Engelm., Trans. Acad. Sci. St. Louis 2: 484 (1868)
Perennials, c. 2–40 (–60) cm tall, loosely caespitose; rhizomes creeping, branched, to 3.5 mm in diam, with internodes to 5 cm; stolons present. Stem compressed, two-edged, 1.5–3.0 mm wide. Cataphylls 1–2, brownish to castaneous, to c. 4 cm long, acute. Basal leaves 2–3. Cauline leaves 1–3, ensiform, pluritubular, imperfectly septate, to 15 (–35) cm long, often exceeding stem, 2–6 mm wide; sheath loose, with membranous margins; auricles ±absent or minute, brownish; leaf apex acute. Lower bract short, leaf-like, c. 1–3 cm long, shorter than inflorescence. Inflorescence variable, of few globose subsessile many-flowered heads or anthelate, of 10 to many, usually 5–8-flowered heads; heads deep castaneous to ferrugineous. Tepals subequal, lanceolate, acuminate, 3.3–4.7 mm long; margins paler, not distinct; inner tepals subacute, sometimes mucronate, with broad membranous margins. Stamens 6; anthers 1.1–1.9 mm long; filaments 0.4–0.8 mm long; style c. 1.0–1.5 mm long, difficult to distinguish from capsule top; stigmas 1.0–2.0 mm long. Capsule narrowly oblong-ovoid, subtrigonous, gradually acuminate, 3.0–5.5 mm long, castaneous-brown, smooth, ±longer than perianth. Seeds ±ovoid, apiculate, c. 0.45–0.55 × 0.3 mm, distinctly reticulate, areas smooth.