round-spike brownish sedge

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 1⁄32″ to 1⁄16″ (1.0 to 1.5 mm) wide, sometimes only 1⁄64″ (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 ⅝″ to 1½″ (1.5 to 4.0 cm) long, sometimes up to 2¾″ (7 cm) long, ⅛″ 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 3⁄16″ 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 19⁄16″ (4 cm) in length, but it is not longer than the inflorescence.

Each spike is globe-shaped or slightly longer than wide, ⅛″ to ¼″ (3 to 7 mm) long, and ⅛″ 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 1⁄16″ to ⅛″ (2.0 to 2.5 mm) long, sometimes just 1⁄16″ (1.5 mm) long, and 1⁄32″ (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, 1⁄128″ to 3⁄128″ (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 1⁄32″to 1⁄16″ (1.25 to 1.5 mm) long and 1⁄32″ (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)

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 1⁄16″ to ⅛″ (1.5 to 2.5 mm) wide, sometimes only 1⁄32″ (1.0 mm) wide. The inflorescence is a usually erect, sometimes nodding, usually ⅝″ 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 1⁄16″ to ⅛″ (2.0 to 2.5 mm) long and 1⁄32″ to 1⁄16″ (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

Sources

3, 4, 29, 30.

Native

Common