Juncus monanthos Jacquin; J. trifidus subsp. carolinianus HamitHämit-Ahti; J. trifidus subsp. monanthos (Jacquin) Ascherson & Graebner; J. trifidus var. monanthos (Jacquin) Bluff & Fingerhuth

Herbs, perennial, tufted, 1--4 dm. Rhizomes densely branching. Culms few to many, erect to drooping. Cataphylls 2--4. Leaves basal and cauline, 2--4; auricles deeply lacerate, to 4 mm, membranous; blade dark green, flat to slightly channeled, 5--12 cm  x 0.5--1 mm, margins finely serrulate. Inflorescences 1--3(--4)-flowered; primary bract usually exceeding inflorescence. Flowers: bracteoles 2, usually lacerate; tepals brownish, widely lanceolate, 2.1--3 mm; inner series slightly shorter, apex acute; stamens 6, filaments 0.3--0.7 mm, anthers 1.2--1.5 mm; stigma 1.5--3 mm. Capsules brown, ellipsoid, 2.2--3.5 x 1.3--1.7 mm, longer than tepals. Seeds brown, obliquely ovoid, 0.89--1.35 mm, not tailed. 2n = 40.

Flowering and fruiting late spring--early summer. Mostly in crevices of granitic (schistose) cliffs or rubble slopes in the higher regions of the Appalachians; 20--2000 m; Greenland; N.B., Nfld. and Labr., N.S., Nunavut, Que.; Maine, N.H., N.Y., N.C., Tenn., Vt., Va.; Europe; n Asia.