Eriophorum viridicarinatum Fernald

Plants cespitose or single-stemmed. Culms 20–90 cm × 0.9–1.2 mm distally. Leaves: blades flat, trigonous in cross section distally, to 30 cm × 2–6 mm; distal leaf blade much longer than sheath. Inflorescences: blade-bearing involucral bracts 2–4, sometimes brown-tinged proximally, leaflike, to 7 cm. Spikelets 3–30, in subumbels, lax, oblong-ovoid, 6–10 mm in flower, 15–30 mm in fruit; peduncles (2–)10–60 mm, scabrous; scales dark green to gray, pale proximally, darker distally, ovate to lanceolate, 4–6 mm, margins scarious 0–0.1 mm wide, to 12 weak lateral ribs, midrib prominent, enlarged distally, reaching tip, sometimes excurrent, apex acute. Flowers: perianth bristles 10 or more, white to pale brown, 15–25 mm, smooth; anthers 0.8–2 mm. Achenes dark brown, narrowly obovoid, 2.5–3.5 mm.