Spikes:

Separate staminate (male) and pistillate (female) spikes, with a single staminate spike at the tip of the stem that rarely has a few female flowers at the tip (gynecandrous). Below the staminate spike are 2 to 4 slender-stalked pistillate spikes, ¼ to ¾ inch long, widely spaced and arising singly from the nodes with a leaf-like bract at the base of the stalk, the bract of the uppermost pistillate spike not rising above the terminal spike. Stalks are typically longer than the associated spike and arching to drooping. Bract sheaths are more than 4 mm long.

Leaves and stems:

Leaves are basal and alternate, mostly crowded near the base, 1 to 3 mm wide, mostly U to V-shaped in cross-section, smooth, erect to ascending, up to 6 inches long and shorter than the flowering stems. Stem leaf sheaths are mostly straight across and translucent whitish. The ligule (membrane where the leaf joins the sheath) is mostly straight across and obscure.

Bases are wrapped in a brown sheath that is somewhat fibrous, the old leaves sometimes persisting to the next season. Stems are very slender, erect to ascending, weakly 3-sided, smooth, elongating up to 2 feet at maturity and longer than the leaves. Not all plants produce flowering stems. Plants form loose to dense clumps.

Fruit:

Fruit develops in late spring, 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 6 to 20 fruits that are overlapping on the stalk but not tightly packed.

Pistillate scales are lance to egg-shaped, blunt to rounded at the tip, whitish to light brown with translucent edging and a green midrib, 1.8 to 2.8 mm long and more or less half as long as the perigynia. Perigynia are 2.3 to 3.5 mm long, .8 to 1.2 mm wide, veinless except for 2 ribs, hairless, turning golden-greenish to brown when mature, the body generally elliptic and abruptly tapering to a short beak, lacking 2 teeth at the tip but may have minute serrations along the edge. Achenes are 1.2 to 1.7 mm long, up to 1 mm wide, 3-sided in cross-section, urn-shaped.

Notes:

Carex capillaris is a small, delicate sedge and uncommon in Minnesota, not officially listed as rare but tracked by the DNR. It is a Special Concern species in Wisconsin. Across its range it is found in a variety of average to moist habitats, typically in sandy or calcareous soils and frequently with or near conifers and mostly in part shade.

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 capillaris is the lone member of the Chlorostachyae section in Minnesota; some of its common traits are: clump forming, leaves 1 to 4 mm wide and V-shaped in cross-section when young, 3 to 6 cylindric spikes on slender stalks, terminal spike either all staminate or with a few perigynia (usually at the tip, occasionally the base), perigynia 2-ribbed and beaked, the beak not toothed or obscurely so, 3-sided achenes, growing in cool temperate and alpine regions.

While C. capillaris is similar to members of the Hymenochlaenae section, which also have slender, drooping pistillate spikes, C. capillaris is distinguished from all other Minnesota sedges by the (usually) all-staminate terminal spike, short pistillate spikes (about ½ inch long), perigynia about 3 mm long and veinless except for 2 ribs. Of note is that some references split the species into 2 varieties, a southern var. having minutely serrated beaks on the perigynia and a northern var. with smooth beaks. Considering one of the specimens we photographed has a serrated beak it is understandable why these vars are not recognized in Minnesota.