Spikes:

A cluster 2 to 4 inches long at the top of the stem, compound with 10 to 15+ branches, the lower branches usually distinct with a few stalkless spikes each and the upper branches more obscure often with a single spike. Branches are overlapping, the upper crowded together and the lower branches often slightly separated from each other. All spikes are alike with staminate (male) flowers at the tip and pistillate (female) flowers at the base (androgynous). At the base of each spike is a bristle-like bract; the lowest bract is longest, sometimes more leaf-like than the rest, usually longer than the associated branch but does not usually over-top the terminal spike. Bracts become shorter as they ascend the stem and are obscure in the uppermost spikes.

Leaves and stems:

Leaves are basal and alternate, mostly on the lower half of the stem, 1.5 to 5 mm wide, the upper leaves usually over-topping the flowering stems. Stem leaf sheaths are straight across to convex at the tip, cross-wrinkled (rugulose) on the front, snugly wrap the stem, translucent whitish, fragile and easily torn or firm, and may be spotted red or brown. The ligule (membrane where the leaf joins the sheath) is wider than long, convex to concave. Leaves are hairless and V-shaped in cross-section when young.

Bases are wrapped in a brown sheath that may become fibrous with age. Stems are erect to ascending, 3-sided, slender, firm, rough textured below the spike clusters, of varying lengths and mostly over-topped by the leaves but some stems may elongate up to about 3 feet at maturity. Plants are densely clump-forming and not colony-forming.

Fruit:

Fruit develops in early to mid summer, the pistillate spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Pistillate spikes each contain several to many fruits that are ascending to spreading and crowded on the stalk.

Pistillate scales are lance-shaped, translucent whitish to brown with a green midrib that extends to an awn up to 3 mm long, the body much shorter than the perigynia but the awn may surpass it. Perigynia are 2 to 3.2 mm long, 1.3 to 1.8 mm wide, yellow-green to light brown at maturity, veinless to faintly 3-veined on both sides, hairless, not much inflated but slightly spongy at the base, flattened on the back side, lance-shaped in outline, widest at or just below the middle of the body, the base rounded, the tip tapering to a toothed beak about as long as the body and is finely toothed along the edges. Achenes are 1.2 to 1.4 mm long and 1 mm wide, flattened lens-shaped, egg-shaped, glossy, and mature to brown.

Notes:

Carex vulpinoidea is one of the most common sedges in Minnesota, primarily found in open, moist to wet habitats including wet meadows, wet ditches and along rivers, streams and lakes.

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 vulpinoidea is in the Multiflorae section; some of its common traits are: clump forming, sometimes long-rhizomatous, stems usually very slender just below the spike clusters, basal sheaths usually fibrous, sheath fronts cross-wrinkled (rugose) and often red-dotted, leaves hairless and V-shaped in cross-section when young, spike clusters branched (compound) or not (simple) and often crowded, 8 to 20+ stalkless spikes (usually 15+), terminal spike with staminate flowers at the tip (androgynous), lateral spikes androgynous or all pistillate, pistillate scales awned or not, perigynia veined on the front, veined or not on the back, widest at/near the middle, the base rounded with spongy tissue, tapered at the tip to a toothed beak, not more than twice as long as wide, flattened lens-shaped achenes. Several of these traits are shared with the Phaestoglochin and Vulpinae sections; the former usually has fewer than 15 spikes and clusters are usually unbranched, the latter usually has stout, spongy stems, perigynia widest at or near the base, mostly at least twice as long as wide, and often more distinct, spongy tissue at the perigynia base.

Carex vulpinoidea is distinguished by its firm, slender, 3-sided stems that are mostly over-topped by the leaves; leaf sheaths that are cross-wrinkled on the front; cluster usually branched at least at the base, branches overlapping but not usually tightly crowded except at the tip; androgynous spikes; perigynia 2 to 3.2 mm long, tapering to a toothed beak that is about as long as the body (measured from the tip of the achene on mature plants), green to light brown at maturity; awned pistillate scales with the awn up to 3 mm long and may extend past the perigynia tip. Of note is many references describe red or brown spotting on the sheaths, but we did not observe this on our specimens, even at high magnification. The only other member of the Multiflorae section in Minnesota is Carex annectens, which may be found in drier habitats, has leaves shorter than the stems, more congested spikes, and the perigynia beak is more abruptly tapered and much shorter than the body.