Northern Ontario Plant Database

Carex reproductive structures: Sedge flowers are unisexual and arranged in spikes, also called heads. Male and female flowers may be arranged on separate spikes or with flowers of one sex clustered at the top of the spike, subtended by flowers of the opposite sex. Sepals and petals are lacking. Female flowers consist of a superior ovary with one style terminating in 2 or 3 stigmas; the ovary is surrounded by a persistent sac-like bract called a perigynium. The mature perigynium is often topped by a beak, which represents the remains of the persistent style base. The beak varies, according to species, from long and tapering, with 2 small teeth at the tip, to blunt and toothless. The ovaries of Carex species with 2 stigmas produce flattened, 2-angled, indehiscent fruits (lenticular achenes), while those species with 3 stigmas produce 3-angled fruits (trigonous achenes). In female spikes, the flowers are each subtended by a bract, called a pistillate scale. In male spikes, with flowers consisting of only 1–3 stamens, the subtending bract is called a staminate scale.

General: Sedges are herbaceous plants with simple, linear or bladeless leaves, their stems are solid and usually 3-angled in cross section; leaves are arranged in 3 rows (3-ranked) along the stem. The leaves and stems of Carex arctata are smooth (glabrous); plants grow in dense cespitose tufts that arise from a short rhizome. The long arching flowering stems, to 1 m tall, bear several thin, cylindrical spikes.

Leaves: Mainly basal, linear, 6–10 mm wide, firm, with purplish to reddish brown bases; overwintering leaves dark green.

Spikes: The terminal spike is staminate throughout, less than 4 cm long; pistillate spikes 2–5, loosely-flowered, linear-cylindrical, to 8 cm long and 3–4 mm wide. Spikes are nodding or drooping in maturity, with the lowest spikes borne on thin peduncles, to 3 cm long.

Perigynia: Lanceolate to ellipsoid, smooth and lustrous, green, 3-angled, nerved at the base, 3–5 mm long, tapering to a short, slightly toothed beak. Pistillate scales are oval, white (hyaline) or pale green, with a darker midrib prolonged into a short awn, to 1.5 mm long; scales shorter than the perigynia.

Habitat and Range: Woods, thickets, openings in cool and upland boreal forests. Carex arctata is native to boreal conifer (hemlock or cedar), deciduous, and mixedwood forests of northeastern North America. In Ontario, it has been reported as far north as Lac Seul, near Sioux Lookout (Scoggan 1978).

Internet Images: This illustration of Carex arctata is from K.K. Mackenzie's "North American Cariceae," displayed on Texas A & M's CyberSedge website. Click on each illustration for a larger image.

See also the image of Carex arctata from the Wisconsin State Herbarium's Vascular Plant Species Database.

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