Spikes:

3 to 10 round to short-cylindrical spikes, each up to ¼ inch long, the lowest separated from the one above it typically by about 1 inch, the uppermost spikes closer together but not overlapping or crowded. At the base of the lowest spike is a narrow, bristle-like bract, rather longer than the spike but much shorter than the inflorescence (group of spikes). All spikes have staminate (male) flowers at the base and pistillate (female) flowers at the tip (gynecandrous); the terminal spike at the tip of the stem is nearly half staminate while the lateral spikes are mostly pistillate with just a few staminate flowers. It is not uncommon for the stem to angle at the lowest spike, nodding from that point.

Leaves and stems:

Leaves are basal and alternate, mostly near the base, .5 to 2.5 mm wide, shorter than the flowering stems, mostly floppy. Stem leaf sheaths tightly wrap the stem and are translucent whitish, typically U-shaped at the tip. The ligule (membrane where the leaf joins the sheath) is as long as or longer than wide. Leaves are hairless and flat, though V-shaped in cross-section when young.

Bases are wrapped in a brown sheath that is not fibrous. Stems are slender, 3-sided and rough textured. Stems often become leaning to arching to nearly prostrate, elongating up to 3 feet at maturity and are much longer than the leaves. Not all plants produce flowering stems. Plants form loose to dense clumps and may create small colonies from short rhizomes.

Fruit:

Fruit develops in late spring through early summer, the pistillate spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. The empty staminate scales persist after fruit has dropped off. Pistillate spikes each contain 5 to 10 fruits that are appressed, ascending or somewhat spreading and not tightly crowded on the stalk.

Pistillate scales are generally egg-shaped, translucent white sometimes tinged brown, with a green midrib, tapering to a pointed tip, and are about as wide and nearly as long as the perigynia. Perigynia are 2 to 2.5 mm long, .8 to 1.5 mm wide, with several light veins that are more visible on the outer surface, hairless but with minute teeth along the edge at the tip end, tightly wrapping the achene but spongy at the base, oval-elliptic, widest near the middle with a short taper to the beak, 2 small teeth at the tip, and a distinct slit on the outer face at the tip end (may be hidden by the scale). Achenes are 1.25 to 1.5 mm long, up to 1 mm wide, flattened lens-shaped, and mature to brown.

Notes:

Carex brunnescens is found in Minnesota from the Metro north, primarily in wet woods, floodplains, and wetland edges. I have often thought that common names of most sedges are pretty unoriginal, this being one example. “Brownish” apparently refers to the color of mature perigynia.

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 brunnescens is in the Glareosae section; some of its common traits are: typically clump forming, leaves V-shaped in cross-section when young, leaves hairless and 4mm or less wide, 2 to 10 stalkless spikes, spikes all essentially alike with staminate flowers at the base (gynecandrous), perigynia ascending to spreading and flattened in cross-section, beaked, the beak usually toothed, flattened lens-shaped achenes, typically growing in wetlands.

Carex brunnescens is distinguished by spikes that are not crowded close together, spikes with only 5 to 10 perigynia, leaves 2.5 mm or less wide, and perigynia usually with a slit on the front. Most similar is Carex canescens, which has leaves to 4 mm wide, 10 to 30 perigynia per spike and perigynia with a shorter, less distinct beak and no slit. There are 2 recognized subspecies of C. brunnescens, both of which have been found in Minnesota: subsp. sphaerostachya is by far the more common, has flowering stems that tend to lean or become arching and leaves up to 1.5 mm wide; subsp. brunnescens is more erect with leaves up to 2.5 mm wide.