Carex sychnocephala (Many-headed Sedge)

Plant Info
Also known as:
Family:Cyperaceae (Sedge)
Life cycle:perennial
Habitat:sun; moist to wet sandy, silty or peaty soil; shores, banks
Fruiting season:July - September
Plant height:4 to 16 inches
Wetland Indicator Status:GP: FACW MW: FACW NCNE: FACW
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Spikes: Cluster type: spike

[photo of spikes just past flowering] 4 to 10 spikes, oblong-elliptic in outline, each up to ½ inch long, crowded together at the tip of the stem though the lowest 1 or 2 spikes may be slightly separated. All spikes have staminate (male) flowers at the base and pistillate (female) flowers at the tip (gynecandrous). At the base of the lowest spikes are broad, erect to ascending, leaf-like bracts, 3 to 5 times (or more) longer than the inflorescence (group of spikes), with shorter bracts at the base of the other spikes, the uppermost bracts reduced to appressed scales. Larger bracts are green with a white papery edging, especially near the base.

Leaves and stems: Leaf attachment: alternate Leaf type: simple

[photo of sheath and ligule] Leaves are mostly alternate with up to 5 leaves per stem, 1.2 to 4 mm wide, shorter than the flowering stem, ascending to spreading. Stem leaf sheaths are concave to U-shaped at the tip, papery translucent whitish-green, loosely to tightly wrap the stem. The ligule (membrane where the leaf joins the sheath) has a broad band of loose tissue around the edge and is longer than wide. Leaves are V-shaped in cross section when young, hairless and smooth.

[photo of basal sheaths] Bases are wrapped in a brown sheath that is somewhat fibrous. Stems are slender, hairless, mostly erect, 3-sided in cross-section with blunt angles. Stems elongate up to 16 inches at maturity and are longer than the leaves, though the leaf-like bracts make it appear the leaves over-top the spikes. Not all plants produce flowering stems. Plants are clump forming, have a small root system and may appear to be an annual.

Fruit: Fruit type: seed without plume

[photo of maturing spikes] Fruit develops in mid to late summer, the spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Perigynia are mostly erect and are tightly crowded on the spike. Each spike contains numerous fruits.

[photo of perigynia, scale and achene] Pistillate scales are narrowly lance-oblong, whitish with a green or golden midrib, tapering to pointed tip, lack awns, mostly shorter than the perigynia but sometimes longer. Perigynia are (4.6)5.5 to 7.3 mm long, .7 to 1.2 mm wide, green to light golden brown at maturity, hairless, conspicuously 3 to 12-veined on the outer face, less conspicuously veined on the inner face, flattened, not inflated, narrowly lance-shaped with a long taper to a straight beak that has minute hair-like serrations along the edges and 2 teeth at the tip, and is narrowly winged along the beak to about halfway down the body. Achenes are lens-shaped, 1 to 1.8 mm long, .6 to .8 mm wide, oval to egg-shaped.


Carex sychnocephala is found scattered across most of Minnesota, found primarily along sandy banks and shores, less often in wet meadows and swales, and may be a successional species that disappears once a closed canopy develops. It is listed as a Special Concern species in Wisconsin.

Carex is a large genus, with over 600 species in North America and 150+ in Minnesota alone. They are grouped into sections, the species in each group having common traits. Carex sychnocephala is the lone member of the Cyperoideae section in Minnesota though some references lump sections Cyperoideae and Ovales together; some common traits of Cyperoideae are: clump forming, inconspicuously rhizomatous, hairless leaves, basal sheaths brown, 4 to 15 spikes, spikes all pistillate at the tip and staminate at the base (gynecandrous), lowest bracts leaf-like and 3 or more times as long at the inflorescence, perigynia erect to ascending, hairless, faintly to conspicuously veined on one or both surfaces, flat, narrowly winged, with a long taper to a toothed beaked, achenes lens-shaped.

Carex sychnocephala is a distinctive species and not likely to be confused with other sedges; it is distinguished by the combination of: spikes tightly clustered at the tip of the stem with long, leaf-like bracts greatly over-topping the spikes, perigynia narrowly lance-shaped, up to 7.3 mm long, several times longer than wide, flattened, serrated and narrowly winged along the edges.

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More photos

Photos by K. Chayka taken in North Dakota. Photos courtesy Peter M. Dziuk taken in Itasca County and in North Dakota.


Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Jason Husveth - Sunfish Lake, Lake Elmo, Washington County
on: 2023-09-28 13:07:52

I found a specimen of Carex sychnocephala in late September 2023, while botanizing the northern shore of Sunfish Lake during late season drawdown. Even though I work extensively with sedges every season, the last time I crossed paths with this particular species was 20+ years ago in Faribault, MN. So it was a real treat to see it so close to home. The plants were along a shoreline and the perigynia/spikes were just barely mature enough to make a positive identification. Will return to see if there's more along this lakeshore. Northelwest shores of Sunfish Lake in Sunfish Lake Park.

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