round-spike brownish sedge

(Carex brunnescens ssp. sphaerostachya)

Conservation Status
IUCN Red List

LC - Least Concern


NNR - Unranked

SNR - Unranked


not listed

Wetland Indicator Status
Great Plains

FAC - Facultative


FACW - Facultative wetland

Northcentral & Northeast

FACW - Facultative wetland



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Brownish sedge (ssp. sphaerostachya) is a perennial, medium sized, true sedge. It is native to the northern forested regions of North America. It is common in Minnesota.

Brownish sedge (ssp. sphaerostachya) is found in a variety of wet, moist, and temporarily dry habitats. It grows in both shaded and exposed areas. It is found in forested peatlands; swampy or boggy areas (mires) with a thin layer of peat; thickets; moderately moist mixed forests; moist, shallow, natural or man-made channels (swales) in woodlands; and moist areas in rock outcrops.

Brownish sedge (ssp. sphaerostachya) is forms small, very dense clumps. It rises from underground, horizontal stems (rhizomes). The rhizomes are slender and short, no more than 2 (5 cm) long and sometimes too short to be recognized as rhizomes. Within the tuft, each individual plant has a single, unbranched, flowering stem with a cluster of leaves at the base.

The flowering stem (culm) is three-angled, curving up from the bottom (ascending) or arching, 12 to 36 (30 to 90 cm) tall, and brown at the base. It is usually longer than the leaves.

The leaves are restricted to the lower half of the culm. The lower part of each leaf that surrounds the culm (sheath) is tight around the culm and is pale brown or medium brown. The front of the sheath is thin and more or less transparent (membranous). The tip is concave. The inner band is thin and translucent. The membrane where the leaf meets the culm (ligule) is as long as wide. Each blade is usually 4 to 10 (10 to 25 cm) long, sometimes up to 15¾ (40 cm) long, and usually 132 to 116 (1.0 to 1.5 mm) wide, sometimes only 164 (0.5 mm) wide. When young, it is V-shaped in cross section. When mature, it is flat, hairless, and green to dark green. The lowest leaves are reduced to bladeless or almost bladeless sheaths, and they are called basal sheaths. The basal sheaths are pale brown and fibrous. They usually do not last for more than a year.

The inflorescence is a flexible, usually to 1½ (1.5 to 4.0 cm) long, sometimes up to 2¾ (7 cm) long, to ¼ (3 to 6 mm) wide, unbranched cluster (raceme) of 5 to 10 groups of flowers (spikes) at the end of the culm. The two spikes at the tip are closely spaced, the remaining spikes are widely separated. The middle and lower spikes are 316 to 1 (5 to 25 mm) apart. Each spike is stalkless and is subtended by a single modified leaf (bract). The lowest bract is stiff, bristle-like, and long, up to 1916 (4 cm) in length, but it is not longer than the inflorescence.

Each spike is globe-shaped or slightly longer than wide, to ¼ (3 to 7 mm) long, and wide. It usually has 5 to 10 female (pistillate) flowers, but it may have up to 15 or even more. The terminal spike has both male and female flowers, with pistillate (female) flowers at the tip and staminate (male) flowers at the base. It is frequently club-shaped, with a narrow staminate base that is not quite as long as the pistillate portion above.

Each pistillate flower is entirely enclosed by a sac-like bract (perigynium) and subtended by a single scale. The scale is egg-shaped and has a pointed tip. It is shorter than the perigynium. It is translucent (hyaline) white on the sides and green with 3 veins in the center. The perigynium is elliptic or slightly egg-shaped, usually 116 to (2.0 to 2.5 mm) long, sometimes just 116 (1.5 mm) long, and 132 (0.8 to 1.25 mm) wide. It may be green or brown. The upper side is convex with indistinct veins, the underside is flat and usually has no veins. The perigynia are appressed and ascending when young and loosely spreading when mature. It often becomes dark brown with old age. The extended tip (beak) is flat and short, 1128 to 3128 (0.2 to 0.6 mm) long. The margins are minutely toothed. Two white stigmas emerge from a small opening at the tip of the perigynium.

The fruit is a dry, pale brown to medium brown, egg-shaped to almost circular, one-seeded capsule (achene). It is 132to 116 (1.25 to 1.5 mm) long and 132 (0.8 to 1.0 mm) wide, much smaller than the perigynium. The style drops off the achene as it matures, which is from early June to early August.

In open sunny areas, the culm is stiff and the scales are strongly tinged brown. In shady areas, the culms are more slender and weaker, and the scales take on little or no brown color.



12 to 36 (30 to 90 cm)


Similar Species

Brownish sedge (Carex brunnescens ssp. brunnescens) is a shorter plant. The culms are slender, usually erect but sometimes nodding, and 6 to 24 (15 to 60 cm) tall. The leaf blade is medium green to yellowish green or grayish green and usually 116 to (1.5 to 2.5 mm) wide, sometimes only 132 (1.0 mm) wide. The inflorescence is a usually erect, sometimes nodding, usually to 2 (1.5 to 5.0 cm) long, sometimes up to 2¾ (7 cm) long. The terminal spike is ellipse shaped or almost club shaped. The perigynium is 116 to (2.0 to 2.5 mm) long and 132 to 116 (1.0 to 1.5 mm) wide. It is much less common.


Moist. Sun or shade. Forested peatlands, mires, thickets, mixed, moderately moist forests; swales, and rock outcrops.



May to June



Early June to early August


Pests and Diseases





Distribution Map



3, 4, 29, 30.









Plantae (green algae and land plants)


Viridiplantae (green plants)


Streptophyta (land plants and green algae)


Embryophyta (land plants)


Tracheophyta (vascular plants)


Spermatophytina (seed plants)


Liliopsida (monocots)


Poales (grasses, sedges, cattails, and allies)


Cyperaceae (sedges)






Carex (true sedges)





Species Carex brunnescens (brownish sedge)

Subordinate Taxa




Carex brunnescens var. gracilior

Carex brunnescens var. sphaerostachya

Carex buckleyi

Carex canescens var. sphaerostachya

Carex canescens var. vulgaris

Carex sphaerostachya


Common Names

brownish sedge

round-spike brownish sedge












A dry, one-chambered, single-seeded seed capsule, formed from a single carpel, with the seed attached to the membranous outer layer (wall) only by the seed stalk; the wall, formed entirely from the wall of the superior ovary, does not split open at maturity, but relies on decay or predation to release the contents.



Growing upward at an angle or curving upward from the base.



On plants: A comparatively short and stout, narrow or prolonged tip on a thickened organ, as on some fruits and seeds. On insects: The protruding, tubular mouthpart of a sucking insect.



Modified leaf at the base of a flower stalk, flower cluster, or inflorescence.



The hollow or pithy stem of a grass, sedge, or rush.



In grasses and sedges, a membranous appendage at the junction of the leaf and the leaf sheath, sometimes no more than a fringe of hairs. In flowering plants, the flat, strap-shaped, petal-like portion of the corolla of a ray floret.



In Carex and other closely related sedges, a sac-like structure that surrounds the pistillate flower and later encloses the achene. Plural: perigynia.



An unbranched, elongated inflorescence with stalked flowers. The flowers mature from the bottom up.



A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.



The lower part of the leaf that surrounds the stem.



The arrangement of an unbranched, elongated inflorescence with stalkless flowers that mature from the base toward the tip. In Cyperaceae, it also denotes a collection of one or a group of stalkless flowers, each subtended by scales, on a single inflorescence axis.



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Created: 6/19/2024

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