(Torr.) Coville, Bull. Torrey Bot. Club 22: 303 (1895)
Perennials, (30–) 40–100 cm tall. Rhizomes stoloniferous, 1–3 mm in diam., with swollen tuberiform nodes. Cataphylls absent, or sometimes 1 (basal leaf with considerably reduced blade); basal leaves 1–3, 13–30 cm long. Cauline leaves 2–5, 13–30 cm long, terete, perfectly septate (septa scarcely distinct externally), unitubular, 1–2 mm in diam.; tip acuminate; sheaths usually ±loose; auricles 1–4 mm, rounded, scarious. Lower bract leaf-like, terete, 4–12 cm long, exceeding inflorescence, erect or ascending; other bracts herbaceous, linear, 6.5–11 mm long. Inflorescence large clusters of (1–) 2–23 heads, 2–5.5 cm tall, with spreading branches; heads globose, 25–100-flowered, 10–15 mm in diam. Tepals unequal, lanceolate-subulate, green to stramineous, occasionally reddish, acuminate; inner tepals (3–) 3.4–4.6 mm long; outer tepals (3.7–) 4–6 mm long; margins narrow, scarious to membranous. Stamens 6, not exserted; anthers 0.4–0.8 mm long; filaments 0.7–1.2 mm long; style 0.1–0.2 mm long; stigmas 0.9–1.2 mm long. Capsules unilocular, lanceolate in outline, strongly trigonous-prismatic distally, tapering to a subulate tip, 4.3–5.7 mm long, stramineous or castaneous-brown, equalling to slightly exceeding perianth. Seeds 0.4–0.5 × 0.2–0.3 mm; appendages absent. 2n = 40, fide S.Snogerup, Bot. Not. 116: 155 (1963).