Carex laxiculmis Schwein.
Family: Cyperaceae
Spreading Sedge
[Carex retrocurva ]
Carex laxiculmis image
Morton Arboretum  
Plants densely cespitose. Culms erect, ascending, or spreading, 9-48 cm × 0.6-1 mm. Leaves: basal sheaths white or very light brown; nonbasal sheaths 7-32 mm, sheath blades 0.9-11.9 cm × 1-7 mm; leaf blades erect, ascending, or spreading, green or glaucous, 8-36 cm × 3-12 mm; blades of vegetative shoots 0-3.5 times wider than bract blades. Inflorescences: spikes (3-)4(-5) per culm, scattered; peduncles of pistillate spikes exserted 0-9 cm; of staminate spikes exserted 0-9.5 cm; bracts 2-11.8 cm × 1.3-4.8 mm. Pistillate spikes: the proximal basal, scattered, drooping. Staminate spike 1, linear, 8-22 × 1.2-3 mm. Pistillate scales keeled, 2.5-3.2 × 1-1.5 mm, midribs green, margins hyaline or, occasionally, reddish brown outward, apex cuspidate to acute, awn to 1 mm, proximal scale of lateral spike sterile or subtending a staminate flower. Staminate scales obovate, 3.5-4.5 × 1-1.2 mm, midribs green, margins hyaline or reddish brown outward, apex acute. Anthers 2-3 mm. Perigynia 4-9 per spike, finely veined, elliptic-ovoid, 2.5-4 × 1.5-2 mm; beak slightly bent, tapering. Achenes obvoid to broadly ovoid, 2.2-3.2 × 1.2-1.8 mm, slightly concave at maturity, tightly fitting in perigynia. Style slender ascending through entire orifice. 2n = 44, 46.
Tufted; stems very weak and slender, 2-5 dm, ascending to reclining; basal sheaths white or light brown; lvs roughened on the margins and hispidulous on the veins toward the tip, those of the sterile shoots 3-10(-12) mm wide, of the fertile ones a little narrower; terminal spike staminate, 1-2 cm, on a very short to elongate (10 cm) peduncle; pistillate spikes 2-4, 0.6-2 cm, scattered, on short and erect to long (9 cm) and drooping peduncles, the lowest one basal; pistillate scales cuspidate to acute, the lowest 1 or 2(3) empty or subtending staminate fls; perigynia 4-9, 2.5-4 mm, finely many-nerved as well as 2-ribbed, elliptic-ovoid and sharply trigonous, abruptly contracted to a short, slightly oblique beak with entire orifice; achene sharply trigonous; 2n=44, 46. Moist or wet woods, especially in heavy clay soils, chiefly in calcareous districts; s. Me. to Mich., s. Wis., and s. Io., s. to N.C., n. Ga., n. Ala., and Mo.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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