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 gracillima are smooth (glabrous) or slightly hairy (pubescent), plants grow in loose clumps; flowering stems are slender, to 1 m tall, much longer than the leaves.

Leaves: Mainly basal, linear, blade flat, 3–9 mm wide, thin (membranaceous), deep green, with purplish to reddish brown bases.

Spikes: The terminal spike is staminate at the base, pistillate towards the tip, lower spikes pistillate, 2–5, linear-cylindric, 1–7 cm long, 2–3.5 mm thick. Spikes drooping in maturity, borne on slender peduncles, to 4 cm long.

Perigynia: Ellipsoid to ovoid, obtusely 3-angled, thin (membranaceous), dull, green, often with red spots, 2–3.7 mm long, 1.3–1.6 mm thick, beakless, ending in a blunt tip, or with a short cuspidate tip, to 1 mm long. Pistillate scales ovate to oblong, blunt to rounded at the tip, whitish (hyaline), about half as long as the perigynia.

Habitat and Range: Dry to moist deciduous or mixedwood forests, thickets, conifer swamps, and meadows. Carex gracillima is native to eastern North America; in Ontario, it is reported as far north as the Thunder Bay and New Liskeard regions (Scoggan 1978).

Internet Images: This illustration of Carex gracillima 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 this image of Carex gracillima from the Wisconsin State Herbarium's Vascular Plant Species Database.

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