根足薹草 gen zu tai cao

Rhizome thick, elongate, covered with fibrous, brown remains of leaf sheath. Culms 30-60 cm tall, soft, trigonous, scabrid on angles. Leaves herbaceous, soft, shorter than culm, blades 2-4 mm wide, flat, margins scabrid. Inflorescence 1-spiked, terminal, androgynous, erect, linear-cylindric, 40-70 × 2-3 mm, bractless; male part very short, 3-5-flowered; female part loosely flowered, sometimes lowermost 2 flowers 1-2 cm apart from each other. Female glumes pale brown laterally, ovate-lanceolate to oblong-lanceolate, 4-5 mm, green costa 3-veined, apex acute to mucronate, or lower glumes shortly awned. Utricles longer than glume, erect, lanceolate, trigonous, ca. 6 mm (including beak), herbaceous, glabrous, abaxially distinctly slenderly many veined, apex abruptly contracted into a subcylindric beak 2-3 mm, orifice distinctly shortly 2-toothed, teeth acute. Nutlet obovate, ca. 2.5 mm, crowned with slightly recurved beak; stigmas 3.

Wet places along waysides. Anhui [Japan].