Herbs, perennial, rhizomatous, 5--9 dm. Rhizomes 2--3 mm diam. Culms erect, 2--6 mm diam. Cataphylls 0 or 1--2, straw-colored, apex narrowly acute. Leaves: basal 1--3, cauline 2--6, straw-colored; auricles absent; blade 10--40 cm x (3--)7--12 mm. Inflorescences panicles or racemes of 20--50 heads, 2--14 cm, erect or ascending branches; primary bract erect; heads 15--70-flowered, obovoid to globose, 7--11 mm diam. Flowers: tepals green to brown or reddish brown, lanceolate, 2.4--3.7 mm, nearly equal, apex acuminate; stamens 6; anthers ½1/2 to equal filament length. Capsules slightly exserted, chestnut to dark brown, 1-locular, ellipsoid, 2.4--3.8 mm, apex acuminate, not beaked. Seeds elliptic to obovate, 0.4--0.6 mm, not tailed. 2n = 40. Fruiting early summer--fall. Salt marshes, moist areas, ditches, springs, lake and stream shores; 500--1600 m; Ariz., Calif., Nev., N.Mex., Utah; Mexico (Baja California). This species and the next (Juncus ensifolius) are closely related and have been treated as members of a single species (J. xiphioides) by Engelmann. Until a study of the complete subgenus is done, I amwe are hesitant to use a varietal name (J. xiphioides var. triandrus) for the widespread western taxon J. ensifolius.