Flower:

Separate staminate (male) and pistillate (female) spikes, with a single staminate spike up to about ¾ inch long at the top of the stem. Below the staminate spike are 1 to 3 widely spaced, cylindric, all-pistillate spikes each ¼ to ¾ inch long, the uppermost 1 or 2 on a slender, erect to ascending stalk, the lowest usually on a long, slender, arching stalk that rises from near the base. Pistillate spikes each have a leaf-like bract at the base of the stalk that does not over-top the terminal spike. The bract sheath is thin and papery and often red/purple tinged.

Leaves and stems:

Leaves are basal and alternate on the lower stem, 5 to 18 inches long, 6 to 30 mm (¼ to 1+ inches) wide, erect to ascending, and shorter than the flowering stem. Stem leaf sheaths loosely wrap the stem and are papery, translucent whitish, often at least partly red-purple tinged. Leaves are bright green and hairless, M-shaped in cross-section when young, with a prominent midrib and 2 conspicuous lateral veins. New leaves emerge when the flowering stems mature, continue growing through summer and overwinter, some of which persist evergreen to the next season then wither away.

Bases are wrapped in a red-purple sheath that is not fibrous. Stems are 3-sided, smooth or nearly so, erect to ascending to sprawling, and may elongate up to 24 inches at maturity. Not all plants produce flowering stems. Plants typically form dense clumps.

Fruit:

Fruit develops in mid to late spring, the pistillate spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Staminate scales are purplish with a prominent green midrib and mostly rounded at the tip. Pistillate spikes have 4 to 9 fruits, the perigynia erect to ascending, overlapping but often loosely and alternately arranged on the spike.

Pistillate scales are lance to egg-shaped, usually purplish with a prominent green midrib, tapering to a pointed tip, and about ¾ as long as the perigynia. Perigynia are green at maturity, 5 to 6.6 mm long, 2.5 to 3 mm wide, many-veined, hairless, not much inflated, strongly 3-sided, oval-elliptic tapering at both ends, straight to slightly bent at the tip with a short, toothless beak. Achenes are 4.5 to 6 mm long, strongly 3-sided in cross-section with concave sides, oval-elliptic in outline, yellowish-brown at maturity.

Notes:

Carex careyana is a sedge of rich deciduous woods, wooded slopes and ravines, and reaches the northwest edge of its range in southeast Minnesota. According to the DNR, it was first discovered during biological surveys in the 1990s but only a handful of locations were ultimately found. It was listed as a State Threatened species in 1996 and elevated to Endangered in 2013. Its rich, woodland habitat is under constant pressures from various commercial, agricultural and recreational activities, but also from invasive species, especially garlic mustard and buckthorn as well as earthworms, which destroy the rich organic layer.

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 careyana is in the Careyanae section; some of its common traits are: clump forming, short rhizomatous, basal sheaths brown or red-purple and not fibrous, leaves M-shaped in cross-section when young, leaves hairless and often over 1 cm (~3/8 inch) wide, 2 to 6 spikes, terminal spike all staminate, lateral spikes all pistillate, lateral spikes subtended by a long-sheathing leaf-like (sometimes bladeless) bract, the lowest spike often at or near the base, perigynia hairless, oval-elliptic to egg-shaped with a toothless beak, distinctly many veined, achenes strongly 3-sided with 3 stigmas, usually growing in woodlands. Members of Careyanae were formerly in Laxiflorae, which is distinguished by perigynia that are round to weakly 3-sided in cross-section, and no pistillate spikes at or near the base.

Carex careyana is distinguished from other Carex species by the combination of: densely clump-forming, broad leaves (10 to 30mm wide), M-shaped in cross-section with 2 prominent lateral veins, strongly red-purple at the base, leaf-like bracts with a long sheath that is often red-purple tinged, usually 3 or 4 spikes well separated, terminal spike all staminate, perigynia strongly 3-sided and many-veined, strongly 3-sided achenes with concave sides.

The broad leaves, with new leaves emerging after the flowering stem elongates then persisting evergreen through winter, combined with the strongly purple base and strongly 3-sided perigynia, are traits shared only with Carex plantanginea, which is distinguished by its bladeless bracts, leafless stems, new leaves with distinct puckering between the lateral veins (like seersucker), and smaller perigynia (max 5mm long). Carex albursina also has broad leaves and is found in the same habitat, but has white basal sheaths and perigynia round in cross-section. Carex laxiculmis, the third member of Careyanae in Minnesota, has brown basal sheaths and narrower leaves, mostly less than 1cm wide, and pistillate spikes often have 1 or 2 staminate flowers at the base.