Three Fruit Sedge

Carex trisperma var. billingsii is a reduced type, distinguished by its narrow leaf-blades (0.3–0.5 mm) and fewer (1–2) perigynia per spike than typical. It is known, at least, from Ontario, Quebec, Newfoundland, New Brunswick, Nova Scotia, Prince Edward Island, Maine, Massachusetts, Michigan, New Jersey, New York, Rhode Island, and Pennsylvania.

Plants loosely cespitose, often in large clumps; rhizomes slender, long. Culms arching, weak, 20–70 cm. Leaves: sheaths pale brown abaxially, inner band tight, thin, hyaline, truncate at summit; ligules as wide as long; blades green, flat or channeled, 5–20 cm × 0.25–2 mm. Inflorescences nodding, 5–10 cm × 3–4 mm; proximal bracts bristlelike, 3–10 cm, exceeding inflorescences. Spikes 1–3, remote, 2–4 cm apart, containing 1–5 perigynia, ovoid, 4–6 × 3–4 mm. Pistillate scales whitish with green, 3-veined center, ovate, subequal to perigynia, apex acute (mucronate). Perigynia ascending, pale green or brownish in age, finely many-veined, ovate-elliptic, 2.5–3.7 × 1.5–2 mm, subcoriaceous; beak entire or with few small teeth. Achenes brown, elliptic-oblong, 1.75–2 × 1.25(–1.5) mm, glossy. 2n = 60.

Greenland; St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask.; Conn., Del., Ill., Ind., Maine, Md., Mass., Mich., Minn., N.H., N.J., N.Y., Ohio, Pa., R.I., Vt., W.Va., Wis.

Fruiting Jun–Aug.

Mires, especially sphagnum bogs, wet woods, lowlands; 0–1300m.

Carex trisperma var. billingsii O. W. Knight

Carex trisperma Dewey, Am. Jour. Sci. 9: 63. pi. C, f. 12. 1825.
Carex qualernaria Spreng. Svst. 3: 809. 1826. (Type from New Jersey.)
Neskiza trisperma Raf. Good Book 27. 1840. (Based on Carex trisperma Dewey.)
Loosely cespitose, in large clumps, with long, very slender, light-brown stolons, the culms weak, nearly filiform, 2-7 dm. high, exceeding the leaves, triangular, roughened above, brownish at base and clothed with the dried-up leaves of the previous year; leaves with well-developed blades 3-5 to a fertile culm, on the lower fourth or third, the blades deep-green, weak, flat or canaliculate, 5-20 cm. long, 0.25-2 mm. wide, smooth, except slightly rough towards the apex, the sheaths tight, thin and white-hyaline ventrally, conspicuously prolonged beyond base of blade and continuous with ligule; spikes 1-3, usually 2, containing 1-5 ascending perigynia and about the same number of inconspicuous basal staminate flowers, the spikes 2-4 cm. apart, 4-6 mm. long, 3-4 mm. wide, the lowest subtended by an elongate, very slender bract 3-10 cm. long, often appearing like a continuation of the culm, the second bract shorter, the uppermost merely cuspidate ; scales ovate, obtuse or acute or short-mucronate, whitish with green 3-nerved center, about width of but somewhat shorter than perigynia; perigynia planoconvex, thick, ovate-oval, 2.5-3.75 mm. long, 1.5-2 mm. wide, subcoriaceous, pale-green or in age brownish, strongly white-puncticulate, sharp-edged, finely many-nerved on both surfaces, rounded, slightly stipitate, spongy at base, tapering at apex into a minute (0.4 mm. long), entire or minutely serrulate beak, obliquely cut dorsally, emarginate, hyaline-tipped; achenes lenticular, minutely truncately-apiculate, brownish, shining, rather closely enveloped, sessile, oval-oblong, 2 mm. long, 1.25 mm. wide; style very short, jointed with achene, at length deciduous; stigmas two, slender, reddish-brown.
Type locality: Williamstown and Deerfield, Massachusetts.
Distribution: Acid soils, wet sphagnum in swampy woods or bogs. Labrador and Newfoundland to Saskatchewan, and southward to Maryland, Illinois, and Minnesota; reported from Nebraska. (Specimens examined from Labrador, Newfoundland. St. Pierre, Quebec. Prince Edward Island Nova Scotia. New Brunswick. Maine. New Hampshire. Vermont, Massachusetts. Rhode Island. Connecticut. New York. New Jersey, Delaware. Pennsylvania. Maryland. West Virginia. Ontario, Ohio Michigan. Indiana. Wisconsin. Illinois, Minnesota. Manitoba. Saskatchewan.

Carex trisperma, the three-seeded sedge, is a species of flowering plant in the genus Carex, native to Canada, Greenland, and the northeastern United States. It is typically found in acidic bogs within forests.