Juncus leptospermus Buch.

Plants perennial, 35--70 cm tall, tufted. Rhizome thick. Stems terete or somewhat compressed. Basal and cauline leaves 2--5; leaf sheath auricles well developed, acute, 1--2 mm, membranous; leaf blade erect, terete, unitubular, to 25 cm (on proximal leaves), sturdy, distinctly and perfectly septate, apex acute. Inflorescences terminal, branched; involucral bract leaflike, shorter than inflorescence; heads 6--12, hemispheric to obconical, 4--8-flowered. Perianth segments chestnut brown to yellowish green, center thickened, margin narrowly hyaline, apex acute; outer segments boatlike, 2.3--2.5 × ca. 0.8 mm; inner segments 2.5--3 × 0.6--1 mm. Stamens 3, shorter than outer perianth segments; filaments 1.5--1.6 mm; anthers 0.6--0.7 mm. Style 0.2--0.4 mm. Capsule reddish brown, trigonous lanceolate, 3.8--4 mm, apex beaked; beak 0.2--0.3 mm. Seeds pale brown, spindlelike, 0.5--0.7 mm, reticulate. Fl. Jun--Aug, fr. Apr--Nov.

Guangdong, Guangxi, Guizhou, Heilongjiang, Shaanxi, Yunnan [Bhutan, India].

Swampy ground at pond margins; 100--3600 m.

Juncus mairei H. Léveillé.