Perennials, 50–100 cm tall, caespitose; rhizome creeping-ascending; stolons absent. Stem compressed, not winged, c. (2–) 3–5 (–10) mm wide. Cataphylls absent or 1–2, loose, 2–6 cm long. Basal leaves 1–2 (–4). Cauline leaves 1–4, pluritubular, imperfectly septate, double-edged-compressed, c. (10–) 3–70 cm long, (3–) 4–8 (–10) mm wide; sheaths loose, dorsally acute; margins narrow; auricles absent. Lower bract ±open, sheath-like, not compressed, usually 2–5 cm long, much shorter than inflorescence; capitulum bracts scarious, ovate, aristate, shorter than perianth. Inflorescence large, ±loose, decompound, c. 10–30 cm long, usually of 20–50 (–80) globose echinate c. 15–25-flowered heads c. 6–12 mm in diam.; primary branches 1–5, ±erect, long; secondary branches long, ±erecto-patent. Tepals ±equal, ±linear-lanceolate, subulate, 3.0–3.6 (–4.0) mm long, pale green and often suffused purplish; margins narrow, scarious. Stamens 3; anthers 0.6–0.9 mm long; filaments 1.2–1.6 mm long; style c. 0.2–0.3 mm long, difficult to distinguish from ovary top; stigmas c. 0.7–1.0 mm long. Capsule unilocular, narrowly ovoid-prismatic, c. 3.6–4.8 mm long, gradually narrowing in acute-triquetrous apex, distinctly exceeding perianth, pale stramineous-brown. Seeds ±ellipsoid, acuminate, 0.5–0.6 × c. 0.2 mm, pale brown, longitudinally striate, regularly distinctly reticulate; appendage absent.