Juncus leptocladus Hayata; J. macer Gray.

Plants perennial, tufted. Stems 10--40 cm ( 0.6--1.2 mm, rigid to weak. Leaves basal; leaf sheath auricles obtuse, 2--4 mm, margin scarious to broadly so; leaf blade flat, 4--23 cm ( 0.5--1.8 mm, margin often involute. Inflorescences terminal panicles, 3--7 cm, usually lax, 6--40-flowered, rarely flowers in a few clusters; involucral bracts 2, leaflike, 4--18 cm. Bracteoles 2. Perianth segments greenish, lanceolate, 3.5--4 ( ca. 1 mm, subequal or outer ones somewhat longer than inner, margin white scarious, apex long tapered to a sharp point. Stamens 6; filaments ca. 1.2 mm; anthers ca. 0.8 mm. Style shorter than ovary; stigmas ca. 1.6 mm. Capsule trigonous ovoid, shorter than to rarely equaling perianth, apex truncate and shortly mucronate to obtuse. Seeds reddish brown, 0.4--0.5 mm, appendaged; appendage white, short. Fl. Jun--Jul, fr. Aug--Sep. 2 n = 30, 32, 84.

Riversides, streamsides, wet grasslands; ca. 400 m. Heilongjiang, Henan, Jiangxi, Shandong, Taiwan, Zhejiang [India, Japan, Korea; Europe, North America].