Troublesome Sedge

Carex molesta, often somewhat weedy, is introduced in California.

Plants cespitose. Culms 35–110 cm; vegetative culms few, inconspicuous, usually fewer than 15 leaves, not strikingly 3-ranked, leaves clustered at apex. Leaves: sheaths adaxially green, narrow hyaline band near collar, adaxially firm, summits U-shaped, smooth; distal ligules 1.5–3.2 mm; blades 3–6 per fertile culm, 12–38 cm × 1.5–4 mm. Inflorescences erect, ± congested, green to light brown, 1.3–3(–3.5) cm × 7–16 mm; proximal internode 1.5–6 mm; 2d internode 2.5–6.5 mm; proximal bracts aristate, with bristle tips shorter than inflorescences. Spikes 2–4(–5), overlapping, globose to ellipsoid, 6–16 × 5–12 mm, base and apex rounded; terminal spike usually lacking conspicuous staminate base. Pistillate scales hyaline-brown, with green or pale midstripe, ovate, 2.9–3.5 mm, much shorter and narrower than perigynia, margins pale, apex acute. Perigynia (25–)30–80 per spike, spreading at maturity, ascending-spreading, pale brown, conspicuously 5-veined or more abaxially, conspicuously 0–6-veined adaxially, elliptic to ± orbiculate, plano-convex, (3–)3.3–4.8(–5.7) × 1.8–3 mm, 0.5–0.6 mm thick, 1.2–1.8 times as long as wide, margin flat, including wing 0.4–0.8 mm wide, smooth; beak light brown at tip, flat, 0.7–1.6(–1.8) mm, ± ciliate-serrulate, abaxial suture with white or hyaline golden brown margin, distance from beak tip to achene 1.6–2.6 mm. Achenes elliptic to narrowly oblong, 1.3–1.7 × 0.9–1.3 mm, 0.5–0.6 mm thick. 2n = 68, 70.

Ont., Que.; Ala., Ark., Calif., Conn., Ill., Ind., Iowa, Kans., Ky., Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.Y., N.Dak., Ohio, Okla., Pa., Tenn., Vt., Va., W.Va., Wis.

Fruiting early summer.

Fields, roadsides, bottomlands, open woods, on dry to wet, often heavy, calcareous soils; 100–700m.

Carex molesta Mackenzie, sp. nov
Cespitose, from short-prolonged, rather slender but tough, black, fibrillose rootstocks, the culms 3-10 dm. high, erect or ascending, slender to base, sharply triangular, exceeding the leaves, roughened above, brownish-black at base and clothed with the short-bladed leaves of the previous year, the lower bladeless; leaves with well-developed blades 4-7 to a fertile culm, on the lower third, regularly disposed and not bunched, the blades flat, ascending, lightgreen, thinnish, usually 1-3 dm. long, 2-3 mm. wide, very rough on the margins, the sheaths tight, green-and-white-mottled dorsally, conspicuously white-hyaline ventrally, prolonged at mouth beyond base of blade, the ligule wider than long; sterile shoots conspicuous, tall, the leaves largely bunched at apex, with ascending blades; spikes 4-8, gynaecandrous, aggregated in an erect head 2-3 cm. long, 10— IS mm. thick, the spikes subglobose, 6-9 mm. long, 5-S mm. wide, rounded at apex, the lateral truncate at base, the terminal shortclavate, the perigynia 15-30, ascending, with conspicuous ascending or spreading beaks, the staminate flowers inconspicuous except in the terminal spike; bracts scale-like or the lower cuspidate-prolonged, short; scales ovate, obtuse or acutish, narrower and much shorter than the perigynia, yellowish-brown with 3-nerved green center and white-hyaline margins ; perigynia plano-convex, ovate, 4.5 mm. long, 2.25 mm. wide, rather thick, submembranaceous, greenish or greenish-white below, rather strongly wing-margined to base, serrulate to below middle, substipitate, rounded at base, faintly few-nerved dorsally, nerveless to strongly few-nerved ventrally, tapering into a beak less than half the length of the body, flat, serrulate, slightly yellowish-brown-tipped, obliquely cut dorsally, shallowly bidentate, the margins of the orifice white or yellowish-brown-tinged; achenes lenticular, suborbicular, 1.75 mm. long, 1.25 mm. wide, yellowish-brown, substipitate, apiculate; style slender, straight, jointed with achene, deciduous; stigmas two, light-reddish-brown, slender, short.
Type collected at Quindaro, Wyandotte County, Kansas {Mackenzie, May 30, 1897). Distribution: Dry woodlands. New York to Kansas and Nebraska. (Specimens examined from New York. Michigan. Indiana, Illinois, Missouri, Kansas, Nebraska.)

Carex molesta is a species of sedge known by the common name troublesome sedge. It is native to eastern and central North America, where it grows in varied wet and dry habitats, performs equally well in full sun and partial shade, including disturbed areas such as roadsides. It is an introduced species and often a weed in California. This sedge produces clumps of stems up to about a meter tall, with several narrow leaves up to about 35 centimetres (14 in) long. The inflorescence is an open cluster of green spherical spikes each 0.5 to 1.5 centimetres (0.20 to 0.59 in) long.