Herbs, perennial, 2--6 dm. Rhizomes long creeping. Culms slightly compressed. Leaves: basal 2--5, cauline 1--3; auricles 1--2.5 mm, apex truncate to obtuse; blade flat, 1--3 dm x 1.5--3 mm, the cauline shorter. Inflorescences glomerules 1--4(--8), each with 3--12 flowers, open or aggregate, 2--6(--10) cm; primary bract shorter than inflorescence. Flowers: tepals brown with green midstripe, lanceolate, 5--6 mm, margins scarious, sometimes papillose; outer series slightly shorter; stamens 6, filaments 0.5--1 mm, anthers 1.2--2 mm; style 0.6 mm. Capsules tan, 3-locular, obovoid, 3--5 mm, shorter than perianth. Seeds ovoid, 0.4--0.6 mm, not tailed. 2n = 40.

Flowering and fruiting summer. Moist ground in mountain meadows; 1000--3300 m; Alta., B.C., Man., Nfld. and Labr. (Nfld.), Ont., Que., Sask.; Ariz., Calif., Colo., Idaho, Mich., Minn., Mont., Nebr., Nev., N.Dak., N.Mex., S.Dak., Oreg., Utah, Wash., Wyo.

Common Name: longstyle rush

Duration: Perennial

Nativity: Native

Lifeform: Graminoid

General: Perennial from long creeping rhizomes, 20-60 cm tall.

Vegetative: Slightly compressed stems, leaves basal 2-5, cauline 1-3, with well-developed auricles 1-2.5 mm, apex truncate to obtuse; blade flat 10-30 cm long by 1.5-3 mm wide, cauline leaves shorter; sheaths scarious margined.

Inflorescence: Glomerules 1-4, each with 3-12 flowers, open or aggregate, 2-6 cm, the primary bract shorter than inflorescence; tepals brown with green midstripe, lanceolate, 5-6 mm, scarious margins, sometimes papillose; outer series slightly shorter, 6 stamens, filaments 0.5-1 mm, anthers 1-2 mm, style about 0.5 mm; capsules tan, 3-locular, obovoid, 3-5 mm, shorter than perianth.

Ecology: Found on moist soils in meadows from 4,500-9,500 ft (1372-2896 m); flowers July-September.

Notes: Distinguished by the outer perianth segments equaling or slightly exceeding the inner ones, flat leaf blades with scarious margins, cream-colored or pale yellow anthers. Blade consistently shorter than stem, sometimes blades can be very reduced.

Ethnobotany: Unknown

Etymology: Juncus comes from the Latin jungere, to join or bind, while longistylis means long style.

Synonyms: Juncus marginatus var. marginatus, Juncus marginatus var. setosus, Juncus setosus

Editor: SBuckley, 2010

Stems arising singly from a slender rhizome, 2-6 dm, with 1-5 adjacent hemispheric heads, these 2-8-fld, 8-15 mm thick; lvs mostly basal; 1 or 2 short cauline lvs often developed; sep carinate, lanceolate, 4.4-5.7 mm, acuminate, narrowly scarious-margined; pet oblong with broad scarious margins, 4.5-6 mm, acute; stamens 6, considerably shorter than the tep; anthers light yellow, 2-2.5 mm, longer than the filaments; fr trilocular, ellipsoid, 4-5 mm, half as thick, with a beak 0.5-1 mm; seeds ca 0.5 mm, apiculate at both ends; 2n=40. Damp meadows and shores; widespread in the w. cordillera, e. to Neb. and nw. Minn.; w. Ont.; Nf.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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