outside of its native post-glaciation range, but recent reviews of records have revised this and the species is now listed by USDA (USDA 2023) as native to Minnesota and Wisconsin. Rarely collected in North America, except where it is locally common in sedge-marshes and black-ash swamps near the western end of Lake Superior. Reported in the Canadian Great Lakes provinces, Minnesota, and Wisconsin.
Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, 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 Sparganium glomeratum are found here.
Full list of USGS occurrences
Table last updated 5/1/2024
† Populations may not be currently present.
* HUCs are not listed for areas where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).
Ecology:
S. glomeratum is a species confined to shallow, emergent wetlands and certain wetlands with woody vegetation growing for at least part of the year in some standing water. Draining, filling, and other abuses to habitat pose severe problems to the survival of S. glomeratum in these places. Remnant populations are in a precarious situation and can easily go extinct from ordinary natural causes (Gilpin and Soule 1986). This species flowers in summer (July through August). It prefers shallow, quiet, neutral, mesotrophic waters.
S. glomeratum is a rare plant in North America, including Minnesota. Until 1990 it was know from only eight different sites on the continent, six of which were in Minnesota. Since then 27 more sites have been reported from Minnesota and Wisconsin. Some of these sites support two or more small patches of S. glomeratum. In most cases these patches consist of leafy shoots and fertile stems sparsely distributed within 20-50 square feet. In Minnesota and Wisconsin there exist situations where there are areas of concentration separated by areas of near to total absence, even though apparently suitable habitat is present.
Great Lakes Means of Introduction:
Unknown.
Great Lakes Status:
Cryptogenic. Until recently, Sparganium glomeratum was thought to be fully nonindigenous to the Great Lakes basin itself, as this region was thought to be outside of its native post-glaciation range, but recent reviews of records have revised this. The initial classification of this species as nonindigenous to the Great Lakes was based on the Mills et al. (1993) which states, “The first occurrence of the European bur reed, known from shallow water and bogs, in North America is from Lake Itasca, Minnesota, in the early 1890s (Lakela 1941, Gleason and Cronquist 1991). This introduction was not successful, however, and the plant was not collected again in North America until 1927 when an apparently established population was discovered in Saguenay County, Quebec, in the Natashaquan River region (Lewis 1931). Gleason and Cronquist (1991) consider this species “interrupted” circumboreal, and Fassett (1957) noted its European distribution and the Duluth record. Although this plant has been considered native in these botanical works, this patchy distribution is indicative of a non-indigenous species.”
The mechanism through which it was released was never specified. However, Ito and Cota-Sanchez (2014) revealed that S. glomeratum is distributed across the Prairie Provinces of Canada and has been long known from Quebec, concluding that it is native. This species has its greatest population center around Western Lake Superior, but it is locally quite common around the Twin Ports and west into northern Minnesota.
Great Lakes Impacts:
Summary of species impacts derived from literature review. Click on an icon to find out more...
Current research on the environmental impact of Sparganium glomeratum in the Great Lakes is inadequate to support proper assessment.
Many Sparganium hybrids have been reported, but none have been verified in the Great Lakes region and their significance to native populations has not been assessed. There is little or no evidence to support that Sparganium glomeratum has significant socioeconomic impacts in the Great Lakes.
There is little or no evidence to support that Sparganium glomeratum has significant beneficial impacts in the Great Lakes.
Tubers of Sparganium spp. have reportedly been used by Native Americans as a food source, and Sparganium infusions have been used to treat chills (USDA Plants, 2019), but no information exists on the beneficial uses of Sparganium glomeratum in particular.
Management:
Regulations (pertaining to the Great Lakes region)
Under the synonym Sparganium erectum, this species is federally listed as a noxious weed (Code of Federal Regulations, Title 7, 360.200). It is additionally listed as prohibited in Minnesota (MN Administrative Rules, 6216.0250 Prohibited). Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
No information is readily available on control of Sparganium glomeratum.
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.
Remarks:
USDA Plants lists this species as native to Minnesota and Wisconsin. Until recently, it was thought to be fully nonindigenous to the Great Lakes basin itself, as this region was thought to be outside of its native post-glaciation range, but recent reviews of records have revised this range and it is now considered a range expander. The initial classification of this species as nonindigenous is based on the Mills et al. 1993 paper that states, “The first occurrence of the European bur reed, known from shallow water and bogs, in North America is from Lake Itasca, Minnesota, in the early 1890s (Lakela 1941, Gleason and Cronquist 1991). This introduction was not successful, however, and the plant was not collected again in North America until 1927 when an apparently established population was discovered in Saguenay County, Quebec, in the Natashaquan River region (Lewis 1931). In the late 1930s, a population of bur reed was found in Duluth, Minnesota, in a bog near Superior Bay (Lakela 1941). Other North American populations of Sparganium glomeratum exist in Dawson, Yukon (Porsild 1942, 1951) and from Labrador, British Columbia, and Alberta (Boivin 1967). Gleason and Cronquist (1991) consider this species "interrupted" circumboreal, and Fassett (1957) noted its European distribution and the Duluth record. Although this plant has been considered native in these botanical works, this patchy distribution is indicative of a non-indigenous species. The mechanism through which it was released remains unknown."
However, expert review in 2019 (Sulman, J, pers. comm) has determined that since this initial assessment in 1993, more frequent and earlier collections of S. glomeratum have surfaced. This species has a singular distribution in North America, and is one of very few that has its greatest population center around Western Lake Superior, but it is locally quite common around the Twin Ports and west into northern Minnesota. Recent floristic research in Canada revealed S. glomeratum is distributed across the Prairie Provinces, and has been long known from Quebec.
References
(click for full reference list)
Author:
Cao, L., and R. Sturtevant
Contributing Agencies:
Revision Date:
1/18/2024
Citation for this information:
Cao, L., and R. Sturtevant, 2024, Sparganium glomeratum (Laestad.) L. Neum.: 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=2701&Potential=N&Type=0&HUCNumber=DGreatLakes, Revision Date: 1/18/2024, 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.