Slender Sedge

In Great Britain and/or Ireland:
Foodplant / parasite
sorus of Anthracoidea subinclusa parasitises live ovary of Carex lasiocarpa
Remarks: Other: uncertain

Foodplant / open feeder
larva of Brachythops w grazes on leaf of Carex lasiocarpa
Other: major host/prey

Foodplant / saprobe
sessile apothecium of Nimbomollisia eriophori is saprobic on dead leaf of Carex lasiocarpa
Remarks: season: 6-10

Foodplant / parasite
telium of Puccinia caricina var. ribis-nigri-lasiocarpae parasitises live Carex lasiocarpa

Carex lasiocarpa is a dominant of boreal wetlands, often forming huge stands. Large stands of the species are quite striking at a distance because of their pale straw color derived from the dried and faded, curly, filiform leaf apices of the vegetative shoots. Sometimes extensive stands occur without fertile culms.

The reported hybrids between Carex lasiocarpa and C. stricta require confirmation (J. Cayouette and P. M. Catling 1992).

North American plants have, on average, slightly smaller perigynia and shorter beak teeth than European and Asian plants and have been distinguished as subsp. americana (Fernald) Hultén.

Plants colonial; rhizomes long-creeping. Culms lateral, trigonous, 40–120 cm, smooth or nearly so. Leaves: basal sheaths reddish purple, fibrillose, bladeless, apex of inner band glabrous; ligules 1–2.5(–3.5) mm; blades gray-green, proximal portion of blade involute or gutter-shaped, becoming narrowly triangular-channeled, blades of vegetative shoots prolonged to curled, filiform tip, midveins of blades and proximal bracts low and rounded, forming inconspicuous keel, 0.7–2(–2.2) mm, glabrous. Inflorescences 6–20 cm; peduncles of terminal spikes (0.8–)2–9 cm; proximal 1–2(–3) spikes pistillate, ascending; distal spikes erect; terminal 1–3 spikes staminate. Pistillate scales lanceolate to ovate, apex acute to acuminate-awned, glabrous or, often, ciliate or finely scabrous-margined apically. Perigynia ascending, veins esentially concealed, broadly ellipsoid, 3–4.3 × 1.5–2.2 mm, densely pubescent, obscuring cellular details and veination; beak 0.5–1.1 mm, firm, bidentulate, teeth straight, 0.2–0.7 mm. 2n = 56.

St. Pierre and Miquelon; B.C., Man., Nfld. and Labr., N.S., Ont., P.E.I., Que., Sask., Yukon; Alaska, Calif., Conn., Idaho, Ill., Ind., Iowa, Maine, Mass., Mich., Minn., Mont., N.H., N.J., N.Y., Ohio, Pa., R.I., Vt., Va., Wash., Wis.; Eurasia.

Fruiting Jun–Aug.

Sedge meadows, fens, bogs, lakeshores, stream banks, usually in very wet sites and sometimes forming floating mats; 0–1300m.

Carex lanuginosa Michaux

Carex lasiocarpa Ehrh. Hannov. Mag. 1784: 132. 1784
"Carex hirta L." Oeder, Fl. Dan. 7: 5. pi. 379 (in part). 1768. (From northwestern Europe.)
"Carex tomentosa L." Lightf. Fl. Scot. 553. 1777. (From Scotland.)
Carex splendida Willd. Fl. Berol. 33. pi. l,f. 3. 1787. (Type from northwestern Germany.)
" Carex filiformis L." Gooden. Trans. Linn. Soc. 2 : 172. pi. 20, f. 5 (and most authors). 1794. (From England.)
Trasus filiformis S. F. Gray, Nat. Arr. Brit. PI. 2: 59. 1821. (As to plant described only. Based on Carex filiformis of authors.)
Diemisa filiformis Raf. Good Book 27. 1840. (Based on Carex filiformis of authors.)
Carex filiformis var. australis L. H. Bailey, Mem. Torrey Club 1: 56. 1889. (Type from central Europe.)
Carex filiformis f. meduanensis Lev. & Vaniot, Bull. Acad. Geogr. Bot. 10: 35. 1901. (Type from France.)
Carex lasiocarpa f. robusta Junge, Verh. Nat. Ver. Hamburg III. 12: 21. 1905. (Type from Germany.)
Carex lasiocarpa f. slricta Junge, Verh. Nat. Ver. Hamburg III. 12 : 22. 1905. (Type from Germany.)
Loosely cespitose with long-creeping rootstocks long stoloniferous, the stolons horizontal, long, tough, scaly, the culms 3-12 dm. high, in large clumps, erect, slender, obtusely triangular, smooth, aphyllopodic, purplish-red at base, the lower sheaths long, breaking and becoming strongly filamentose; sterile shoots very numerous, elongate; leaves with well-developed blades 2-5 to a fertile culm, more numerous on the sterile shoots, septate-nodulose, the blades light-green, thinnish, very elongate, often 7 dm. long, 2 mm. or less wide, flattish at base, strongly involute above, the tip very long-attenuate, roughened triangular and soon becoming dried-up, the sheaths yellowish-brown-tinged ventrally, concave at mouth, the ligule as long as wide; staminate spikes usually 2 (the lower often small), slender, erect, long-peduncled, 2-6 cm. long, 2.5-3.5 mm. wide, the scales oblanceolate, acute to cuspidate, smooth, light-reddishbrown with lighter center and dull-hyaline margins; pistillate spikes 1, 2 or 3, widely separate, erect, sessile or very nearly so, 0.5-5 cm. long, 5-8 mm. wide, oblong-cylindric, closely flowered, the perigynia 15-50, ascending in several to many rows; bracts sheathless or very short-sheathing, or at times the lowest long-sheathing, the blade of the lowest strongly exceeding the culm, those of the others shorter than to exceeding the culm; scales lanceolate or ovate-lanceolate, sparingly ciliate at tip, narrower than the perigynia, the lower mucronate-awned and exceeding the perigynia, the upper acute and exceeded by the perigynia, purplish-brown with broad 3nerved green center and very narrow dull-hyaline margins; perigynia oblong-obovoid or oblong-ovoid, suborbicular in cross-section, somewhat inflated, 3-5 mm. long, 1.75 mm. wide, coriaceous, dull-brownish-green, densely soft-hairy, the ribs very obscure, round-tapering at base, strongly contracted at apex into a short, ,bidentate beak 1 mm. long, the teeth erect, 0.5 mm. long; achenes broadly ovoid, triangular with concave sides and blunt angles, rather loosely enveloped, 1.75-2 mm. long, 1.5 mm. wide, sessile or nearly so, yellowish-brown, strongly punctate, abruptly slenderly apiculate, the tip bent, jointed with the straight or flexuous slender style; stigmas 3, slender, blackish.
Type locality: Sweden.
Distribution: Sphagnum swamps, usually in large colonies on borders of lakes, calcareous districts, glaciated regions. Newfoundland to Keewatin and British Columbia and southward to northern New Jersey, Pennsylvania, Iowa, Idaho and Washington. (Specimens examined from Newfoundland, Quebec, Nova Scotia, New Brunswick, Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Ontario, Ohio, Michigan, Wisconsin, Indiana, Illinois, Iowa, Minnesota, Manitoba, Saskatchewan, Keewatin, Idaho, Washington, British Columbia, Vancouver.)

Carex lasiocarpa is a broadly distributed species of wetland sedge sometimes known as woollyfruit sedge or slender sedge. It is considered a species of Least Concern by the IUCN Red List due to its extensive range (much of North America, Europe, and Asia) with many stable populations.