Spikes:

1 to 3 erect spikes at the tip of the stem, short-stalked to stalkless, oblong-elliptic in outline. The terminal spike is usually all-pistillate (female), sometimes all-staminate (male), occasionally staminate only at the base and pistillate at the tip (gynecandrous) or vice versa (androgynous). Lateral spikes are all-pistillate and not more than half as long as the terminal spike. At the base of the lowest spike is a leaf-like bract that may or may not over-top the terminal spike.

Leaves and stems:

Leaves are basal and alternate, all near the base, 2 to 3.5 mm wide, much shorter than the flowering stems. Stem leaf sheaths are membranous on the front. The ligule (membrane where the leaf joins the sheath) is longer than wide and blunt to pointed at the tip. Leaves are hairless, V-shaped when young and becoming flat.

Bases are wrapped in a sheath that is reddish-brown to reddish-purple at the base and becomes fibrous with age. Stems are erect to ascending, slender, 3-sided, smooth except near the spikes, elongating up to about 12 inches at maturity, and are much longer than the leaves. Plants form loose clumps and may form loose colonies from long rhizomes.

Fruit:

Fruit develops in late spring through mid-summer, the pistillate spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Terminal pistillate spikes contain numerous fruits that are appressed to ascending and crowded on the spike.

Pistillate scales are broadly lance-oblong, rounded at the tip with an abrupt taper to a pointed tip, dark purplish-brown with a narrow white edging around the tip half, awnless, are about as wide as the perigynia and as long or slightly longer, completely covering it. Perigynia are 2 to 3 mm long, 2 to 2.5 mm wide, hairless, greenish-yellow to brown at maturity, nerveless or at most 2 ribs, not much inflated, oval-elliptic in outline, widest at or above the middle, tapering at the base, more abruptly tapered at the tip to a short beak with 2 obscure teeth. Achenes are 3-sided in cross-section, widest near the tip.

Notes:

Carex hallii, formerly Carex parrayana var. hallii, is an uncommon species of the Great Plains and reaches the eastern edge of its range in Minnesota's western counties. It is found primarily in wet-mesic prairies and swales in saline or calcareous soils but is occasionally introduced elsewhere from restoration seed mixes. According to the DNR, most of the prairie habitat in western MN has been either plowed under in favor of row crops or mined for gravel. Only a few fragmented remnants remain, which is incredibly sad. C. hallii was originally listed as a Threatened species in 1984 and downgraded to Special Concern in 1996 after biological surveys located additional populations.

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 hallii is in the Racemosae (formerly Atratae) section; some of its common traits are: loosely to densely clump forming, sometimes rhizomatous, base usually red-purple and often fibrous, leaves hairless and V-shaped in cross-section when young, 1 to 10 spikes, the lowest bract leaf-like or thread-like, spikes round to cylindric in outline, terminal spike usually pistillate at the tip and staminate at the base (gynecandrous), lateral spikes all-pistillate or with a few staminate flowers at the base, pistillate scales dark brown to black and blunt-tipped to awned, perigynia erect to spreading, hairless, somewhat flattened, short-beaked to beakless, the beak sometimes toothed, 3-sided achenes, usually calcareous habitats.

Carex hallii should not be confused with any other sedge in Minnesota; it is distinguished by the combination of: 1 to 3 spikes overlapping at the tip; terminal spike usually all-pistillate, sometimes all-staminate, occasionally staminate only at the base (gynecandrous) or tip (androgynous); lateral spikes (when present) all-pistillate and less than half as long as the terminal spike; pistillate scales about as large as or slightly larger than the perigynia and completely covering it; hairless perigynia 2 to 3 mm long with a very short beak; usually a moist, saline habitat. It superficially resembles Carex scirpoidea, with which it may grow, but which usually has a single spike that is either all-staminate or all-pistillate, and its sheaths, perigynia and pistillate scales are all distinctly hairy. Of note is members of the Racemosae section should not have androgynous terminal spikes, but the DNR notes this species may have them, and that trait was evident in at least one of our specimens.