Juncus tenuis Willdenow var. anthelatus Wiegand, Bull. Torrey Bot. Club. 27: 523. 1900; J. macer Gray var. anthelatus (Wiegand) F. J. Hermann

Herbs, perennial, cespitose, to (3--)7--9 dm. Cataphylls 1--2. Leaves basal, 2--3(--5); auricles transparent, 2--3.5 mm at summit of leaf sheath, apex acutish, membranous; blade flat, (10--)20--30 cm x 0.5--2.3 mm, margins entire. Inflorescences 10--100-flowered, diffuse; internodes of monochasia greater than 6 mm, primary bract usually exceeding inflorescence. Flowers: pedicels 0.1--0.3(--3) mm; bracteoles 2; tepals green, lanceolate, 3.2--4.5 x 0.7--1 mm; outer and inner series nearly equal, in fruit apically erect; stamens 6, filaments 0.8--1.1 mm, anthers 0.3--0.7 mm; style 0.2 mm. Capsules tan, 1-locular, widely ellipsoid to obovoid, 2--3.2 x 1.1--1.6 mm. Seeds tan, ellipsoid, 0.33--0.556 mm, not tailed. 2n = 80.

Flowering and fruiting spring. Exposed or partially shaded sites in moist or seasonally wet, sandy or clay soils; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.