Plants perennial. Rhizome creeping, 40--70(--120) cm. Stems terete, 2--3.5 mm in diam., hollow. Basal leaves few, cauline leaves 3 or 4(or 5); leaf sheath auricles well developed; leaf blade terete, 8--23 cm × 1--2.5(--3) mm, ribbed, perfectly septate, apex acute. Inflorescences terminal, 3--5-branched; involucral bract leaflike, 7--10 cm, apex acute; heads 35--70, globose, ca. 6 mm in diam., 6--16-flowered; bracts broadly lanceolate, 1.5--2.2 mm, 1-veined. Perianth segments chestnut brown, lanceolate; inner segments 2.5--3 × ca. 0.8 mm, slightly longer than outer ones, veins 1--3, apex acute. Stamens 6, 1.5--2 mm; anthers 0.7--1 mm, equaling or slightly longer than filaments. Stigmas ca. 2 mm. Capsule trigonous ovoid, 2.2--2.6 mm, 1-loculed, apex abruptly contracted to a short beak. Seeds ovoid, 0.3--0.5 mm, reticulate. Fl. Jul--Aug, fr. Aug--Sep.
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