There are 11 verified occurrences, 23 historical occurrences.
In New York, Small Bur-reed has been found in a wide variety of habitats with still, open water. It occurs in small pools within both bogs and fens, as well as in Northern White-cedar swamps, beaver ponds, and shrub swamps (New York Natural Heritage Program 2011). Small open water pools at edge of fen mat; open water sections of fen near open stream flow; mucky shrub swamps with open water zones; mountain pool surrounded by trees; small swamps surrounded by northern white cedar woods; open water within willow swamps; open water in dwarf shrub bogs; submergent/emergent communities along a beaver affected area along streams; dwarf shrub bogs with small stream channels of wet peat; shallow depressions within shrub and hummock swamps; (New York Natural Heritage Program 2011). Cool, quiet, slightly acid to somewhat basic waters of bays, pools, ditches, and peat bogs, usually in shallow water but sometimes to 60 cm depth (FNA 2000). Clean, relatively still, shallow waters of lakes, ponds, bog pools, limestone sinkholes, small creeks, interdunal ponds, and deepwater marshes; often in alkaline water (Jenkins 1990). Ponds, bogs, beach pools and interdunal swales (of the Great Lakes), and other wet places (Voss 1972). Shallow pools, brooks, springs, etc. (Fernald 1970).
Scattered throughout the state north of Long Island.
Distinguishing characteristics: small aquatic plants with slender creeping rhizomes; stems 10-40 cm long, decumbent or ascending, often floating, slender, flexuous, or rarely suberect and emergent in very shallow water or on mud and then short; lower leaves 10-40 cm long, (1.5) 3-7 (9) mm wide, flat and keelless; inflorescence unbranched with 1-4 (usually 2 or 3) equally spaced axillary, pistillate heads and 1 (2) remote staminate head(s), all but the lowest most pistillate head sessile; stigma ovate to lanceolate, 0.3-0.8 mm long; fruiting heads (5) 7-12 mm in diameter; achenes 2-3.5 mm long, 1-2.5 mm thick, tapering to an obconic base and a conic beak 0.5-1.5 mm long, only slightly if at all contracted near middle; sepals elliptic or cuneate-spatulate, one-half to two-thirds as long as the body of the fruit. Best life stage for ID: with mature fruit. Characteristics needed to ID: complete plant with mature fruits.
Sparganium hyperboreum is the most closely related plant, but this is a more northern plant that reaches in southern limit around Nova Scotia. Other small Sparganium species that may be confused with S. natans include S. angustifolium, S. erectum and S. fluctuans. The achene beak in all three of these species is 1.5-6 mm long with a stipe 1-5 mm, and two or more staminate heads. Sparganium fluctuans usually has branched flowering heads with several male flowers, the achenes are typically 4-5 mm long with a conspicuous stipe, and the beaks are 2-3 mm long and curved. Sparganium angustifolium has some pistillate flowers which are attached to the stalk 5+ mm above the axil of the subtending bract (super-axillary) with achenes 3-5 mm long contracted abruptly to a 1 mm beak. Sparganium chlorocarpum will have some super-axillary flowers and achene beaks 3-6 mm long.
Surveys should be done when fruiting plants may be found, from mid-July through mid-September.
The time of year you would expect to find Small Bur-reed flowering and fruiting in New York.
Sparganium natans L.
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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.
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Jenkins, Jerry. 1990. A preliminary report on the status of the least bur-reed (Sparganium minimum) in Vermont. Unpublished report. White Creek, NY. January 22. 24 pp.
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.
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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.
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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
This guide was authored by: Richard M. Ring
Information for this guide was last updated on: August 8, 2012
Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Sparganium natans. Available from: https://guides.nynhp.org/small-bur-reed/. Accessed January 17, 2019.