(Engelm.) Coville, Mem. Torrey Bot. Club 5: 106 (1894)
Perennials, 30–90 cm tall, caespitose; rhizome densely branching. Cataphylls 1–2 or absent, loose, greenish-stramineous, 3–5 cm long; basal leaves 1–2, 4–25 cm long. Cauline leaves 1–2, 4–25 cm long, terete, 1–2.5 mm in diam., unitubular, septate, scabrous; tip blunt; auricles 1–7.5 mm long, rounded. Lower bract leaf-like, terete, 1.7–4.5 cm long, much shorter than the inflorescence, erect; other bracts castaneous, lanceolate, 3–11 mm long. Inflorescence panicles of 5–30 heads, 12–15 cm tall, with erect to ascending branches; heads broadly obovoid, 2–6-flowered, 5–10 mm in diam.; pedicels 0.7–2 cm long. Tepals unequal, lanceolate, green, sometimes suffused reddish brown, acuminate; inner tepals 3.9–4.7 mm long; outer tepals 3.3–3.9 mm long; margins broad, membranous. Stamens 6, not exserted; anthers 0.9–1.2 mm long; filaments 1.0–1.4 mm long; style 0.5–0.6 mm long; stigmas 1–1.2 mm long. Capsule trilocular, ±narrowly ovoid, acuminate, 4.5–5.3 mm long including a conical rostrum to 1 mm long, castaneous-brown, shiny, exceeding perianth. Seeds 0.9–1.1 × 0.3–0.4, 2.1–2.6 mm long including appendages; appendages unequal, 0.7–0.8 mm and 0.5–0.7 mm long; outer seed coat loose, faintly reticulate.